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      3 <title>Android 4.3 Compatibility Definition</title>
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      8 <span style="color: red; font-weight: bold;"><h2>Revision 1</h2></span><br/>
      9 <span style="color: red;">Last updated: July 23, 2013</span>
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     11 <p><b><font color="red">Revision 1</font></b><br/>
     12 Last updated: July 23, 2013
     13 </p>
     14 <p>Copyright &copy; 2013, Google Inc. All rights reserved.<br/>
     15 <a href="mailto:compatibility (a] android.com">compatibility (a] android.com</a>
     16 </p>
     17 
     18 <h2> Table of Contents</h2>
     19 <div style="margin-left: 2em;">
     20   <a href="#section-1">1. Introduction</a><br/>
     21   <a href="#section-2">2. Resources</a><br/>
     22   <a href="#section-3">3. Software</a><br/>
     23   <div style="margin-left: 2em;">
     24     <a href="#section-3.1">3.1. Managed API Compatibility</a><br/>
     25     <a href="#section-3.2">3.2. Soft API Compatibility</a><br/>
     26     <div style="margin-left: 2em;">
     27       <a href="#section-3.2.1">3.2.1. Permissions</a><br/>
     28       <a href="#section-3.2.2">3.2.2. Build Parameters</a><br/>
     29       <a href="#section-3.2.3">3.2.3. Intent Compatibility</a><br/>
     30       <div style="margin-left: 2em;">
     31         <a href="#section-3.2.3.1">3.2.3.1. Core Application Intents</a><br/>
     32         <a href="#section-3.2.3.2">3.2.3.2. Intent Overrides</a><br/>
     33         <a href="#section-3.2.3.3">3.2.3.3. Intent Namespaces</a><br/>
     34         <a href="#section-3.2.3.4">3.2.3.4. Broadcast Intents</a><br/>
     35       </div>
     36     </div>
     37     <a href="#section-3.3">3.3. Native API Compatibility</a><br/>
     38     <div style="margin-left: 2em;">
     39       <a href="#section-3.3.1">3.3.1 Application Binary Interfaces</a><br/>
     40     </div>
     41     <a href="#section-3.4">3.4. Web Compatibility</a><br/>
     42     <div style="margin-left: 2em;">
     43       <a href="#section-3.4.1">3.4.1. WebView Compatibility</a><br/>
     44       <a href="#section-3.4.2">3.4.2. Browser Compatibility</a><br/>
     45     </div>
     46     <a href="#section-3.5">3.5. API Behavioral Compatibility</a><br/>
     47     <a href="#section-3.6">3.6. API Namespaces</a><br/>
     48     <a href="#section-3.7">3.7. Virtual Machine Compatibility</a><br/>
     49     <a href="#section-3.8">3.8. User Interface Compatibility</a><br/>
     50     <div style="margin-left: 2em;">
     51       <a href="#section-3.8.1">3.8.1. Launcher (Home Screen)</a><br/>
     52       <a href="#section-3.8.2">3.8.2. Widgets</a><br/>
     53       <a href="#section-3.8.3">3.8.3. Notifications</a><br/>
     54       <a href="#section-3.8.4">3.8.4. Search</a><br/>
     55       <a href="#section-3.8.5">3.8.5. Toasts</a><br/>
     56       <a href="#section-3.8.6">3.8.6. Themes</a><br/>
     57       <a href="#section-3.8.7">3.8.7. Live Wallpapers</a><br/>
     58       <a href="#section-3.8.8">3.8.8. Recent Application Display</a><br/>
     59       <a href="#section-3.8.9">3.8.9. Input Management</a><br/>
     60       <a href="#section-3.8.10">3.8.10. Lock Screen Media Remote Control</a><br/>
     61       <a href="#section-3.8.11">3.8.11. Dreams</a><br/>
     62     </div>
     63     <a href="#section-3.9">3.9 Device Administration</a><br/>
     64     <a href="#section-3.10">3.10 Accessibility</a><br/>
     65     <a href="#section-3.11">3.11 Text-to-Speech</a><br/>
     66   </div>
     67   <a href="#section-4">4. Application Packaging Compatibility</a><br/>
     68   <a href="#section-5">5. Multimedia Compatibility</a><br/>
     69     <div style="margin-left: 2em;">
     70       <a href="#section-5.1">5.1. Media Codecs</a><br/>
     71       <a href="#section-5.2">5.2. Video Encoding</a><br/>
     72       <a href="#section-5.3">5.3. Video Decoding</a><br/>
     73       <a href="#section-5.4">5.4. Audio Recording</a><br/>
     74       <a href="#section-5.5">5.5. Audio Latency</a><br/>
     75       <a href="#section-5.6">5.6. Network Protocols</a><br/>
     76     </div>
     77   <a href="#section-6">6. Developer Tools and Options Compatibility</a><br/>
     78     <div style="margin-left: 2em;">
     79       <a href="#section-6.1">6.1. Developer Tools</a><br/>
     80       <a href="#section-6.2">6.2. Developer Options</a><br/>
     81     </div>
     82   <a href="#section-7">7. Hardware Compatibility</a><br/>
     83   <div style="margin-left: 2em;">
     84     <a href="#section-7.1">7.1. Display and Graphics</a><br/>
     85     <div style="margin-left: 2em;">
     86       <a href="#section-7.1.1">7.1.1. Screen Configuration</a><br/>
     87       <a href="#section-7.1.2">7.1.2. Display Metrics</a><br/>
     88       <a href="#section-7.1.3">7.1.3. Screen Orientation</a><br/>
     89       <a href="#section-7.1.4">7.1.4. 2D and 3D Graphics Acceleration</a><br/>
     90       <a href="#section-7.1.5">7.1.5. Legacy Application Compatibility Mode</a><br/>
     91       <a href="#section-7.1.6">7.1.6. Screen Types</a><br/>
     92       <a href="#section-7.1.7">7.1.7. Screen Technology</a><br/>
     93       <a href="#section-7.1.8">7.1.8. External Displays</a><br/>
     94     </div>
     95     <a href="#section-7.2">7.2. Input Devices</a><br/>
     96     <div style="margin-left: 2em;">
     97       <a href="#section-7.2.1">7.2.1. Keyboard</a><br/>
     98       <a href="#section-7.2.2">7.2.2. Non-touch Navigation</a><br/>
     99       <a href="#section-7.2.3">7.2.3. Navigation keys</a><br/>
    100       <a href="#section-7.2.4">7.2.4. Touchscreen input</a><br/>
    101       <a href="#section-7.2.5">7.2.5. Fake touch input</a><br/>
    102       <a href="#section-7.2.6">7.2.6. Microphone</a><br/>
    103     </div>
    104     <a href="#section-7.3">7.3. Sensors</a><br/>
    105     <div style="margin-left: 2em;">
    106       <a href="#section-7.3.1">7.3.1. Accelerometer</a><br/>
    107       <a href="#section-7.3.2">7.3.2. Magnetometer</a><br/>
    108       <a href="#section-7.3.3">7.3.3. GPS</a><br/>
    109       <a href="#section-7.3.4">7.3.4. Gyroscope</a><br/>
    110       <a href="#section-7.3.5">7.3.5. Barometer</a><br/>
    111       <a href="#section-7.3.6">7.3.6. Thermometer</a><br/>
    112       <a href="#section-7.3.7">7.3.7. Photometer</a><br/>
    113       <a href="#section-7.3.8">7.3.8. Proximity Sensor</a><br/>
    114     </div>
    115     <a href="#section-7.4">7.4. Data Connectivity</a><br/>
    116     <div style="margin-left: 2em;">
    117       <a href="#section-7.4.1">7.4.1. Telephony</a><br/>
    118       <a href="#section-7.4.2">7.4.2. IEEE 802.11 (WiFi)</a><br/>
    119       <div style="margin-left: 2em;">
    120         <a href="#section-7.4.2.1">7.4.2.1. WiFi Direct</a><br/>
    121       </div>
    122       <a href="#section-7.4.3">7.4.3. Bluetooth</a><br/>
    123       <a href="#section-7.4.4">7.4.4. Near-Field Communications</a><br/>
    124       <a href="#section-7.4.5">7.4.5. Minimum Network Capability</a><br/>
    125     </div>
    126     <a href="#section-7.5">7.5. Cameras</a><br/>
    127     <div style="margin-left: 2em;">
    128       <a href="#section-7.5.1">7.5.1. Rear-Facing Camera</a><br/>
    129       <a href="#section-7.5.2">7.5.2. Front-Facing Camera</a><br/>
    130       <a href="#section-7.5.3">7.5.3. Camera API Behavior</a><br/>
    131       <a href="#section-7.5.4">7.5.4. Camera Orientation</a><br/>
    132     </div>
    133     <a href="#section-7.6">7.6. Memory and Storage</a><br/>
    134     <div style="margin-left: 2em;">
    135       <a href="#section-7.6.1">7.6.1. Minimum Memory and Storage</a><br/>
    136       <a href="#section-7.6.2">7.6.2. Application Shared Storage</a><br/>
    137     </div>
    138     <a href="#section-7.7">7.7. USB</a><br/>
    139   </div>
    140   <a href="#section-8">8. Performance Compatibility</a><br/>
    141   <a href="#section-9">9. Security Model Compatibility</a><br/>
    142   <div style="margin-left: 2em;">
    143     <a href="#section-9.1">9.1. Permissions</a><br/>
    144     <a href="#section-9.2">9.2. UID and Process Isolation</a><br/>
    145     <a href="#section-9.3">9.3. Filesystem Permissions</a><br/>
    146     <a href="#section-9.4">9.4. Alternate Execution Environments</a><br/>
    147     <a href="#section-9.5">9.5. Multi-User Support</a><br/>
    148     <a href="#section-9.6">9.6. Premium SMS Warning</a><br/>
    149     <a href="section-9.7">9.7. Kernel Security Features</a><br/>
    150   </div>
    151   <a href="#section-10">10. Software Compatibility Testing</a><br/>
    152   <div style="margin-left: 2em;">
    153     <a href="#section-10.1">10.1. Compatibility Test Suite</a><br/>
    154     <a href="#section-10.2">10.2. CTS Verifier</a><br/>
    155     <a href="#section-10.3">10.3. Reference Applications</a><br/>
    156   </div>
    157   <a href="#section-11">11. Updatable Software</a><br/>
    158   <a href="#section-12">12. Contact Us</a><br/>
    159 </div>
    160 
    161 <div style="page-break-before: always;"></div>
    162 
    163 <a name="section-1"></a><h2>1. Introduction</h2>
    164 <p>This document enumerates the requirements that must be met in order for
    165 devices to be compatible with Android 4.3.</p>
    166 <p>The use of "must", "must not", "required", "shall", "shall not", "should",
    167 "should not", "recommended", "may" and "optional" is per the IETF standard
    168 defined in RFC2119 [<a href="#resources01">Resources, 1</a>].</p>
    169 <p>As used in this document, a "device implementer" or "implementer" is a
    170 person or organization developing a hardware/software solution running Android
    171 4.3. A "device implementation" or "implementation" is the hardware/software
    172 solution so developed.</p>
    173 <p>To be considered compatible with Android 4.3, device implementations
    174 MUST meet the requirements presented in this Compatibility Definition,
    175 including any documents incorporated via reference.</p>
    176 <p>Where this definition or the software tests described in <a
    177 href="#section-10">Section 10</a> is silent, ambiguous, or incomplete, it is
    178 the responsibility of the device implementer to ensure compatibility with
    179 existing implementations.</p>
    180 <p>For this reason, the Android Open Source Project [<a
    181 href="#resources03">Resources, 3</a>] is both the reference and preferred
    182 implementation of Android. Device implementers are strongly encouraged to base
    183 their implementations to the greatest extent possible on the "upstream" source
    184 code available from the Android Open Source Project. While some components can
    185 hypothetically be replaced with alternate implementations this practice is
    186 strongly discouraged, as passing the software tests will become substantially
    187 more difficult. It is the implementer's responsibility to ensure full
    188 behavioral compatibility with the standard Android implementation, including
    189 and beyond the Compatibility Test Suite. Finally, note that certain component
    190 substitutions and modifications are explicitly forbidden by this document.</p>
    191 <a name="section-2"></a><h2>2. Resources</h2>
    192 <ol>
    193 <a name="resources01"></a><li>IETF RFC2119 Requirement Levels: <a href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a></li>
    194 <a name="resources02"></a><li>Android Compatibility Program Overview: <a href="http://source.android.com/compatibility/index.html">http://source.android.com/compatibility/index.html</a></li>
    195 <a name="resources03"></a><li>Android Open Source Project: <a href="http://source.android.com/">http://source.android.com/</a></li>
    196 <a name="resources04"></a><li>API definitions and documentation: <a href="http://developer.android.com/reference/packages.html">http://developer.android.com/reference/packages.html</a></li>
    197 <a name="resources05"></a><li>Android Permissions reference: <a href="http://developer.android.com/reference/android/Manifest.permission.html">http://developer.android.com/reference/android/Manifest.permission.html</a></li>
    198 <a name="resources06"></a><li>android.os.Build reference: <a href="http://developer.android.com/reference/android/os/Build.html">http://developer.android.com/reference/android/os/Build.html</a></li>
    199 <a name="resources07"></a><li>Android 4.3 allowed version strings: <a href="http://source.android.com/compatibility/4.3/versions.html">http://source.android.com/compatibility/4.3/versions.html</a></li>
    200 <a name="resources08"></a><li>Renderscript: <a href="http://developer.android.com/guide/topics/graphics/renderscript.html">http://developer.android.com/guide/topics/graphics/renderscript.html</a></li>
    201 <a name="resources09"></a><li>Hardware Acceleration: <a href="http://developer.android.com/guide/topics/graphics/hardware-accel.html">http://developer.android.com/guide/topics/graphics/hardware-accel.html</a></li>
    202 <a name="resources10"></a><li>android.webkit.WebView class: <a href="http://developer.android.com/reference/android/webkit/WebView.html">http://developer.android.com/reference/android/webkit/WebView.html</a></li>
    203 <a name="resources11"></a><li>HTML5: <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/">http://www.whatwg.org/specs/web-apps/current-work/multipage/</a></li>
    204 <a name="resources12"></a><li>HTML5 offline capabilities: <a href="http://dev.w3.org/html5/spec/Overview.html#offline">http://dev.w3.org/html5/spec/Overview.html#offline</a></li>
    205 <a name="resources13"></a><li>HTML5 video tag: <a href="http://dev.w3.org/html5/spec/Overview.html#video">http://dev.w3.org/html5/spec/Overview.html#video</a></li>
    206 <a name="resources14"></a><li>HTML5/W3C geolocation API: <a href="http://www.w3.org/TR/geolocation-API/">http://www.w3.org/TR/geolocation-API/</a></li>
    207 <a name="resources15"></a><li>HTML5/W3C webdatabase API: <a href="http://www.w3.org/TR/webdatabase/">http://www.w3.org/TR/webdatabase/</a></li>
    208 <a name="resources16"></a><li>HTML5/W3C IndexedDB API: <a href="http://www.w3.org/TR/IndexedDB/">http://www.w3.org/TR/IndexedDB/</a></li>
    209 <a name="resources17"></a><li>Dalvik Virtual Machine specification: available in the Android source code, at dalvik/docs</li>
    210 <a name="resources18"></a><li>AppWidgets: <a href="http://developer.android.com/guide/practices/ui_guidelines/widget_design.html">http://developer.android.com/guide/practices/ui_guidelines/widget_design.html</a></li>
    211 <a name="resources19"></a><li>Notifications: <a href="http://developer.android.com/guide/topics/ui/notifiers/notifications.html">http://developer.android.com/guide/topics/ui/notifiers/notifications.html</a></li>
    212 <a name="resources20"></a><li>Application Resources: <a href="http://code.google.com/android/reference/available-resources.html">http://code.google.com/android/reference/available-resources.html</a></li>
    213 <a name="resources21"></a><li>Status Bar icon style guide: <a href="http://developer.android.com/guide/practices/ui_guidelines/icon_design_status_bar.html">http://developer.android.com/guide/practices/ui_guidelines/icon_design_status_bar.html</a></li>
    214 <a name="resources22"></a><li>Search Manager: <a href="http://developer.android.com/reference/android/app/SearchManager.html">http://developer.android.com/reference/android/app/SearchManager.html</a></li>
    215 <a name="resources23"></a><li>Toasts: <a href="http://developer.android.com/reference/android/widget/Toast.html">http://developer.android.com/reference/android/widget/Toast.html</a></li>
    216 <a name="resources24"></a><li>Themes: <a href="http://developer.android.com/guide/topics/ui/themes.html">http://developer.android.com/guide/topics/ui/themes.html</a></li>
    217 <a name="resources25"></a><li>R.style class: <a href="http://developer.android.com/reference/android/R.style.html">http://developer.android.com/reference/android/R.style.html</a></li>
    218 <a name="resources26"></a><li>Live Wallpapers: <a href="http://developer.android.com/resources/articles/live-wallpapers.html">http://developer.android.com/resources/articles/live-wallpapers.html</a></li>
    219 <a name="resources27"></a><li>Android Device Administration: <a href="http://developer.android.com/guide/topics/admin/device-admin.html">http://developer.android.com/guide/topics/admin/device-admin.html</a></li>
    220 <a name="resources28"></a><li>DevicePolicyManager reference: <a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html">http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html</a></li>
    221 <a name="resources29"></a><li>Android Accessibility Service APIs: <a href="http://developer.android.com/reference/android/accessibilityservice/package-summary.html">http://developer.android.com/reference/android/accessibilityservice/package-summary.html</a></li>
    222 <a name="resources30"></a><li>Android Accessibility APIs: <a href="http://developer.android.com/reference/android/view/accessibility/package-summary.html">http://developer.android.com/reference/android/view/accessibility/package-summary.html</a></li>
    223 <a name="resources31"></a><li>Eyes Free project: <a href="http://http://code.google.com/p/eyes-free">http://code.google.com/p/eyes-free</a></li>
    224 <a name="resources32"></a><li>Text-To-Speech APIs: <a href="http://developer.android.com/reference/android/speech/tts/package-summary.html">http://developer.android.com/reference/android/speech/tts/package-summary.html</a></li>
    225 <a name="resources33"></a><li>Reference tool documentation (for adb, aapt, ddms, systrace): <a href="http://developer.android.com/guide/developing/tools/index.html">http://developer.android.com/guide/developing/tools/index.html</a></li>
    226 <a name="resources34"></a><li>Android apk file description: <a href="http://developer.android.com/guide/topics/fundamentals.html">http://developer.android.com/guide/topics/fundamentals.html</a></li>
    227 <a name="resources35"></a><li>Manifest files: <a href="http://developer.android.com/guide/topics/manifest/manifest-intro.html">http://developer.android.com/guide/topics/manifest/manifest-intro.html</a></li>
    228 <a name="resources36"></a><li>Monkey testing tool: <a href="http://developer.android.com/guide/developing/tools/monkey.html">http://developer.android.com/guide/developing/tools/monkey.html</a></li>
    229 <a name="resources37"></a><li>Android android.content.pm.PackageManager class and Hardware Features List: <a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">http://developer.android.com/reference/android/content/pm/PackageManager.html</a></li>
    230 <a name="resources38"></a><li>Supporting Multiple Screens: <a href="http://developer.android.com/guide/practices/screens_support.html">http://developer.android.com/guide/practices/screens_support.html</a></li>
    231 <a name="resources39"></a><li>android.util.DisplayMetrics: <a href="http://developer.android.com/reference/android/util/DisplayMetrics.html">http://developer.android.com/reference/android/util/DisplayMetrics.html</a></li>
    232 <a name="resources40"></a><li>android.content.res.Configuration: <a href="http://developer.android.com/reference/android/content/res/Configuration.html">http://developer.android.com/reference/android/content/res/Configuration.html</a></li>
    233 <a name="resources41"></a><li>android.hardware.SensorEvent: <a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">http://developer.android.com/reference/android/hardware/SensorEvent.html</a></li>
    234 <a name="resources42"></a><li>Bluetooth API: <a href="http://developer.android.com/reference/android/bluetooth/package-summary.html">http://developer.android.com/reference/android/bluetooth/package-summary.html</a></li>
    235 <a name="resources43"></a><li>NDEF Push Protocol: <a href="http://source.android.com/compatibility/ndef-push-protocol.pdf">http://source.android.com/compatibility/ndef-push-protocol.pdf</a></li>
    236 <a name="resources44"></a><li>MIFARE MF1S503X: <a href="http://www.nxp.com/documents/data_sheet/MF1S503x.pdf">http://www.nxp.com/documents/data_sheet/MF1S503x.pdf</a></li>
    237 <a name="resources45"></a><li>MIFARE MF1S703X: <a href="http://www.nxp.com/documents/data_sheet/MF1S703x.pdf">http://www.nxp.com/documents/data_sheet/MF1S703x.pdf</a></li>
    238 <a name="resources46"></a><li>MIFARE MF0ICU1: <a href="http://www.nxp.com/documents/data_sheet/MF0ICU1.pdf">http://www.nxp.com/documents/data_sheet/MF0ICU1.pdf</a></li>
    239 <a name="resources47"></a><li>MIFARE MF0ICU2: <a href="http://www.nxp.com/documents/short_data_sheet/MF0ICU2_SDS.pdf">http://www.nxp.com/documents/short_data_sheet/MF0ICU2_SDS.pdf</a></li>
    240 <a name="resources48"></a><li>MIFARE AN130511: <a href="http://www.nxp.com/documents/application_note/AN130511.pdf">http://www.nxp.com/documents/application_note/AN130511.pdf</a></li>
    241 <a name="resources49"></a><li>MIFARE AN130411: <a href="http://www.nxp.com/documents/application_note/AN130411.pdf">http://www.nxp.com/documents/application_note/AN130411.pdf</a></li>
    242 <a name="resources50"></a><li>Camera orientation API: <a href="http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)">http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)</a></li>
    243 <a name="resources51"></a><li>Camera: <a href="http://developer.android.com/reference/android/hardware/Camera.html">http://developer.android.com/reference/android/hardware/Camera.html</a></li>
    244 <a name="resources52"></a><li>Android Open Accessories: <a href="http://developer.android.com/guide/topics/usb/accessory.html">http://developer.android.com/guide/topics/usb/accessory.html</a></li>
    245 <a name="resources53"></a><li>USB Host API: <a href="http://developer.android.com/guide/topics/usb/host.html">http://developer.android.com/guide/topics/usb/host.html</a></li>
    246 <a name="resources54"></a><li>Android Security and Permissions reference: <a href="http://developer.android.com/guide/topics/security/security.html">http://developer.android.com/guide/topics/security/security.html</a></li>
    247 <a name="resources55"></a><li>Apps for Android: <a href="http://code.google.com/p/apps-for-android">http://code.google.com/p/apps-for-android</a></li>
    248 <a name="resources56"></a><li>Android DownloadManager: <a href="http://developer.android.com/reference/android/app/DownloadManager.html">http://developer.android.com/reference/android/app/DownloadManager.html</a></li>
    249 <a name="resources57"></a><li>Android File Transfer: <a href="http://www.android.com/filetransfer">http://www.android.com/filetransfer</a></li>
    250 <a name="resources58"></a><li>Android Media Formats: <a href="http://developer.android.com/guide/appendix/media-formats.html">http://developer.android.com/guide/appendix/media-formats.html</a></li>
    251 <a name="resources59"></a><li>HTTP Live Streaming Draft Protocol: <a href="http://tools.ietf.org/html/draft-pantos-http-live-streaming-03">http://tools.ietf.org/html/draft-pantos-http-live-streaming-03</a></li>
    252 <a name="resources60"></a><li>NFC Connection Handover: <a href="http://www.nfc-forum.org/specs/spec_list/#conn_handover/">http://www.nfc-forum.org/specs/spec_list/#conn_handover</a></li>
    253 <a name="resources61"></a><li>Bluetooth Secure Simple Pairing Using NFC: <a href="http://www.nfc-forum.org/resources/AppDocs/NFCForum_AD_BTSSP_1_0.pdf">http://www.nfc-forum.org/resources/AppDocs/NFCForum_AD_BTSSP_1_0.pdf</a></li>
    254 <a name="resources62"></a><li>Wifi Multicast API: <a href="http://developer.android.com/reference/android/net/wifi/WifiManager.MulticastLock.html">http://developer.android.com/reference/android/net/wifi/WifiManager.MulticastLock.html</a></li>
    255 <a name="resources63"></a><li>Action Assist: <a href="http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST">http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST</a></li>
    256 <a name="resources64"></a><li>USB Charging Specification: <a href="http://www.usb.org/developers/devclass_docs/USB_Battery_Charging_1.2.pdf">http://www.usb.org/developers/devclass_docs/USB_Battery_Charging_1.2.pdf</a></li>
    257 <a name="resources65"></a><li>Android Beam: <a href="http://developer.android.com/guide/topics/nfc/nfc.html">http://developer.android.com/guide/topics/nfc/nfc.html</a></li>
    258 <a name="resources66"></a><li>Android USB Audio: <a href="http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO">http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO</a></li>
    259 <a name="resources67"></a><li>Android NFC Sharing Settings: <a href="http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFCSHARING_SETTINGS">http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFCSHARING_SETTINGS</a></li>
    260 <a name="resources68"></a><li>Wifi Direct (Wifi P2P): <a href="http://developer.android.com/reference/android/net/wifi/p2p/WifiP2pManager.html">http://developer.android.com/reference/android/net/wifi/p2p/WifiP2pManager.html</a></li>
    261 <a name="resources69"></a><li>Lock and Home Screen Widget: <a href="http://developer.android.com/reference/android/appwidget/AppWidgetProviderInfo.html">http://developer.android.com/reference/android/appwidget/AppWidgetProviderInfo.html</a></li>
    262 <a name="resources70"></a><li>UserManager reference: <a href="http://developer.android.com/reference/android/os/UserManager.html">http://developer.android.com/reference/android/os/UserManager.html</a></li>
    263 <a name="resources71"></a><li>External Storage reference: <a href="http://source.android.com/tech/storage">http://source.android.com/tech/storage</a></li>
    264 <a name="resources72"></a><li>External Storage APIs: <a href="http://developer.android.com/reference/android/os/Environment.html">http://developer.android.com/reference/android/os/Environment.html</a></li>
    265 <a name="resources73"></a><li>SMS Short Code: <a href="http://en.wikipedia.org/wiki/Short_code">http://en.wikipedia.org/wiki/Short_code</a></li>
    266 <a name="resources74"></a><li>Media Remote Control Client: <a href="http://developer.android.com/reference/android/media/RemoteControlClient.html">http://developer.android.com/reference/android/media/RemoteControlClient.html</a></li>
    267 <a name="resources75"></a><li>Display Manager: <a href="http://developer.android.com/reference/android/hardware/display/DisplayManager.html">http://developer.android.com/reference/android/hardware/display/DisplayManager.html</a></li>
    268 <a name="resources76"></a><li>Dreams: <a href="http://developer.android.com/reference/android/service/dreams/DreamService.html">http://developer.android.com/reference/android/service/dreams/DreamService.html</a></li>
    269 <a name="resources77"></a><li>Android Application Development-Related Settings: <a href="http://developer.android.com/reference/android/provider/Settings.html#ACTION_APPLICATION_DEVELOPMENT_SETTINGS">http://developer.android.com/reference/android/provider/Settings.html#ACTION_APPLICATION_DEVELOPMENT_SETTINGS</a></li>
    270 <a name="resources78"></a><li>Camera: <a href="http://developer.android.com/reference/android/hardware/Camera.Parameters.html">http://developer.android.com/reference/android/hardware/Camera.Parameters.html</a></li>
    271 <a name="resources79"></a><li>EGL Extension-EGL_ANDROID_RECORDABLE: <a href="http://www.khronos.org/registry/egl/extensions/ANDROID/EGL_ANDROID_recordable.txt">http://www.khronos.org/registry/egl/extensions/ANDROID/EGL_ANDROID_recordable.txt</a></li>
    272 <a name="resources80"></a><li>Motion Event API: <a href="http://developer.android.com/reference/android/view/MotionEvent.html">http://developer.android.com/reference/android/view/MotionEvent.html</a></li>
    273 <a name="resources81"></a><li>Touch Input Configuration: <a href="http://source.android.com/devices/tech/input/touch-devices.html">http://source.android.com/devices/tech/input/touch-devices.html</a></li>
    274 </ol>
    275 <p>Many of these resources are derived directly or indirectly from the Android
    276 4.3 SDK, and will be functionally identical to the information in that SDK's
    277 documentation. In any cases where this Compatibility Definition or the
    278 Compatibility Test Suite disagrees with the SDK documentation, the SDK
    279 documentation is considered authoritative. Any technical details provided in
    280 the references included above are considered by inclusion to be part of this
    281 Compatibility Definition.</p>
    282 
    283 <a name="section-3"></a><h2>3. Software</h2>
    284 <a name="section-3.1"></a><h3>3.1. Managed API Compatibility</h3>
    285 <p>The managed (Dalvik-based) execution environment is the primary vehicle for
    286 Android applications. The Android application programming interface (API) is
    287 the set of Android platform interfaces exposed to applications running in the
    288 managed VM environment. Device implementations MUST provide complete
    289 implementations, including all documented behaviors, of any documented API
    290 exposed by the Android 4.3 SDK [<a href="#resources04">Resources, 4</a>].</p>
    291 <p>Device implementations MUST NOT omit any managed APIs, alter API interfaces
    292 or signatures, deviate from the documented behavior, or include no-ops, except
    293 where specifically allowed by this Compatibility Definition.</p>
    294 <p>This Compatibility Definition permits some types of hardware for which
    295 Android includes APIs to be omitted by device implementations. In such cases,
    296 the APIs MUST still be present and behave in a reasonable way. See
    297 <a href="#section-7">Section 7</a> for specific requirements for this scenario.
    298 </p>
    299 
    300 <a name="section-3.2"></a><h3>3.2. Soft API Compatibility</h3>
    301 <p>In addition to the managed APIs from Section 3.1, Android also includes a
    302 significant runtime-only "soft" API, in the form of such things such as
    303 Intents, permissions, and similar aspects of Android applications that cannot
    304 be enforced at application compile time.</p>
    305 <a name="section-3.2.1"></a><h4>3.2.1. Permissions</h4>
    306 <p>Device implementers MUST support and enforce all permission constants as
    307 documented by the Permission reference page [<a
    308 href="#resources05">Resources, 5</a>]. Note that Section 9 lists additional
    309 requirements related to the Android security model.</p>
    310 <a name="section-3.2.2"></a><h4>3.2.2. Build Parameters</h4>
    311 <p>The Android APIs include a number of constants on the <code>android.os.Build</code>
    312 class [<a href="#resources06">Resources, 6</a>] that are intended to describe
    313 the current device. To provide consistent, meaningful values across device
    314 implementations, the table below includes additional restrictions on the
    315 formats of these values to which device implementations MUST conform.</p>
    316 <table>
    317 <tbody>
    318 <tr>
    319 <td><b>Parameter</b></td>
    320 <td><b>Comments</b></td>
    321 </tr>
    322 <tr>
    323 <td>android.os.Build.VERSION.RELEASE</td>
    324 <td>The version of the currently-executing Android system, in human-readable
    325 format. This field MUST have one of the string values defined in [<a
    326 href="#resources07">Resources, 7</a>].</td>
    327 </tr>
    328 <tr>
    329 <td>android.os.Build.VERSION.SDK</td>
    330 <td>The version of the currently-executing Android system, in a format
    331 accessible to third-party application code. For Android 4.3, this
    332 field MUST have the integer value 18.</td>
    333 </tr>
    334 <tr>
    335 <td>android.os.Build.VERSION.SDK_INT</td>
    336 <td>The version of the currently-executing Android system, in a format
    337 accessible to third-party application code. For Android 4.3, this
    338 field MUST have the integer value 18.</td>
    339 </tr>
    340 <tr>
    341 <td>android.os.Build.VERSION.INCREMENTAL</td>
    342 <td>A value chosen by the device implementer designating the specific build of
    343 the currently-executing Android system, in human-readable format. This value
    344 MUST NOT be re-used for different builds made available to end users. A typical use
    345 of this field is to indicate which build number or source-control change
    346 identifier was used to generate the build. There are no requirements on the
    347 specific format of this field, except that it MUST NOT be null or the empty
    348 string ("").</td>
    349 </tr>
    350 <tr>
    351 <td>android.os.Build.BOARD</td>
    352 <td>A value chosen by the device implementer identifying the specific internal
    353 hardware used by the device, in human-readable format. A possible use of this
    354 field is to indicate the specific revision of the board powering the device.
    355 The value of this field MUST be encodable as 7-bit ASCII and match the regular expression
    356 <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>
    357 </tr>
    358 <tr>
    359 <td>android.os.Build.BRAND</td>
    360 <td>A value chosen by the device implementer identifying the name of the
    361 company, organization, individual, etc. who produced the device, in
    362 human-readable format. A possible use of this field is to indicate the OEM
    363 and/or carrier who sold the device. The value of this field MUST be
    364 encodable as 7-bit ASCII and match the regular expression
    365 <code>"^[a-zA-Z0-9.,_-]+$"</code>.
    366 </td>
    367 </tr>
    368 <tr>
    369 <td>android.os.Build.CPU_ABI</td>
    370 <td>The name of the instruction set (CPU type + ABI convention) of native code.
    371 See <a href="#section-3.3">Section 3.3: Native API Compatibility</a>.
    372 </td>
    373 </tr>
    374 <tr>
    375 <td>android.os.Build.CPU_ABI2</td>
    376 <td>The name of the second instruction set (CPU type + ABI convention) of native code.
    377 See <a href="#section-3.3">Section 3.3: Native API Compatibility</a>.
    378 </td>
    379 </tr>
    380 <tr>
    381 <td>android.os.Build.DEVICE</td>
    382 <td>A value chosen by the device implementer identifying the specific
    383 configuration or revision of the body (sometimes called "industrial design")
    384 of the device. The value of this field MUST be encodable as 7-bit ASCII and
    385 match the regular expression <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>
    386 </tr>
    387 <tr>
    388 <td>android.os.Build.FINGERPRINT</td>
    389 <td>A string that uniquely identifies this build. It SHOULD be reasonably
    390 human-readable. It MUST follow this template:
    391 <br/><code>$(BRAND)/$(PRODUCT)/$(DEVICE):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)</code><br/>
    392 For example:
    393 <br/><code>acme/mydevice/generic:4.3/JRN53/3359:userdebug/test-keys</code><br/>
    394 The fingerprint MUST NOT include whitespace characters. If other fields included in the
    395 template above have whitespace characters, they MUST be replaced in the build
    396 fingerprint with another character, such as the underscore ("_") character.
    397 The value of this field MUST be encodable as 7-bit ASCII.</td>
    398 </tr>
    399 <tr>
    400 <td>android.os.Build.HARDWARE</td>
    401 <td>The name of the hardware (from the kernel command line or /proc).  It SHOULD be
    402 reasonably human-readable. The value of this field MUST be encodable as 7-bit ASCII and
    403 match the regular expression <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>
    404 </tr>
    405 <tr>
    406 <td>android.os.Build.HOST</td>
    407 <td>A string that uniquely identifies the host the build was built on, in
    408 human readable format. There are no requirements on the specific format of
    409 this field, except that it MUST NOT be null or the empty string ("").</td>
    410 </tr>
    411 <tr>
    412 <td>android.os.Build.ID</td>
    413 <td>An identifier chosen by the device implementer to refer to a specific
    414 release, in human readable format. This field can be the same as
    415 android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value sufficiently
    416 meaningful for end users to distinguish between software builds. The value of
    417 this field MUST be encodable as 7-bit ASCII and match the regular expression
    418 <code>"^[a-zA-Z0-9.,_-]+$"</code>.
    419 </td>
    420 </tr>
    421 <tr>
    422 <td>android.os.Build.MANUFACTURER</td>
    423 <td>The trade name of the Original Equipment Manufacturer (OEM) of the product.
    424 There are no requirements on the specific format of this field, except that it
    425 MUST NOT be null or the empty string ("").</td>
    426 </tr>
    427 <tr>
    428 <td>android.os.Build.MODEL</td>
    429 <td>A value chosen by the device implementer containing the name of the device
    430 as known to the end user. This SHOULD be the same name under which the device
    431 is marketed and sold to end users. There are no requirements on the specific
    432 format of this field, except that it MUST NOT be null or the empty string
    433 ("").</td>
    434 </tr>
    435 <tr>
    436 <td>android.os.Build.PRODUCT</td>
    437 <td>A value chosen by the device implementer containing the development name
    438 or code name of the product (SKU). MUST be human-readable, but is not necessarily
    439 intended for view by end users. The value of this field MUST be encodable as 7-bit
    440 ASCII and match the regular expression
    441 <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>
    442 </tr>
    443 <tr>
    444 <td>android.os.Build.SERIAL</td>
    445 <td>A hardware serial number, if available. The value of this field MUST be encodable
    446 as 7-bit ASCII and match the regular expression
    447 <code>"^([a-zA-Z0-9]{0,20})$"</code>.</td>
    448 </tr>
    449 <tr>
    450 <td>android.os.Build.TAGS</td>
    451 <td>A comma-separated list of tags chosen by the device implementer that
    452 further distinguishes the build. For example, "unsigned,debug". The value of
    453 this field MUST be encodable as 7-bit ASCII and match the regular expression
    454 <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>
    455 </tr>
    456 <tr>
    457 <td>android.os.Build.TIME</td>
    458 <td>A value representing the timestamp of when the build occurred.</td>
    459 </tr>
    460 <tr>
    461 <td>android.os.Build.TYPE</td>
    462 <td>A value chosen by the device implementer specifying the runtime
    463 configuration of the build. This field SHOULD have one of the values
    464 corresponding to the three typical Android runtime configurations: "user",
    465 "userdebug", or "eng". The value of this field MUST be
    466 encodable as 7-bit ASCII and match the regular expression
    467 <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>
    468 </tr>
    469 <tr>
    470 <td>android.os.Build.USER</td>
    471 <td>A name or user ID of the user (or automated user) that generated the
    472 build. There are no requirements on the specific format of this field, except
    473 that it MUST NOT be null or the empty string ("").</td>
    474 </tr>
    475 </tbody>
    476 </table>
    477 <a name="section-3.2.3"></a><h4>3.2.3. Intent Compatibility</h4>
    478 <p>
    479 Device implementations MUST honor Android's loose-coupling Intent system, as
    480 described in the sections below. By "honored", it is meant that the device
    481 implementer MUST provide an Android Activity or Service that specifies a
    482 matching Intent filter and binds to and implements correct behavior for each
    483 specified Intent pattern.</p>
    484 <a name="section-3.2.3.1"></a><h4>3.2.3.1. Core Application Intents</h4>
    485 <p>The Android upstream project defines a number of core applications, such as
    486 contacts, calendar, photo gallery, music player, and so on. Device implementers
    487 MAY replace these applications with alternative versions.</p>
    488 <p>However, any such alternative versions MUST honor the same Intent patterns
    489 provided by the upstream project. For example, if a device contains an
    490 alternative music player, it must still honor the Intent pattern issued by
    491 third-party applications to pick a song.</p>
    492 <p>The following applications are considered core Android system
    493 applications:</p>
    494 <ul>
    495 <li>Desk Clock</li>
    496 <li>Browser</li>
    497 <li>Calendar</li>
    498 <li>Contacts</li>
    499 <!--<li>Email</li>-->
    500 <li>Gallery</li>
    501 <li>GlobalSearch</li>
    502 <li>Launcher</li>
    503 <!-- <li>LivePicker (that is, the Live Wallpaper picker application; MAY be omitted
    504 if the device does not support Live Wallpapers, per Section 3.8.5.)</li> -->
    505 <!-- <li>Messaging (AKA "Mms")</li> -->
    506 <li>Music</li>
    507 <!-- <li>Phone</li> -->
    508 <li>Settings</li>
    509 <!-- <li>SoundRecorder</li> -->
    510 </ul>
    511 <p>The core Android system applications include various Activity, or Service
    512 components that are considered "public".  That is, the attribute
    513 "android:exported" may be absent, or may have the value "true".</p>
    514 <p>For every Activity or Service defined
    515 in one of the core Android system apps that is not marked as non-public via an
    516 android:exported attribute with the value "false", device implementations MUST
    517 include a component of the same type implementing the same Intent filter
    518 patterns as the core Android system app.</p>
    519 <p>In other words, a device implementation MAY replace core Android system
    520 apps; however, if it does, the device implementation MUST support all Intent
    521 patterns defined by each core Android system app being replaced.</p>
    522 <a name="section-3.2.3.2"></a><h4>3.2.3.2. Intent Overrides</h4>
    523 <p>As Android is an extensible platform, device implementations MUST allow each
    524 Intent pattern referenced in Section 3.2.3.2 to be overridden by third-party
    525 applications. The upstream Android open source implementation allows this by
    526 default; device implementers MUST NOT attach special privileges to system
    527 applications' use of these Intent patterns, or prevent third-party
    528 applications from binding to and assuming control of these patterns. This
    529 prohibition specifically includes but is not limited to disabling the
    530 "Chooser" user interface that allows the user to select between multiple
    531 applications which all handle the same Intent pattern.</p>
    532 <p>However, device implementations MAY provide default activities for specific
    533 URI patterns (eg. http://play.google.com) if the default activity provides a
    534 more specific filter for the data URI. For example, an intent filter specifying
    535 the data URI "http://www.android.com" is more specific than the browser filter
    536 for "http://". Device implementations MUST provide a user interface for users
    537 to modify the default activity for intents.</p>
    538 
    539 <a name="section-3.2.3.3"></a><h4>3.2.3.3. Intent Namespaces</h4>
    540 <p>Device implementations MUST NOT include any Android component that honors any
    541 new Intent or Broadcast Intent patterns using an ACTION, CATEGORY, or other
    542 key string in the android.* or com.android.* namespace. Device implementers
    543 MUST NOT include any Android components that honor any new Intent or Broadcast
    544 Intent patterns using an ACTION, CATEGORY, or other key string in a package
    545 space belonging to another organization. Device implementers MUST NOT alter or
    546 extend any of the Intent patterns used by the core apps listed in Section
    547 3.2.3.1. Device implementations MAY include Intent patterns using
    548 namespaces clearly and obviously associated with their own organization.</p>
    549 <p>This prohibition is analogous to that specified for Java language classes
    550 in Section 3.6.</p>
    551 <a name="section-3.2.3.4"></a><h4>3.2.3.4. Broadcast Intents</h4>
    552 <p>Third-party applications rely on the platform to broadcast certain Intents
    553 to notify them of changes in the hardware or software environment.
    554 Android-compatible devices MUST broadcast the public broadcast Intents in
    555 response to appropriate system events. Broadcast Intents are described in the
    556 SDK documentation.</p>
    557 
    558 <a name="section-3.3"></a><h3>3.3. Native API Compatibility</h3>
    559 <a name="section-3.3.1"></a><h4>3.3.1 Application Binary Interfaces</h4>
    560 <p>Managed code running in Dalvik can call into native code provided in the
    561 application .apk file as an ELF .so file compiled for the appropriate device
    562 hardware architecture. As native code is highly dependent on the underlying
    563 processor technology, Android defines a number of Application Binary
    564 Interfaces (ABIs) in the Android NDK, in the file
    565 <code>docs/CPU-ARCH-ABIS.html</code>. If a device implementation is compatible
    566 with one or more defined ABIs, it SHOULD implement compatibility with the
    567 Android NDK, as below.</p>
    568 <p>If a device implementation includes support for an Android ABI, it:</p>
    569 <ul>
    570 <li>MUST include support for code running in the managed environment to call
    571 into native code, using the standard Java Native Interface (JNI)
    572 semantics</li>
    573 <li>MUST be source-compatible (i.e. header compatible) and binary-compatible
    574 (for the ABI) with each required library in the list below</li>
    575 <li>MUST accurately report the native Application Binary Interface (ABI)
    576 supported by the device, via the <code>android.os.Build.CPU_ABI</code>
    577 API</li>
    578 <li>MUST report only those ABIs documented in the latest version of the
    579 Android NDK, in the file <code>docs/CPU-ARCH-ABIS.txt</code></li>
    580 <li>SHOULD be built using the source code and header files available in the
    581 upstream Android Open Source Project</li>
    582 </ul>
    583 <p>The following native code APIs MUST be available to apps that include
    584 native code:</p>
    585 <ul>
    586 <li>libc (C library)</li>
    587 <li>libm (math library)</li>
    588 <li>Minimal support for C++</li>
    589 <li>JNI interface</li>
    590 <li>liblog (Android logging)</li>
    591 <li>libz (Zlib compression)</li>
    592 <li>libdl (dynamic linker)</li>
    593 <li>libGLESv1_CM.so (OpenGL ES 1.0)</li>
    594 <li>libGLESv2.so (OpenGL ES 2.0)</li>
    595 <li>libGLESv3.so (OpenGL ES 3.0)</li>
    596 <li>libEGL.so (native OpenGL surface management)</li>
    597 <li>libjnigraphics.so</li>
    598 <li>libOpenSLES.so (OpenSL ES 1.0.1 audio support)</li>
    599 <li>libOpenMAXAL.so (OpenMAX AL 1.0.1 support)</li>
    600 <li>libandroid.so (native Android activity support)</li>
    601 <li>Support for OpenGL, as described below</li>
    602 </ul>
    603 <p>Note that future releases of the Android NDK may introduce support for
    604 additional ABIs. If a device implementation is not compatible with an existing
    605 predefined ABI, it MUST NOT report support for any ABI at all.</p>
    606 <p>Note that device implementations MUST include libGLESv3.so and it MUST symlink (symbolic)
    607 link to libGLESv2.so. On device implementations that declare support for OpenGL ES 3.0, libGLESv2.so
    608 MUST export the OpenGL ES 3.0 function symbols in addition to the OpenGL ES 2.0 function symbols.</p>
    609 <p>Native code compatibility is challenging. For this reason, it should be
    610 repeated that device implementers are VERY strongly encouraged to use the
    611 upstream implementations of the libraries listed above to help ensure
    612 compatibility.</p>
    613 
    614 <a name="section-3.4"></a><h3>3.4. Web Compatibility</h3>
    615 <a name="section-3.4.1"></a><h4>3.4.1. WebView Compatibility</h4>
    616 <p>The Android Open Source implementation uses the WebKit rendering engine to
    617 implement the <code>android.webkit.WebView</code> [<a href="#resources10">Resources, 10</a>] . Because it is not feasible
    618 to develop a comprehensive test suite for a web rendering system, device
    619 implementers MUST use the specific upstream build of WebKit in the WebView
    620 implementation. Specifically:</p>
    621 <ul>
    622 <li>Device implementations' <code>android.webkit.WebView</code>
    623 implementations MUST be based on the 534.30 WebKit build from the upstream
    624 Android Open Source tree for Android 4.3. This build includes a specific set
    625 of functionality and security fixes for the WebView. Device implementers MAY
    626 include customizations to the WebKit implementation; however, any such
    627 customizations MUST NOT alter the behavior of the WebView, including rendering
    628 behavior.</li>
    629 <li>The user agent string reported by the WebView MUST be in this format:<br/>
    630     <code>Mozilla/5.0 (Linux; U; Android $(VERSION); $(LOCALE); $(MODEL) Build/$(BUILD)) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30</code>
    631   <ul>
    632   <li>The value of the $(VERSION) string MUST be the same as the value for <code>android.os.Build.VERSION.RELEASE</code></li>
    633   <li>The value of the $(LOCALE) string SHOULD follow the ISO conventions for country code and language, and SHOULD refer to the current configured locale of the device</li>
    634   <li>The value of the $(MODEL) string MUST be the same as the value for <code>android.os.Build.MODEL</code></li>
    635   <li>The value of the $(BUILD) string MUST be the same as the value for <code>android.os.Build.ID</code></li>
    636   <li>Device implementations MAY omit <code>Mobile</code> in the user agent string</li>
    637   </ul>
    638 </li>
    639 </ul>
    640 <p>The WebView component SHOULD include support for as much of HTML5 [<a
    641 href="#resources11">Resources, 11</a>] as possible.
    642 Minimally, device implementations MUST support each of these APIs associated
    643 with HTML5 in the WebView:</p>
    644 <ul>
    645 <li>application cache/offline operation [<a href="#resources12">Resources, 12</a>]</li>
    646 <li>the &lt;video&gt; tag [<a href="#resources13">Resources, 13</a>]</li>
    647 <li>geolocation [<a href="#resources14">Resources, 14</a>]</li>
    648 </ul>
    649 <p>Additionally, device implementations MUST support the HTML5/W3C webstorage
    650 API [<a href="#resources15">Resources, 15</a>], and SHOULD support the
    651 HTML5/W3C IndexedDB API [<a href="#resources16">Resources, 16</a>]. <i>Note
    652 that as the web development standards bodies are transitioning to favor
    653 IndexedDB over webstorage, IndexedDB is expected to become a required
    654 component in a future version of Android.</i></p>
    655 <p>HTML5 APIs, like all JavaScript APIs, MUST be disabled by default in a
    656 WebView, unless the developer explicitly enables them via the usual Android
    657 APIs.</p>
    658 
    659 <a name="section-3.4.2"></a><h4>3.4.2. Browser Compatibility</h4>
    660 <p>Device implementations MUST include a standalone Browser application for
    661 general user web browsing. The standalone Browser MAY be based on a
    662 browser technology other than WebKit. However, even if an alternate Browser
    663 application is used, the <code>android.webkit.WebView</code> component
    664 provided to third-party applications MUST be based on WebKit, as described in
    665 Section 3.4.1.</p>
    666 <p>Implementations MAY ship a custom user agent string in the standalone
    667 Browser application.</p>
    668 <p>The standalone Browser application (whether based on the upstream
    669 WebKit Browser application or a third-party replacement) SHOULD include support
    670 for as much of HTML5 [<a href="#resources11">Resources, 11</a>] as possible.
    671 Minimally, device implementations MUST support each of these APIs associated
    672 with HTML5:</p>
    673 <ul>
    674 <li>application cache/offline operation [<a href="#resources12">Resources, 12</a>]</li>
    675 <li>the &lt;video&gt; tag [<a href="#resources13">Resources, 13</a>]</li>
    676 <li>geolocation [<a href="#resources14">Resources, 14</a>]</li>
    677 </ul>
    678 <p>Additionally, device implementations MUST support the HTML5/W3C webstorage
    679 API [<a href="#resources15">Resources, 15</a>], and SHOULD support the
    680 HTML5/W3C IndexedDB API [<a href="#resources16">Resources, 16</a>]. <i>Note
    681 that as the web development standards bodies are transitioning to favor
    682 IndexedDB over webstorage, IndexedDB is expected to become a required
    683 component in a future version of Android.</i></p>
    684 
    685 <a name="section-3.5"></a><h3>3.5. API Behavioral Compatibility</h3>
    686 <p>The behaviors of each of the API types (managed, soft, native, and web)
    687 must be consistent with the preferred implementation of the upstream Android
    688 Open Source Project [<a href="#resources03">Resources, 3</a>]. Some specific areas
    689 of compatibility are:</p>
    690 <ul>
    691 <li>Devices MUST NOT change the behavior or semantics of a standard Intent</li>
    692 <li>Devices MUST NOT alter the lifecycle or lifecycle semantics of a
    693     particular type of system component (such as Service, Activity,
    694     ContentProvider, etc.)</li>
    695 <li>Devices MUST NOT change the semantics of a standard permission</li>
    696 </ul>
    697 <p>The above list is not comprehensive. The Compatibility Test Suite (CTS)
    698 tests significant portions of the platform for behavioral compatibility, but
    699 not all. It is the responsibility of the implementer to ensure behavioral
    700 compatibility with the Android Open Source Project.  For this reason, device
    701 implementers SHOULD use the source code available via the Android Open Source
    702 Project where possible, rather than re-implement significant parts of the
    703 system.</p>
    704 
    705 
    706 <a name="section-3.6"></a><h3>3.6. API Namespaces</h3>
    707 <p>Android follows the package and class namespace conventions defined by the
    708 Java programming language. To ensure compatibility with third-party
    709 applications, device implementers MUST NOT make any prohibited modifications
    710 (see below) to these package namespaces:</p>
    711 <ul>
    712 <li>java.*</li>
    713 <li>javax.*</li>
    714 <li>sun.*</li>
    715 <li>android.*</li>
    716 <li>com.android.*</li>
    717 </ul>
    718 <p>Prohibited modifications include:</p>
    719 <ul>
    720 <li>Device implementations MUST NOT modify the publicly exposed APIs on the
    721 Android platform by changing any method or class signatures, or by removing
    722 classes or class fields.</li>
    723 <li>Device implementers MAY modify the underlying implementation of the APIs,
    724 but such modifications MUST NOT impact the stated behavior and Java-language
    725 signature of any publicly exposed APIs.</li>
    726 <li>Device implementers MUST NOT add any publicly exposed elements (such as
    727 classes or interfaces, or fields or methods to existing classes or interfaces)
    728 to the APIs above.</li>
    729 </ul>
    730 <p>A "publicly exposed element" is any construct which is not decorated with
    731 the "@hide" marker as used in the upstream Android source code. In other
    732 words, device implementers MUST NOT expose new APIs or alter existing APIs in
    733 the namespaces noted above. Device implementers MAY make internal-only
    734 modifications, but those modifications MUST NOT be advertised or otherwise
    735 exposed to developers.</p>
    736 <p>Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a
    737 namespace owned by or referring to another organization. For instance, device
    738 implementers MUST NOT add APIs to the com.google.* or similar namespace; only
    739 Google may do so. Similarly, Google MUST NOT add APIs to other companies'
    740 namespaces. Additionally, if a device implementation includes custom APIs
    741 outside the standard Android namespace, those APIs MUST be packaged in an
    742 Android shared library so that only apps that explicitly use them (via the
    743 <code>&lt;uses-library&gt;</code> mechanism) are affected by the increased
    744 memory usage of such APIs.</p>
    745 <p>If a device implementer proposes to improve one of the package namespaces
    746 above (such as by adding useful new functionality to an existing API, or
    747 adding a new API), the implementer SHOULD visit source.android.com and begin
    748 the process for contributing changes and code, according to the information on
    749 that site.</p>
    750 <p>Note that the restrictions above correspond to standard conventions for
    751 naming APIs in the Java programming language; this section simply aims to
    752 reinforce those conventions and make them binding through inclusion in this
    753 compatibility definition.</p>
    754 
    755 <a name="section-3.7"></a><h3>3.7. Virtual Machine Compatibility</h3>
    756 <p>Device implementations MUST support the full Dalvik Executable (DEX)
    757 bytecode specification and Dalvik Virtual Machine semantics [<a
    758 href="#resources17">Resources, 17</a>].</p>
    759 <p>Device implementations MUST configure Dalvik to allocate memory in
    760 accordance with the upstream Android platform, and as specified by the following
    761 table.  (See <a href="#section-7.1.1">Section 7.1.1</a> for screen size and screen
    762 density definitions.)</p>
    763 
    764 <p>Note that memory values specified below are considered minimum values,
    765 and device implementations MAY allocate more memory per application.</p>
    766 <table>
    767 <tbody>
    768 <tr>
    769 <td><b>Screen Size</b></td>
    770 <td><b>Screen Density</b></td>
    771 <td><b>Application Memory</b></td>
    772 </tr>
    773 <tr>
    774 <td>small / normal / large</td>
    775 <td>ldpi / mdpi</td>
    776 <td>16MB</td>
    777 </tr>
    778 <tr>
    779 <td>small / normal / large</td>
    780 <td>tvdpi / hdpi</td>
    781 <td>32MB</td>
    782 </tr>
    783 <tr>
    784 <td>small / normal / large</td>
    785 <td>xhdpi</td>
    786 <td>64MB</td>
    787 </tr>
    788 <tr>
    789 <td>xlarge</td>
    790 <td>mdpi</td>
    791 <td>32MB</td>
    792 </tr>
    793 <tr>
    794 <td>xlarge</td>
    795 <td>tvdpi / hdpi</td>
    796 <td>64MB</td>
    797 </tr>
    798 <tr>
    799 <td>xlarge</td>
    800 <td>xhdpi</td>
    801 <td>128MB</td>
    802 </tr>
    803 </tbody>
    804 </table>
    805 
    806 <a name="section-3.8"></a><h3>3.8. User Interface Compatibility</h3>
    807 
    808 <a name="section-3.8.1"></a><h4>3.8.1. Launcher (Home Screen)</h4>
    809 <p>Android 4.3 includes a launcher application (home screen) and support for third party applications to replace the device
    810 launcher (home screen). Device implementations that allow third party applications to replace the device home screen
    811 MUST declare the platform feature <code>android.software.home_screen</code>.</p>
    812 
    813 <a name="section-3.8.2"></a><h4>3.8.2. Widgets</h4>
    814 <p>Android defines a component type and corresponding API and lifecycle that allows applications to expose an "AppWidget"
    815 to the end user [<a href="#resources18">Resources, 18</a>]. Device implementations that support embedding widgets on the
    816 home screen MUST meet the following requirements and declare support for platform feature <code>android.software.app_widgets</code>.</p>
    817 <ul>
    818  <li>Device launchers MUST include built-in support for AppWidgets, and expose user
    819       interface affordances to add, configure, view, and remove AppWidgets directly within the Launcher.</li>
    820  <li>Device implementations MUST be capable of rendering widgets that are 4 x 4 in the standard grid size.
    821      (See the App Widget Design Guidelines in the Android SDK documentation [<a href="#resources18">Resources, 18</a>] for details.</li>
    822  <li>Device implementations that include support for lock screen MUST support application widgets on the lock screen.</li>
    823 </ul>
    824 
    825 <a name="section-3.8.3"></a><h4>3.8.3. Notifications</h4>
    826 <p>Android includes APIs that allow developers to notify users of notable
    827 events [<a href="#resources19">Resources, 19</a>], using hardware and software
    828 features of the device.</p>
    829 <p>Some APIs allow applications to perform notifications or attract attention
    830 using hardware, specifically sound, vibration, and light. Device implementations
    831 MUST support notifications that use hardware features, as described in the SDK
    832 documentation, and to the extent possible with the device implementation
    833 hardware. For instance, if a device implementation includes a vibrator, it
    834 MUST correctly implement the vibration APIs. If a device implementation lacks
    835 hardware, the corresponding APIs MUST be implemented as no-ops. Note that this
    836 behavior is further detailed in <a href="#section-7">Section 7.</a></p>
    837 <p>Additionally, the implementation MUST correctly render all resources
    838 (icons, sound files, etc.) provided for in the APIs [<a
    839 href="#resources20">Resources, 20</a>], or in the
    840 Status/System Bar icon style guide [<a href="#resources21">Resources, 21</a>].
    841 Device implementers MAY provide an alternative user experience for
    842 notifications than that provided by the reference Android Open Source
    843 implementation; however, such alternative notification systems MUST support
    844 existing notification resources, as above.</p>
    845 <p>Android 4.3 includes support for rich notifications, such as interactive
    846 Views for ongoing notifications. Device implementations MUST properly display
    847 and execute rich notifications, as documented in the Android APIs.</p>
    848 <a name="section-3.8.4"></a><h4>3.8.4. Search</h4>
    849 <p>Android includes APIs [<a href="#resources22">Resources, 22</a>] that allow
    850 developers to incorporate search into their applications, and expose their
    851 application's data into the global system search. Generally speaking, this
    852 functionality consists of a single, system-wide user interface that allows users
    853 to enter queries, displays suggestions as users type, and displays results. The
    854 Android APIs allow developers to reuse this interface to provide search within
    855 their own apps, and allow developers to supply results to the common global
    856 search user interface.</p>
    857 <p>Device implementations MUST include a single, shared, system-wide search
    858 user interface capable of real-time suggestions in response to user input.
    859 Device implementations MUST implement the APIs that allow developers to reuse
    860 this user interface to provide search within their own applications. Device
    861 implementations MUST implement the APIs that allow third-party applications to
    862 add suggestions to the search box when it is run in global search mode. If no
    863 third-party applications are installed that make use of this functionality,
    864 the default behavior SHOULD be to display web search engine results and
    865 suggestions.</p>
    866 <a name="section-3.8.5"></a><h4>3.8.5. Toasts</h4>
    867 <p>Applications can use the "Toast" API (defined in [<a
    868 href="#resources23">Resources, 23</a>]) to
    869 display short non-modal strings to the end user, that disappear after a brief
    870 period of time. Device implementations MUST display Toasts from applications
    871 to end users in some high-visibility manner.</p>
    872 
    873 <a name="section-3.8.6"></a><h4>3.8.6. Themes</h4>
    874 <p>Android provides "themes" as a mechanism for applications to apply styles
    875 across an entire Activity or application. Android 4.3 includes a "Holo"
    876 or "holographic" theme as a set of defined styles for application developers to
    877 use if they want to match the Holo theme look and feel as defined by the Android
    878 SDK [<a href="#resources24">Resources, 24</a>]. Device implementations MUST NOT
    879 alter any of the Holo theme attributes exposed to applications
    880 [<a href="#resources25">Resources, 25</a>].</p>
    881 <p>Android 4.3 includes a new "Device Default" theme as a set of defined
    882 styles for application developers to use if they want to match the look and feel
    883 of the device theme as defined by the device implementer. Device implementations
    884 MAY modify the DeviceDefault theme attributes exposed to applications
    885 [<a href="#resources25">Resources, 25</a>].</p>
    886 
    887 <a name="section-3.8.7"></a><h4>3.8.7. Live Wallpapers</h4>
    888 <p>Android defines a component type and corresponding API and lifecycle that
    889 allows applications to expose one or more "Live Wallpapers" to the end user
    890 [<a href="#resources26">Resources, 26</a>]. Live Wallpapers are animations,
    891 patterns, or similar images with limited input capabilities that display as a
    892 wallpaper, behind other applications.</p>
    893 <p>Hardware is considered capable of reliably running live wallpapers if it
    894 can run all live wallpapers, with no limitations on functionality, at a
    895 reasonable framerate with no adverse affects on other applications. If
    896 limitations in the hardware cause wallpapers and/or applications to crash,
    897 malfunction, consume excessive CPU or battery power, or run at unacceptably
    898 low frame rates, the hardware is considered incapable of running live
    899 wallpaper. As an example, some live wallpapers may use an Open GL 1.0 or 2.0
    900 context to render their content. Live wallpaper will not run reliably on
    901 hardware that does not support multiple OpenGL contexts because the live
    902 wallpaper use of an OpenGL context may conflict with other applications that
    903 also use an OpenGL context.</p>
    904 <p>Device implementations capable of running live wallpapers reliably as
    905 described above SHOULD implement live wallpapers. Device implementations
    906 determined to not run live wallpapers reliably as described above MUST NOT
    907 implement live wallpapers.</p>
    908 <a name="section-3.8.8"></a><h4>3.8.8. Recent Application Display</h4>
    909 <p>The upstream Android 4.3 source code includes a user interface for
    910 displaying recent applications using a thumbnail image of the application's
    911 graphical state at the moment the user last left the application. Device
    912 implementations MAY alter or eliminate this user interface; however, a future
    913 version of Android is planned to make more extensive use of this
    914 functionality. Device implementations are strongly encouraged to use the
    915 upstream Android 4.3 user interface (or a similar thumbnail-based interface)
    916 for recent applications, or else they may not be compatible with a future
    917 version of Android.</p>
    918 <a name="section-3.8.9"></a><h4>3.8.9. Input Management </h4>
    919 <p>Android 4.3 includes support for Input Management and support for third party input method editors.
    920 Device implementations that allow users to use third party input methods on the device MUST declare the platform feature
    921 <code>android.software.input_methods</code> and support IME APIs as defined in the Android SDK documentation.</p>
    922 <p>Device implementations that declare the <code>android.software.input_methods</code> feature MUST provide a user-accessible mechanism
    923 to add and configure third party input methods. Device implementations MUST display the settings interface in response to the
    924 <code>android.settings.INPUT_METHOD_SETTINGS</code> intent.</p>
    925 
    926 <a name="section-3.8.10"></a><h4>3.8.10. Lock Screen Media Remote Control</h4>
    927 <p>Android 4.3 includes support for Remote Control API that lets media applications integrate with playback controls
    928 that are displayed in a remote view like the device lock screen [<a href="#resources74">Resources, 74</a>]. Device implementations 
    929 that support lock screen in the device and allow users to add widgets on the home screen MUST
    930 include support for embedding remote controls in the device lock screen [<a href="#resources69">Resources, 69</a>].</p>
    931 
    932 <a name="section-3.8.11"></a><h4>3.8.11. Dreams</h4>
    933 <p>Android 4.3 includes support for interactive screensavers called Dreams [<a href="#resources76">Resources, 76</a>].
    934 Dreams allows users to interact with applications when a charging device is idle, or docked in a desk dock. Device implementations
    935 MUST include support for Dreams and provide a settings option for users to configure Dreams.</p>
    936 
    937 <a name="section-3.9"></a><h3>3.9 Device Administration</h3>
    938 <p>Android 4.3 includes features that allow security-aware applications
    939 to perform device administration functions at the system level, such as enforcing
    940 password policies or performing remote wipe, through the Android Device
    941 Administration API [<a href="#resources27">Resources, 27</a>]. Device
    942 implementations MUST provide an implementation of the <code>DevicePolicyManager</code>
    943 class [<a href="#resources28">Resources, 28</a>]. Device implementations that include support for lock screen
    944 MUST support the full range of device administration policies defined in the Android SDK
    945 documentation [<a href="#resources27">Resources, 27</a>].</p>
    946 
    947 <a name="section-3.10"></a><h3>3.10 Accessibility</h3>
    948 <p>Android 4.3 provides an accessibility layer that helps users with disabilities
    949 to navigate their devices more easily. In addition, Android 4.3 provides
    950 platform APIs that enable accessibility service implementations to receive
    951 callbacks for user and system events and generate alternate feedback mechanisms,
    952 such as text-to-speech, haptic feedback, and trackball/d-pad navigation
    953 [<a href="#resources29">Resources, 29</a>]. Device implementations MUST provide an
    954 implementation of the Android accessibility framework consistent with the
    955 default Android implementation.  Specifically, device implementations MUST meet
    956 the following requirements.</p>
    957 <ul>
    958  <li>Device implementations MUST support third party accessibility service
    959      implementations through the <code>android.accessibilityservice</code>
    960      APIs [<a href="#resources30">Resources, 30</a>].</li>
    961  <li>Device implementations MUST generate <code>AccessibilityEvents</code>
    962      and deliver these events to all registered <code>AccessibilityService
    963      </code> implementations in a manner consistent with the default Android
    964      implementation.</li>
    965  <li>Device implementations MUST provide a user-accessible mechanism to enable
    966      and disable accessibility services, and MUST display this interface in
    967      response to the
    968      <code>android.provider.Settings.ACTION_ACCESSIBILITY_SETTINGS</code>
    969      intent.</li>
    970 </ul>
    971 <p>Additionally, device implementations SHOULD provide an implementation
    972 of an accessibility service on the device, and SHOULD provide a mechanism
    973 for users to enable the accessibility service during device setup.  An open
    974 source implementation of an accessibility service is available from the Eyes
    975 Free project [<a href="#resources31">Resources, 31</a>].</p>
    976 
    977 <a name="section-3.11"></a><h3>3.11 Text-to-Speech</h3>
    978 <p>Android 4.3 includes APIs that allow applications to make use of
    979 text-to-speech (TTS) services, and allows service providers to provide
    980 implementations of TTS services [<a href="#resources32">Resources, 32</a>].
    981 Device implementations MUST meet these requirements related to the Android TTS
    982 framework:</p>
    983 <ul>
    984   <li>Device implementations MUST support the Android TTS framework APIs and
    985       SHOULD include a TTS engine supporting the languages available on the
    986       device. Note that the upstream Android open source software includes a
    987       full-featured TTS engine implementation.</li>
    988   <li>Device implementations MUST support installation of third-party TTS
    989       engines.</li>
    990   <li>Device implementations MUST provide a user-accessible interface that allows
    991       users to select a TTS engine for use at the system level.</li>
    992 </ul>
    993 
    994 <a name="section-4"></a><h2>4. Application Packaging Compatibility</h2>
    995 <p>Device implementations MUST install and run Android ".apk" files as
    996 generated by the "aapt" tool included in the official Android SDK [<a
    997 href="#resources33">Resources, 33</a>].</p>
    998 <p>Devices implementations MUST NOT extend either the .apk [<a
    999 href="#resources34">Resources, 34</a>], Android Manifest [<a
   1000 href="#resources35">Resources, 35</a>],
   1001 Dalvik bytecode [<a href="#resources17">Resources, 17</a>], or renderscript
   1002 bytecode formats in such a way that would prevent those files from installing
   1003 and running correctly on other compatible devices. Device implementers SHOULD
   1004 use the reference upstream implementation of Dalvik, and the reference
   1005 implementation's package management system.</p>
   1006 
   1007 <a name="section-5"></a><h2>5. Multimedia Compatibility</h2>
   1008 <p>Device implementations MUST include at least one form of audio output, such as
   1009 speakers, headphone jack, external speaker connection, etc.</p>
   1010 <a name="section-5.1"></a><h3>5.1. Media Codecs</h3>
   1011 <p>Device implementations MUST support the core media formats specified
   1012 in the Android SDK documentation [<a href="#resources58">Resources, 58</a>] except
   1013 where explicitly permitted in this document. Specifically, device implementations
   1014 MUST support the media formats, encoders, decoders, file types and container
   1015 formats defined in the tables below. All of these codecs are provided as
   1016 software implementations in the preferred Android implementation from the Android
   1017 Open Source Project.</p>
   1018 
   1019 <p><strong>Please note that neither Google nor the Open Handset Alliance make any
   1020 representation that these codecs are unencumbered by third-party patents.
   1021 Those intending to use this source code in hardware or software products are
   1022 advised that implementations of this code, including in open source software
   1023 or shareware, may require patent licenses from the relevant patent
   1024 holders.</strong></p>
   1025 
   1026 <p>Note that these tables do not list specific bitrate requirements for
   1027 most video codecs because current device hardware does not necessarily support
   1028 bitrates that map exactly to the required bitrates specified by the relevant
   1029 standards. Instead, device implementations SHOULD support the highest bitrate
   1030 practical on the hardware, up to the limits defined by the specifications.</p>
   1031 <div style="page-break-before: always;"></div>
   1032 <table>
   1033 <tbody>
   1034 
   1035 <tr>
   1036 <th>Type</th>
   1037 <th>Format / Codec</th>
   1038 <th>Encoder</th>
   1039 <th>Decoder</th>
   1040 <th>Details</th>
   1041 <th>File Type(s) / Container Formats</th>
   1042 </tr>
   1043 
   1044 <tr>
   1045 <td rowspan="11">Audio</td>
   1046 <td>MPEG-4 AAC Profile (AAC LC)</td>
   1047 <td>REQUIRED for device implementations that include microphone hardware
   1048 and define <code>android.hardware.microphone</code>.</td>
   1049 <td style="text-align: center;">REQUIRED</td>
   1050 <td rowspan="1"> Support for mono/stereo/5.0/5.1* content with standard sampling rates from 8 to 48 kHz.</td>
   1051 <td rowspan="4">
   1052   <ul>
   1053     <li>3GPP (.3gp)</li>
   1054     <li>MPEG-4 (.mp4, .m4a)</li>
   1055     <li>ADTS raw AAC (.aac, decode in Android 3.1+, encode in Android 4.0+, ADIF not supported)</li>
   1056     <li>MPEG-TS (.ts, not seekable, Android 3.0+)</li>
   1057   </ul>
   1058 </td>
   1059 </tr>
   1060 
   1061 <tr>
   1062 <td>MPEG-4 HE AAC Profile (AAC+)</td>
   1063 <td>REQUIRED for device implementations that include microphone hardware and define android.hardware.microphone</td>
   1064 <td style="text-align: center;">REQUIRED</td>
   1065 <td>Support for mono/stereo/5.0/5.1* content with standard sampling rates from 16 to 48 kHz.</td>
   1066 </tr>
   1067 
   1068 <tr>
   1069 <td>MPEG-4 HE AAC v2 Profile (enhanced AAC+)</td>
   1070 <td>&nbsp;</td>
   1071 <td style="text-align: center;">REQUIRED</td>
   1072 <td>Support for mono/stereo/5.0/5.1* content with standard sampling rates from 16 to 48 kHz.</td>
   1073 </tr>
   1074 
   1075 <tr>
   1076 <td>MPEG-4 Audio Object Type ER AAC ELD (Enhanced Low Delay AAC)</td>
   1077 <td>REQUIRED for device implementations that include microphone hardware and define android.hardware.microphone</td>
   1078 <td style="text-align: center;">REQUIRED</td>
   1079 <td>Support for mono/stereo content with standard
   1080 sampling rates from 16 to 48 kHz.</td>
   1081 </tr>
   1082 
   1083 <tr>
   1084 <td>AMR-NB</td>
   1085 <td>REQUIRED for device implementations that include microphone hardware
   1086 and define <code>android.hardware.microphone</code>.</td>
   1087 <td style="text-align: center;">REQUIRED</td>
   1088 <td>4.75 to 12.2 kbps sampled @ 8kHz</td>
   1089 <td>3GPP (.3gp)
   1090 </td>
   1091 </tr>
   1092 
   1093 <tr>
   1094 <td>AMR-WB</td>
   1095 <td>REQUIRED for device implementations that include microphone hardware
   1096 and define <code>android.hardware.microphone</code>.</td>
   1097 <td style="text-align: center;">REQUIRED</td>
   1098 <td>9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16kHz</td>
   1099 <td>3GPP (.3gp)</td>
   1100 </tr>
   1101 
   1102 <tr>
   1103 <td>FLAC</td>
   1104 <td>&nbsp;</td>
   1105 <td style="text-align: center;">REQUIRED<br/><small>(Android 3.1+)</small></td>
   1106 <td>Mono/Stereo (no multichannel). Sample rates up to 48 kHz (but up to 44.1
   1107 kHz is recommended on devices with 44.1 kHz output, as the 48 to 44.1 kHz
   1108 downsampler does not include a low-pass filter). 16-bit recommended;
   1109 no dither applied for 24-bit.
   1110 </td>
   1111 <td>FLAC (.flac) only</td>
   1112 </tr>
   1113 
   1114 <tr>
   1115 <td>MP3</td>
   1116 <td>&nbsp;</td>
   1117 <td style="text-align: center;">REQUIRED</td>
   1118 <td>Mono/Stereo 8-320Kbps constant (CBR) or variable bit-rate (VBR)
   1119 </td>
   1120 <td>MP3 (.mp3)</td>
   1121 </tr>
   1122 
   1123 <tr>
   1124 <td>MIDI</td>
   1125 <td>&nbsp;</td>
   1126 <td style="text-align: center;">REQUIRED</td>
   1127 <td>MIDI Type 0 and 1. DLS Version 1 and 2. XMF and Mobile XMF. Support for ringtone formats RTTTL/RTX, OTA, and iMelody </td>
   1128 <td>
   1129   <ul>
   1130     <li>Type 0 and 1 (.mid, .xmf, .mxmf)</li>
   1131     <li>RTTTL/RTX (.rtttl, .rtx)</li>
   1132     <li>OTA (.ota)</li>
   1133     <li>iMelody (.imy)</li>
   1134   </ul>
   1135 </td>
   1136 </tr>
   1137 
   1138 <tr>
   1139 <td>Vorbis</td>
   1140 <td>&nbsp;</td>
   1141 <td style="text-align: center;">REQUIRED</td>
   1142 <td>&nbsp;</td>
   1143 <td>
   1144   <ul>
   1145     <li>Ogg (.ogg)</li>
   1146     <li>Matroska (.mkv)</li>
   1147   </ul>
   1148 </td>
   1149 </tr>
   1150 
   1151 <tr>
   1152 <td>PCM/WAVE</td>
   1153 <td style="text-align: center;">REQUIRED</td>
   1154 <td style="text-align: center;">REQUIRED</td>
   1155 <td>8-bit and 16-bit linear PCM** (rates up to limit of hardware).Devices MUST support sampling rates
   1156 for raw PCM recording at 8000,16000 and 44100 Hz frequencies</td>
   1157 <td>WAVE (.wav)</td>
   1158 </tr>
   1159 
   1160 <tr>
   1161 <td rowspan="5">Image</td>
   1162 <td>JPEG</td>
   1163 <td style="text-align: center;">REQUIRED</td>
   1164 <td style="text-align: center;">REQUIRED</td>
   1165 <td>Base+progressive</td>
   1166 <td>JPEG (.jpg)</td>
   1167 </tr>
   1168 
   1169 <tr>
   1170 <td>GIF</td>
   1171 <td>&nbsp;</td>
   1172 <td style="text-align: center;">REQUIRED</td>
   1173 <td>&nbsp;</td>
   1174 <td>GIF (.gif)</td>
   1175 </tr>
   1176 
   1177 <tr>
   1178 <td>PNG</td>
   1179 <td style="text-align: center;">REQUIRED</td>
   1180 <td style="text-align: center;">REQUIRED</td>
   1181 <td>&nbsp;</td>
   1182 <td>PNG (.png)</td>
   1183 </tr>
   1184 
   1185 <tr>
   1186 <td>BMP</td>
   1187 <td>&nbsp;</td>
   1188 <td style="text-align: center;">REQUIRED</td>
   1189 <td>&nbsp;</td>
   1190 <td>BMP (.bmp)</td>
   1191 </tr>
   1192 
   1193 
   1194 <tr>
   1195 <td>WEBP</td>
   1196 <td style="text-align: center;">REQUIRED</td>
   1197 <td style="text-align: center;">REQUIRED</td>
   1198 <td>&nbsp;</td>
   1199 <td>WebP (.webp)</td>
   1200 </tr>
   1201 
   1202 <tr>
   1203 <td rowspan="4">Video</td>
   1204 <td>H.263</td>
   1205 <td>REQUIRED for device implementations that include camera hardware
   1206 and define <code>android.hardware.camera</code> or
   1207 <code>android.hardware.camera.front</code>.</td>
   1208 <td style="text-align: center;">REQUIRED</td>
   1209 <td>&nbsp;</td>
   1210 <td>
   1211   <ul>
   1212     <li>3GPP (.3gp)</li>
   1213     <li>MPEG-4 (.mp4)</li>
   1214   </ul>
   1215 </td>
   1216 </tr>
   1217 
   1218 <tr>
   1219 <td>H.264 AVC</td>
   1220 <td>REQUIRED for device implementations that include camera hardware
   1221 and define <code>android.hardware.camera</code> or
   1222 <code>android.hardware.camera.front</code>.</td>
   1223 <td style="text-align: center;">REQUIRED</td>
   1224 <td>Baseline Profile (BP)</td>
   1225 <td>
   1226   <ul>
   1227     <li>3GPP (.3gp)</li>
   1228     <li>MPEG-4 (.mp4)</li>
   1229     <li>MPEG-TS (.ts, AAC audio only, not seekable, Android 3.0+)</li>
   1230   </ul>
   1231 </td>
   1232 </tr>
   1233 
   1234 <tr>
   1235 <td>MPEG-4 SP</td>
   1236 <td>&nbsp;</td>
   1237 <td style="text-align: center;">REQUIRED</td>
   1238 <td>&nbsp;</td>
   1239 <td>3GPP (.3gp)</td>
   1240 </tr>
   1241 
   1242 <tr>
   1243 <td>VP8</td>
   1244 <td style="text-align: center;">REQUIRED<br/><small>(Android 4.3+)</small></td>
   1245 <td style="text-align: center;">REQUIRED<br/><small>(Android 2.3.3+)</small></td>
   1246 <td>&nbsp;</td>
   1247 <td><a href="http://www.webmproject.org/">WebM</a> (.webm) and Matroska (.mkv, Android 4.0+)***</td>
   1248 </tr>
   1249 
   1250 </tbody></table>
   1251 <ul>
   1252 <li>*Note: Only downmix of 5.0/5.1 content is required; recording or rendering more than 2 channels is optional.</li>
   1253 <li>**Note: 16-bit linear PCM capture is mandatory. 8-bit linear PCM capture is not mandatory.</li>
   1254 <li>***Note: Device implementations SHOULD support writing Matroska WebM files.</li>
   1255 </ul>
   1256 
   1257 <a name="section-5.2"></a><h3>5.2 Video Encoding</h3>
   1258 <p>Android device implementations that include a rear-facing camera and declare
   1259 <code>android.hardware.camera</code> SHOULD support the following H.264 video encoding
   1260 profiles.</p>
   1261 <table>
   1262   <thead>
   1263   <tr>
   1264     <th>&nbsp;</th>
   1265     <th>SD (Low quality)</th>
   1266     <th>SD (High quality)</th>
   1267     <th>HD (When supported by hardware)</th>
   1268   </tr>
   1269   </thead>
   1270   <tbody>
   1271   <tr>
   1272     <th>Video resolution</th>
   1273     <td>176 x 144 px</td>
   1274     <td>480 x 360 px</td>
   1275     <td>1280 x 720 px</td>
   1276   </tr>
   1277   <tr>
   1278     <th>Video frame rate</th>
   1279     <td>12 fps</td>
   1280     <td>30 fps</td>
   1281     <td>30 fps</td>
   1282   </tr>
   1283   <tr>
   1284     <th>Video bitrate</th>
   1285     <td>56 Kbps</td>
   1286     <td>500 Kbps or higher</td>
   1287     <td>2 Mbps or higher</td>
   1288   </tr>
   1289   <tr>
   1290     <th>Audio codec</th>
   1291     <td>AAC-LC</td>
   1292     <td>AAC-LC</td>
   1293     <td>AAC-LC</td>
   1294   </tr>
   1295   <tr>
   1296     <th>Audio channels</th>
   1297     <td>1 (mono)</td>
   1298     <td>2 (stereo)</td>
   1299     <td>2 (stereo)</td>
   1300   </tr>
   1301   <tr>
   1302     <th>Audio bitrate</th>
   1303     <td>24 Kbps</td>
   1304     <td>128 Kbps</td>
   1305     <td>192 Kbps</td>
   1306   </tr>
   1307   </tbody>
   1308 </table>
   1309 
   1310 <p>Android device implementations that include a rear-facing camera and declare
   1311 <code>android.hardware.camera</code> SHOULD support the following VP8 video encoding profiles</p>
   1312 <table>
   1313   <thead>
   1314   <tr>
   1315     <th>&nbsp;</th>
   1316     <th>SD (Low quality)</th>
   1317     <th>SD (High quality)</th>
   1318     <th>HD 720p <br/> (When supported by hardware)</th>
   1319     <th>HD 1080p <br/>(When supported by hardware)</th>
   1320   </tr>
   1321   </thead>
   1322   <tbody>
   1323   <tr>
   1324     <th>Video resolution</th>
   1325     <td>320 x 180 px</td>
   1326     <td>640 x 360 px</td>
   1327     <td>1280 x 720 px</td>
   1328     <td>1920 x 1080 px</td>
   1329   </tr>
   1330   <tr>
   1331     <th>Video frame rate</th>
   1332     <td>30 fps</td>
   1333     <td>30 fps</td>
   1334     <td>30 fps</td>
   1335     <td>30 fps</td>
   1336   </tr>
   1337   <tr>
   1338     <th>Video bitrate</th>
   1339     <td>800 Kbps</td>
   1340     <td>2 Mbps</td>
   1341     <td>4 Mbps</td>
   1342     <td>10 Mbps</td>
   1343   </tr>
   1344   </tbody>
   1345 </table>
   1346 
   1347 <a name="section-5.3"></a><h3>5.3 Video Decoding</h3>
   1348 <p>Android device implementations SHOULD support the following VP8 and H.264 video decoding profiles.</p>
   1349 <table>
   1350   <thead>
   1351   <tr>
   1352     <th>&nbsp;</th>
   1353     <th>SD (Low quality)</th>
   1354     <th>SD (High quality)</th>
   1355     <th>HD 720p <br/> (When supported by hardware)</th>
   1356     <th>HD 1080p <br/>(When supported by hardware)</th>
   1357   </tr>
   1358   </thead>
   1359   <tbody>
   1360   <tr>
   1361     <th>Video resolution</th>
   1362     <td>320 x 180 px</td>
   1363     <td>640 x 360 px</td>
   1364     <td>1280 x 720 px</td>
   1365     <td>1920 x 1080 px</td>
   1366   </tr>
   1367   <tr>
   1368     <th>Video frame rate</th>
   1369     <td>30 fps</td>
   1370     <td>30 fps</td>
   1371     <td>30 fps</td>
   1372     <td>30 fps</td>
   1373   </tr>
   1374   <tr>
   1375     <th>Video bitrate</th>
   1376     <td>800 Kbps</td>
   1377     <td>2 Mbps</td>
   1378     <td>8 Mbps</td>
   1379     <td>20 Mbps</td>
   1380   </tr>
   1381   </tbody>
   1382 </table>
   1383 
   1384 <a name="section-5.4"></a><h3>5.4. Audio Recording</h3>
   1385 <p>When an application has used the <code>android.media.AudioRecord</code> API to
   1386 start recording an audio stream, device implementations that include microphone
   1387 hardware and declare <code>android.hardware.microphone</code> MUST sample and
   1388 record audio with each of these behaviors:</p>
   1389 <ul>
   1390 <li>The device SHOULD exhibit approximately flat amplitude versus frequency
   1391     characteristics; specifically, &plusmn;3 dB, from 100 Hz to 4000 Hz</li>
   1392 <li>Audio input sensitivity SHOULD be set such that a 90 dB sound power level
   1393     (SPL) source at 1000 Hz yields RMS of 2500 for 16-bit samples.</li>
   1394 <li>PCM amplitude levels SHOULD linearly track input SPL changes over at least
   1395     a 30 dB range from -18 dB to +12 dB re 90 dB SPL at the microphone.</li>
   1396 <li>Total harmonic distortion SHOULD be less than 1% for 1Khz at 90 dB SPL input level.</li>
   1397 </ul>
   1398 <p>In addition to the above recording specifications, when an application has
   1399 started recording an audio stream using the
   1400 <code>android.media.MediaRecorder.AudioSource.VOICE_RECOGNITION</code> audio
   1401 source:</p>
   1402 <ul>
   1403 <li>Noise reduction processing, if present, MUST be disabled.</li>
   1404 <li>Automatic gain control, if present, MUST be disabled.</li>
   1405 </ul>
   1406 <p><b>Note:</b> while some of the requirements outlined above are stated as "SHOULD"
   1407 for Android 4.3, the Compatibility Definition for a future version is planned
   1408 to change these to "MUST". That is, these requirements are optional in Android
   1409 4.3 but <b>will be required</b> by a future version. Existing and new devices
   1410 that run Android 4.3 are <b>very strongly encouraged to meet
   1411 these requirements in Android 4.3</b>, or they will not be able to attain
   1412 Android compatibility when upgraded to the future version.</p>
   1413 
   1414 <a name="section-5.5"></a><h3>5.5. Audio Latency</h3>
   1415 <p>Audio latency is the time delay as an audio signal passes through a system.
   1416 Many classes of
   1417 applications rely on short latencies, to achieve real-time sound effects.</p>
   1418 <p>For the purposes of this section:</p>
   1419 <ul>
   1420 <li>"output latency" is defined as the interval between when an application
   1421 writes a frame of PCM-coded data and when the corresponding sound can be heard
   1422 by an external listener or observed by a transducer</li>
   1423 <li>"cold output latency" is defined as the output latency for the first frame, when
   1424     the audio output system has been idle and powered down prior to the request</li>
   1425 <li>"continuous output latency" is defined as the output latency for subsequent frames,
   1426     after the device is already playing audio</li>
   1427 <li>"input latency" is the interval between when an external sound is presented
   1428 to the device and when an application reads the corresponding frame of PCM-coded data</li>
   1429 <li>"cold input latency" is defined as the sum of lost input time
   1430     and the input latency for the first frame, when
   1431     the audio input system has been idle and powered down prior to the request</li>
   1432 <li>"continuous input latency" is defined as the input latency for subsequent frames,
   1433     while the device is already capturing audio</li>
   1434 <li>"OpenSL ES PCM buffer queue API" is the set of PCM-related OpenSL ES APIs within Android NDK;
   1435 see <i>NDK_root</i><code>/docs/opensles/index.html</code></li>
   1436 </ul>
   1437 <p>Per <a href="#section-5">Section 5</a>,
   1438 all compatible device implementations MUST include at least one form of audio output.
   1439 Device implementations SHOULD meet or exceed these output latency requirements:</p>
   1440 <ul>
   1441 <li>cold output latency of 100 milliseconds or less</li>
   1442 <li>continuous output latency of 45 milliseconds or less</li>
   1443 </ul>
   1444 <p>If a device implementation meets the requirements of this section
   1445 after any initial calibration
   1446 when using the OpenSL ES PCM buffer queue API,
   1447 for continuous output latency and cold output latency
   1448 over at least one supported audio output device, it MAY
   1449 report support for low-latency audio, by reporting the feature
   1450 "android.hardware.audio.low-latency" via the
   1451 <code>android.content.pm.PackageManager</code> class. [<a
   1452 href="#resources37">Resources, 37</a>] Conversely, if the device
   1453 implementation does not meet these requirements it MUST NOT report support for
   1454 low-latency audio.</p>
   1455 <p>
   1456 Per <a href="#section-7.2.5">Section 7.2.5</a>,
   1457 microphone hardware may be omitted by device implementations.</p>
   1458 <p>
   1459 Device implementations that include microphone
   1460 hardware and declare <code>android.hardware.microphone</code> SHOULD
   1461 meet these input audio latency requirements:</p>
   1462 <ul>
   1463 <li>cold input latency of 100 milliseconds or less</li>
   1464 <li>continuous input latency of 50 milliseconds or less</li>
   1465 </ul>
   1466 
   1467 <a name="section-5.6"></a><h3>5.6. Network Protocols</h3>
   1468 <p>Devices MUST support the media network protocols for audio and video playback
   1469 as specified in the Android SDK documentation
   1470 [<a href="#resources58">Resources, 58</a>].  Specifically, devices MUST support
   1471 the following media network protocols:</p>
   1472 <ul>
   1473 <li>RTSP (RTP, SDP)</li>
   1474 <li>HTTP(S) progressive streaming</li>
   1475 <li>HTTP(S) Live Streaming draft protocol, Version 3 [<a href="#resources59">Resources, 59</a>]</li>
   1476 </ul>
   1477 <a name="section-6"></a><h2>6. Developer Tools and Options Compatibility</h2>
   1478 
   1479 <a name="section-6.1"></a><h3>6.1 Developer Tools</h3>
   1480 <p>Device implementations MUST support the Android Developer Tools provided in the Android SDK.
   1481 Specifically, Android-compatible devices MUST be compatible with:</p>
   1482 <ul>
   1483 <li><b>Android Debug Bridge (known as adb)</b> [<a href="#resources33">Resources, 33</a>]<br/>
   1484 Device implementations MUST support all <code>adb</code> functions as
   1485 documented in the Android SDK. The device-side <code>adb</code> daemon MUST
   1486 be inactive by default, and there MUST be a user-accessible mechanism to turn
   1487 on the Android Debug Bridge.</li>
   1488 <li>Android 4.3 includes support for secure adb. Secure adb enables adb on known authenticated hosts.
   1489 Device implementations MUST support secure adb.</li>
   1490 <li><b>Dalvik Debug Monitor Service (known as ddms)</b> [<a href="#resources33">Resources, 33</a>]<br/>
   1491 Device implementations MUST support all <code>ddms</code> features as documented in the
   1492 Android SDK. As <code>ddms</code> uses <code>adb</code>, support for
   1493 <code>ddms</code> SHOULD be inactive by default,
   1494 but MUST be supported whenever the user has activated the Android Debug
   1495 Bridge, as above.</li>
   1496 <li><b>Monkey</b> [<a href="#resources36">Resources, 36</a>]<br/>
   1497 Device implementations MUST include the Monkey framework, and make it
   1498 available for applications to use.</li>
   1499 <li><b>SysTrace</b> [<a href="#resources33">Resources, 33</a>]<br/>
   1500 Device implementations MUST support systrace tool as documented in the Android SDK.
   1501 Systrace must be inactive by default, and there MUST be a user-accessible mechanism to turn
   1502 on Systrace.</li>
   1503 </ul>
   1504 <p>Most Linux-based systems and Apple Macintosh systems recognize Android
   1505 devices using the standard Android SDK tools, without additional support;
   1506 however Microsoft Windows systems typically require a driver for new Android
   1507 devices. (For instance, new vendor IDs and sometimes new device IDs require
   1508 custom USB drivers for Windows systems.) If a device implementation is
   1509 unrecognized by the <code>adb</code> tool as provided in the standard Android
   1510 SDK, device implementers MUST provide Windows drivers allowing developers to
   1511 connect to the device using the <code>adb</code> protocol. These drivers MUST
   1512 be provided for Windows XP, Windows Vista, Windows 7, and Windows 8, in both 32-bit and
   1513 64-bit versions.</p>
   1514 
   1515 <a name="section-6.2"></a><h3>6.2 Developer Options</h3>
   1516 <p>Android 4.3 includes support for developers to configure application development-related settings.
   1517 Device implementations MUST honor the android.settings.APPLICATION_DEVELOPMENT_SETTINGS intent to show
   1518 application development-related settings [<a href="#resources77">Resources, 77</a>]. The upstream Android
   1519 implementation hides the Developer Options menu by default, and enables users to launch Developer Options
   1520 after pressing seven (7) times on the Settings > About Device > Build Number menu item. Device implementations
   1521 MUST provide a consistent experience for Developer Options. Specifically, device implementations MUST hide
   1522 Developer Options by default and MUST provide a mechanism to enable Developer Options that is consistent with
   1523 the upstream Android implementation.</p>
   1524 
   1525 <a name="section-7"></a><h2>7. Hardware Compatibility</h2>
   1526 <p>If a device includes a particular hardware component that has a
   1527 corresponding API for third-party developers, the device implementation MUST
   1528 implement that API as described in the Android SDK documentation. If an API in
   1529 the SDK interacts with a hardware component that is stated to be optional and
   1530 the device implementation does not possess that component:</p>
   1531 <ul>
   1532 <li>complete class definitions (as documented by the SDK) for the component's
   1533 APIs MUST still be present</li>
   1534 <li>the API's behaviors MUST be implemented as no-ops in some reasonable
   1535 fashion</li>
   1536 <li>API methods MUST return null values where permitted by the SDK
   1537 documentation</li>
   1538 <li>API methods MUST return no-op implementations of classes where null
   1539 values are not permitted by the SDK documentation</li>
   1540 <li>API methods MUST NOT throw exceptions not documented by the SDK
   1541 documentation</li>
   1542 </ul>
   1543 <p>A typical example of a scenario where these requirements apply is the
   1544 telephony API: even on non-phone devices, these APIs must be implemented as
   1545 reasonable no-ops.</p>
   1546 <p>Device implementations MUST accurately report accurate hardware configuration
   1547 information via the <code>getSystemAvailableFeatures()</code> and
   1548 <code>hasSystemFeature(String)</code> methods on the
   1549 <code>android.content.pm.PackageManager</code> class. [<a
   1550 href="#resources37">Resources, 37</a>]</p>
   1551 
   1552 <a name="section-7.1"></a><h3>7.1. Display and Graphics</h3>
   1553 <p>Android 4.3 includes facilities that automatically adjust application
   1554 assets and UI layouts appropriately for the device, to ensure that third-party
   1555 applications run well on a variety of hardware configurations [<a
   1556 href="#resources38">Resources, 38</a>]. Devices MUST properly implement these
   1557 APIs and behaviors, as detailed in this section.</p>
   1558 
   1559 <p>The units referenced by the requirements in this section are defined as follows:</p>
   1560 <ul>
   1561 <li>"Physical diagonal size" is the distance in inches between two opposing
   1562 corners of the illuminated portion of the display.</li>
   1563 <li>"dpi" (meaning "dots per inch") is the number of pixels encompassed by a
   1564 linear horizontal or vertical span of 1". Where dpi values are listed, both
   1565 horizontal and vertical dpi must fall within the range.</li>
   1566 <li>"Aspect ratio" is the ratio of the longer dimension of the screen to the
   1567 shorter dimension. For example, a display of 480x854 pixels would be 854 / 480
   1568 = 1.779, or roughly "16:9".</li>
   1569 <li>A "density-independent pixel" or ("dp") is the virtual pixel unit normalized to a
   1570 160 dpi screen, calculated as:
   1571 <code>pixels = dps * (density / 160)</code>.</li>
   1572 </ul>
   1573 
   1574 
   1575 <a name="section-7.1.1"></a><h4>7.1.1. Screen Configuration</h4>
   1576 
   1577 <p style="font-weight:bold;">Screen Size</p>
   1578 <p>The Android UI framework supports a variety of different screen sizes, and
   1579 allows applications to query the device screen size (aka "screen layout") via
   1580 <code>android.content.res.Configuration.screenLayout</code> with the
   1581 <code>SCREENLAYOUT_SIZE_MASK</code>. Device implementations MUST report the
   1582 correct screen size as defined in the Android SDK documentation
   1583 [<a href="#resources38">Resources, 38</a>] and determined by the upstream
   1584 Android platform. Specifically, device implementations must report the correct
   1585 screen size according to the following logical density-independent pixel (dp)
   1586 screen dimensions.</p>
   1587 <ul>
   1588 <li>Devices MUST have screen sizes of at least 426 dp x 320 dp ('small')</li>
   1589 <li>Devices that report screen size 'normal' MUST have screen sizes of at least
   1590 480 dp x 320 dp</li>
   1591 <li>Devices that report screen size 'large' MUST have screen sizes of at least
   1592 640 dp x 480 dp</li>
   1593 <li>Devices that report screen size 'xlarge' MUST have screen sizes of at least
   1594 960 dp x 720 dp</li>
   1595 </ul>
   1596 <p>In addition, devices MUST have screen sizes of at least 2.5 inches in
   1597 physical diagonal size.</p>
   1598 
   1599 <p>Devices MUST NOT change their reported screen size at any time.</p>
   1600 <p>Applications optionally indicate which screen sizes they support via the
   1601 <code>&lt;supports-screens&gt;</code> attribute in the AndroidManifest.xml
   1602 file. Device implementations MUST correctly honor applications' stated support
   1603 for small, normal, large, and xlarge screens, as described in the Android
   1604 SDK documentation.</p>
   1605 
   1606 <p style="font-weight:bold;">Screen Aspect Ratio</p>
   1607 <p>The aspect ratio MUST be between 1.3333 (4:3) and 1.85 (16:9).</p>
   1608 
   1609 <p style="font-weight:bold;">Screen Density</p>
   1610 <p>The Android UI framework defines a set of standard logical densities to
   1611 help application developers target application resources. Device
   1612 implementations MUST report one of the following logical Android framework
   1613 densities through the <code>android.util.DisplayMetrics</code> APIs, and MUST
   1614 execute applications at this standard density.
   1615 <ul>
   1616 <li>120 dpi, known as 'ldpi'</li>
   1617 <li>160 dpi, known as 'mdpi'</li>
   1618 <li>213 dpi, known as 'tvdpi'</li>
   1619 <li>240 dpi, known as 'hdpi'</li>
   1620 <li>320 dpi, known as 'xhdpi'</li>
   1621 <li>480 dpi, known as 'xxhdpi'</li>
   1622 <li>640 dpi, known as 'xxxhdpi'</li>
   1623 </ul>
   1624 Device implementations SHOULD define the standard Android framework density
   1625 that is numerically closest to the physical density of the screen, unless that
   1626 logical density pushes the reported screen size below the minimum supported.
   1627 If the standard Android framework density that is numerically closest to the
   1628 physical density results in a screen size that is smaller than the smallest
   1629 supported compatible screen size (320 dp width), device implementations SHOULD
   1630 report the next lowest standard Android framework density.</p>
   1631 
   1632 <a name="section-7.1.2"></a><h4>7.1.2. Display Metrics</h4>
   1633 <p>Device implementations MUST report correct values for all display metrics
   1634 defined in <code>android.util.DisplayMetrics</code> [<a
   1635 href="#resources39">Resources, 39</a>].</p>
   1636 
   1637 <a name="section-7.1.3"></a><h4>7.1.3. Screen Orientation</h4>
   1638 <p>Devices MUST support dynamic orientation by applications to
   1639 either portrait or landscape screen orientation. That is, the device must
   1640 respect the application's request for a specific screen orientation. Device
   1641 implementations MAY select either portrait or landscape orientation as the
   1642 default.</p>
   1643 <p>Devices MUST report the correct value for the device's current orientation,
   1644 whenever queried via the android.content.res.Configuration.orientation,
   1645 android.view.Display.getOrientation(), or other APIs.</p>
   1646 <p>Devices MUST NOT change the reported screen size or density when changing
   1647 orientation.</p>
   1648 <p>Devices MUST report which screen orientations they support (
   1649 <code>android.hardware.screen.portrait</code> and/or
   1650 <code>android.hardware.screen.landscape</code>) and MUST report at least one
   1651 supported orientation.  For example, a device with a fixed-orientation
   1652 landscape screen, such as a television or laptop, MUST only report
   1653 <code>android.hardware.screen.landscape</code>.</p>
   1654 
   1655 <a name="section-7.1.4"></a><h4>7.1.4. 2D and 3D Graphics Acceleration</h4>
   1656 <p>Device implementations MUST support both OpenGL ES 1.0 and 2.0, as embodied
   1657 and detailed in the Android SDK documentations. Device implementations SHOULD support
   1658 OpenGL ES 3.0 on devices capable of supporting OpenGL ES 3.0.
   1659 Device implementations MUST also support Android Renderscript, as detailed in the Android SDK
   1660 documentation [<a href="#resources08">Resources, 8</a>].</p>
   1661 <p>Device implementations MUST also correctly identify themselves as
   1662 supporting OpenGL ES 1.0, OpenGL ES 2.0, or OpenGL ES 3.0. That is:</p>
   1663 <ul>
   1664 <li>The managed APIs (such as via the <code>GLES10.getString()</code> method)
   1665 MUST report support for OpenGL ES 1.0 and OpenGL ES 2.0 </li>
   1666 <li>The native C/C++ OpenGL APIs (that is, those available to apps via
   1667 libGLES_v1CM.so, libGLES_v2.so, or libEGL.so) MUST report support for
   1668 OpenGL ES 1.0 and OpenGL ES 2.0.</li>
   1669 <li>Device implementations that declare support for OpenGL ES 3.0 MUST support
   1670 OpenGL ES 3.0 managed APIs and include support for native C/C++ APIs. On device
   1671 implementations that declare support for OpenGL ES 3.0, libGLESv2.so MUST export the OpenGL ES 3.0
   1672 function symbols in addition to the OpenGL ES 2.0 function symbols.
   1673 </li>
   1674 </ul>
   1675 
   1676 <p>Device implementations MAY implement any desired OpenGL ES extensions.
   1677 However, device implementations MUST report via the OpenGL ES managed and
   1678 native APIs all extension strings that they do support, and conversely MUST
   1679 NOT report extension strings that they do not support.</p>
   1680 <p>Note that Android 4.3 includes support for applications to optionally
   1681 specify that they require specific OpenGL texture compression formats. These
   1682 formats are typically vendor-specific. Device implementations are not required
   1683 by Android 4.3 to implement any specific texture compression format. However,
   1684 they SHOULD accurately report any texture compression formats that they do
   1685 support, via the <code>getString()</code> method in the OpenGL API.</p>
   1686 
   1687 <p>Android 4.3 includes a mechanism for applications to declare that they
   1688 wanted to enable hardware acceleration for 2D graphics at the Application,
   1689 Activity, Window or View level through the use of a manifest tag
   1690 <code>android:hardwareAccelerated</code> or direct API calls
   1691 [<a href="#resources09">Resources, 9</a>].</p>
   1692 <p>In Android 4.3, device implementations MUST enable hardware acceleration by
   1693 default, and MUST disable hardware acceleration if the developer so requests
   1694 by setting <code>android:hardwareAccelerated="false"</code> or disabling
   1695 hardware acceleration directly through the Android View APIs.</p>
   1696 <p>In addition, device implementations MUST exhibit behavior consistent with the
   1697 Android SDK documentation on hardware acceleration
   1698 [<a href="#resources09">Resources, 9</a>].</p>
   1699 <p>Android 4.3 includes a <code>TextureView</code> object that lets developers
   1700 directly integrate hardware-accelerated OpenGL ES textures as rendering targets
   1701 in a UI hierarchy. Device implementations MUST support the <code>TextureView
   1702 </code> API, and MUST exhibit consistent behavior with the upstream Android
   1703 implementation.</p>
   1704 <p>Android 4.3 includes support for <code>EGL_ANDROID_RECORDABLE</code>, a EGLConfig attribute
   1705 that indicates whether the EGLConfig supports rendering to an ANativeWindow that records images to a video.
   1706 Device implementations MUST support <code>EGL_ANDROID_RECORDABLE</code> extension [<a href="#resources79">Resources, 79</a>].</p>
   1707 
   1708 <a name="section-7.1.5"></a><h4>7.1.5. Legacy Application Compatibility Mode</h4>
   1709 <p>Android 4.3 specifies a "compatibility mode" in which the framework
   1710 operates in an 'normal' screen size equivalent (320dp width) mode for the benefit
   1711 of legacy applications not developed for old versions of Android that pre-date
   1712 screen-size independence. Device implementations MUST include support for legacy
   1713 application compatibility mode as implemented by the upstream Android open source
   1714 code. That is, device implementations MUST NOT alter the triggers or thresholds at
   1715 which compatibility mode is activated, and MUST NOT alter the behavior of the
   1716 compatibility mode itself.</p>
   1717 
   1718 <a name="section-7.1.6"></a><h4>7.1.6. Screen Types</h4>
   1719 <p>Device implementation screens are classified as one of two types:</p>
   1720 <ul>
   1721 <li>Fixed-pixel display implementations: the screen is a single panel that supports only a
   1722 single pixel width and height. Typically the screen is physically integrated with
   1723 the device. Examples include mobile phones, tablets, and so on.</li>
   1724 <li>Variable-pixel display implementations: the device implementation either has no
   1725 embedded screen and includes a video output port such as VGA, HDMI or a wireless port
   1726 for display, or has an embedded screen that can change pixel dimensions. Examples
   1727 include televisions, set-top boxes, and so on.</li>
   1728 </ul>
   1729 <p style="font-weight: bold;">Fixed-Pixel Device Implementations</p>
   1730 <p>Fixed-pixel device implementations MAY use screens of any pixel dimensions, provided
   1731 that they meet the requirements defined this Compatibility Definition.</p>
   1732 <p>Fixed-pixel implementations MAY include a video output port for use with an
   1733 external display. However, if that display is ever used for running apps, the
   1734 device MUST meet the following requirements:</p>
   1735 <ul>
   1736 <li>The device MUST report the same screen configuration and display metrics, as detailed
   1737 in Sections 7.1.1 and 7.1.2, as the fixed-pixel display.</li>
   1738 <li>The device MUST report the same logical density as the fixed-pixel display.</li>
   1739 <li>The device MUST report screen dimensions that are the same as, or very close to,
   1740 the fixed-pixel display.</li>
   1741 </ul>
   1742 <p>For example, a tablet that is 7" diagonal size with a 1024x600 pixel resolution is
   1743 considered a fixed-pixel large mdpi display implementation.  If it contains a video
   1744 output port that displays at 720p or 1080p, the device implementation MUST scale the output so that
   1745 applications are only executed in a large mdpi window, regardless of whether the fixed-pixel display
   1746 or video output port is in use.</p>
   1747 
   1748 <p style="font-weight: bold;">Variable-Pixel Device Implementations</p>
   1749 <p>Variable-pixel device implementations MUST support one or both of 1280x720,
   1750 or 1920x1080 (that is, 720p or 1080p). Device implementations with
   1751 variable-pixel displays MUST NOT support any other screen configuration or
   1752 mode. Device implementations with variable-pixel screens MAY change screen
   1753 configuration or mode at runtime or boot-time. For example, a user of a
   1754 set-top box may replace a 720p display with a 1080p display, and the device
   1755 implementation may adjust accordingly.</p>
   1756 
   1757 <p>Additionally, variable-pixel device implementations MUST report the following
   1758 configuration buckets for these pixel dimensions:</p>
   1759 <ul>
   1760 <li>1280x720 (also known as 720p): 'large' screen size, 'tvdpi' (213 dpi)
   1761 density</li>
   1762 <li>1920x1080 (also known as 1080p): 'large' screen size, 'xhdpi' (320 dpi)
   1763 density</li>
   1764 </ul>
   1765 <p>For clarity, device implementations with variable pixel dimensions are
   1766 restricted to 720p or 1080p in Android 4.3, and MUST be configured to report
   1767 screen size and density buckets as noted above.</p>
   1768 
   1769 <a name="section-7.1.7"></a><h4>7.1.7. Screen Technology</h4>
   1770 <p>The Android platform includes APIs that allow applications to render rich
   1771 graphics to the display. Devices MUST support all of these APIs as defined by
   1772 the Android SDK unless specifically allowed in this document.  Specifically:</p>
   1773 <ul>
   1774 <li>Devices MUST support displays capable of rendering 16-bit color graphics and
   1775 SHOULD support displays capable of 24-bit color graphics.</li>
   1776 <li>Devices MUST support displays capable of rendering animations.</li>
   1777 <li>The display technology used MUST have a pixel aspect ratio (PAR) between
   1778     0.9 and 1.1. That is, the pixel aspect ratio MUST be near square (1.0) with
   1779     a 10% tolerance.</li>
   1780 </ul>
   1781 <a name="section-7.1.8"></a><h4>7.1.8. External Displays</h4>
   1782 <p>Android 4.3 includes support for secondary display to enable media sharing capabilities and
   1783 developer APIs for accessing external displays. If a device supports an external display either via
   1784 a wired, wireless or an embedded additional display connection then the device implementation MUST
   1785 implement the display manager API as described in the Android SDK documentation [<a href="#resources75">Resources, 75</a>].
   1786 Device implementations that support secure video output and are capable of supporting secure surfaces MUST declare support
   1787 for <code>Display.FLAG_SECURE</code>. Specifically, device implementations that declare support for <code>Display.FLAG_SECURE</code>,
   1788 MUST support <b>HDCP 2.x or higher</b> for Miracast wireless displays or <b>HDCP 1.2 or higher</b> for wired displays. The upstream
   1789 Android open source implementation includes support for wireless (Miracast) and wired (HDMI) displays that satisfies this requirement.</p>
   1790 
   1791 <a name="section-7.2"></a><h3>7.2. Input Devices</h3>
   1792 <a name="section-7.2.1"></a><h4>7.2.1. Keyboard</h4>
   1793 <p>Device implementations:</p>
   1794 <ul>
   1795 <li>MUST include support for the Input Management Framework (which allows third
   1796 party developers to create Input Management Engines - i.e. soft keyboard) as
   1797 detailed at <a href="http://developer.android.com">http://developer.android.com</a>
   1798 </li>
   1799 <li>MUST provide at least one soft keyboard implementation (regardless of whether
   1800 a hard keyboard is present)</li>
   1801 <li>MAY include additional soft keyboard implementations</li>
   1802 <li>MAY include a hardware keyboard</li>
   1803 <li>MUST NOT include a hardware keyboard that does not match one of the
   1804 formats specified in <code>android.content.res.Configuration.keyboard</code>
   1805 [<a href="#resources40">Resources, 40</a>] (that is, QWERTY, or 12-key)</li>
   1806 </ul>
   1807 <a name="section-7.2.2"></a><h4>7.2.2. Non-touch Navigation</h4>
   1808 <p>Device implementations:</p>
   1809 <ul>
   1810 <li>MAY omit a non-touch navigation option (that is, may omit a trackball, d-pad,
   1811 or wheel)</li>
   1812 <li>MUST report the correct value for
   1813 <code>android.content.res.Configuration.navigation</code>
   1814 [<a href="#resources40">Resources, 40</a>]</li>
   1815 <li>MUST provide a reasonable alternative user interface mechanism for the
   1816 selection and editing of text, compatible with Input Management Engines. The
   1817 upstream Android open source implementation includes a selection mechanism suitable
   1818 for use with devices that lack non-touch navigation inputs.</li>
   1819 </ul>
   1820 <a name="section-7.2.3"></a><h4>7.2.3. Navigation keys</h4>
   1821 <p>The Home, Menu and Back functions are essential to the Android navigation
   1822 paradigm. Device implementations MUST make these functions available to the
   1823 user at all times when running applications. These functions MAY be implemented
   1824 via dedicated physical buttons (such as mechanical or capacitive touch buttons),
   1825 or MAY be implemented using dedicated software keys, gestures, touch panel, etc.
   1826 Android 4.3 supports both implementations.</p>
   1827 
   1828 <p>Android 4.3 includes support for assist action [<a href="#resources63">Resources, 63</a>].
   1829 Device implementations MUST make the assist action available to the user at all times when running applications.
   1830 This function MAY be implemented via hardware or software keys.</p>
   1831 
   1832 <p>Device implementations MAY use a distinct portion of the screen to display
   1833 the navigation keys, but if so, MUST meet these requirements:</p>
   1834 
   1835 <ul>
   1836   <li>Device implementation navigation keys MUST use a distinct portion of the
   1837       screen, not available to applications, and MUST NOT obscure or otherwise
   1838       interfere with the portion of the screen available to applications.</li>
   1839   <li>Device implementations MUST make available a portion of the display to
   1840       applications that meets the requirements defined in
   1841       <a href="section-7.1.1">Section 7.1.1</a>.</li>
   1842   <li>Device implementations MUST display the navigation keys when applications
   1843       do not specify a system UI mode, or specify
   1844       <code>SYSTEM_UI_FLAG_VISIBLE</code>.</li>
   1845   <li>Device implementations MUST present the navigation keys in an unobtrusive
   1846       "low profile" (eg. dimmed) mode when applications specify
   1847       <code>SYSTEM_UI_FLAG_LOW_PROFILE</code>.</li>
   1848   <li>Device implementations MUST hide the navigation keys when applications
   1849       specify <code>SYSTEM_UI_FLAG_HIDE_NAVIGATION</code>.</li>
   1850   <li>Device implementation MUST present a Menu key to applications when
   1851       targetSdkVersion &lt;= 10 and SHOULD NOT present a Menu key when the
   1852       targetSdkVersion &gt; 10.</li>
   1853 </ul>
   1854 <a name="section-7.2.4"></a><h4>7.2.4. Touchscreen input</h4>
   1855 <p>Device implementations SHOULD have a pointer input system of some kind (either mouse-like, or touch). However, if a device
   1856 implementation does not support a pointer input system, it MUST NOT report the <code>android.hardware.touchscreen</code> or
   1857 <code>android.hardware.faketouch</code> feature constant. Device implementations that do include a pointer input system:</p>
   1858 <ul>
   1859 <li>SHOULD support fully independently tracked pointers, if the device input system supports multiple pointers</li>
   1860 <li>MUST report the value of <code>android.content.res.Configuration.touchscreen</code> [<a href="#resources40">Resources, 40</a>]
   1861 corresponding to the type of the specific touchscreen on the device</li>
   1862 </ul>
   1863 
   1864 <p>Android 4.3 includes support for a variety of touch screens, touch pads, and fake touch input devices.
   1865 Touch screen based device implementations are associated with a display [<a href="#resources81">Resources, 81</a>]
   1866 such that the user has the impression of directly manipulating items on screen. Since the user is directly touching the screen,
   1867 the system does not require any additional affordances to indicate the objects being manipulated.
   1868 In contrast, a fake touch interface provides a user input system that approximates a subset of touchscreen capabilities.
   1869 For example, a mouse or remote control that drives an on-screen cursor approximates touch, but requires the user to first
   1870 point or focus then click. Numerous input devices like the mouse, trackpad, gyro-based air mouse, gyro-pointer, joystick,
   1871 and multi-touch trackpad can support fake touch interactions. Android 4.0 includes the feature constant <code>android.hardware.faketouch</code>,
   1872 which corresponds to a high-fidelity non-touch (that is, pointer-based) input device such as a mouse or trackpad that can adequately emulate touch-based
   1873 input (including basic gesture support), and indicates that the device supports an emulated subset of touchscreen
   1874 functionality. Device implementations that declare the fake touch feature MUST meet the fake touch requirements in <a href="section 7.2.5">Section 7.2.5</a>.</p>
   1875 
   1876 <p>Device implementations MUST report the correct feature corresponding to the type of input used. Device implementations that
   1877 include a touchscreen (single-touch or better) MUST report the platform feature constant <code>android.hardware.touchscreen</code>.
   1878 Device implementations that report the platform feature constant <code>android.hardware.touchscreen</code> MUST also report the platform feature constant
   1879 <code>android.hardware.faketouch</code>. Device implementations that do not include a touchscreen (and rely on a pointer device only) MUST NOT report any
   1880 touchscreen feature, and MUST report only <code>android.hardware.faketouch</code> if they meet the fake touch requirements in <a href="section 7.2.5">Section 7.2.5</a>.</p>
   1881 
   1882 <a name="section-7.2.5"></a><h4>7.2.5. Fake touch input</h4>
   1883 <p>Device implementations that declare support for <code>android.hardware.faketouch</code></p>
   1884 <ul>
   1885 <li> MUST report the absolute X and Y screen positions of the pointer location and display a visual pointer on the screen [<a href="#resources80">Resources, 80</a>] </li>
   1886 <li> MUST report touch event with the action code [<a href="#resources80">Resources, 80</a>] that specifies the state change
   1887 that occurs on the pointer going <code>down</code> or <code>up</code> on the screen [<a href="#resources80">Resources, 80</a>] </li>
   1888 <li> MUST support pointer <code>down</code> and <code>up</code> on an object on the screen, which allows users to emulate tap on an object on the screen</li>
   1889 <li> MUST support pointer <code>down</code>, pointer <code>up</code>, pointer <code>down</code> then pointer <code>up</code> in the same place on an object on the screen
   1890 within a time threshold, which allows users to emulate double tap on an object on the screen [<a href="#resources80">Resources, 80</a>]</li>
   1891 <li>MUST support pointer <code>down</code> on an arbitrary point on the screen, pointer move to any other arbitrary point on the screen,
   1892 followed by a pointer <code>up</code>, which allows users to emulate a touch drag</li>
   1893 <li> MUST support pointer <code>down</code> then allow users to quickly move the object to a different position on the screen
   1894 and then pointer <code>up</code> on the screen, which allows users to fling an object on the screen</li>
   1895 </ul>
   1896 
   1897 <p>Devices that declare support for <code>android.hardware.faketouch.multitouch.distinct</code> MUST meet the requirements for
   1898 faketouch above, and MUST also support distinct tracking of two or more independent pointer inputs.</p>
   1899 
   1900 <a name="section-7.2.6"></a><h4>7.2.6. Microphone</h4>
   1901 <p>Device implementations MAY omit a microphone. However, if a device
   1902 implementation omits a microphone, it MUST NOT report the
   1903 <code>android.hardware.microphone</code> feature constant, and must implement
   1904 the audio recording API as no-ops, per <a href="section-7">Section 7</a>.
   1905 Conversely, device implementations that do possess a microphone:</p>
   1906 <ul>
   1907 <li>MUST report the <code>android.hardware.microphone</code> feature constant</li>
   1908 <li>SHOULD meet the audio quality requirements in <a href="section-5.4">Section 5.4</a></li>
   1909 <li>SHOULD meet the audio latency requirements in <a href="section-5.5">Section 5.5</a></li>
   1910 </ul>
   1911 
   1912 <a name="section-7.3"></a><h3>7.3. Sensors</h3>
   1913 <p>Android 4.3 includes APIs for accessing a variety of sensor types. Devices
   1914 implementations generally MAY omit these sensors, as provided for in the
   1915 following subsections. If a device includes a particular sensor type that has a
   1916 corresponding API for third-party developers, the device implementation MUST
   1917 implement that API as described in the Android SDK documentation. For example,
   1918 device implementations:</p>
   1919 <ul>
   1920 <li>MUST accurately report the presence or absence of sensors per the
   1921 <code>android.content.pm.PackageManager</code> class. [<a
   1922 href="#resources37">Resources, 37</a>]</li>
   1923 <li>MUST return an accurate list of supported sensors via the
   1924 <code>SensorManager.getSensorList()</code> and similar methods</li>
   1925 <li>MUST behave reasonably for all other sensor APIs (for example, by
   1926 returning true or false as appropriate when applications attempt to register
   1927 listeners, not calling sensor listeners when the corresponding sensors are not
   1928 present; etc.)</li>
   1929 <li>MUST report all sensor measurements using the relevant International System
   1930 of Units (i.e. metric) values for each sensor type as defined in the Android SDK
   1931 documentation [<a href="#resources41">Resources, 41</a>]</li>
   1932 </ul>
   1933 <p>The list above is not comprehensive; the documented behavior of the Android
   1934 SDK is to be considered authoritative.</p>
   1935 <p>Some sensor types are synthetic, meaning they can be derived from data
   1936 provided by one or more other sensors. (Examples include the orientation
   1937 sensor, and the linear acceleration sensor.) Device implementations SHOULD
   1938 implement these sensor types, when they include the prerequisite physical
   1939 sensors.</p>
   1940 <p>The Android 4.3 includes a notion of a "streaming" sensor, which is
   1941 one that returns data continuously, rather than only when the data changes.
   1942 Device implementations MUST continuously provide periodic data samples for any
   1943 API indicated by the Android 4.3 SDK documentation to be a streaming
   1944 sensor. Note that the device implementations MUST ensure that the sensor stream must not
   1945 prevent the device CPU from entering a suspend state or waking up from a suspend state.</p>
   1946 
   1947 <a name="section-7.3.1"></a><h4>7.3.1. Accelerometer</h4>
   1948 <p>Device implementations SHOULD include a 3-axis accelerometer. If a device
   1949 implementation does include a 3-axis accelerometer, it:</p>
   1950 <ul>
   1951 <li>SHOULD be able to deliver events at 120 Hz or greater. Note that while the
   1952 accelerometer frequency above is stated as "SHOULD" for Android 4.3, the Compatibility Definition
   1953 for a future version is planned to change these to "MUST". That is, these standards are
   1954 optional in Android 4.3 but <b>will be required</b> in future versions. Existing and
   1955 new devices that run Android 4.3 are <b>very strongly encouraged to meet these requirements
   1956 in Android 4.3</b> so they will be able to upgrade to the future platform releases
   1957 </li>
   1958 <li>MUST comply with the Android sensor coordinate system as detailed
   1959 in the Android APIs (see [<a href="#resources41">Resources, 41</a>])</li>
   1960 <li>MUST be capable of measuring from freefall up to twice gravity (2g) or
   1961 more on any three-dimensional vector</li>
   1962 <li>MUST have 8-bits of accuracy or more</li>
   1963 <li>MUST have a standard deviation no greater than 0.05 m/s^2</li>
   1964 </ul>
   1965 <a name="section-7.3.2"></a><h4>7.3.2. Magnetometer</h4>
   1966 <p>Device implementations SHOULD include a 3-axis magnetometer (i.e. compass.)
   1967 If a device does include a 3-axis magnetometer, it:</p>
   1968 <ul>
   1969 <li>MUST be able to deliver events at 10 Hz or greater</li>
   1970 <li>MUST comply with the Android sensor coordinate system as detailed
   1971 in the Android APIs (see [<a href="#resources41">Resources, 41</a>]).</li>
   1972 <li>MUST be capable of sampling a range of field strengths adequate to cover the
   1973 geomagnetic field</li>
   1974 <li>MUST have 8-bits of accuracy or more</li>
   1975 <li>MUST have a standard deviation no greater than 0.5 &micro;T</li>
   1976 </ul>
   1977 <a name="section-7.3.3"></a><h4>7.3.3. GPS</h4>
   1978 <p>Device implementations SHOULD include a GPS receiver. If a device
   1979 implementation does include a GPS receiver, it SHOULD include
   1980 some form of "assisted GPS" technique to minimize GPS lock-on time.</p>
   1981 <a name="section-7.3.4"></a><h4>7.3.4. Gyroscope</h4>
   1982 <p>Device implementations SHOULD include a gyroscope (i.e. angular change
   1983 sensor.) Devices SHOULD NOT include a gyroscope sensor unless a 3-axis
   1984 accelerometer is also included. If a device implementation includes a
   1985 gyroscope, it:</p>
   1986 <ul>
   1987 <li>MUST be temperature compensated</li>
   1988 <li>MUST be capable of measuring orientation changes up to 5.5*Pi
   1989 radians/second (that is, approximately 1,000 degrees per second)</li>
   1990 <li>SHOULD be able to deliver events at 200 Hz or greater. Note that while the
   1991 gyroscope frequency above is stated as "SHOULD" for Android 4.3, the Compatibility Definition
   1992 for a future version is planned to change these to "MUST". That is, these standards are
   1993 optional in Android 4.3 but <b>will be required</b> in future versions. Existing and
   1994 new devices that run Android 4.3 are <b>very strongly encouraged to meet these requirements
   1995 in Android 4.3</b> so they will be able to upgrade to the future platform releases
   1996 </li>
   1997 <li>MUST have 12-bits of accuracy or more</li>
   1998 <li>MUST have a variance no greater than 1e-7 rad^2 / s^2 per Hz (variance per Hz, or rad^2 / s).
   1999 The variance is allowed to vary with the sampling rate, but must be constrained by this value.
   2000 In other words, if you measure the variance of the gyro at 1 Hz sampling rate it should be no
   2001 greater than 1e-7 rad^2/s^2. </li>
   2002 <li>MUST have timestamps as close to when the hardware event happened as possible. The constant latency must be removed.</li>
   2003 </ul>
   2004 <a name="section-7.3.5"></a><h4>7.3.5. Barometer</h4>
   2005 <p>Device implementations MAY include a barometer (i.e. ambient air pressure
   2006 sensor.) If a device implementation includes a barometer, it:</p>
   2007 <ul>
   2008 <li>MUST be able to deliver events at 5 Hz or greater</li>
   2009 <li>MUST have adequate precision to enable estimating altitude</li>
   2010 <li>MUST be temperature compensated</li>
   2011 </ul>
   2012 <a name="section-7.3.6"></a><h4>7.3.6. Thermometer</h4>
   2013 <p>Device implementations MAY but SHOULD NOT include a thermometer (i.e.
   2014 temperature sensor.) If a device implementation does include a thermometer, it
   2015 MUST measure the temperature of the device CPU. It MUST NOT measure any other
   2016 temperature. (Note that this sensor type is deprecated in the Android 4.3
   2017 APIs.)</p>
   2018 <a name="section-7.3.7"></a><h4>7.3.7. Photometer</h4>
   2019 <p>Device implementations MAY include a photometer (i.e. ambient light
   2020 sensor.)</p>
   2021 <a name="section-7.3.8"></a><h4>7.3.8. Proximity Sensor</h4>
   2022 <p>Device implementations MAY include a proximity sensor.  If a device
   2023 implementation does include a proximity sensor, it MUST measure the proximity
   2024 of an object in the same direction as the screen. That is, the proximity
   2025 sensor MUST be oriented to detect objects close to the screen, as the
   2026 primary intent of this sensor type is to detect a phone in use by the
   2027 user. If a device implementation includes a proximity sensor with any other
   2028 orientation, it MUST NOT be accessible through this API. If a device
   2029 implementation has a proximity sensor, it MUST be have 1-bit of accuracy or
   2030 more.</p>
   2031 
   2032 <a name="section-7.4"></a><h3>7.4. Data Connectivity</h3>
   2033 <a name="section-7.4.1"></a><h4>7.4.1. Telephony</h4>
   2034 <p>"Telephony" as used by the Android 4.3 APIs and this document refers
   2035 specifically to hardware related to placing voice calls and sending SMS
   2036 messages via a GSM or CDMA network. While these voice calls may or may not be
   2037 packet-switched, they are for the purposes of Android 4.3 considered
   2038 independent of any data connectivity that may be implemented using the same
   2039 network. In other words, the Android "telephony" functionality and APIs refer
   2040 specifically to voice calls and SMS; for instance, device implementations that
   2041 cannot place calls or send/receive SMS messages MUST NOT report the
   2042 "android.hardware.telephony" feature or any sub-features, regardless of
   2043 whether they use a cellular network for data connectivity.</p>
   2044 <p>Android 4.3 MAY be used on devices that do not include telephony hardware.
   2045 That is, Android 4.3 is compatible with devices that are not phones.
   2046 However, if a device implementation does include GSM or CDMA telephony, it
   2047 MUST implement full support for the API for that technology. Device
   2048 implementations that do not include telephony hardware MUST implement the full
   2049 APIs as no-ops.</p>
   2050 <a name="section-7.4.2"></a><h4>7.4.2. IEEE 802.11 (WiFi)</h4>
   2051 <p>Android 4.3 device implementations SHOULD include support for one or more
   2052 forms of 802.11 (b/g/a/n, etc.) If a device implementation does include
   2053 support for 802.11, it MUST implement the corresponding Android API.</p>
   2054 <p>Device implementations MUST implement the multicast API as described in
   2055 the SDK documentation [<a href="#resources62">Resources, 62</a>]. Device
   2056 implementations that do include Wifi support MUST support multicast DNS (mDNS).
   2057 Device implementations MUST NOT filter mDNS packets (224.0.0.251) at any time
   2058 of operation including when the screen is not in an active state.</p>
   2059 
   2060 <a name="section-7.4.2.1"></a><h4>7.4.2.1. WiFi Direct</h4>
   2061 <p>Device implementations SHOULD include support for Wifi direct (Wifi peer-to-peer).
   2062 If a device implementation does include support for Wifi direct, it MUST implement the corresponding 
   2063 Android API as described in the SDK documentation [<a href="#resources68">Resources, 68</a>].
   2064 If a device implementation includes support for Wifi direct, then it:</p>
   2065 <ul>
   2066   <li>MUST support regular Wifi operation</li>
   2067   <li>SHOULD support concurrent wifi and wifi Direct operation</li>
   2068 </ul>
   2069 
   2070 <a name="section-7.4.3"></a><h4>7.4.3. Bluetooth</h4>
   2071 <p>Device implementations SHOULD include a Bluetooth transceiver. Device
   2072 implementations that do include a Bluetooth transceiver MUST enable the
   2073 RFCOMM-based Bluetooth API as described in the SDK documentation and declare
   2074 hardware feature android.hardware.bluetooth [<a href="#resources42">Resources, 42</a>].
   2075 Device implementations SHOULD implement relevant Bluetooth profiles, such as A2DP, AVRCP, OBEX, etc. as
   2076 appropriate for the device.</p>
   2077 
   2078 <p>Device implementations that do include support for Bluetooth GATT (generic attribute profile)
   2079 to enable communication with Bluetooth Smart or Smart Ready devices MUST enable the
   2080 GATT-based Bluetooth API as described in the SDK documentation and declare hardware feature
   2081 android.hardware.bluetooth_le [<a href="#resources42">Resources, 42</a>].</p>
   2082 
   2083 <a name="section-7.4.4"></a><h4>7.4.4. Near-Field Communications</h4>
   2084 <p>Device implementations SHOULD include a transceiver and related hardware
   2085 for Near-Field Communications (NFC). If a device implementation does include
   2086 NFC hardware, then it:</p>
   2087 <ul>
   2088   <li>MUST report the android.hardware.nfc feature from the
   2089       <code>android.content.pm.PackageManager.hasSystemFeature()</code> method.
   2090       [<a href="#resources37">Resources, 37</a>]</li>
   2091   <li>MUST be capable of reading and writing NDEF messages via the following NFC
   2092       standards:
   2093    <ul>
   2094     <li>MUST be capable of acting as an NFC Forum reader/writer
   2095         (as defined by the NFC Forum technical specification
   2096         NFCForum-TS-DigitalProtocol-1.0) via the following NFC standards:
   2097      <ul>
   2098       <li>NfcA (ISO14443-3A)</li>
   2099       <li>NfcB (ISO14443-3B) </li>
   2100       <li>NfcF (JIS 6319-4)</li>
   2101       <li>IsoDep (ISO 14443-4)</li>
   2102       <li>NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)</li>
   2103      </ul>
   2104     </li>
   2105    </ul>
   2106   </li>
   2107   <li>SHOULD be capable of reading and writing NDEF messages via the following
   2108       NFC standards. Note that while the NFC standards below are stated as
   2109       "SHOULD" for Android 4.3, the Compatibility Definition for a future
   2110       version is planned to change these to "MUST". That is, these standards are
   2111       optional in Android 4.3 but <b>will be required</b> in future versions.
   2112       Existing and new devices that run Android 4.3 are <b>very strongly
   2113       encouraged to meet these requirements in Android 4.3</b> so they will be
   2114       able to upgrade to the future platform releases.
   2115     <ul>
   2116       <li>NfcV (ISO 15693)</li>
   2117     </ul>
   2118   </li>
   2119   <li>MUST be capable of transmitting and receiving data via the following
   2120       peer-to-peer standards and protocols:
   2121     <ul>
   2122       <li>ISO 18092</li>
   2123       <li>LLCP 1.0 (defined by the NFC Forum)</li>
   2124       <li>SDP 1.0 (defined by the NFC Forum)</li>
   2125       <li>NDEF Push Protocol [<a href="#resources43">Resources, 43</a>]</li>
   2126       <li>SNEP 1.0 (defined by the NFC Forum)</li>
   2127     </ul>
   2128   </li>
   2129   <li>MUST include support for Android Beam [<a href="#resources65">Resources, 65</a>]:
   2130    <ul>
   2131     <li>MUST implement the SNEP default server. Valid NDEF messages received
   2132         by the default SNEP server MUST be dispatched to applications using
   2133         the android.nfc.ACTION_NDEF_DISCOVERED intent. Disabling Android Beam
   2134         in settings MUST NOT disable dispatch of incoming NDEF message.</li>
   2135     <li>Device implementations MUST honor the android.settings.NFCSHARING_SETTINGS intent
   2136         to show NFC sharing settings [<a href="#resources67">Resources, 67</a>].</li>
   2137     <li>MUST implement the NPP server. Messages received by the NPP server MUST
   2138         be processed the same way as the SNEP default server.</li>
   2139     <li>MUST implement a SNEP client and attempt to send outbound P2P NDEF to
   2140         the default SNEP server when Android Beam is enabled. If no default
   2141         SNEP server is found then the client MUST attempt to send to an NPP
   2142         server.</li>
   2143     <li>MUST allow foreground activities to set the outbound P2P NDEF message
   2144         using android.nfc.NfcAdapter.setNdefPushMessage, and
   2145         android.nfc.NfcAdapter.setNdefPushMessageCallback, and
   2146         android.nfc.NfcAdapter.enableForegroundNdefPush.</li>
   2147     <li>SHOULD use a gesture or on-screen confirmation, such as 'Touch to Beam',
   2148         before sending outbound P2P NDEF messages.</li>
   2149     <li>SHOULD enable Android Beam by default</li>
   2150     <li>MUST support NFC Connection handover to Bluetooth when the device supports Bluetooth Object Push Profile.
   2151         Device implementations must support connection handover to Bluetooth when using android.nfc.NfcAdapter.setBeamPushUris,
   2152         by implementing the "Connection Handover version 1.2" [<a href="#resources60">Resources, 60</a>]
   2153         and "Bluetooth Secure Simple Pairing Using NFC version 1.0" [<a href="#resources61">Resources, 61</a>]
   2154         specs from the NFC Forum. Such an implementation SHOULD use SNEP GET
   2155         requests for exchanging the handover request / select records over NFC, and it MUST
   2156         use the Bluetooth Object Push Profile for the actual Bluetooth data transfer.</li>
   2157    </ul>
   2158   </li>
   2159   <li>MUST poll for all supported technologies while in NFC discovery mode.</li>
   2160   <li>SHOULD be in NFC discovery mode while the device is awake with the screen active
   2161       and the lock-screen unlocked.</li>
   2162 </ul>
   2163 
   2164 <p>(Note that publicly available links are not available for the JIS, ISO, and
   2165 NFC Forum specifications cited above.)</p>
   2166 <p>Additionally, device implementations MAY include reader/writer support for
   2167 the following MIFARE technologies.</p>
   2168 <ul>
   2169   <li>MIFARE Classic (NXP MF1S503x [<a href="#resources44">Resources, 44</a>],
   2170       MF1S703x [<a href="#resources45">Resources, 45</a>])</li>
   2171   <li>MIFARE Ultralight (NXP MF0ICU1 [<a href="#resources46">Resources, 46</a>],
   2172       MF0ICU2 [<a href="#resources47">Resources, 47</a>])</li>
   2173   <li>NDEF on MIFARE Classic (NXP AN130511 [<a href="#resources48">Resources, 48</a>],
   2174       AN130411 [<a href="#resources49">Resources, 49</a>])</li>
   2175 </ul>
   2176 <p>Note that Android 4.3 includes APIs for these MIFARE types. If a
   2177 device implementation supports MIFARE in the reader/writer role, it:</p>
   2178 <ul>
   2179   <li>MUST implement the corresponding Android APIs as documented by the
   2180   Android SDK</li>
   2181   <li>MUST report the feature com.nxp.mifare from the
   2182   <code>android.content.pm.PackageManager.hasSystemFeature()</code> method.
   2183   [<a href="#resources37">Resources, 37</a>] Note that this is not a standard
   2184   Android feature, and as such does not appear as a constant on the
   2185   <code>PackageManager</code> class.</li>
   2186   <li>MUST NOT implement the corresponding Android APIs nor report the
   2187   com.nxp.mifare feature unless it also implements general NFC support as
   2188   described in this section</li>
   2189 </ul>
   2190 <p>If a device implementation does not include NFC hardware, it MUST NOT
   2191 declare the android.hardware.nfc feature from the
   2192 <code>android.content.pm.PackageManager.hasSystemFeature()</code> method [<a
   2193 href="#resources37">Resources, 37</a>], and MUST implement the Android 4.3 NFC
   2194 API as a no-op.</p>
   2195 <p>As the classes <code>android.nfc.NdefMessage</code> and
   2196 <code>android.nfc.NdefRecord</code> represent a protocol-independent data
   2197 representation format, device implementations MUST implement these APIs even
   2198 if they do not include support for NFC or declare the android.hardware.nfc
   2199 feature.</p>
   2200 <a name="section-7.4.5"></a><h4>7.4.5. Minimum Network Capability</h4>
   2201 <p>Device implementations MUST include support for one or more forms of data
   2202 networking. Specifically, device implementations MUST include support for at
   2203 least one data standard capable of 200Kbit/sec or greater. Examples of
   2204 technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g,
   2205 Ethernet, etc.</p>
   2206 <p>Device implementations where a physical networking standard (such as
   2207 Ethernet) is the primary data connection SHOULD also include support for at
   2208 least one common wireless data standard, such as 802.11 (WiFi).</p>
   2209 <p>Devices MAY implement more than one form of data connectivity.</p>
   2210 
   2211 
   2212 <a name="section-7.5"></a><h3>7.5. Cameras</h3>
   2213 <p>Device implementations SHOULD include a rear-facing camera, and MAY include
   2214 a front-facing camera. A rear-facing camera is a camera located on the side of
   2215 the device opposite the display; that is, it images scenes on the far side of
   2216 the device, like a traditional camera. A front-facing camera is a camera
   2217 located on the same side of the device as the display; that is, a camera
   2218 typically used to image the user, such as for video conferencing and similar
   2219 applications.</p>
   2220 <a name="section-7.5.1"></a><h4>7.5.1. Rear-Facing Camera</h4>
   2221 <p>Device implementations SHOULD include a rear-facing camera. If a device
   2222 implementation includes a rear-facing camera, it:</p>
   2223 <ul>
   2224 <li>MUST have a resolution of at least 2 megapixels</li>
   2225 <li>SHOULD have either hardware auto-focus, or software auto-focus implemented
   2226 in the camera driver (transparent to application software)</li>
   2227 <li>MAY have fixed-focus or EDOF (extended depth of field) hardware</li>
   2228 <li>MAY include a flash. If the Camera includes a flash, the flash lamp MUST
   2229 NOT be lit while an android.hardware.Camera.PreviewCallback instance has been
   2230 registered on a Camera preview surface, unless the application has explicitly
   2231 enabled the flash by enabling the <code>FLASH_MODE_AUTO</code> or
   2232 <code>FLASH_MODE_ON</code> attributes of a <code>Camera.Parameters</code>
   2233 object. Note that this constraint does not apply to the device's built-in
   2234 system camera application, but only to third-party applications using
   2235 <code>Camera.PreviewCallback</code>.</li>
   2236 </ul>
   2237 <a name="section-7.5.2"></a><h4>7.5.2. Front-Facing Camera</h4>
   2238 <p>Device implementations MAY include a front-facing camera. If a device
   2239 implementation includes a front-facing camera, it:</p>
   2240 <ul>
   2241 <li>MUST have a resolution of at least VGA (that is, 640x480 pixels)</li>
   2242 <li>MUST NOT use a front-facing camera as the default for the Camera API.
   2243 That is, the camera API in Android 4.3 has specific support for front-facing
   2244 cameras, and device implementations MUST NOT configure the API to to treat a
   2245 front-facing camera as the default rear-facing camera, even if it is the only
   2246 camera on the device.</li>
   2247 <li>MAY include features (such as auto-focus, flash, etc.)
   2248 available to rear-facing cameras as described in Section 7.5.1.</li>
   2249 <li>MUST horizontally reflect (i.e. mirror) the stream displayed by an app in a
   2250 CameraPreview, as follows:</li>
   2251 <ul>
   2252 <li>If the device implementation is capable of being rotated by user (such as
   2253 automatically via an accelerometer or manually via user input), the camera
   2254 preview MUST be mirrored horizontally relative to the device's current
   2255 orientation.</li>
   2256 <li>If the current application has explicitly requested that the Camera
   2257 display be rotated via a call to the
   2258 <code>android.hardware.Camera.setDisplayOrientation()</code> [<a
   2259 href="#resources50">Resources, 50</a>] method, the camera preview MUST be
   2260 mirrored horizontally relative to the orientation specified by the
   2261 application.</li>
   2262 <li>Otherwise, the preview MUST be mirrored along the device's default horizontal axis.</li>
   2263 </ul>
   2264 <li>MUST mirror the image displayed by the postview in the same manner as
   2265 the camera preview image stream. (If the device implementation does not
   2266 support postview, this requirement obviously does not apply.)</li>
   2267 <li>MUST NOT mirror the final captured still image or video streams returned
   2268 to application callbacks or committed to media storage</li>
   2269 </ul>
   2270 <a name="section-7.5.3"></a><h4>7.5.3. Camera API Behavior</h4>
   2271 <p>Device implementations MUST implement the following behaviors for the
   2272 camera-related APIs, for both front- and rear-facing cameras:</p>
   2273 <ol>
   2274 <li>If an application has never called
   2275 <code>android.hardware.Camera.Parameters.setPreviewFormat(int)</code>, then the
   2276 device MUST use <code>android.hardware.PixelFormat.YCbCr_420_SP</code> for
   2277 preview data provided to application callbacks.</li>
   2278 <li>If an application registers an <code>android.hardware.Camera.PreviewCallback
   2279 </code> instance and the system calls the <code>onPreviewFrame()</code> method
   2280 when the preview format is YCbCr_420_SP, the data in the <code>byte[]</code>
   2281 passed into <code>onPreviewFrame()</code> must further be in the NV21 encoding
   2282 format. That is, NV21 MUST be the default.</li>
   2283 <li>Device implementations MUST support the YV12 format (as denoted by the
   2284 <code>android.graphics.ImageFormat.YV12</code> constant) for camera previews
   2285 for both front- and rear-facing cameras.  (The hardware video encoder and camera
   2286 may use any native pixel format, but the device implementation MUST support conversion
   2287 to YV12.)</li>
   2288 </ol>
   2289 <p>Device implementations MUST implement the full Camera API included in the
   2290 Android 4.3 SDK documentation [<a href="#resources51">Resources, 51</a>]),
   2291 regardless of whether the device includes hardware autofocus or other
   2292 capabilities. For instance, cameras that lack autofocus MUST still call any
   2293 registered <code>android.hardware.Camera.AutoFocusCallback</code> instances (even though
   2294 this has no relevance to a non-autofocus camera.) Note that this does apply
   2295 to front-facing cameras; for instance, even though most front-facing cameras
   2296 do not support autofocus, the API callbacks must still be "faked" as
   2297 described.</p>
   2298 <p>Device implementations MUST recognize and honor each parameter name defined
   2299 as a constant on the <code>android.hardware.Camera.Parameters</code> class, if the
   2300 underlying hardware supports the feature. If the device hardware does not
   2301 support a feature, the API must behave as documented. Conversely, Device
   2302 implementations MUST NOT honor or recognize string constants passed
   2303 to the <code>android.hardware.Camera.setParameters()</code> method other than
   2304 those documented as constants on the
   2305 <code>android.hardware.Camera.Parameters</code>.  That is,
   2306 device implementations MUST support all standard Camera parameters if the
   2307 hardware allows, and MUST NOT support custom Camera parameter types.
   2308 For instance, device implementations that support image capture using high dynamic range (HDR)
   2309 imaging techniques MUST support camera parameter <code>Camera.SCENE_MODE_HDR</code>
   2310 [<a href="#resources78">Resources, 78</a>]).</p>
   2311 <p>Device implementations MUST broadcast the <code>Camera.ACTION_NEW_PICTURE</code>
   2312 intent whenever a new picture is taken by the camera and the entry of the picture
   2313 has been added to the media store.</p>
   2314 <p>Device implementations MUST broadcast the <code>Camera.ACTION_NEW_VIDEO</code>
   2315 intent whenever a new video is recorded by the camera and the entry of the picture
   2316 has been added to the media store.</p>
   2317 <a name="section-7.5.4"></a><h4>7.5.4. Camera Orientation</h4>
   2318 <p>Both front- and rear-facing cameras, if present, MUST be oriented so that
   2319 the long dimension of the camera aligns with the screen's long dimension. That
   2320 is, when the device is held in the landscape orientation, cameras MUST
   2321 capture images in the landscape orientation. This applies regardless of the
   2322 device's natural orientation; that is, it applies to landscape-primary devices
   2323 as well as portrait-primary devices.</p>
   2324 
   2325 <a name="section-7.6"></a><h3>7.6. Memory and Storage</h3>
   2326 <a name="section-7.6.1"></a><h4>7.6.1. Minimum Memory and Storage</h4>
   2327 <p>Device implementations MUST have at least 340MB of memory available to the
   2328 kernel and userspace. The 340MB MUST be in addition to any memory dedicated to
   2329 hardware components such as radio, video, and so on that is not under the
   2330 kernel's control.</p>
   2331 <p>Device implementations MUST have at least 512MB of non-volatile storage available
   2332 for application private data. That is, the <code>/data</code> partition MUST be at
   2333 least 512MB. Device implementations that run Android 4.3 are <b>very strongly encouraged to
   2334 have at least 1GB of non-volatile storage for application private data</b> so they will be
   2335 able to upgrade to the future platform releases.</p>
   2336 
   2337 <p>The Android APIs include a Download Manager that applications may use to
   2338 download data files [<a href="#resources56">Resources, 56</a>]. The device
   2339 implementation of the Download Manager MUST be capable of downloading individual
   2340 files of at least 100MB in size to the default "cache" location.</p>
   2341 <a name="section-7.6.2"></a><h4>7.6.2. Application Shared Storage</h4>
   2342 <p>Device implementations MUST offer shared storage for applications. The
   2343 shared storage provided MUST be at least 1GB in size.</p>
   2344 <p>Device implementations MUST be configured with shared storage mounted by
   2345 default, "out of the box". If the shared storage is not mounted on the Linux
   2346 path <code>/sdcard</code>, then the device MUST include a Linux symbolic link
   2347 from <code>/sdcard</code> to the actual mount point.</p>
   2348 <p>Device implementations MUST enforce as documented the
   2349 <code>android.permission.WRITE_EXTERNAL_STORAGE</code> permission on this
   2350 shared storage. Shared storage MUST otherwise be writable by any application
   2351 that obtains that permission.</p>
   2352 <p>Device implementations MAY have hardware for user-accessible removable
   2353 storage, such as a Secure Digital card. Alternatively, device implementations
   2354 MAY allocate internal (non-removable) storage as shared storage for apps.</p>
   2355 <p>Regardless of the form of shared storage used, device implementations MUST
   2356 provide some mechanism to access the contents of shared storage from a host
   2357 computer, such as USB mass storage (UMS) or Media Transfer Protocol (MTP). Device
   2358 implementations MAY use USB mass storage, but SHOULD use Media Transfer
   2359 Protocol. If the device implementation supports Media Transfer Protocol:</p>
   2360 <ul>
   2361 <li>The device implementation SHOULD be compatible with the reference Android
   2362 MTP host, Android File Transfer [<a href="#resources57">Resources, 57</a>].</li>
   2363 <li>The device implementation SHOULD report a USB device class of <code>0x00</code>.</li>
   2364 <li>The device implementation SHOULD report a USB interface name of 'MTP'.</li>
   2365 </ul>
   2366 <p>If the device implementation lacks USB ports, it MUST provide a host
   2367 computer with access to the contents of shared storage by some other means,
   2368 such as a network file system.</p>
   2369 <p>It is illustrative to consider two common examples. If a device
   2370 implementation includes an SD card slot to satisfy the shared storage
   2371 requirement, a FAT-formatted SD card 1GB in size or larger MUST be included
   2372 with the device as sold to users, and MUST be mounted by default.
   2373 Alternatively, if a device implementation uses internal fixed storage to
   2374 satisfy this requirement, that storage MUST be 1GB in size or larger
   2375 and mounted on <code>/sdcard</code> (or <code>/sdcard</code>
   2376 MUST be a symbolic link to the physical location if it is mounted elsewhere.)</p>
   2377 <p>Device implementations that include multiple shared storage paths (such as
   2378 both an SD card slot and shared internal storage) SHOULD modify the core
   2379 applications such as the media scanner and ContentProvider to transparently
   2380 support files placed in both locations.</p>
   2381 
   2382 <a name="section-7.7"></a><h3>7.7. USB</h3>
   2383 <p>Device implementations SHOULD include a USB client port, and SHOULD include
   2384 a USB host port.</p>
   2385 <p>If a device implementation includes a USB client port:</p>
   2386 <ul>
   2387 <li>the port MUST be connectable to a USB host with a standard USB-A port</li>
   2388 <li>the port SHOULD use the micro USB form factor on the device side. Existing and
   2389 new devices that run Android 4.3 are <b>very strongly encouraged to meet these requirements
   2390 in Android 4.3</b> so they will be able to upgrade to the future platform releases</li>
   2391 <li>the port SHOULD be centered in the middle of an edge. Device implementations SHOULD either
   2392 locate the port on the bottom of the device (according to natural orientation) or enable software
   2393 screen rotation for all apps (including home screen), so that the display draws correctly when the device
   2394 is oriented with the port at bottom. Existing and new devices that run Android 4.3 are <b>very strongly
   2395 encouraged to meet these requirements in Android 4.3</b> so they will be able to upgrade to future platform releases.</li>
   2396 <li>if the device has other ports (such as a non-USB charging port) it SHOULD be on the same edge as the
   2397 micro-USB port</li>
   2398 <li>it MUST allow a host connected to the device to access the contents of the
   2399 shared storage volume using either USB mass storage or Media Transfer
   2400 Protocol</li>
   2401 <li>it MUST implement the Android Open Accessory API and specification as documented
   2402 in the Android SDK documentation, and MUST declare support for the hardware
   2403 feature <code>android.hardware.usb.accessory</code> [<a href="#resources52">Resources,
   2404 52</a>]</li>
   2405 <li>it MUST implement the USB audio class as documented in the Android SDK documentation [<a href="#resources66">Resources, 66</a>]</li>
   2406 <li>it SHOULD implement support for USB battery charging specification [<a href="#resources64">Resources, 64</a>]
   2407 Existing and new devices that run Android 4.3 are <b>very strongly encouraged to meet these requirements in Android 4.3</b>
   2408 so they will be able to upgrade to the future platform releases</li>
   2409 
   2410 </ul>
   2411 <p>If a device implementation includes a USB host port:</p>
   2412 <ul>
   2413 <li>it MAY use a non-standard port form factor, but if so MUST ship with a
   2414 cable or cables adapting the port to standard USB-A</li>
   2415 <li>it MUST implement the Android USB host API as documented in the Android
   2416 SDK, and MUST declare support for the hardware feature
   2417 <code>android.hardware.usb.host</code> [<a href="#resources53">Resources, 53</a>]</li>
   2418 </ul>
   2419 <p>Device implementations MUST implement the Android Debug Bridge. If a device
   2420 implementation omits a USB client port, it MUST implement the Android Debug
   2421 Bridge via local-area network (such as Ethernet or 802.11)</p>
   2422 
   2423 <a name="section-8"></a><h2>8. Performance Compatibility</h2>
   2424 <p>Device implementations MUST meet the key performance metrics of an Android
   2425 4.3 compatible device defined in the table below:</p>
   2426 <table><tbody><tr>
   2427 <td><b>Metric</b></td>
   2428 <td><b>Performance Threshold</b></td>
   2429 <td><b>Comments</b></td>
   2430 </tr>
   2431 <tr>
   2432 <td>Application Launch Time</td>
   2433 <td>The following applications should launch within the specified time.<ul>
   2434 <li>Browser: less than 1300ms</li>
   2435 <li>Contacts: less than 700ms</li>
   2436 <li>Settings: less than 700ms</li>
   2437 </ul></td>
   2438 <td>The launch time is measured as the total time to
   2439 complete loading the default activity for the application, including the time
   2440 it takes to start the Linux process, load the Android package into the Dalvik
   2441 VM, and call onCreate.</td>
   2442 </tr>
   2443 <tr>
   2444 <td>Simultaneous Applications</td>
   2445 <td>When multiple applications have been launched, re-launching an
   2446 already-running application after it has been launched must take less than the
   2447 original launch time.</td>
   2448 <td>&nbsp;</td>
   2449 </tr>
   2450 </tbody>
   2451 </table>
   2452 
   2453 <a name="section-9"></a><h2>9. Security Model Compatibility</h2>
   2454 <p>Device implementations MUST implement a security model consistent with the
   2455 Android platform security model as defined in Security and Permissions
   2456 reference document in the APIs [<a href="#resources54">Resources, 54</a>] in the
   2457 Android developer documentation. Device implementations MUST support
   2458 installation of self-signed applications without requiring any additional
   2459 permissions/certificates from any third parties/authorities.  Specifically,
   2460 compatible devices MUST support the security mechanisms described in the
   2461 follow sub-sections.</p>
   2462 <a name="section-9.1"></a><h3>9.1. Permissions</h3>
   2463 <p>Device implementations MUST support the Android permissions model as
   2464 defined in the Android developer documentation [<a
   2465 href="#resources54">Resources, 54</a>]. Specifically,
   2466 implementations MUST enforce each permission defined as described in the SDK
   2467 documentation; no permissions may be omitted, altered, or ignored.
   2468 Implementations MAY add additional permissions, provided the new permission ID
   2469 strings are not in the android.* namespace.</p>
   2470 <a name="section-9.2"></a><h3>9.2. UID and Process Isolation</h3>
   2471 <p>Device implementations MUST support the Android application sandbox model,
   2472 in which each application runs as a unique Unix-style UID and in a separate
   2473 process.  Device implementations MUST support running multiple applications as
   2474 the same Linux user ID, provided that the applications are properly signed and
   2475 constructed, as defined in the Security and Permissions reference [<a
   2476 href="#resources54">Resources, 54</a>].</p>
   2477 <a name="section-9.3"></a><h3>9.3. Filesystem Permissions</h3>
   2478 <p>Device implementations MUST support the Android file access permissions
   2479 model as defined in the Security and Permissions reference [<a
   2480 href="#resources54">Resources, 54</a>].</p>
   2481 <a name="section-9.4"></a><h3>9.4. Alternate Execution Environments</h3>
   2482 <p>Device implementations MAY include runtime environments that execute
   2483 applications using some other software or technology than the Dalvik virtual
   2484 machine or native code. However, such alternate execution environments MUST
   2485 NOT compromise the Android security model or the security of installed Android
   2486 applications, as described in this section.</p>
   2487 <p>Alternate runtimes MUST themselves be Android applications, and abide by
   2488    the standard Android security model, as described elsewhere in Section 9.</p>
   2489 <p>Alternate runtimes MUST NOT be granted access to resources protected by
   2490    permissions not requested in the runtime's AndroidManifest.xml file via the
   2491    <code>&lt;uses-permission&gt;</code> mechanism.</p>
   2492 <p>Alternate runtimes MUST NOT permit applications to make use of features
   2493    protected by Android permissions restricted to system applications.</p>
   2494 <p>Alternate runtimes MUST abide by the Android sandbox model.  Specifically:</p>
   2495 <ul>
   2496 <li>Alternate runtimes SHOULD install apps via the PackageManager into
   2497     separate Android sandboxes (that is, Linux user IDs, etc.)</li>
   2498 <li>Alternate runtimes MAY provide a single Android sandbox shared by all
   2499     applications using the alternate runtime</li>
   2500 <li>Alternate runtimes and installed applications using an alternate runtime
   2501     MUST NOT reuse the sandbox of any other app installed on the device, except
   2502     through the standard Android mechanisms of shared user ID and signing
   2503     certificate</li>
   2504 <li>Alternate runtimes MUST NOT launch with, grant, or be granted access to
   2505     the sandboxes corresponding to other Android applications</li>
   2506 </ul>
   2507 <p>Alternate runtimes MUST NOT be launched with, be granted, or grant to other
   2508    applications any privileges of the superuser (root), or of any other user ID.</p>
   2509 <p>The .apk files of alternate runtimes MAY be included in the system image of
   2510    a device implementation, but MUST be signed with a key distinct
   2511    from the key used to sign other applications included with the device
   2512    implementation.</p>
   2513 <p>When installing applications, alternate runtimes MUST obtain user consent
   2514    for the Android permissions used by the application. That is, if an
   2515    application needs to make use of a device resource for which there is a
   2516    corresponding Android permission (such as Camera, GPS, etc.), the alternate
   2517    runtime MUST inform the user that the application will be able to access
   2518    that resource. If the runtime environment does not record application
   2519    capabilities in this manner, the runtime environment MUST list all
   2520    permissions held by the runtime itself when installing any application
   2521    using that runtime.</p>
   2522 
   2523 <a name="section-9.5"></a><h3>9.5. Multi-User Support </h3>
   2524 <p>Android 4.3 includes support for multiple users and provides support for full user isolation
   2525 [<a href="#resources70">Resources, 70</a>].</p>
   2526 <p>Device implementations MUST meet these requirements related to multi-user support [<a href="#resources71">Resources, 71</a>]:</p>
   2527 <ul>
   2528 <li>As the behavior of the telephony APIs on devices with multiple users is currently undefined, device implementations that
   2529 declare android.hardware.telephony MUST NOT enable multi-user support. </li>
   2530 <li>Device implementations MUST, for each user, implement a security model consistent with the Android platform security model
   2531 as defined in Security and Permissions reference document in the APIs [Resources, 54]</li>
   2532 <li>Android 4.3 includes support for restricted profiles, a feature that allows device owners to manage additional users and their capabilities
   2533 on the device. With restricted profiles, device owners can quickly set up separate environments for additional users to work in, with the ability to
   2534 manage finer-grained restrictions in the apps that are available in those environments. Device implementations that include support for multiple users
   2535 MUST include support for restricted profiles. The upstream Android Open Source Project includes an implementation that satisfies this requirement.</li>
   2536 </ul>
   2537 
   2538 <p>Each user instance on an Android device MUST have separate and isolated external storage directories. Device implementations MAY store multiple users' data on the same volume or filesystem.
   2539 However, the device implementation MUST ensure that applications owned by and running on behalf a given user cannot list, read, or write to data owned by any other user.
   2540 Note that removable media, such as SD card slots, can allow one user to access another's data by means of a host PC. For this reason, device implementations that use removable media for the
   2541 external storage APIs MUST encrypt the contents of the SD card if multi-user is enabled using a key stored only on non-removable media accessible only to the system. As this will make the 
   2542 media unreadable by a host PC, device implementations will be required to switch to MTP or a similar system to provide host PCs with access to the current user's data. Accordingly, device
   2543 implementations MAY but SHOULD NOT enable multi-user if they use removable media [<a href="#resources72">Resources, 72</a>] for primary external storage. The upstream Android Open Source
   2544 Project includes an implementation that uses internal device storage for application external storage APIs; device implementations SHOULD use this configuration and software implementation.
   2545 Device implementations that include multiple external storage paths MUST NOT allow Android applications to write to the secondary external storage.</p>
   2546 
   2547 <a name="section-9.6"></a><h3>9.6. Premium SMS Warning</h3>
   2548 <p>Android 4.3 includes support for warning users for any outgoing premium SMS message [<a href="#resources73">Resources, 73</a>] . Premium SMS messages are text messages sent to a service registered with a carrier that may incur a charge to the user.
   2549 Device implementations that declare support for <code>android.hardware.telephony</code> MUST warn users before sending a SMS message to numbers identified by regular expressions defined in <code>/data/misc/sms/codes.xml</code> file in the device.
   2550 The upstream Android Open Source Project provides an implementation that satisfies this requirement.
   2551 </p>
   2552 
   2553 <a name="section-9.7"></a><h3>9.7. Kernel Security Features</h3>
   2554 <p>The Android Sandbox in Android 4.3 includes features that can use the SELinux
   2555 mandatory access control system (MAC) and other security features in the Linux kernel.
   2556 Device implementations MUST support SELinux MAC. Note that the upstream Android Open Source
   2557 Project provides an implementation that satisfies this requirement.</p>
   2558 
   2559 <p>SELinux or any security features implemented below the Android framework MUST maintain
   2560 compatibility with existing applications. These features SHOULD be invisible to users and developers.
   2561 These features SHOULD NOT be user or developer configurable. If any API for configuration of policy is
   2562 exposed to an application that can affect another application (such as a Device Administration API),
   2563 the API MUST NOT allow configurations that break compatibility. To ensure continued compatibility the
   2564 reference implementation allows the use of SELinux in a permissive mode and supports dynamic policy updates
   2565 without requiring a system image update. Device implementations using SELinux MUST support this permissive
   2566 mode, support dynamic policy updates and log any policy violations without breaking applications or affecting
   2567 system behavior. Implementations using SELinux SHOULD load policy from <code>/sepolicy</code> file on the device.
   2568 The upstream Android Open Source Project provides an implementation that satisfies this requirement.
   2569 Device implementations SHOULD use the reference implementation in the Android Open Source Project, and
   2570 device implementations MUST be compatible with the upstream Android Open Source Project.</p>
   2571 
   2572 <a name="section-10"></a><h2>10. Software Compatibility Testing</h2>
   2573 <p>Device implementations MUST pass all tests described in this section.</p>
   2574 <p>However, note that no software test package is fully comprehensive. For
   2575 this reason, device implementers are very strongly encouraged to make the
   2576 minimum number of changes as possible to the reference and preferred
   2577 implementation of Android 4.3 available from the Android Open Source Project.
   2578 This will minimize the risk of introducing bugs that create incompatibilities
   2579 requiring rework and potential device updates.</p>
   2580 <a name="section-10.1"></a><h3>10.1. Compatibility Test Suite</h3>
   2581 <p>Device implementations MUST pass the Android Compatibility Test Suite (CTS)
   2582 [<a href="#resources02">Resources, 2</a>] available from the Android Open Source
   2583 Project, using the final shipping software on the device. Additionally, device
   2584 implementers SHOULD use the reference implementation in the Android Open
   2585 Source tree as much as possible, and MUST ensure compatibility in cases of
   2586 ambiguity in CTS and for any reimplementations of parts of the reference
   2587 source code.</p>
   2588 <p>The CTS is designed to be run on an actual device. Like any software, the
   2589 CTS may itself contain bugs.  The CTS will be versioned independently of this
   2590 Compatibility Definition, and multiple revisions of the CTS may be released
   2591 for Android 4.3. Device implementations MUST pass the latest CTS version
   2592 available at the time the device software is completed.</p>
   2593 <a name="section-10.2"></a><h3>10.2. CTS Verifier</h3>
   2594 <p>Device implementations MUST correctly execute all applicable cases in the
   2595 CTS Verifier. The CTS Verifier is included with the Compatibility Test Suite,
   2596 and is intended to be run by a human operator to test functionality that
   2597 cannot be tested by an automated system, such as correct functioning of a
   2598 camera and sensors.</p>
   2599 <p>The CTS Verifier has tests for many kinds of hardware, including some
   2600 hardware that is optional. Device implementations MUST pass all tests for
   2601 hardware which they possess; for instance, if a device possesses an
   2602 accelerometer, it MUST correctly execute the Accelerometer test case in the
   2603 CTS Verifier. Test cases for features noted as optional by this Compatibility
   2604 Definition Document MAY be skipped or omitted.</p>
   2605 <p>Every device and every build MUST correctly run the CTS Verifier, as noted
   2606 above. However, since many builds are very similar, device implementers are
   2607 not expected to explicitly run the CTS Verifier on builds that differ only in
   2608 trivial ways. Specifically, device implementations that differ from an
   2609 implementation that has passed the CTS Verifier only by the set of included
   2610 locales, branding, etc. MAY omit the CTS Verifier test.</p>
   2611 <a name="section-10.3"></a><h3>10.3. Reference Applications</h3>
   2612 <p>Device implementers MUST test implementation compatibility using the
   2613 following open source applications:</p>
   2614 <ul>
   2615 <li>The "Apps for Android" applications [<a href="#resources55">Resources, 55</a>]</li>
   2616 <li>Replica Island (available in Google Play Store)</li>
   2617 </ul>
   2618 <p>Each app above MUST launch and behave correctly on the implementation, for
   2619 the implementation to be considered compatible.</p>
   2620 
   2621 
   2622 <a name="section-11"></a><h2>11. Updatable Software</h2>
   2623 <p>Device implementations MUST include a mechanism to replace the entirety of
   2624 the system software. The mechanism need not perform "live" upgrades - that
   2625 is, a device restart MAY be required.</p>
   2626 <p>Any method can be used, provided that it can replace the entirety of the
   2627 software preinstalled on the device. For instance, any of the following
   2628 approaches will satisfy this requirement:</p>
   2629 <ul>
   2630 <li>Over-the-air (OTA) downloads with offline update via reboot</li>
   2631 <li>"Tethered" updates over USB from a host PC</li>
   2632 <li>"Offline" updates via a reboot and update from a file on removable
   2633 storage</li>
   2634 </ul>
   2635 <p>The update mechanism used MUST support updates without wiping user data.
   2636 That is, the update mechanism MUST preserve application private data
   2637 and application shared data. Note that the upstream Android software includes
   2638 an update mechanism that satisfies this requirement.</p>
   2639 <p>If an error is found in a device implementation after it has been released
   2640 but within its reasonable product lifetime that is determined in consultation
   2641 with the Android Compatibility Team to affect the compatibility of third-party
   2642 applications, the device implementer MUST correct the error via a software
   2643 update available that can be applied per the mechanism just described.</p>
   2644 
   2645 <a name="section-12"></a><h2>12. Contact Us</h2>
   2646 <p>You can contact the document authors at <a
   2647 href="mailto:compatibility (a] android.com">compatibility (a] android.com</a> for
   2648 clarifications and to bring up any issues that you think the document does not
   2649 cover.</p>
   2650 
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