1 page.title=Audio Framework CTS Verifier 2 @jd:body 3 4 <!-- 5 Copyright 2016 The Android Open Source Project 6 7 Licensed under the Apache License, Version 2.0 (the "License"); 8 you may not use this file except in compliance with the License. 9 You may obtain a copy of the License at 10 11 http://www.apache.org/licenses/LICENSE-2.0 12 13 Unless required by applicable law or agreed to in writing, software 14 distributed under the License is distributed on an "AS IS" BASIS, 15 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 16 See the License for the specific language governing permissions and 17 limitations under the License. 18 --> 19 <div id="qv-wrapper"> 20 <div id="qv"> 21 <h2>In this document</h2> 22 <ol id="auto-toc"> 23 </ol> 24 </div> 25 </div> 26 27 <p>This new suite of tests requires human intervention and some external hardware 28 including a <a href="#loopback_latency">Loopback Plug</a>, a <a 29 href="#audio_frequency_speaker_test">USB reference microphone</a> and <a 30 href="#audio_frequency_microphone_test">external speakers</a>. For devices without 3.5 31 mm () headset port, the user will be able to skip the test and mark it as 32 successful. See the sections below for details.</p> 33 34 <h2 id=loopback_latency>Loopback plug latency test</h2> 35 36 <p><a 37 href="{@docRoot}devices/audio/latency_measure.html#measuringRoundTrip">Round 38 trip latency</a> in audio is defined as the time it takes an audio signal to be 39 recorded, processed and output back.</p> 40 41 <p>To measure round-trip latency using CTS Verifier, connect a loopback 42 plug to the 3.5 mm () headset connector. (If you dont have a loopback plug, 43 you can easily make one following the <a 44 href="{@docRoot}devices/audio/loopback.html">Audio Loopback Dongle</a> 45 instructions.</p> 46 47 <table> 48 <tr> 49 <td width="50%">Start CTS Verifier Loopback Test</td> 50 <td width="50%"><img src="images/audio-framework0.png" alt="audio latency loopback" width="300" 51 id="audio_latency_loopback" /></td> 52 </tr> 53 <tr> 54 <td>Summary of instructions is displayed</td> 55 <td><img src="images/audio-framework1.png" alt="summary of instructions" width="300" 56 id="loopback_instructions" /></td> 57 </tr> 58 <tr> 59 <td>Report if the device has a headset port:<br> 60 <strong>YES</strong> if the device under test has a physical headset port<br> 61 <strong>NO</strong> if there is no headset port</td> 62 <td><img src="images/audio-framework-port.png" alt="audio loopback latency" width="300" 63 id="port_check" /></td> 64 </tr> 65 <tr> 66 <td>If the answer was <strong>NO</strong> in the previous step, press 67 <strong>Pass</strong> (green check) on the bottom of the test and finish</td> 68 <td><img src="images/audio-framework-pass.png" alt="audio pass button" width="300" 69 id="port_pass" /></td> 70 </tr> 71 <tr> 72 <td>If the answer was <strong>YES</strong> in the previous step, continue 73 to connect loopback plug.<br> 74 Connect a loopback plug to the headset port<br> 75 Press the <strong>Loopback Plug Ready</strong> button 76 <td><img src="images/audio-framework2.png" alt="audio pass button" width="300" 77 id="port_pass" /></td> 78 </tr> 79 <tr> 80 <td>Move the slider until the signal level is greater than 60%<br> 81 Press <strong>TEST</strong></td> 82 <td><img src="images/audio-framework3.png" alt="audio level 1" width="300" 83 id="audio_level1" /> 84 <img src="images/audio-framework4.png" alt="audio level 2" width="300" 85 id="audio_level2"></td> 86 </tr> 87 <tr> 88 <td>Wait several seconds while the latency test is performed</td> 89 <td><img src="images/audio-framework5.png" alt="test running" width="300" 90 id="test_running" /></td> 91 </tr> 92 <tr> 93 <td>When the test is finished, results are shown<br> 94 The minimum confidence level for a test to succeed is 0.6<br> 95 Lower latency numbers are preferred, but no number is enforced</td> 96 <td><img src="images/audio-framework6.png" alt="test finished" width="300" 97 id="test_finished" /> 98 </td> 99 </tr> 100 <tr> 101 <td>Press the <strong>Pass</strong> (green, only available if successful) or 102 <strong>Failed</strong> (red) button to record the results.</td> 103 <td><img src="images/audio-framework7.png" alt="Pass button" width="300" 104 id="pass_button" /><br> 105 <img src="images/audio-framework8.png" alt="Failed button" width="300" 106 id="failed_button" /></td> 107 </tr> 108 </table> 109 110 <h2 id=audio_frequency_line_test>Audio frequency line test</h2> 111 112 <p>Using a loopback plug, this test will characterize the left/right line audio 113 output and use the mic feedback from the plug to capture audio and compute a 114 frequency response for each channel.</p> 115 116 <p>A simple criterion for minimum energy expected in each band (out of four) is 117 applied per channel.</p> 118 <table> 119 <tr> 120 <td width="50%">Start CTS Audio Frequency Line Test</td> 121 <td width="50%"><img src="images/audio-framework9.png" alt="start frequency line" width="300" 122 id="start_line_test" /></td> 123 </tr> 124 <tr> 125 <td>Summary of instructions is displayed</td> 126 <td><img src="images/audio-framework10.png" alt="instructions" width="300" 127 id="summary_instructions" /></td> 128 </tr> 129 <tr> 130 <td>Report if the device has a headset port:<br> 131 <strong>YES</strong> if the device under test has a physical headset port<br> 132 <strong>NO</strong> if there is no headset port</td> 133 <td><img src="images/audio-framework-line-port.png" alt="audio frequency line" width="300" 134 id="line_port_check" /></td> 135 </tr> 136 <tr> 137 <td>If the answer was <strong>NO</strong> in the previous step, press 138 <strong>Pass</strong> (green check) on the bottom of the test and finish</td> 139 <td><img src="images/audio-framework-pass.png" alt="audio pass button" width="300" 140 id="port_pass" /></td> 141 </tr> 142 <tr> 143 <td>If the answer was <strong>YES</strong> in the previous step, continue 144 to connect loopback plug<br> 145 Connect a Loopback Plug to the headset connector (see <a 146 href="#loopback_latency">Loopback plug latency test</a>)<br> 147 Press the <strong>Loopback Plug Ready</strong> button 148 <td><img src="images/audio-framework11.png" alt="loopback plug ready" width="300" 149 id="port_pass" /></td> 150 </tr> 151 <td>Press <strong>TEST</strong></td> 152 <td><img src="images/audio-framework12.png" alt="loopback plug test" width="300" 153 id="loopback_plug_test" /></td> 154 </tr> 155 <tr> 156 <td>Wait several seconds while the frequency tests are performed</td> 157 <td><img src="images/audio-framework13.png" alt="testing left capture" width="300" 158 id="left_capture" /></td> 159 </tr> 160 <tr> 161 <td>When the test is finished, results are shown</td> 162 <td><img src="images/audio-framework14.png" alt="testing complete" width="300" 163 id="test_complete" /></td> 164 </tr> 165 <td>Press the <strong>Pass</strong> (only available if successful) or 166 <strong>Failed</strong> button to record the results</td> 167 <td><img src="images/audio-framework15.png" alt="Pass button" width="300" 168 id="pass_button" /><br> 169 <img src="images/audio-framework16.png" alt="Failed button" width="300" 170 id="failed_button" /></td> 171 </tr> 172 </table> 173 174 <h2 id=audio_frequency_speaker_test>Audio frequency speaker test</h2> 175 176 <p>This test uses the signal captured by an external USB reference microphone to 177 assess the frequency response of left (and right, if it exists) loudspeakers.</p> 178 179 <p>A reference microphone is defined as that one that delivers flat, uncolored 180 response. They are often used for analysis and measurement equipment. </p> 181 182 <p>There are some inexpensive USB Reference microphones (e.g., <a 183 href="https://minidsp.com/products/acoustic-measurement/umik-1">miniDSP USB 184 Measurement calibrated microphone</a>, <a 185 href="http://www.daytonaudio.com/index.php/umm-6-usb-measurement-microphone.html">Dayton 186 Audio UMM-6 USB Measurement Microphone</a>), mostly used for the home theater 187 enthusiasts to calibrate their setups.</p> 188 189 <p>Minimum recommended reference microphone characteristics:<br> 190 Flat Frequency response on range 100 Hz - 20 kHz: +/- 2 dB<br> 191 S/N ration 70 dB (A-weighted)<br> 192 THD Ratio @ 1000 Hz less than 1 % at 127 dB SPL<p> 193 194 <table> 195 <tr> 196 <td width="50%">Start CTS Audio Frequency Speaker Test</td> 197 <td width="50%"><img src="images/audio-framework17.png" alt="start speaker test" width="300" 198 id="start_speaker" /></td> 199 </tr> 200 <tr> 201 <td>Summary of instructions is displayed</td> 202 <td><img src="images/audio-framework18.png" alt="instructions" width="300" 203 id="summary_instructions" /></td> 204 </tr> 205 <tr> 206 <td>Connect a USB reference microphone (see <a 207 href="#audio_frequency_speaker_test">Audio frequency speaker test</a>)<br> 208 Press <strong>USB REFERENCE MICROPHONE READY</strong></td> 209 <td><img src="images/audio-framework19.png" alt="mic ready" width="300" 210 id="mic_ready" /></td> 211 </tr> 212 <tr> 213 <td>Set up DUT (Device Under Test) in a quiet room and USB microphone 20cms 214 perpendicular to center of screen</td> 215 <td><img src="images/audio-framework20.png" alt="device under test" width="300" 216 id="dut" /></td> 217 </tr> 218 <tr> 219 <td>Press <strong>TEST</strong></td> 220 <td><img src="images/audio-framework21.png" alt="click test" width="300" 221 id="click_test" /></td> 222 </tr> 223 <tr> 224 <td>Wait several seconds while the frequency tests are performed</td> 225 <td><img src="images/audio-framework22.png" alt="test underway" width="300" 226 id="right_capture" /></td> 227 </tr> 228 <tr> 229 <td>When the test is finished, results are shown</td> 230 <td><img src="images/audio-framework23.png" alt="test complete" width="300" 231 id="test_complete" /></td> 232 </tr> 233 </tr> 234 <td>Press the <strong>Pass</strong> (only available if successful) or 235 <strong>Failed</strong> button to record the results</td> 236 <td><img src="images/audio-framework24.png" alt="Pass button" width="300" 237 id="pass_button" /><br> 238 <img src="images/audio-framework25.png" alt="Failed button" width="300" 239 id="failed_button" /></td> 240 </tr> 241 </table> 242 243 <h2 id=audio_frequency_microphone_test>Audio frequency microphone test</h2> 244 245 <p>This test is more involved than the previous ones. It requires the use of both: 246 External speakers for a white noise sound source, and a USB reference 247 microphone to use as a reference for the sound. Although this process is more 248 involved, it can be performed with affordable, easy to get, hardware</p> 249 250 <p>External speakers positioned 40cm from the device are used to deliver a white 251 noise sound source. These speakers dont need to have a Flat frequency 252 response, but need good coverage from low frequencies (100 hz) to high 253 frequencies (20khz) is expected which is usually met by portable or medium size 254 self powered speakers (e.g. Sony SRS-X5 portable speakers) </p> 255 256 <p>The key element here is that a step for calibration (using the USB reference 257 microphone) is performed, to estimate the actual response of the speakers, thus 258 have a solid reference to compare the built in microphone against.</p> 259 <table> 260 <tr> 261 <td width="50%">Start CTS Audio Frequency Microphone Test</td> 262 <td width="50%"><img src="images/audio-framework26.png" alt="start mic test" width="300" 263 id="start_mic_test" /></td> 264 </tr> 265 <tr> 266 <td>Summary of instructions is displayed</td> 267 <td><img src="images/audio-framework27.png" alt="instructions" width="300" 268 id="summary_instructions" /></td> 269 </tr> 270 <tr> 271 <td>Set up DUT in a quiet room<br> 272 Position the speakers 40cm perpendicular to the center of the screen 273 of the DUT (see <a href="#audio_frequency_microphone_test">Audio 274 frequency microphone test </a>)</td> 275 <td><img src="images/audio-framework28.png" alt="device under test" width="300" 276 id="device_position" /></td> 277 </tr> 278 <tr> 279 <td>Report if the device has a headset port:<br> 280 <strong>YES</strong> if the device under test has a physical headset port<br> 281 <strong>NO</strong> if there is no headset port</td> 282 <td><img src="images/audio-framework-mic-port.png" alt="audio microphone test" width="300" 283 id="mic_port_check" /></td> 284 </tr> 285 <tr> 286 <td>If the answer was <strong>NO</strong> in the previous step, press 287 <strong>Pass</strong> (green check) on the bottom of the test and finish</td> 288 <td><img src="images/audio-framework-pass.png" alt="mic headset pass button" width="300" 289 id="mic_port_pass" /></td> 290 </tr> 291 <tr> 292 <td>If the answer was <strong>YES</strong> in the previous step, continue 293 to connect external speakers.<br> 294 Connect external speakers using the headphone/line out connector 295 (remember to unplug any USB microphone)<br> 296 Press <strong>EXTERNAL SPEAKERS READY</strong></td> 297 <td><img src="images/audio-framework29.png" alt="external speakers ready" width="300" 298 id="speakers_ready" /></td> 299 </tr> 300 <tr> 301 <td>Press <strong>TEST 1</strong></td> 302 <td><img src="images/audio-framework30.png" alt="no USB device" width="300" 303 id="no_usb_device" /></td> 304 </tr> 305 <tr> 306 <td>Wait several seconds for test 1 to complete.</td> 307 <td><img src="images/audio-framework31.png" alt="testing underway" width="300" 308 id="testing_incomplete" /></td> 309 </tr> 310 <tr> 311 <td>When test 1 is completed, results for the built in microphone are shown.</td> 312 <td><img src="images/audio-framework32.png" alt="test results" width="300" 313 id="testing_complete" /></td> 314 </tr> 315 <tr> 316 <td>Connect a USB Reference microphone (see <a 317 href="#audio_frequency_speaker_test">Audio frequency speaker test 318 </a>)<br> 319 Press <strong>USB REFERENCE MICROPHONE READY</strong></td> 320 <td><img src="images/audio-framework33.png" alt="microphone ready" width="300" 321 id="mic_ready" /></td> 322 </tr> 323 <tr> 324 <td>Position USB microphone right next to built-in microphone in DUT, 325 pointing towards external speakers</td> 326 <td><img src="images/audio-framework34.jpg" alt="device position" width="300" 327 id="device_position" /><br> 328 <img src="images/audio-framework35.png" alt="mic position" width="300" 329 id="mic-position" /></td> 330 </tr> 331 <tr> 332 <td>Press <strong>TEST 2</strong></td> 333 <td><img src="images/audio-framework36.png" alt="USB detected" width="300" 334 id="usb-detected" /></td> 335 </tr> 336 <tr> 337 <td>Wait several seconds while the test 2 runs</td> 338 <td><img src="images/audio-framework37.png" alt="test running" width="132" 339 id="test_running" /></td> 340 </tr> 341 <tr> 342 <td>When test 2 is completed, results for the USB reference microphone are 343 shown.</td> 344 <td><img src="images/audio-framework38.png" alt="testing completed" width="300" 345 id="testing_completed" /></td> 346 </tr> 347 <tr> 348 <td>Press the <strong>Pass</strong> (only available if successful) or 349 <strong>Failed</strong> button to record the results.</td> 350 <td><img src="images/audio-framework39.png" alt="Pass button" width="300" 351 id="pass_button" /><br> 352 <img src="images/audio-framework40.png" alt="Failed button" width="300" 353 id="failed_button" /></td> 354 </tr> 355 </table> 356
