Home | History | Annotate | Download | only in media 
      1 page.title=Audio Capture
      2 page.tags=mediarecorder
      3 @jd:body
      4 
      5     <div id="qv-wrapper">
      6     <div id="qv">
      7 
      8 <h2>In this document</h2>
      9 <ol>
     10 <li><a href="#audiocapture">Performing Audio Capture</a>
     11    <ol>
     12       <li><a href='#example'>Code Example</a></li>
     13    </ol>
     14 </li>
     15 </ol>
     16 
     17 <h2>Key classes</h2>
     18 <ol>
     19 <li>{@link android.media.MediaRecorder}</li>
     20 </ol>
     21 
     22 <h2>See also</h2>
     23 <ol>
     24   <li><a href="{@docRoot}guide/appendix/media-formats.html">Android Supported Media Formats</a></li>
     25   <li><a href="{@docRoot}guide/topics/data/data-storage.html">Data Storage</a></li>
     26   <li><a href="{@docRoot}guide/topics/media/mediaplayer.html">MediaPlayer</a>
     27 </ol>
     28 
     29 </div>
     30 </div>
     31 
     32 <p>The Android multimedia framework includes support for capturing and encoding a variety of common
     33 audio formats, so that you can easily integrate audio into your applications. You can record audio
     34 using the {@link android.media.MediaRecorder} APIs if supported by the device hardware.</p>
     35 
     36 <p>This document shows you how to write an application that captures audio from a device
     37 microphone, save the audio and play it back.</p>
     38 
     39 <p class="note"><strong>Note:</strong> The Android Emulator does not have the ability to capture
     40 audio, but actual devices are likely to provide these capabilities.</p>
     41 
     42 <h2 id="audiocapture">Performing Audio Capture</h2>
     43 
     44 <p>Audio capture from the device is a bit more complicated than audio and video playback, but still
     45 fairly simple:</p>
     46 <ol>
     47   <li>Create a new instance of {@link android.media.MediaRecorder android.media.MediaRecorder}.</li>
     48   <li>Set the audio source using
     49         {@link android.media.MediaRecorder#setAudioSource MediaRecorder.setAudioSource()}. You will
     50 probably want to use
     51   <code>MediaRecorder.AudioSource.MIC</code>.</li>
     52   <li>Set output file format using
     53         {@link android.media.MediaRecorder#setOutputFormat MediaRecorder.setOutputFormat()}.
     54   </li>
     55   <li>Set output file name using
     56         {@link android.media.MediaRecorder#setOutputFile MediaRecorder.setOutputFile()}.
     57   </li>
     58   <li>Set the audio encoder using
     59         {@link android.media.MediaRecorder#setAudioEncoder MediaRecorder.setAudioEncoder()}.
     60   </li>
     61   <li>Call {@link android.media.MediaRecorder#prepare MediaRecorder.prepare()}
     62    on the MediaRecorder instance.</li>
     63   <li>To start audio capture, call
     64   {@link android.media.MediaRecorder#start MediaRecorder.start()}. </li>
     65   <li>To stop audio capture, call {@link android.media.MediaRecorder#stop MediaRecorder.stop()}.
     66   <li>When you are done with the MediaRecorder instance, call
     67 {@link android.media.MediaRecorder#release MediaRecorder.release()} on it. Calling
     68 {@link android.media.MediaRecorder#release MediaRecorder.release()} is always recommended to
     69 free the resource immediately.</li>
     70 </ol>
     71 
     72 <h3 id="example">Example: Record audio and play the recorded audio</h3>
     73 <p>The example class below illustrates how to set up, start and stop audio capture, and to play the
     74 recorded audio file.</p>
     75 <pre>
     76 /*
     77  * The application needs to have the permission to write to external storage
     78  * if the output file is written to the external storage, and also the
     79  * permission to record audio. These permissions must be set in the
     80  * application's AndroidManifest.xml file, with something like:
     81  *
     82  * &lt;uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /&gt;
     83  * &lt;uses-permission android:name="android.permission.RECORD_AUDIO" /&gt;
     84  *
     85  */
     86 package com.android.audiorecordtest;
     87 
     88 import android.app.Activity;
     89 import android.widget.LinearLayout;
     90 import android.os.Bundle;
     91 import android.os.Environment;
     92 import android.view.ViewGroup;
     93 import android.widget.Button;
     94 import android.view.View;
     95 import android.view.View.OnClickListener;
     96 import android.content.Context;
     97 import android.util.Log;
     98 import android.media.MediaRecorder;
     99 import android.media.MediaPlayer;
    100 
    101 import java.io.IOException;
    102 
    103 
    104 public class AudioRecordTest extends Activity
    105 {
    106     private static final String LOG_TAG = "AudioRecordTest";
    107     private static String mFileName = null;
    108 
    109     private RecordButton mRecordButton = null;
    110     private MediaRecorder mRecorder = null;
    111 
    112     private PlayButton   mPlayButton = null;
    113     private MediaPlayer   mPlayer = null;
    114 
    115     private void onRecord(boolean start) {
    116         if (start) {
    117             startRecording();
    118         } else {
    119             stopRecording();
    120         }
    121     }
    122 
    123     private void onPlay(boolean start) {
    124         if (start) {
    125             startPlaying();
    126         } else {
    127             stopPlaying();
    128         }
    129     }
    130 
    131     private void startPlaying() {
    132         mPlayer = new MediaPlayer();
    133         try {
    134             mPlayer.setDataSource(mFileName);
    135             mPlayer.prepare();
    136             mPlayer.start();
    137         } catch (IOException e) {
    138             Log.e(LOG_TAG, "prepare() failed");
    139         }
    140     }
    141 
    142     private void stopPlaying() {
    143         mPlayer.release();
    144         mPlayer = null;
    145     }
    146 
    147     private void startRecording() {
    148         mRecorder = new MediaRecorder();
    149         mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    150         mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
    151         mRecorder.setOutputFile(mFileName);
    152         mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
    153 
    154         try {
    155             mRecorder.prepare();
    156         } catch (IOException e) {
    157             Log.e(LOG_TAG, "prepare() failed");
    158         }
    159 
    160         mRecorder.start();
    161     }
    162 
    163     private void stopRecording() {
    164         mRecorder.stop();
    165         mRecorder.release();
    166         mRecorder = null;
    167     }
    168 
    169     class RecordButton extends Button {
    170         boolean mStartRecording = true;
    171 
    172         OnClickListener clicker = new OnClickListener() {
    173             public void onClick(View v) {
    174                 onRecord(mStartRecording);
    175                 if (mStartRecording) {
    176                     setText("Stop recording");
    177                 } else {
    178                     setText("Start recording");
    179                 }
    180                 mStartRecording = !mStartRecording;
    181             }
    182         };
    183 
    184         public RecordButton(Context ctx) {
    185             super(ctx);
    186             setText("Start recording");
    187             setOnClickListener(clicker);
    188         }
    189     }
    190 
    191     class PlayButton extends Button {
    192         boolean mStartPlaying = true;
    193 
    194         OnClickListener clicker = new OnClickListener() {
    195             public void onClick(View v) {
    196                 onPlay(mStartPlaying);
    197                 if (mStartPlaying) {
    198                     setText("Stop playing");
    199                 } else {
    200                     setText("Start playing");
    201                 }
    202                 mStartPlaying = !mStartPlaying;
    203             }
    204         };
    205 
    206         public PlayButton(Context ctx) {
    207             super(ctx);
    208             setText("Start playing");
    209             setOnClickListener(clicker);
    210         }
    211     }
    212 
    213     public AudioRecordTest() {
    214         mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
    215         mFileName += "/audiorecordtest.3gp";
    216     }
    217 
    218     &#64;Override
    219     public void onCreate(Bundle icicle) {
    220         super.onCreate(icicle);
    221 
    222         LinearLayout ll = new LinearLayout(this);
    223         mRecordButton = new RecordButton(this);
    224         ll.addView(mRecordButton,
    225             new LinearLayout.LayoutParams(
    226                 ViewGroup.LayoutParams.WRAP_CONTENT,
    227                 ViewGroup.LayoutParams.WRAP_CONTENT,
    228                 0));
    229         mPlayButton = new PlayButton(this);
    230         ll.addView(mPlayButton,
    231             new LinearLayout.LayoutParams(
    232                 ViewGroup.LayoutParams.WRAP_CONTENT,
    233                 ViewGroup.LayoutParams.WRAP_CONTENT,
    234                 0));
    235         setContentView(ll);
    236     }
    237 
    238     &#64;Override
    239     public void onPause() {
    240         super.onPause();
    241         if (mRecorder != null) {
    242             mRecorder.release();
    243             mRecorder = null;
    244         }
    245 
    246         if (mPlayer != null) {
    247             mPlayer.release();
    248             mPlayer = null;
    249         }
    250     }
    251 }
    252 </pre>
    253