AudioTrack使用

AudioTrack用来播放音频的原始数据PCM。MediaPlayer把音频解码后的数据交给AudioTrack来播放。

我们看下AudioTrack的构造函数

  public AudioTrack(AudioAttributes attributes, AudioFormat format, int bufferSizeInBytes,int mode, int sessionId)throws IllegalArgumentException {this(attributes, format, bufferSizeInBytes, mode, sessionId, false /*offload*/,ENCAPSULATION_MODE_NONE, null /* tunerConfiguration */);}

AudioAttributes attributes

        AudioAttributes audioAttributes = (new AudioAttributes.Builder()).setContentType(AudioAttributes.CONTENT_TYPE_MUSIC).build();

设置当前要播放什么内容的数据

我们看源码包括下面一下信息

public final class AudioAttributes implements Parcelable {private final static String TAG = "AudioAttributes";/*** Content type value to use when the content type is unknown, or other than the ones defined.*/public final static int CONTENT_TYPE_UNKNOWN = 0;/*** Content type value to use when the content type is speech.*/public final static int CONTENT_TYPE_SPEECH = 1;/*** Content type value to use when the content type is music.*/public final static int CONTENT_TYPE_MUSIC = 2;/*** Content type value to use when the content type is a soundtrack, typically accompanying* a movie or TV program.*/public final static int CONTENT_TYPE_MOVIE = 3;/*** Content type value to use when the content type is a sound used to accompany a user* action, such as a beep or sound effect expressing a key click, or event, such as the* type of a sound for a bonus being received in a game. These sounds are mostly synthesized* or short Foley sounds.*/public final static int CONTENT_TYPE_SONIFICATION = 4;

包括了演讲电影音乐等类型。我们这里选择

CONTENT_TYPE_MUSIC

AudioFormat format

 AudioFormat.Builder builder = new AudioFormat.Builder();builder.setChannelMask(AudioFormat.CHANNEL_OUT_STEREO).setEncoding(AudioFormat.ENCODING_PCM_16BIT).setSampleRate(44100);AudioFormat audioFormat = builder.build();

设置声道掩码，比如采集音视频我们设置了AudioFormat.CHANNEL_IN_STEREO，那么播放的时候要设置成AudioFormat.CHANNEL_OUT_STEREO

设置编码格式AudioFormat.ENCODING_PCM_16BIT 每个采样大小是2个字节

设置采样率 44100

builder还提供了setChannelIndexMask方法，setChannelIndexMask和setChannelMask是互斥的。

setChannelIndexMask
Added in API level 23
AudioFormat.Builder setChannelIndexMask (int channelIndexMask)
设置频道索引掩码。 通道索引掩码指定帧中的音频采样与编号的端点通道的关联。 信道索引掩码中的第i位对应于第i个端点信道。 例如，具有四个通道的端点被表示为索引掩码位0至3.这个位置掩码解释的这个setChannelMask(int) 。AudioTrack和AudioRecord支持通道索引掩码。 如果指定了通道索引掩码，则使用该掩码，否则使用由setChannelMask指定的通道位置掩码。 对于AudioTrack和AudioRecord ，如果指定了通道索引掩码，则不需要通道位置掩码。

int bufferSizeInBytes

     *   See {@link #getMinBufferSize(int, int, int)} to determine the estimated minimum buffer size*   for an AudioTrack instance in streaming mode.

注释中写道对于流模式AudioTrack getMinBufferSize

int mode

@param mode streaming or static buffer. See {@link #MODE_STATIC} and {@link #MODE_STREAM}.

MODE_STATIC 一次把数据传进来

MODE_STREAM 传很多次数据

int sessionId 会话id

AudioManager.AUDIO_SESSION_ID_GENERATE

AudioManager.generateAudioSessionId()

开始播放

 Runnable recordRunnable = new Runnable() {@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)@Overridepublic void run() {try {//设置线程的优先级android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);byte[] tempBuffer = new byte[buffersize];int readCount = 0;while (inputStream.available() > 0) {readCount= inputStream.read(tempBuffer);if (readCount == AudioTrack.ERROR_INVALID_OPERATION || readCount == AudioTrack.ERROR_BAD_VALUE) {continue;}if (readCount != 0 && readCount != -1) {//一边播放一边写入语音数据//判断AudioTrack未初始化，停止播放的时候释放了，状态就为STATE_UNINITIALIZEDif(mAudioTrack.getState() == mAudioTrack.STATE_UNINITIALIZED){init();}mAudioTrack.play();mAudioTrack.write(tempBuffer, 0, readCount);}}stopPlay();//播放完就停止播放} catch (Exception e) {e.printStackTrace();}}};

停止播放

 public void stopPlay() {try {if (mAudioTrack != null) {if (mAudioTrack.getState() == AudioRecord.STATE_INITIALIZED) {//初始化成功mAudioTrack.stop();//停止播放}if (mAudioTrack != null) {mAudioTrack.release();//释放audioTrack资源}}if (inputStream != null) {inputStream.close();//关闭数据输入流}} catch (Exception e) {e.printStackTrace();}}

完整代码

package com.yuanxuzhen.androidmedia.audio;import android.media.AudioAttributes;
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioRecord;
import android.media.AudioTrack;
import android.os.Build;
import android.provider.MediaStore;
import android.util.Log;import androidx.annotation.RequiresApi;import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;public class AudioTrackManager {private static volatile AudioTrackManager instance;private AudioTrack mAudioTrack;private static final int AUDIO_FORMAT = AudioFormat.ENCODING_PCM_16BIT;private int buffersize;private ExecutorService executorService;private DataInputStream inputStream;private AudioTrackManager() {init();}public static AudioTrackManager getInstance() {if (instance == null) {synchronized (AudioTrackManager.class) {if (instance == null) {instance = new AudioTrackManager();}}}return instance;}@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)private void init() {executorService = Executors.newCachedThreadPool();AudioFormat.Builder builder = new AudioFormat.Builder();builder.setChannelMask(AudioFormat.CHANNEL_OUT_STEREO).setEncoding(AudioFormat.ENCODING_PCM_16BIT).setSampleRate(44100);AudioFormat audioFormat = builder.build();buffersize = AudioTrack.getMinBufferSize(44100,AudioFormat.CHANNEL_OUT_STEREO,AudioFormat.ENCODING_PCM_16BIT);Log.e("yuanAudioTrack", "init buffersize=" + buffersize);AudioAttributes audioAttributes = (new AudioAttributes.Builder()).setContentType(AudioAttributes.CONTENT_TYPE_MUSIC).build();mAudioTrack = new AudioTrack(audioAttributes,audioFormat,buffersize,AudioTrack.MODE_STREAM,AudioManager.AUDIO_SESSION_ID_GENERATE);}/*** 播放线程*/Runnable recordRunnable = new Runnable() {@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)@Overridepublic void run() {try {//设置线程的优先级android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);byte[] tempBuffer = new byte[buffersize];int readCount = 0;while (inputStream.available() > 0) {readCount= inputStream.read(tempBuffer);if (readCount == AudioTrack.ERROR_INVALID_OPERATION || readCount == AudioTrack.ERROR_BAD_VALUE) {continue;}if (readCount != 0 && readCount != -1) {//一边播放一边写入语音数据//判断AudioTrack未初始化，停止播放的时候释放了，状态就为STATE_UNINITIALIZEDif(mAudioTrack.getState() == mAudioTrack.STATE_UNINITIALIZED){init();}mAudioTrack.play();mAudioTrack.write(tempBuffer, 0, readCount);}}stopPlay();//播放完就停止播放} catch (Exception e) {e.printStackTrace();}}};private void setPath(String path) throws Exception {File file = new File(path);inputStream = new DataInputStream(new FileInputStream(file));}public void stopPlay() {try {if (mAudioTrack != null) {if (mAudioTrack.getState() == AudioRecord.STATE_INITIALIZED) {//初始化成功mAudioTrack.stop();//停止播放}if (mAudioTrack != null) {mAudioTrack.release();//释放audioTrack资源}}if (inputStream != null) {inputStream.close();//关闭数据输入流}} catch (Exception e) {e.printStackTrace();}}public void startPlay(String path) {try {setPath(path);executorService.execute(recordRunnable);} catch (Exception e) {e.printStackTrace();}}}

gitee地址

https://gitee.com/creat151/android-media.git