目录

1、wav文件格式

2、wav文件解析

3、wav文件播放

QA：

开始播放wav的时候使用了系统的播放器mediaplayer进行播放，但是无奈mediaplayer支持的实在不好。

好些年前自己做过pcm播放使用的是audiotrack，参考：CSDN

其实两者之间只差了一个wav文件头而已，所以实现了一套audiotrack播放wav的功能。

1、wav文件格式

参考了：wav文件格式解析_全职编码的博客-CSDN博客_wav文件格式

 其中对我们比较重要的字段：

1. NumChannels ： 声道（一般1-8）
2. SampleRate：采样频率（常见的有8000,16000，44100，48000）
3. BitsPerSample：采样精度（常见的有8、16、32，分别代表着一个采样占据1、2、4个字节）

其余字段解释，详见wav文件格式解析_全职编码的博客-CSDN博客_wav文件格式

wav文件头共44个字节，文件头后紧跟着的就是pcm数据，也就是真正的播放数据了。

2、wav文件解析

package com.macoli.wav_playerimport java.io.DataInputStream
import java.io.InputStream
import java.nio.ByteBuffer
import java.nio.ByteOrder
class Wav(private val inputStream : InputStream) {val wavHeader : WavHeader = WavHeader()init {parseHeader()}private fun parseHeader() {val dataInputStream : DataInputStream = DataInputStream(inputStream)val intValue = ByteArray(4)val shortValue = ByteArray(2)try {wavHeader.mChunkID = "" + Char(dataInputStream.readByte().toUShort()) + Char(dataInputStream.readByte().toUShort()) + Char(dataInputStream.readByte().toUShort()) + Char(dataInputStream.readByte().toUShort())dataInputStream.read(intValue)wavHeader.mChunkSize = byteArrayToInt(intValue)wavHeader.mFormat = "" + Char(dataInputStream.readByte().toUShort()) + Char(dataInputStream.readByte().toUShort()) + Char(dataInputStream.readByte().toUShort()) + Char(dataInputStream.readByte().toUShort())wavHeader.mSubChunk1ID = "" + Char(dataInputStream.readByte().toUShort()) + Char(dataInputStream.readByte().toUShort()) + Char(dataInputStream.readByte().toUShort()) + Char(dataInputStream.readByte().toUShort())dataInputStream.read(intValue)wavHeader.mSubChunk1Size = byteArrayToInt(intValue)dataInputStream.read(shortValue)wavHeader.mAudioFormat = byteArrayToShort(shortValue)dataInputStream.read(shortValue)wavHeader.mNumChannel = byteArrayToShort(shortValue)dataInputStream.read(intValue)wavHeader.mSampleRate = byteArrayToInt(intValue)dataInputStream.read(intValue)wavHeader.mByteRate = byteArrayToInt(intValue)dataInputStream.read(shortValue)wavHeader.mBlockAlign = byteArrayToShort(shortValue)dataInputStream.read(shortValue)wavHeader.mBitsPerSample = byteArrayToShort(shortValue)wavHeader.mSubChunk2ID = "" + Char(dataInputStream.readByte().toUShort()) + Char(dataInputStream.readByte().toUShort()) + Char(dataInputStream.readByte().toUShort()) + Char(dataInputStream.readByte().toUShort())dataInputStream.read(intValue)wavHeader.mSubChunk2Size = byteArrayToInt(intValue)} catch (e: Exception) {e.printStackTrace()}}private fun byteArrayToShort(b: ByteArray): Short {return ByteBuffer.wrap(b).order(ByteOrder.LITTLE_ENDIAN).short}private fun byteArrayToInt(b: ByteArray): Int {return ByteBuffer.wrap(b).order(ByteOrder.LITTLE_ENDIAN).int}/*** WAV文件头* */class WavHeader {var mChunkID = "RIFF"var mChunkSize = 0var mFormat = "WAVE"var mSubChunk1ID = "fmt "var mSubChunk1Size = 16var mAudioFormat: Short = 1var mNumChannel: Short = 1var mSampleRate = 8000var mByteRate = 0var mBlockAlign: Short = 0var mBitsPerSample: Short = 8var mSubChunk2ID = "data"var mSubChunk2Size = 0constructor() {}constructor(chunkSize: Int, sampleRateInHz: Int, channels: Int, bitsPerSample: Int) {mChunkSize = chunkSizemSampleRate = sampleRateInHzmBitsPerSample = bitsPerSample.toShort()mNumChannel = channels.toShort()mByteRate = mSampleRate * mNumChannel * mBitsPerSample / 8mBlockAlign = (mNumChannel * mBitsPerSample / 8).toShort()}override fun toString(): String {return "WavFileHeader{" +"mChunkID='" + mChunkID + '\'' +", mChunkSize=" + mChunkSize +", mFormat='" + mFormat + '\'' +", mSubChunk1ID='" + mSubChunk1ID + '\'' +", mSubChunk1Size=" + mSubChunk1Size +", mAudioFormat=" + mAudioFormat +", mNumChannel=" + mNumChannel +", mSampleRate=" + mSampleRate +", mByteRate=" + mByteRate +", mBlockAlign=" + mBlockAlign +", mBitsPerSample=" + mBitsPerSample +", mSubChunk2ID='" + mSubChunk2ID + '\'' +", mSubChunk2Size=" + mSubChunk2Size +'}'}}
}

3、wav文件播放

使用audiotrack播放wav一般有3个步骤：

1. 下载wav文件
2. 初始化audiotrack

private void initAudioTracker(){AudioAttributes audioAttributes = new AudioAttributes.Builder().setUsage(AudioAttributes.USAGE_MEDIA).setContentType(AudioAttributes.CONTENT_TYPE_MUSIC).build();AudioFormat audioFormat = new AudioFormat.Builder().setEncoding(getEncoding()).setSampleRate(mWav.getWavHeader().getMSampleRate()).build();mAudioTrack = new AudioTrack(audioAttributes, audioFormat, getMiniBufferSize(), AudioTrack.MODE_STREAM, AudioManager.AUDIO_SESSION_ID_GENERATE);}

1. audiotrack.write播放音频

使用单独的Downloader线程对wav文件进行下载，加快缓冲速度，避免播放出现卡顿杂音现象。

使用RealPlayer线程对wav文件进行播放。

其中Downloader线程对应生产者，RealPlayer对应消费者。mSoundData则是生产者消费者之间的缓冲区。

package com.macoli.wav_player;import android.media.AudioAttributes;
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioTrack;import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.ShortBuffer;
import java.util.Arrays;
import java.util.concurrent.LinkedBlockingQueue;public class WavPlayer {public volatile boolean isPlaying = false ;private final LinkedBlockingQueue mSoundData = new LinkedBlockingQueue<>() ;private volatile Wav mWav ;private volatile int mDownloadComplete = -1 ;private final byte[] mWavReady = new byte[1] ;public WavPlayer() {}public void play(String urlStr , boolean local) {isPlaying = true ;mSoundData.clear();mDownloadComplete = -1 ;mWav = null ;new Thread(new Downloader(urlStr , local)).start();new Thread(new RealPlayer()).start();}private int getChannel() {return mWav.getWavHeader().getMNumChannel() == 1 ? AudioFormat.CHANNEL_OUT_MONO : AudioFormat.CHANNEL_OUT_STEREO;}private int getEncoding() {int ENCODING = AudioFormat.ENCODING_DEFAULT;if (mWav.getWavHeader().getMBitsPerSample() == 8) {ENCODING = AudioFormat.ENCODING_PCM_8BIT;} else if (mWav.getWavHeader().getMBitsPerSample() == 16) {ENCODING = AudioFormat.ENCODING_PCM_16BIT;} else if (mWav.getWavHeader().getMBitsPerSample() == 32) {ENCODING = AudioFormat.ENCODING_PCM_FLOAT;}return ENCODING ;}private int getMiniBufferSize() {return AudioTrack.getMinBufferSize(mWav.getWavHeader().getMSampleRate(), getChannel(), getEncoding());}private WavOnCompletionListener onCompletionListener ;public void setOnCompletionListener(WavOnCompletionListener onCompletionListener) {this.onCompletionListener = onCompletionListener ;}public interface WavOnCompletionListener{void onCompletion(int status) ;}private class Downloader implements Runnable {private final String mUrlStr ;private final boolean isLocal ;private Downloader(String urlStr , boolean local) {mUrlStr = urlStr ;isLocal = local ;}@Overridepublic void run() {mDownloadComplete = -1 ;InputStream in = null ;try {if (!isLocal) {URL url = new URL(mUrlStr);URLConnection urlConnection = url.openConnection() ;in = new BufferedInputStream(urlConnection.getInputStream()) ;} else {in = new BufferedInputStream(new FileInputStream(mUrlStr)) ;}if (in == null) {mDownloadComplete = -2 ;isPlaying = false ;onCompletionListener.onCompletion(-2);synchronized (mWavReady) {mWavReady.notifyAll();}return ;}synchronized (mWavReady) {mWav = new Wav(in) ;mWavReady.notifyAll();}} catch (Exception e) {mDownloadComplete = -2 ;isPlaying = false ;onCompletionListener.onCompletion(-2);synchronized (mWavReady) {mWavReady.notifyAll();}return ;}int iniBufferSize = getMiniBufferSize() ;byte[] buffer = new byte[iniBufferSize] ;int read = 0 ;long startTime = System.currentTimeMillis() ;try {int bufferFilledCount = 0 ;while ((read = in.read(buffer , bufferFilledCount , iniBufferSize - bufferFilledCount)) != -1) {bufferFilledCount += read ;if (bufferFilledCount >= iniBufferSize) {byte[] newBuffer = Arrays.copyOf(buffer , iniBufferSize) ;mSoundData.put(newBuffer) ;read = 0 ;bufferFilledCount = 0 ;}}mDownloadComplete = 1 ;} catch (IOException | InterruptedException e) {mDownloadComplete = -2 ;isPlaying = false ;onCompletionListener.onCompletion(-2);} finally {if (in != null) {try {in.close();} catch (IOException e) {e.printStackTrace();}}}}}private class RealPlayer implements Runnable{private AudioTrack mAudioTrack;private void initAudioTracker(){AudioAttributes audioAttributes = new AudioAttributes.Builder().setUsage(AudioAttributes.USAGE_MEDIA).setContentType(AudioAttributes.CONTENT_TYPE_MUSIC).build();AudioFormat audioFormat = new AudioFormat.Builder().setEncoding(getEncoding()).setSampleRate(mWav.getWavHeader().getMSampleRate()).build();mAudioTrack = new AudioTrack(audioAttributes, audioFormat, getMiniBufferSize(), AudioTrack.MODE_STREAM, AudioManager.AUDIO_SESSION_ID_GENERATE);}public void play() {mAudioTrack.play() ;byte[] buffer ;try {while(true) {buffer = mSoundData.take();if (mWav.getWavHeader().getMBitsPerSample() == 8) {try {mAudioTrack.write(buffer, 0, buffer.length, AudioTrack.WRITE_BLOCKING);} catch (Exception e) {}} else if (mWav.getWavHeader().getMBitsPerSample() == 16) {try {ShortBuffer sb = ByteBuffer.wrap(buffer, 0, buffer.length).order(ByteOrder.LITTLE_ENDIAN).asShortBuffer();short[] out = new short[sb.capacity()];sb.get(out);mAudioTrack.write(out, 0, out.length, AudioTrack.WRITE_BLOCKING);} catch (Exception e) {}} else if (mWav.getWavHeader().getMBitsPerSample() == 32) {try {FloatBuffer fb = ByteBuffer.wrap(buffer, 0, buffer.length).order(ByteOrder.LITTLE_ENDIAN).asFloatBuffer();float[] out = new float[fb.capacity()];fb.get(out);mAudioTrack.write(out, 0, out.length, AudioTrack.WRITE_BLOCKING);
//                        mAudioTrack.write(mBuffer, 0, read ,  AudioTrack.WRITE_BLOCKING);} catch (Exception e) {}}if ((1 == mDownloadComplete && mSoundData.isEmpty()) || -2 == mDownloadComplete) {break ;}}} catch (Exception e) {isPlaying = false ;onCompletionListener.onCompletion(-2);return ;} finally {mAudioTrack.stop();mAudioTrack.release();mAudioTrack = null;isPlaying = false ;}onCompletionListener.onCompletion(1);}@Overridepublic void run() {synchronized (mWavReady) {if (mWav == null) {try {mWavReady.wait();if (mWav == null) {return ;}} catch (InterruptedException e) {e.printStackTrace();}}}initAudioTracker() ;play();}}
}

播放wav：

wavplayer.play(url , 是否是本地wav文件)

 val wavPlayer = WavPlayer()wavPlayer.play("/sdcard/Music/3.wav" , true)

QA：

Q：1、播放wav第一帧有爆音。

A： 由于wav文件有44字节的文件头，在读取文件的时候需要跳过wav文件头再向AudioTrack.write中进行写入。

Q：2、播放网络wav有杂音。

A：由于网络读取wav文件每次读取的字节数会远远小于我们设置的minbuffer，所以每次读取网络流的时候我们都要等待minbuffer填充满的时候再使用AudioTrack.write进行写入。

int bufferFilledCount = 0 ;while ((read = in.read(buffer , bufferFilledCount , iniBufferSize - bufferFilledCount)) != -1) {bufferFilledCount += read ;if (bufferFilledCount >= iniBufferSize) {byte[] newBuffer = Arrays.copyOf(buffer , iniBufferSize) ;mSoundData.put(newBuffer) ;read = 0 ;bufferFilledCount = 0 ;}}

Q：3、播放wav失败，全部都是杂音。

A：查看wav文件头，看看wav的采样精度，如果采样精度是32的话，必须使用write(float[])，否则肯定播放失败。

public int write(@NonNull float[] audioData, int offsetInFloats, int sizeInFloats,@WriteMode int writeMode)

完整源码已上传：https://gitee.com/gggl/wav-player