Android音视频任务列表之(二)——在 Android 平台使用 AudioRecord 和 AudioTrack API 完成音频 PCM 数据的采集和播放，并实现读写音频 wav 文件

本文主要是介绍Android音视频任务列表之(二)——在 Android 平台使用 AudioRecord 和 AudioTrack API 完成音频 PCM 数据的采集和播放，并实现读写音频 wav 文件，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

一.主要使用方法

1.获取缓存大小

AudioRecord.getMinBufferSize(int sampleRateInHz, int channelConfig, int audioFormat)
参数：
sampleRateInHz：采样率
channelConfig：通道组（单通道，双通道）
audioFormat：音频数据的格式

2.创建录音对象

AudioRecord(int audioSource, int sampleRateInHz, int channelConfig, int audioFormat,
int bufferSizeInBytes)
参数：
audioSource：音频源
sampleRateInHz ：采样率
channelConfig：音频通道
audioFormat：返回音频数据的格式。
bufferSizeInBytes：写入音频数据的缓冲区的大小

3.开始录音

audioRecord.startRecording()

4.获取录音数据

audioRecord.read(@NonNull byte[] audioData, int offsetInBytes, int sizeInBytes)
参数：
audioData：记录音频数据的数组
offsetInBytes：开始索引
sizeInBytes：数据大小

5.开始播放

audioTrack.play()

二.实现过程

1.申请权限：RECORD_AUDIO，READ_EXTERNAL_STORAGE，WRITE_EXTERNAL_STORAGE
2.开始录音

 // 音频来源：麦克风private final static int AUDIO_INPUT = MediaRecorder.AudioSource.MIC;// 采样率// 采样频率一般共分为22.05KHz、44.1KHz、48KHz三个等级private final static int AUDIO_SAMPLE_RATE = 44100;// 音频通道 单声道private final static int AUDIO_CHANNEL = AudioFormat.CHANNEL_IN_STEREO;// 音频格式：PCM编码private final static int AUDIO_ENCODING = AudioFormat.ENCODING_PCM_16BIT;private final String pcmFileName = Environment.getExternalStorageDirectory() + "/record.pcm";private final String wavFileName = Environment.getExternalStorageDirectory() + "/record.wav";private AudioRecord audioRecord = null;private int recordBufSize = 0; // 声明recoordBufffer的大小字段private byte[] buffer;private boolean isRecording;private void start(){//audioRecord能接受的最小的buffer大小recordBufSize = AudioRecord.getMinBufferSize(AUDIO_SAMPLE_RATE, AUDIO_CHANNEL, AUDIO_ENCODING);audioRecord = new AudioRecord(AUDIO_INPUT, AUDIO_SAMPLE_RATE, AUDIO_CHANNEL, AUDIO_ENCODING, recordBufSize);buffer = new byte[recordBufSize];//开始录音audioRecord.startRecording();isRecording = true;new Thread(() -> {FileOutputStream os = null;try {File pcmFile= new File(pcmFileName);if(!pcmFile.exists()){pcmFile.createNewFile();}os = new FileOutputStream(pcmFileName);} catch (Exception e) {e.printStackTrace();}if (null != os) {while (isRecording) {int read = audioRecord.read(buffer, 0, recordBufSize);// 如果读取音频数据没有出现错误，就将数据写入到文件if (AudioRecord.ERROR_INVALID_OPERATION != read) {try {os.write(buffer);} catch (IOException e) {e.printStackTrace();}}}try {os.close();} catch (IOException e) {e.printStackTrace();}}}).start();}

3.停止录音

  private void stop(){isRecording = false;if (null != audioRecord) {audioRecord.stop();audioRecord.release();audioRecord = null;}}

4.播放PCM文件

private void play(){Toast.makeText(this,"开始播放",Toast.LENGTH_LONG).show();int channelConfig = AudioFormat.CHANNEL_OUT_MONO;audioTrack = new AudioTrack(new AudioAttributes.Builder().setUsage(AudioAttributes.USAGE_MEDIA).setContentType(AudioAttributes.CONTENT_TYPE_MUSIC).build(),new AudioFormat.Builder().setSampleRate(44100).setEncoding(AUDIO_ENCODING).setChannelMask(channelConfig).build(),recordBufSize,AudioTrack.MODE_STREAM,AudioManager.AUDIO_SESSION_ID_GENERATE);audioTrack.play();File file = new File(pcmFileName);try {FileInputStream   fileInputStream = new FileInputStream(file);new Thread(new Runnable() {@Overridepublic void run() {try {byte[] tempBuffer = new byte[recordBufSize];while (fileInputStream.available() > 0) {int readCount = fileInputStream.read(tempBuffer);if (readCount == AudioTrack.ERROR_INVALID_OPERATION ||readCount == AudioTrack.ERROR_BAD_VALUE) {continue;}if (readCount != 0 && readCount != -1) {audioTrack.write(tempBuffer, 0, readCount);}}} catch (IOException e) {e.printStackTrace();}}}).start();} catch (IOException e) {e.printStackTrace();}}

5.PCM转WAV

Pcm2WavUtil.pcmToWav(AUDIO_SAMPLE_RATE, AUDIO_CHANNEL,recordBufSize, pcmFileName, wavFileName);

6.Pcm2WavUtil工具类

public class Pcm2WavUtil {/*** pcm文件转wav文件* @param inFilename 源文件路径* @param outFilename 目标文件路径*/public static void pcmToWav(long mSampleRate, int mChannel, int mBufferSize, String inFilename, String outFilename) {FileInputStream in;FileOutputStream out;long totalAudioLen;long totalDataLen;long longSampleRate = mSampleRate;int channels = mChannel == AudioFormat.CHANNEL_IN_MONO ? 1 : 2;long byteRate = 16 * mSampleRate * channels / 8;byte[] data = new byte[mBufferSize];try {in = new FileInputStream(inFilename);out = new FileOutputStream(outFilename);totalAudioLen = in.getChannel().size();totalDataLen = totalAudioLen + 36;writeWaveFileHeader(out, totalAudioLen, totalDataLen,longSampleRate, channels, byteRate);while (in.read(data) != -1) {out.write(data);}in.close();out.close();} catch (IOException e) {e.printStackTrace();}}// 添加wav文件头private static void writeWaveFileHeader(FileOutputStream out, long totalAudioLen,long totalDataLen, long longSampleRate, int channels, long byteRate)throws IOException {byte[] header = new byte[44];header[0] = 'R';header[1] = 'I';header[2] = 'F';header[3] = 'F';header[4] = (byte) (totalDataLen & 0xff);header[5] = (byte) ((totalDataLen >> 8) & 0xff);header[6] = (byte) ((totalDataLen >> 16) & 0xff);header[7] = (byte) ((totalDataLen >> 24) & 0xff);header[8] = 'W';header[9] = 'A';header[10] = 'V';header[11] = 'E';header[12] = 'f';header[13] = 'm';header[14] = 't';header[15] = ' ';header[16] = 16;header[17] = 0;header[18] = 0;header[19] = 0;header[20] = 1;header[21] = 0;header[22] = (byte) channels;header[23] = 0;header[24] = (byte) (longSampleRate & 0xff);header[25] = (byte) ((longSampleRate >> 8) & 0xff);header[26] = (byte) ((longSampleRate >> 16) & 0xff);header[27] = (byte) ((longSampleRate >> 24) & 0xff);header[28] = (byte) (byteRate & 0xff);header[29] = (byte) ((byteRate >> 8) & 0xff);header[30] = (byte) ((byteRate >> 16) & 0xff);header[31] = (byte) ((byteRate >> 24) & 0xff);header[32] = (byte) (2 * 16 / 8);header[33] = 0;header[34] = 16;header[35] = 0;header[36] = 'd';header[37] = 'a';header[38] = 't';header[39] = 'a';header[40] = (byte) (totalAudioLen & 0xff);header[41] = (byte) ((totalAudioLen >> 8) & 0xff);header[42] = (byte) ((totalAudioLen >> 16) & 0xff);header[43] = (byte) ((totalAudioLen >> 24) & 0xff);out.write(header, 0, 44);}
}