安卓开发:挑战每天发布一个封装类02--Wav录音封装类AudioChannel 1.0-编程知识

简介

库名称：AudioChannel

版本:1.0

由于项目需求录音并base64编码存到服务器中，就顺手改装了一个别人的封装类

原封装类地址:Android AudioRecord音频录制wav文件输出 - 简书 (jianshu.com)

描述：此封装类基于AudioRecord实现wav的音频录制，本封装类对原版进行了以下修改:

1.部分修正

(1).可以看到，原封装类继承Thread，代码逻辑很清晰，因此改动过程也较轻松，单次运行能够正常，但是在二次运行，发现报错:

D/CompatibilityChangeReporter: Compat change id reported: 147798919; UID 10428; state: ENABLED
W/System.err: java.lang.IllegalThreadStateException
W/System.err:     at java.lang.Thread.start(Thread.java:960)at com.yy.audiochannaldemo.AudioChannel.startLive(AudioChannel.java:84)

经过跟踪发现，在二次运行的时候，线程的state变为TERMINATED，这意味着线程已经完成了它的执行并且已经退出。一旦线程终止，不能重新启动，因此新版封装类不再继承Thread，而是通过priavate线程重建函数initThread来实现。

(2).首先AudioRecord不能够直接保存录音为wav，因此必须先保存为pcm文件，再通过头部写入数据，转换为wav文件，在这个过程中注意到原封装库，没有对保存pcm的文件进行删除处理，后续可能导致容量过大

(3).构建函数，传入context，以此就无需动态授权外部存储写入权限，也方便后续需要context的操作部分

2.权限控制

在使用过程注意到，原版库并没有处理权限申请，在改版加上了，6.0以上安卓加入了权限控制，另外去除了使用外部存储，需要额外动态授权的情况，直接存入cache

3.功能实现

在原先基础上加入了音高、声音贝计算，并通过onResult接口回调这三个变量，不过db和hz都有一定偏差

一、配置部分

需要先在清单中加入这两项:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />

此封装库需要配置的部分就这么多。

需要在build.gradle加入以下依赖添加代码

    implementation 'com.github.wendykierp:JTransforms:3.1'

二、代码部分

1.PcmToWavUtil.java:Pcm转Wav工具类

public class PcmToWavUtil {private int mBufferSize;  //缓存的音频大小private int mSampleRate = 8000;// 8000|16000private int mChannelConfig = AudioFormat.CHANNEL_IN_STEREO;   //立体声private int mChannelCount = 2;private int mEncoding = AudioFormat.ENCODING_PCM_16BIT;public PcmToWavUtil() {this.mBufferSize = AudioRecord.getMinBufferSize(mSampleRate, mChannelConfig, mEncoding);}public PcmToWavUtil(int sampleRate, int channelConfig, int channelCount, int encoding) {this.mSampleRate = sampleRate;this.mChannelConfig = channelConfig;this.mChannelCount = channelCount;this.mEncoding = encoding;this.mBufferSize = AudioRecord.getMinBufferSize(mSampleRate, mChannelConfig, mEncoding);}public void pcmToWav(String inFilename, String outFilename) {FileInputStream in;FileOutputStream out;long totalAudioLen;long totalDataLen;long longSampleRate = mSampleRate;int channels = mChannelCount;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;//44-8(RIFF+dadasize(4个字节))writeWaveFileHeader(out, totalAudioLen, totalDataLen,longSampleRate, channels, byteRate);while (in.read(data) != -1) {out.write(data);}in.close();out.close();}  catch (IOException e) {e.printStackTrace();}}/*** 加入wav文件头*/private void writeWaveFileHeader(FileOutputStream out, long totalAudioLen,long totalDataLen, long longSampleRate, int channels, long byteRate)throws IOException {byte[] header = new byte[44];header[0] = 'R'; // RIFF/WAVE headerheader[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';  //WAVEheader[9] = 'A';header[10] = 'V';header[11] = 'E';header[12] = 'f'; // 'fmt ' chunkheader[13] = 'm';header[14] = 't';header[15] = ' ';header[16] = 16;  // 4 bytes: size of 'fmt ' chunkheader[17] = 0;header[18] = 0;header[19] = 0;header[20] = 1;   // format = 1header[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); // block alignheader[33] = 0;header[34] = 16;  // bits per sampleheader[35] = 0;header[36] = 'd'; //dataheader[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);}
}

2.AudioChannel.java:录音封装类主体

package com.yy.audiochannaldemo;import android.Manifest;
import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager;
import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;
import android.util.Log;
import android.widget.Toast;import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;import org.jtransforms.fft.DoubleFFT_1D;import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;public class AudioChannel {private int sampleRate;private int channelConfig;private int minBufferSize;private byte[] buffer;private Thread recordThread;private AudioRecord audioRecord;private boolean isRecoding;private SimpleDateFormat sdf;String filename;Context context;long startTime;private onResult onResult;private DoubleFFT_1D fft;public AudioChannel(int sampleRate, int channels, Context context) {this.sampleRate = sampleRate;this.context = context;channelConfig = channels == 2 ? AudioFormat.CHANNEL_IN_STEREO : AudioFormat.CHANNEL_IN_MONO;minBufferSize = AudioRecord.getMinBufferSize(sampleRate, channelConfig, AudioFormat.ENCODING_PCM_16BIT);Log.i("AudioChannel", "minBufferSize: " + minBufferSize);buffer = new byte[minBufferSize];sdf = new SimpleDateFormat("yyyy-MM-dd-HH:mm:ss");fft = new DoubleFFT_1D(minBufferSize/ 2);}private double calculateRMS(byte[] audioBuffer) {double sum = 0.0;for (byte sample : audioBuffer) {sum += sample * sample;}return Math.sqrt(sum / audioBuffer.length);}// 将RMS值转换为分贝值的方法private double rmsToDB(double rms) {// 假设参考值为1（通常是最小可听声音的RMS值）double reference = 1.0;return 20 * Math.log10(rms / reference);}private double calculateHZ(byte[] buffer) {// Convert byte array to double array for FFTdouble[] fftBuffer = new double[buffer.length / 2];for (int i = 0; i < buffer.length; i += 2) {short sample = (short) ((buffer[i] << 8) | (buffer[i + 1] & 0xFF));fftBuffer[i / 2] = sample;}// 执行 FFTfft.realForward(fftBuffer);double maxAmplitude = 0.0;int pitchIndex = 0;for (int i = 0; i < fftBuffer.length-1; i++) {double amplitude = fftBuffer[i] * fftBuffer[i] + fftBuffer[i + 1] * fftBuffer[i + 1];if (i < fftBuffer.length / 2 && amplitude > maxAmplitude) {maxAmplitude = amplitude;pitchIndex = i;}}//计算hz，不过偏差比较大double frequency = (double) pitchIndex * sampleRate / (fftBuffer.length / 2) ;return frequency /100;}void initPremission() {ActivityCompat.requestPermissions((Activity)context, new String[]{Manifest.permission.RECORD_AUDIO}, 169);}void initThread() {this.recordThread=new Thread(){ //开线程@Overridepublic void run() {audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, sampleRate, channelConfig, AudioFormat.ENCODING_PCM_16BIT, minBufferSize);audioRecord.startRecording();FileOutputStream writer = null;Date current = new Date();String time = sdf.format(current);byte[] audioBuffer = new byte[minBufferSize];  // 创建一个缓冲区try {filename = context.getCacheDir() + "/" + time + ".pcm"; //cache目录不需要权限writer = new FileOutputStream(filename, true);while (!Thread.currentThread().isInterrupted() && isRecoding) { //如果线程没有Interrupted而且isRecording变量为True代表在录制状态的情况if (audioRecord.getRecordingState() == AudioRecord.RECORDSTATE_RECORDING) {audioRecord.read(audioBuffer, 0, minBufferSize); // 读取音频数据到缓冲区double rms = calculateRMS(audioBuffer);double db = rmsToDB(rms); //db的值double hz = calculateHZ(audioBuffer);int seaconds =(int) (System.currentTimeMillis() -startTime) /1000;if (isRecoding)  {((Activity)context).runOnUiThread(new Runnable() {@Overridepublic void run() {onResult.update(seaconds,db,hz); //如果还在线程运行状态把信息回调出来}});}writer.write(audioBuffer);}}} catch (IOException e) {e.printStackTrace();} finally {audioRecord.stop();audioRecord.release();audioRecord = null;try {writer.close();} catch (IOException e) {e.printStackTrace();}}new PcmToWavUtil(44100,  AudioFormat.CHANNEL_IN_STEREO, 2, AudioFormat.ENCODING_PCM_16BIT).pcmToWav(filename, filename.replace("pcm","wav"));}};}public void startLive() { //录制initThread();initPremission();if (ContextCompat.checkSelfPermission(context, Manifest.permission.RECORD_AUDIO) ==PackageManager.PERMISSION_GRANTED) {isRecoding = true;recordThread.start();startTime = System.currentTimeMillis();} else {Toast.makeText(context,"没有录音权限",Toast.LENGTH_LONG).show();}}public void stopLive(int mode) { //mode为-1时代表取消，为0代表取消if (!isRecoding) return;try {isRecoding = false;recordThread.join();} catch (Exception e){isRecoding = false;e.printStackTrace();}new File(filename).delete();switch (mode) {case 0:onResult.finish(filename.replace("pcm","wav")); //正常结束后pcm会被转换成wavbreak;case -1:new File(filename.replace("pcm","wav")).delete();onResult.cancel(); //取消回调break;}}public interface onResult { //三个回调void update(int seaconds,double db,double hz);void finish(String filename);void cancel();}public void onResult(onResult onResult) { //功能点击this.onResult = onResult;}}