概述
引用
感谢灰色飘零大佬的这篇指南
概念
Android提供了两种音频录制方式, 这里讲比较底层一些的AudioRecord.
引用一下google的定义:
AudioRecord类管理Java程序的音频资源, 以记录来自音频输入硬件的音频. 这是通过向AudioRecord对象读取数据来实现的. 应用通过以下三种方法之一及时的查询AudioRecord对象:
- read(byte[], int, int)
- read(short[], int, int)
- read(ByteBuffer, int)
具体使用哪个, 是根据音频数据存储格式自由选择的. 创建后, AudioRecord对象初始化其关联的音频缓冲区, 它将填充新的音频数据. 在构造期间指定的缓冲区大小决定了AudioRecord在"过度运行"时, 尚未读取的数据可以保存多长时间. 因此从音频硬件读取的数据块大小应该小于缓冲区大小.
下面是具体实现
权限申请
private void checkPermission() {
//6.0以后需要动态申请权限
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
//检查是否已经获取权限, 没有获取的权限放到list里
for (String permission : permissions) {
if (ContextCompat.checkSelfPermission(this, permission)
!= PackageManager.PERMISSION_GRANTED) {
mPermissionList.add(permission);
}
}
//list不为空, 就去申请所需要的权限
if (!mPermissionList.isEmpty()) {
String[] permissions = mPermissionList.toArray(new String[0]);
ActivityCompat.requestPermissions(this, permissions, MY_PERMISSIONS_REQUEST);
}
}
}
复制代码创建AudioRecord
这里写了个方法来创建AudioRecord:
private void createAudioRecord() {
//这里通过AudioRecord类获取最小的缓存大小
recordBufSize =
AudioRecord.getMinBufferSize(GlobalConfig.SAMPLE_RATE_INHZ, GlobalConfig.CHANNEL_CONFIG,
GlobalConfig.AUDIO_FORMAT);
mAudioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, GlobalConfig.SAMPLE_RATE_INHZ,
GlobalConfig.CHANNEL_CONFIG, GlobalConfig.AUDIO_FORMAT, recordBufSize);
}
复制代码用到的配置类:
public class GlobalConfig {
//采样率
public static final int SAMPLE_RATE_INHZ = 44100;
//声道
public static final int CHANNEL_CONFIG = AudioFormat.CHANNEL_IN_MONO;
//返回的音频数据格式
public static final int AUDIO_FORMAT = AudioFormat.ENCODING_PCM_16BIT;
}
复制代码开始录制音频
private void startRecord() {
createAudioRecord();
//buffer, 用来从AudioRecord中获取录制的音频
final byte[] data = new byte[recordBufSize];
//pcm文件存储位置
final File file = new File(getExternalFilesDir(Environment.DIRECTORY_MUSIC), "test.pcm");
if (!file.mkdirs()) {
Log.d(TAG, "startRecord: " + "Directory not created");
}
if (file.exists()) {
file.delete();
}
//开始录制
mAudioRecord.startRecording();
//录制标记
isRecording = true;
//不阻塞主线程
new Thread(new Runnable() {
@Override public void run() {
//新建文件输出流, 把录制音频存储
FileOutputStream fileOutputStream = null;
try {
fileOutputStream = new FileOutputStream(file);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
if (fileOutputStream != null) {
while (isRecording) {
//将录制音频传到buffer里
int read = mAudioRecord.read(data, 0, recordBufSize);
if (read != AudioRecord.ERROR_INVALID_OPERATION) {
try {
//buffer数据没问题写入到文件中
fileOutputStream.write(data);
} catch (IOException e) {
e.printStackTrace();
}
}
}
try {
//不要忘记关文件输出流
fileOutputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}).start();
}
复制代码停止录制
private void stopRecord() {
//停止录音
isRecording = false;
//不要泄露
if (mAudioRecord != null) {
mAudioRecord.stop();
mAudioRecord.release();
mAudioRecord = null;
}
}
复制代码原始音频文件转化
这里直接给一个大佬提供的转化工具类:
/**
* 将pcm音频文件转换为wav音频文件
*/
public class PcmToWavUtil {
/**
* 缓存的音频大小
*/
private int mBufferSize;
/**
* 采样率
*/
private int mSampleRate;
/**
* 声道数
*/
private int mChannel;
/**
* @param sampleRate sample rate、采样率
* @param channel channel、声道
* @param encoding Audio data format、音频格式
*/
PcmToWavUtil(int sampleRate, int channel, int encoding) {
this.mSampleRate = sampleRate;
this.mChannel = channel;
this.mBufferSize = AudioRecord.getMinBufferSize(mSampleRate, mChannel, encoding);
}
/**
* pcm文件转wav文件
*
* @param inFilename 源文件路径
* @param outFilename 目标文件路径
*/
public void pcmToWav(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();
}
}
/**
* 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];
// RIFF/WAVE header
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);
//WAVE
header[8] = 'W';
header[9] = 'A';
header[10] = 'V';
header[11] = 'E';
// 'fmt ' chunk
header[12] = 'f';
header[13] = 'm';
header[14] = 't';
header[15] = ' ';
// 4 bytes: size of 'fmt ' chunk
header[16] = 16;
header[17] = 0;
header[18] = 0;
header[19] = 0;
// format = 1
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);
// block align
header[32] = (byte) (2 * 16 / 8);
header[33] = 0;
// bits per sample
header[34] = 16;
header[35] = 0;
//data
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);
}
}
复制代码总结
到这里, 就可以进行音频录制啦
转载于:https://juejin.im/post/5c67b89451882561ff304e60
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