如何将音频录制类中识别的声音保存在文件中?

Question

我的应用程序可以识别我的声音并将其转换为文本。我想同时将识别出的声音保存为可播放的格式。如果我想将此语音文件和文本发布到另一台服务器。

private static final int[] SAMPLE_RATE_CANDIDATES = new int[]{16000, 11025, 22050, 44100};
private static final int CHANNEL = AudioFormat.CHANNEL_IN_MONO;
private static final int ENCODING = AudioFormat.ENCODING_PCM_16BIT;

我试图在文件中写入流。虽然我不确定，但有时它可能会写一些东西，因为我看到文件大小已经增加。但是当我将其发送到服务器端时，文件无法播放。

public void start() {
// Stop recording if it is currently ongoing.
stop();
// Try to create a new recording session.
mAudioRecord = createAudioRecord();
if (mAudioRecord == null) {
throw new RuntimeException("Cannot instantiate VoiceRecorder");
}
// Start recording.
mAudioRecord.startRecording();
// Start processing the captured audio.
mThread = new Thread(new ProcessVoice());
mThread.start();
}    

/** * 持续处理捕获的音频并通知 {@link #mCallback} 相应的 *事件。 */私有类 ProcessVoice 实现 Runnable {

@Override
public void run() {
while (true) {
synchronized (mLock) {
if (Thread.currentThread().isInterrupted()) {
break;
}
final int size = mAudioRecord.read(mBuffer, 0, mBuffer.length);
try {
os.write(mBuffer, 0, mBuffer.length);
} catch (IOException e) {
Log.e(LOGTAG, "Error saving recording ", e);
return;
}
final long now = System.currentTimeMillis();
if (isHearingVoice(mBuffer, size)) {
if (mLastVoiceHeardMillis == Long.MAX_VALUE) {
mVoiceStartedMillis = now;
mCallback.onVoiceStart();
}
mCallback.onVoice(mBuffer, size);
mLastVoiceHeardMillis = now;
if (now - mVoiceStartedMillis > MAX_SPEECH_LENGTH_MILLIS) {
end();
}
} else if (mLastVoiceHeardMillis != Long.MAX_VALUE) {
mCallback.onVoice(mBuffer, size);
if (now - mLastVoiceHeardMillis > SPEECH_TIMEOUT_MILLIS) {
end();
mCallback.onVoiceStart();
}
}
}
}
}

Answer 1

您正在输出流中写入原始数据(即 PCM(。要使此文件可播放，您必须将此数据编码为某种可播放的格式。最简单和最简单的是WAV，它实际上是Header+PCM原始数据。

在输出流中写入数据后，您可以像这样添加wav 标头：

int byteRate = sample_rate*1*16/8;    //sample_rate*channel*bits_per_sample/8
int blockAlign = 1*16/8;     //channel*bits_per_sample/8
int dataLength = 36+(int)outputWAVFile.length();    //Open outputWavFile using FileOutputStream. The one which contains raw data.
byte[] header = new byte[44];
header[0] = 'R';  // RIFF/WAVE header
header[1] = 'I';
header[2] = 'F';
header[3] = 'F';
header[4] = (byte) (dataLength & 0xff);
header[5] = (byte) ((dataLength >> 8) & 0xff);
header[6] = (byte) ((dataLength >> 16) & 0xff);
header[7] = (byte) ((dataLength >> 24) & 0xff);
header[8] = 'W';
header[9] = 'A';
header[10] = 'V';
header[11] = 'E';
header[12] = 'f';  // 'fmt ' chunk
header[13] = 'm';
header[14] = 't';
header[15] = ' ';
header[16] = 16;  // 4 bytes: size of 'fmt ' chunk
header[17] = 0;
header[18] = 0;
header[19] = 0;
header[20] = 1;  // format = 1
header[21] = 0;
header[22] = (byte) 1;  //channel
header[23] = 0;
header[24] = (byte) (sample_rate & 0xff);
header[25] = (byte) ((sample_rate >> 8) & 0xff);
header[26] = (byte) ((sample_rate >> 16) & 0xff);
header[27] = (byte) ((sample_rate >> 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) blockAlign;  // block align
header[33] = 0;
header[34] = 16;  // bits per sample
header[35] = 0;
header[36] = 'd';
header[37] = 'a';
header[38] = 't';
header[39] = 'a';
header[40] = (byte) (outputWAVFile.length() & 0xff);
header[41] = (byte) ((outputWAVFile.length() >> 8) & 0xff);
header[42] = (byte) ((outputWAVFile.length() >> 16) & 0xff);
header[43] = (byte) ((outputWAVFile.length() >> 24) & 0xff);

raf = new RandomAccessFile(outputWAVFile,"rw");
raf.seek(0);
raf.write(header);
} catch (FileNotFoundException e) {
e.printStackTrace();
return false;
} catch (IOException e) {
e.printStackTrace();
return false;
}finally {
try {
raf.close();
} catch (IOException e) {
e.printStackTrace();
}
}

请记住，输出WavFile应该是.wav格式。