我在尝试着
- 使用 AudioRecord 录制 PCM 数据并将它们保存到 .wav 文件中。（完毕）
- 稍后在播放之前录制的文件时录制另一个 PCM 文件
- 将新录音保存到另一个文件
- 混合（叠加）第一个和新的录音。
我的问题是第二个录制文件（2.）和第一个录制文件（1.）不同步。一旦我将它们混合在一起，我就会听到我没有记录的延迟。为了测试我的应用程序，我对着麦克风说“测试 1 2 3”。在第二个录音中，我同时说“Test 1 2 3”。但是，在混合（叠加）我的 2 个文件之后，我得到了延迟。
我做错什么了？
final Thread recordingThread = new Thread(new Runnable() {
final int SAMPLING_RATE = 44100;
final int AUDIO_SOURCE = MediaRecorder.AudioSource.MIC;
final int CHANNEL_IN_CONFIG = AudioFormat.CHANNEL_IN_MONO;
final int AUDIO_FORMAT = AudioFormat.ENCODING_PCM_16BIT;
final int BUFFER_SIZE = AudioRecord.getMinBufferSize(SAMPLING_RATE, CHANNEL_IN_CONFIG, AUDIO_FORMAT);
final String AUDIO_RECORDING_FILE_NAME = project.getPath()+"/track"+String.valueOf(project.getTrackNumber())+".raw";
final int playbackBufferSize = AudioTrack.getMinBufferSize(SAMPLING_RATE, CHANNEL_IN_CONFIG, AUDIO_FORMAT);
@Override
public void run() {
android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);
Log.d("Record", "[Starting recording]");
byte audioData[] = new byte[BUFFER_SIZE];
boolean playSound = true;
ByteArrayOutputStream playbackOutput = new ByteArrayOutputStream();
BufferedInputStream in = null;
try {
in = new BufferedInputStream(new FileInputStream(project.getPath()+"/output.wav"));
} catch (FileNotFoundException e) {
playSound = false;
}
int playbackRead = 1;
byte[] playbackBuffer = new byte[BUFFER_SIZE];
AudioRecord recorder = new AudioRecord(AUDIO_SOURCE,
SAMPLING_RATE, CHANNEL_IN_CONFIG,
AUDIO_FORMAT, BUFFER_SIZE);
AudioTrack player = new AudioTrack(AudioManager.STREAM_MUSIC, SAMPLING_RATE, AudioFormat.CHANNEL_OUT_MONO, AUDIO_FORMAT, playbackBufferSize, AudioTrack.MODE_STREAM);
player.play();
recorder.startRecording();
String filePath = AUDIO_RECORDING_FILE_NAME;
BufferedOutputStream os = null;
try {
os = new BufferedOutputStream(new FileOutputStream(filePath));
} catch (FileNotFoundException e) {
Log.e("Record", "File not found for recording ", e);
}
while (!mStop) {
int status = recorder.read(audioData, 0, audioData.length);
if (status == AudioRecord.ERROR_INVALID_OPERATION ||
status == AudioRecord.ERROR_BAD_VALUE) {
Log.e("Record", "Error reading audio data!");
return;
}
try {
os.write(audioData, 0, audioData.length);
if (playSound) {
try {
if (playbackRead > 0) {
playbackRead = in.read(playbackBuffer);
}
if (playbackRead > 0){
player.write(playbackBuffer, 0, playbackBuffer.length);
}
} catch (IOException e) {
Toast.makeText(MainActivity.this, "ERROR!", Toast.LENGTH_SHORT).show();
return;
}
}
} catch (IOException e) {
Log.e("Record", "Error saving recording ", e);
return;
}
}
try {
os.close();
recorder.stop();
recorder.release();
player.stop();
player.release();
Log.v("Record", "Recording done…");
mStop = false;
File out = new File(project.getPath()+"/output.wav");
if (!out.exists()) {
out.createNewFile();
SoundUtils.rawToWave(new File(AUDIO_RECORDING_FILE_NAME), out, SAMPLING_RATE);
} else {
mixSound(project.getPath()+"/track1.raw", project.getPath()+"/track2.raw", project.getPath()+"/track3.raw", project.getPath()+"/track4.raw");
}
} catch (IOException e) {
Log.e("Record", "Error when releasing", e);
}
}
});
解释：
- 在线程中运行
- 使用相同的设置创建 AudioTrack 和 AudioRecord
- boolean playSound：如果第一次录音已经完成并且 wav 可用，则为 true
- 在循环：
- 读取录音机音频数据并将其写入输出流
- 读取之前录制的 wav 的一部分并将其写入播放器
(- 一旦没有什么可播放的，playbackRead 为-1)
之后我尝试混合我的录音。但是，我的第二次录制有延迟，我没有录制。
我究竟做错了什么？我如何（几乎）完全正确地同步 AudioRecord 和 AudioTrack，以便当我说某事时，它会在背景录音的位置播放，就像我录制它时一样？