我正在使用AudioRecord录制原始音频进行处理。 音频记录完全没有任何噪音,但是当播放生成的原始PCM数据时,它的播放就好像它已经加速了很多(高达两倍左右)。 我在Audacity中查看和播放PCM数据。我正在使用实际手机(三星Galaxy S5670)进行测试。 录音以44100 Hz,16位完成。知道可能导致这种情况的原因吗?
以下是录制代码:
public class TestApp extends Activity
{
File file;
OutputStream os;
BufferedOutputStream bos;
AudioRecord recorder;
int iAudioBufferSize;
boolean bRecording;
int iBytesRead;
Thread recordThread = new Thread(){
@Override
public void run()
{
byte[] buffer = new byte[iAudioBufferSize];
int iBufferReadResult;
iBytesRead = 0;
while(!interrupted())
{
iBufferReadResult = recorder.read(buffer, 0, iAudioBufferSize);
// Android is reading less number of bytes than requested.
if(iAudioBufferSize > iBufferReadResult)
{
iBufferReadResult = iBufferReadResult +
recorder.read(buffer, iBufferReadResult - 1, iAudioBufferSize - iBufferReadResult);
}
iBytesRead = iBytesRead + iBufferReadResult;
for (int i = 0; i < iBufferReadResult; i++)
{
try
{
bos.write(buffer[i]);
} catch (IOException e)
{
e.printStackTrace();
}
}
}
}
};
@Override
public void onCreate(Bundle savedInstanceState)
{
// File Creation and UI init stuff etc.
bRecording = false;
bPlaying = false;
int iSampleRate = AudioTrack.getNativeOutputSampleRate(AudioManager.STREAM_SYSTEM);
iAudioBufferSize = AudioRecord.getMinBufferSize(iSampleRate, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT);
recorder = new AudioRecord(AudioSource.MIC, iSampleRate, AudioFormat.CHANNEL_IN_MONO,
AudioFormat.ENCODING_PCM_16BIT, iAudioBufferSize);
bt_Record.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
if (!bRecording)
{
try
{
recorder.startRecording();
bRecording = true;
recordThread.start();
}
catch(Exception e)
{
tv_Error.setText(e.getLocalizedMessage());
}
}
else
{
recorder.stop();
bRecording = false;
recordThread.interrupt();
try
{
bos.close();
}
catch(IOException e)
{
}
tv_Hello.setText("Recorded Sucessfully. Total " + iBytesRead + " bytes.");
}
}
});
}
}
决议:我在与它挣扎1-2天之后发布了这个。但是,具有讽刺意味的是,我在发布后很快找到了解决方缓冲输出流写入在for循环中花费了太多时间,因此流正在跳过样本。将其更改为阻止写入,删除for循环。效果很好。
答案 0 :(得分:5)
音频跳过是由写入缓冲区的延迟引起的。 解决方案就是替换这个FOR循环:
for (int i = 0; i < iBufferReadResult; i++)
{
try
{
bos.write(buffer[i]);
} catch (IOException e)
{
e.printStackTrace();
}
}
通过单一写入,如下:
bos.write(buffer, 0, iBufferReadResult);
我曾使用过一本书中的代码,我认为这样可以降低采样率和缓冲区更新。