问题
I am trying to record and process audio data based on differences in what gets recorded in the left and right channel. For this I am using Audio Record class, with MIC as input and STEREO mode.
recorder = new AudioRecord(MediaRecorder.AudioSource.MIC, sampleRate,
AudioFormat.CHANNEL_IN_STEREO,
AudioFormat.ENCODING_PCM_16BIT, bufferSize);
My issue is that I get exactly the same data in both the channels. (alternate samples are separated to get individual channel inputs). Please help. I am not sure why this is happening.
回答1:
Using this configuration:
private int audioSource = MediaRecorder.AudioSource.MIC;
private static int sampleRateInHz = 48000;
private static int channelConfig = AudioFormat.CHANNEL_IN_STEREO;
private static int audioFormat = AudioFormat.ENCODING_PCM_16BIT;
The data in the audio data is as follows.
leftChannel data: [0,1],[4,5]...
rightChannel data: [2,3],[6,7]...
So you need to seperate the data.
readSize = audioRecord.read(audioShortData, 0, bufferSizeInBytes);
for(int i = 0; i < readSize/2; i = i + 2)
{
leftChannelAudioData[i] = audiodata[2*i];
leftChannelAudioData[i+1] = audiodata[2*i+1];
rightChannelAudioData[i] = audiodata[2*i+2];
rightChannelAudioData[i+1] = audiodata[2*i+3];
}
Hope this helpful.
回答2:
Here is a working example for capturing audio in stereo (tested with Samsung Galaxy S3 4.4.2 SlimKat):
private void startRecording() {
String filename = Environment.getExternalStorageDirectory().getPath()+"/SoundRecords/"+System.currentTimeMillis()+".aac";
File record = new File(filename);
recorder = new MediaRecorder();
recorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
recorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
recorder.setAudioEncodingBitRate(128000);
recorder.setAudioSamplingRate(96000);
recorder.setAudioChannels(2);
recorder.setOutputFile(filename);
t_filename.setText(record.getName());
try {
recorder.prepare();
recorder.start();
} catch (IOException e) {
e.printStackTrace();
}
}
If your phone supports stereo capturing, then this should work :)
回答3:
You cannot obtain a stereo input in this way on your device.
Although the Nexus 4 has two microphones, they are not intended for stereo recording, but instead are likely for background noise cancellation.
See https://groups.google.com/forum/#!topic/android-platform/SptXI964eEI where various low-level modifications of the audio system are discussed in an attempt to accomplish stereo recording.
来源:https://stackoverflow.com/questions/20634477/audio-recording-in-stereo-giving-same-data-in-left-and-right-channels