android - split two channels of AudioRecord of CHANNEL_IN_STEREO

Question

I'm working on a project using stereo record of the Android phones (note 3). But I need to split the data from different channels (right, left). Any idea of how to perform that?

Now, I use AudioRecord to record the sound of internal microphones. And I can record, save the sound to .raw and .wav files.

Some codes as follows.

private int audioSource = MediaRecorder.AudioSource.MIC;  
private static int sampleRateInHz = 44100;  
private static int channelConfig = AudioFormat.CHANNEL_IN_STEREO;  
private static int audioFormat = AudioFormat.ENCODING_PCM_16BIT;


bufferSizeInBytes = AudioRecord.getMinBufferSize(sampleRateInHz,  
            channelConfig, audioFormat);  

audioRecord = new AudioRecord(audioSource, sampleRateInHz,  
            channelConfig, audioFormat, bufferSizeInBytes);

// some other codes....

//get the data from audioRecord
readsize = audioRecord.read(audiodata, 0, bufferSizeInBytes); 

Answer 1

Finally, I got the answers. I used stereo record of android phone. And the audioFormat is PCM_16BIT.

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;  

which means the data stored in buffer as follows.

leftChannel data: [0,1],[4,5]...
rightChannel data: [2,3],[6,7]...

So the code of splitting data of stereo record.

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];
}

Then you can write the data to file.

leftChannelFos = new FileOutputStream(rawLeftChannelDataFile);
rightChannelFos = new FileOutputStream(rawRightChannelDataFile);
leftChannelBos = new BufferedOutputStream(leftChannelFos);
rightChannelBos = new BufferedOutputStream(rightChannelFos);
leftChannelDos = new DataOutputStream(leftChannelBos);
rightChannelDos = new  DataOutputStream(rightChannelBos);

leftChannelDos.write(leftChannelAudioData);
rightChannelDos.write(rightChannelAudioData);

Happy coding!