Android Visualizer.OnDataCaptureListener

[gsus24]

I try to change audio capture instead with microphone with Visualizer.OnDataCaptureListener
https://developer.android.com/reference/android/media/audiofx/Visualizer.OnDataCaptureListener
The output format is an 8-bit unsigned mono PCM

But how to pass it to addPCM8( unsigned char PCMdata[2][1024])?
https://github.com/projectM-visualizer/projectm/blob/d789acbd3414a3c3b431455f0bc40f287928f4c4/src/libprojectM/PCM.cpp#L222

First: Why need addPCM8() an two dimensional array? Android outputs is one dimensional byte [1024]!

Second: My idea was to wait for next capture byte[] and then call addPCM8() and pass the last two.
Any idea to pass the multi array it to JNIEXPORT and finally call addPCM8()?

[gsus24]

Nobody out there? I get it work by convert to 16bit and pass it to addPCM() like in the example. Its moving to the beat.
It was more try and error, than exactly knowing what i did.

public void jniCalladdPCM(byte bytes[]){

            short[] audioBuffer = new short[512];
            short bufferSize = 512;
            short multi = 2;

            for(int i=0, j=0; i<audioBuffer.length; i++,j+=2){

               audioBuffer[i] = ((short) ((bytes[j] -0x80 & 0xff) | (bytes[j+1] -0x80 << 8)));

            }

            libprojectMJNIWrapper.addPCM(audioBuffer, bufferSize);
        }

I convert the out coming byte[1024] from onWaveFormDataCapture(Visualizer visualizer, byte[] bytes, int i) by putting two bytes together and removing the 8th bit of each of them.

Suggestions for improvement are welcome.

[revmischa]

If I recall, the 2 dimensions are left/right channels. If your source is mono, I suggest putting the same byte in both channels.

            for(int i=0; i<audioBuffer.length; i+=2){
               audioBuffer[i] = audioBuffer[i+1] = bytes[i];
            }

Something like that perhaps