Why do we use only the first buffer in aurioTouch project
===

I'm investigating [aurioTouch2][1] sample code.  
And I noticed, that when we analize audio data, we use only the first buffer of this data, and never other buffers.
in `void FFTBufferManager::GrabAudioData(AudioBufferList *inBL)` function:

        UInt32 bytesToCopy = min(inBL->mBuffers[0].mDataByteSize, mAudioBufferSize - mAudioBufferCurrentIndex * sizeof(Float32));
    	memcpy(mAudioBuffer+mAudioBufferCurrentIndex, inBL->mBuffers[0].mData, bytesToCopy);
in function

    static OSStatus	PerformThru(
    							void						*inRefCon, 
    							AudioUnitRenderActionFlags 	*ioActionFlags, 
    							const AudioTimeStamp 		*inTimeStamp, 
    							UInt32 						inBusNumber, 
    							UInt32 						inNumberFrames, 
    							AudioBufferList 			*ioData)
    if (THIS->displayMode == aurioTouchDisplayModeOscilloscopeWaveform)
    {
            AudioConverterConvertComplexBuffer(THIS->audioConverter, inNumberFrames, ioData, THIS->drawABL);
    		SInt8 *data_ptr = (SInt8 *)(THIS->drawABL->mBuffers[0].mData);
    }

The question is why do we ignore data in inBL->mBuffers[1].mData?

  [1]: http://developer.apple.com/library/ios/#samplecode/aurioTouch2/Introduction/Intro.html