CMSampleBufferSetDataBufferFromAudioBufferList returning error 12731

Question

I am trying to capture app sound and pass it to AVAssetWriter as input.
I am setting callback for audio unit to get AudioBufferList.
The problem starts with conver

Answer 1

Since there is a similar question without answer all over the internet.
I managed to solve it and the recording fully works.
My problem was wrong parameter passed to CMSampleBufferCreate.
numSamples instead of 1 should be equal to numberOfFrames.

So the final call is:

CMSampleBufferCreate(kCFAllocatorDefault,NULL,false,NULL,NULL,format,
                    (CMItemCount)numberOfFrames, 1, &timing, 0, NULL, &buff);