/**
* Read frame_count samples into buffer. buffer must be at least
* |frame_count * GetSampleSize(format) * channel_count| bytes long.
*
* @param frame_count number of frames to read
* @param buffer buffer to store samples in
*
* @return number of frames actually read
*/
ADR_METHOD(int) read(int frame_count, void* buffer) = 0;

You'll need to have a buffer that can fit 64 samples, and the size calculation
is shown above.

Clear enough?
Cool. :)
Chad