INTERFACING REAL-TIME AUDIO AND FILE I/O

Programming a computer to record or play a sound file in real-time is not as easy as it may seem. The naive approach is to call file I/O APIs from within the routine that handles real-time audio I/O. This leads to audible glitches whenever the time taken to access a file exceeds the time available to deliver a buffer of real-time audio. This paper describes an approach to streaming file playback and recording that operates correctly under these conditions. It performs file I/O in a separate thread, buffers audio data to mask file I/O delays, and uses asynchronous message passing and lock-free queues for interthread communication.

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