Python piping received tcp/udp pcm data from network socket into subprocess (aplay)

Question

I can't for the life of me figure this out.. I'm trying to take data received on a network connection, and then pipe it to a subprocess, which will stream the data to my soundcard via aplay.

I've managed to do this, but it pauses briefly while it receives the data.

while True: 
    data = sock.recv(1024)
    p1.stdin.write(data)

What is the best way to setup a pipe that will stream from a network connection indefinitely? Setting up multiprocessing or threading to do this?

Thanks!

Answer 1

Playing back sound is especially tricky - human ears are sensitive to any kind of break in sound playback and the perceived quality would be bad. Further, you can never predict the delays/jitter/latency in the network. Hence, the following model is the best:

1. Multi-threading - One thread receives from the network and submits to a queue. Another thread reads from the queue and submits audio data to sound card.
2. Have a jitter buffer that can hold 1-2 seconds worth of data. (Depends on your application. If you are writing a voice chat app, not more than 150 msec of data should be buffered).
3. If you run out of data in this buffer, re-buffer before starting playback. A temporary pause in playback is better than constant breaks in audio.