问题
I've got a dedicated thread that caputures audio from Alsa through snd_pcm_readi(). Periodically I get a short read, meaning snd_pcm_readi() returns a positive integer lower than my buffer size, and there's obviously a 'pop' sound in my audio stream. Then I set the thread priority to real-time and this gives a tangible benefit, far less short reads, but this doesn't solve.
Now the question: before going down the bumpy road of a real-time patched Linux kernel, there's something else I can do to squeeze out some more performance? Is calling snd_pcm_readi() in a dedicated thread the best way to pull audio out of Alsa?
回答1:
For playback, the buffer size determines the latency.
For capture, it does not; only the period size determines how long you must wait until recorded samples are reported to be available.
So to prevent overruns, make the buffer as large as possible (e.g., by calling snd_pcm_hw_params_set_buffer_size_max() after setting the other parameters).
来源：https://stackoverflow.com/questions/49751938/alsa-snd-pci-readi-and-real-time-threads