>> ... endless clicking noise intermixed with music ... > sounds like the mp "delayed interrupt notification" issue that wreaks > havoc on audio. >
I don't know if I'm telling anything new and whether this is useful. (my coding skills may be lacking as well) I seem to be able to reproduce the following reliably: When I create a producer/consumer loop using circular buffers where the producer (WAVE file) is much faster than the consumer (audio device), using polling to see whether there is work to do for either the producer or consumer: - in blocking mode everything seems fine: The producer fills the buffers, if it overruns it's paused. The consumer takes the buffers one at the time and when it's about to underrun it resumes the producer. This seems to produce uninterrupted sound just fine. - in non-blocking mode: This basically follows the same procedure as with blocking mode. However, it appears that the audio device becomes available prematurely. (within a few ms independent of the amount of data that was written) e.g.: when I try to send the audio data in ~20ms chunks, I hear a lot of clicks, and the audio appears to be sped up somewhat. Increasing the length of the audio chunks (~2s) makes it sound like it is in fast forward. Just a few ms of each 2s buffer appear to be played before advancing to the next buffer skipping over the song really fast, playing only tiny fragments of the song. It doesn't necessarily seem to be related to sndio/aucat. I seem to get the same results with audio(4). I was expecting the writes to the audio device to fail (EAGAIN) if the previous buffer isn't done playing yet. Basically I don't expect POLLOUT to be set until all software buffers have been drained and the data has been written to the device completely. Unless I'm doing something wrong or misinterpreting something, this doesn't seem to be the case.
