Hi, I found a strange issue that ALSA consume pcm data faster than normal. Does any one had come across it?
When I sychronize video frame against audio, the video thread will check how much pcm data has been written to ALSA API but has not been fetched by DMA. This query causes ALSA consume pcm data faster than normal, noise appears too. A stream that is 131 seconds will playback just 112 seconds. It only appears when audio is stereo and sampling rate is directly supported by hardware.
This bug can be reproduced with aplay. To reproduce it with aplay, you just need to add a thread and query the ALSA latency 20~30times every second.
My system: XSCALE PXA300/zylonite, Linux2.6.25, alsa-lib-1.0.13(I tried alsa-lib-1.0.17, bugs too), codec: wm9713. Linux2.6.14 has this issue too, but I did not find it in 2.6.21 and 2.6.24.
Does anyone has idea about it? Thanks!
Jun Nie