[gst-embedded] noise due to synchronization

[Nie Jun]

Dear All,
    I am in trouble when we upgrade Linux kernel from 2.6.24 to
2.6.25. It seems that synchronization causes noise when using ALSA as
sink. Moreover, only 44.1K and 48K audio sampling rate has this issue,
22K, 24K, 32K is trouble free. I test osssink, it has not this
problem.
    I'm using XSCALE platform with CPU fixed in 624MHz, so resource
should not be the root cause. The following are my experiment:

gst-launch filesrc location=$STR  ! qtdemux name=t ! queue ! aacdec ! alsasink
No noise, duration is OK.


gst-launch filesrc location=$STR  ! qtdemux name=t ! queue ! aacdec !
alsasink  t. ! queue ! h264dec ! overlay2sink
With this command, noise is on, duration is shorter than it should be,
video is 35fps while it should be 30fps. I dump the PCM data to file
when ALSA write API is called, all the data is same with decoder
output.


gst-launch filesrc location=$STR  ! qtdemux name=t ! queue ! aacdec !
alsasink  t. ! queue ! fakesink sync=1
Noise is on, even video part is dropped.


gst-launch filesrc location=$STR  ! qtdemux name=t ! queue ! aacdec !
alsasink  t. ! queue ! fakesink sync=0
No noise, duration is OK.


Any idea is welcome, Thanks!