[MPlayer-dev-eng] Sound synchronization problem

Reza Jelveh reza.jelveh at tu-harburg.de
Sun Aug 8 19:01:57 CEST 2004


hi,

On Sat, 7 Aug 2004 16:00:16 +0200
Adam Tla/lka <atlka at pg.gda.pl> wrote:

> Hmm, I am using ALSA through dmix and plug plugins so resampling is

you still havent answered my question tho. does -srate 48000 fix your
a/v sync? 

> done by ALSA itself. Next I wrote that using command aoss mplayer
> film.avi -ao oss with the same ALSA config I got perfect A/V sync. In
> second case I use a library wrapper which simulates OSS on top of
> ALSA. So ALSA is used in both situactions - film is also the same. So

-ao oss goes through the oss emulation ie. it "perfectly" emulates oss
behaviour, whereas the library wrapper just allows oss apps to use
standard alsa output with oss. 

> in my opinion problem lays on mplayer's side.

the problem could probably be "hidden" inside ao alsa through automatic
resampling but infact lies in your audio hardware. my kt600 mobo has a
48k only chip inside too so i know the problem. if you are referring to
actually it might be that alsa does the rate conversion without mplayer
knowing about it thus resulting in wrong timing or something like that
but as i dont really know the internals of the synching you might as
well talk to zsolt barat the alsa maintainer... maybe he has a solution
to this problem. untill then use a real sound card or srate :)



regards,
reza jelveh




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