[MPlayer-dev-eng] [PATCH] fix for ao_alsa9 and surround

[Tom Lees]

On Thu, Dec 05, 2002 at 02:09:14AM +0000, gabor wrote:
> > EXCEPT that (at least in 5.1 mode)
> > whenever you seek in the file, the channel mappings seem to get messed
> > up (eg center in left speaker etc). I'm not sure whether this is an ALSA
> > bug or some other weirdness going on.
> 
> could you describe this problem more, so i can test it?

I run e.g. mplayer -dvd 2 -ao alsa9:surround51 -channels 6 then use UpArrow
to fast-forward it a bit and the speech (center channel) (seemingly)
randomly comes out of the left speaker or one of the rear speakers, and
other channels are swapped to the wrong speakers. Sometimes it will play
with speech in front-left for a short amount of time then switch to another
(wrong) channel. It seems to do this 3 times before just satying with a
(usually wrong) set.

I have a theory that it's the way ALSA does its surround51 mode that's
causing the problems but I don't know enough about ALSA to try to fix it; or
alternatively somehow samples are being sent to the driver not in multiples
of the number of speakers. I will try to investigate this further.

I have ALSA 0.9.0rc5, mplayer latest CVS.

Tom