[MPlayer-users] 4-speaker support

[Felix Buenemann]

On Saturday, 17. November 2001 19:48, you wrote:
> > > is support for 4-speaker audio output planed?
> > The prob is there is no real 4 speaker support on linux yet that I'd know
> > of...
>
>  SB Live has 4 speaker support with the OSS driver (included in the
> kernel). The front two speakers are in /dev/dsp and the back two speakers
> are in /dev/dsp1. Maybe you could add a command line switch like that:
> -fsd <front sound device> -bsd <back sound device>
>  Does anybody know of another linux sound driver supporting 4 speaker
> output and how it is supported?
Ahh nice thing, last time I read up on this creatives docu just stated that 
rear speakers are reversed l/r of front channels.

Actually thing to do then would be:
- someone with insight to libac3 should write a 5.1 to 4 downmixing method 
(maybe there already is, but guess not)
- add support to mplayer core to handle two audiostreams or add a new pcm 
format that multiplexes the four channels into a stream or already do this in 
libac3, I suggest second way it's much cleaner
- add support two ao_oss to handle AFMT_4CHANPCM or whatever it's named and 
demux it two two several pcm streams that are then written two the different 
dsp devices.

Btw. one also could enhance it to possible 3 dsp devices, so one could get 
full 5.1 decoding without downmixing with for example sblive + onboard 
soundcard.
-- 
Best Regards,
	Atmos
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