[pulseaudio-discuss] Using pulseaudio with surround sound for DVD playing

[Jan-Benedict Glaw]

On Fri, 2007-10-26 01:29:05 +0200, Lennart Poettering <lennart at poettering.net> wrote:
> On Sat, 20.10.07 12:12, Alex Malinovich (demonbane at the-love-shack.net) wrote:
> 
> > The one thing to note here is that this setup works great for surround
> > movies in mplayer. However, watching them in Totem actually requires a
> > DIFFERENT setup since mplayer and totem seem to have different ideas
> > about what channels they should play audio to. So for totem, I use:
> > 
> > load-module module-alsa-sink device=hw:0,0 sink_name=alsa_front channel_map=front-left,front-right rate=48000
> > load-module module-alsa-sink device=hw:0,1 sink_name=alsa_rear channel_map=side-left,side-right rate=48000
> > load-module module-combine sink_name=combined master=alsa_front slaves=alsa_rear channel_map=front-left,front-right,side-left,side-right channels=4
> > set-default-sink combined
> 
> Until recently GStreamer (Totem) didn't export any info about the
> channel order whatsoever. This has changed now. And if you get a fresh
> gst-pulse snapshot from SVN you'll find that the channel mapping
> should work correctly out of the box.

My initial problem was that anything played to the card (with
channels=8) was played slow by about 4 times.

These days, I found out that this was due to wrong ALSA devices being
used for the ALSA sinks. You may /not/ use hw:0 or hw:1, but need to
use the "surround71" or "surround51" virtual devices. Especially for
my setup (with three cards), I also had problems figuring out how to
address the 2nd (or third) card with just a simple "surround71"
device.

So for me, a working config looks like:

set-default-sink cmipci71_sink
load-module module-alsa-sink device=surround71:0        sink_name=cmipci71_sink channels=8
load-module module-alsa-sink device=surround51:1        sink_name=cmipci51_sink channels=6
load-module module-alsa-sink device=hw:2,0 sink_name=sb_front channel_map=front-left,front-right
load-module module-alsa-sink device=hw:2,2 sink_name=sb_rear  channel_map=side-left,side-right
load-module module-combine sink_name=emu10k40 master=sb_front slaves=sb_rear channel_map=front-left,front-right,side-left,side-right channels=4

The surround devices can be followed by a colon and card index number
as the hw devices are. That's probably a problem of ALSA
documentation, but I guess a number of well placed examples in the PA
documentation or "Module" page would be helpful. Should I add
something about that?

MfG, JBG

-- 
      Jan-Benedict Glaw      jbglaw at lug-owl.de              +49-172-7608481
Signature of:                   ...und wenn Du denkst, es geht nicht mehr,
the second  :                          kommt irgendwo ein Lichtlein her.
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