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

[Lennart Poettering]

On Fri, 09.11.07 22:02, Jan-Benedict Glaw (jbglaw at lug-owl.de) wrote:

> 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?

Might be useful. However, I reworked most of the Surround support in
PA now, and so everything has changed now, and any documentation added
would be out-of-date with 0.9.8.

YOu may now pass a device_id= (instead of device=) to
module-alsa-sink. It will then try to find the appropriate device
automatically for the specified id. A device id is something like "0", and
the module will prepend "surround51:" and so on how it matches best
the sample spec and channel map you specified. I.e.

load-module module-alsa-sink device_id=0 channels=6

is most likely enough to configure 5.1.

With some numbers of channels it is of ambiguous which channel layout
is chosen (i.e. 4.1 vs. 5.0) in which case you should pass
channel_map= and the module will do its best to find an ALSA device
that provides the requested channels.

i.e. use something like this for 4.1:

load-module module-alsa-sink device_id=0 channels=5 channel_map=front-left,front-right,rear-left,rear-right,lfe

This will end up using surround41:0

or use this for 5.0:

load-module module-alsa-sink device_id0 channels=5 channel_map=front-left,front-right,rear-left,rear-right,front-center

This will end up using surround50:0

Lennart

--
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
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