[Pkg-alsa-devel] Bug#503839: Bug#503839: /usr/lib/alsa-lib/libasound_module_pcm_vdownmix.so: vdownmix from 5.1 does not incorporate LFE channel

[Apelete Seketeli]

On Sat, Sep 5, 2009 at 16:45, Josh Triplett<josh at joshtriplett.org> wrote:
> With the lines you suggested added to the stanza I mentioned in the
> original report:
>
> ~$ speaker-test -c 6 -t wav
>
> speaker-test 1.0.20
>
> Playback device is default
> Stream parameters are 48000Hz, S16_LE, 6 channels
> WAV file(s)
> Segmentation fault

This is to be expected. You can only use one of the setup
instructions, not both. The following lines does not enable surround
sound on my side, it simply doesn't work:

pcm.!surround51 {
	type vdownmix
	slave.pcm "default"
}

> If you had something different in mind than either of the two
> alternatives I tried, please tell me what full .asoundrc to try and I'll
> try it.

Vdownmix setup seems to be device dependant, according to what you say.
On a Thinkpad X60 with Intel HDA sound card I'm able to play 5.1 video
files just fine (through stereo headphones), using only these lines in
my ~/.asoundrc:

pcm.!downmix51 {
 type vdownmix
 slave.pcm "surround51"
}

pcm.!default "plug:downmix51"


If it really doesn't work then there's something 'wrong' with vdownmix.
Maybe vdownmix setup depends on the sound card ? I know that it took
me a few trials before getting 5.1 to play on my computer, and yet it
doesn't work like I would like it to (sound mixing is disabled when
vdownmix is enabled, for instance)...

--
Apelete Seketeli <apelete at seketeli.org>