[pulseaudio-discuss] module-remap-sink not working for surround card

Tanu Kaskinen tanu.kaskinen at linux.intel.com
Wed Jan 21 03:10:45 PST 2015

On Sun, 2015-01-18 at 13:54 +0100, Martin Klein wrote:
> 2015-01-14 21:16 GMT+01:00 Tanu Kaskinen <tanu.kaskinen at linux.intel.com>:
> > On Mon, 2015-01-12 at 14:42 +0100, Martin Klein wrote:
> >> 2015-01-09 12:59 GMT+01:00 Tanu Kaskinen <tanu.kaskinen at linux.intel.com>:
> >> > It sounds like the surround51 alsa device isn't working as it should.
> >> > What if you try "speaker-test -D surround51:0 -c 6 -t wav"? Does it work
> >> > as expected?
> >> >
> >> This is working as expected (i.e. the from the rear output I hear
> >> "rear left, rear right" and from my front output I hear "front").
> >> However, changing the volumes of rear in pavucontrol still doesn't
> >> change anyting. Changing the volume of front effects all output
> >> channels. In alsamixer, changing the volume of rear and front works as
> >> expected.
> >
> > I suggest that you don't think too much about the volume controls at
> > this point, because volume control can contain extra complications.
> >
> > If speaker-test -D surround51:0 works, then it indeed appears to be a
> > problem in pulseaudio. What if you don't load the remap sinks, and just
> > try to play noise to the different channels of the alsa sink like this:
> >
> >     pacat --volume=1000 --no-remix --channels=1 --channel-map=front-left /dev/urandom
> >
> > (I set the volume to a relatively low value, because the noise can be
> > pretty loud.)
> >
> > Try that command with different channel maps. Always specify just one
> > channel of the 5.1 setup. There should be noise from only one channel,
> > and if the specified channel is e.g. "rear-right", you of course should
> > hear the noise from the rear right speaker. Does it work?
> >
> Okay, this works as expected, i.e. I hear the noise on the intended
> speaker. Thank you for suggesting this test. Now to summarize: In
> principle surround seems to work with both Alsa and Pulse (i.e. I can
> output sound on only the intended speaker). However, both volume
> controls and module-remap-sink does not work for the surround channels
> with pulseaudio. Any ideas on how to debug this further?

If we still ignore the volume control problem, the next step is to
investigate what goes wrong with module-remap-sink. You said it doesn't
give any output. Check the volume and mute state of the remap sink and
the sink input between the remap sink and the master sink. If those are
ok, check that the mixing matrix looks ok (the matrix is shown in the
debug log of the server when you load module-remap-sink).


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