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

[Tanu Kaskinen]

On Fri, 2015-01-23 at 14:25 +0200, Tanu Kaskinen wrote:
> On Thu, 2015-01-22 at 20:37 +0100, Martin Klein wrote:
> > 2015-01-21 12:10 GMT+01:00 Tanu Kaskinen <tanu.kaskinen at linux.intel.com>:
> > > On Sun, 2015-01-18 at 13:54 +0100, Martin Klein wrote:
> > >> 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).
> > >
> > Checking the volume and mute state of the remap sink was the first
> > thing I checked. The channel is unmuted, I toggled the mute state and
> > increased the volume to the max. All to no avail. Thank you for your
> > suggestion regarding the channel matrix. Unfortunately I couldn't find
> > any documentation on how to interpret the channel matrix. I think I
> > found the two matrices corresponding to my to remap sinks:
> > http://pastebin.com/CuDjDaM4
> > I have no idea on how to interpret this. I'm a little bit confused by
> > the separator line for in the first matrix. Also, the asymmetry of the
> > second matrix looks weird to me (there is an empty row between the 1
> > of the second columns.
> 
> The channel factors (the ones and zeros) seem to be correct, but the
> printing is messed up. It looks like each line is duplicated in the log.
> How did you create that log?
> 
> I'll explain how to interpret the matrix. In this example I have loaded
> module-null-sink with six channels, and the channel map is
> front-left,front-left-of-center,front-center,front-right,front-right-of-center,rear-center. Then I play a stream with channel map front-left,front-right, with remixing disabled. The resulting matrix looks like this:
> 
>        I00   I01 
>     +------------
> O00 | 1.000 0.000
> O01 | 0.000 0.000
> O02 | 0.000 0.000
> O03 | 0.000 1.000
> O04 | 0.000 0.000
> O05 | 0.000 0.000
> 
> I00 and I01 are the input channels, and O00-O05 are the output channels.
> The matrix shows that I00 goes to O00 and I01 goes to O03. Other output
> channels don't have any inputs, so they get silence.
> 
> Now, back to your setup, it remains a mystery why you don't get any
> audio with module-remap-sink. The next step could be to record from both
> the monitor of the alsa sink and from the monitor of the remap sink. Are
> one or both of the recordings silent?

FYI, on my machine module-remap-sink seems to be working fine (I don't
have surround output for testing, but I created a remap sink on a stereo
sink, such that the remap sink plays only to the right channel).

-- 
Tanu