[pulseaudio-discuss] Monitor sources are silent when recording over LAN

[Tanu Kaskinen]

On Fri, 2017-10-13 at 10:57 +0300, Martin Laakso wrote:
> On 11.10.2017 17:39, Tanu Kaskinen wrote:
> > I added pulseaudio-discuss back to Cc.
> > 
> > On Tue, 2017-10-10 at 08:28 +0300, Martin Laakso wrote:
> > > This works, so apparently only the tunnel module fails.
> > 
> > Weird. Can you run "pactl list" on both machines while recording from
> > the tunnel source, and attach the output in email?
> > 
> 
> Command outputs attached; mediacenter.local.txt is from the computer 
> playing audio and list.txt is from the one recording.

Now I know what's happening. You have a tunnel sink whose name is

    tunnel.mediacenter.local.alsa_output.pci-0000_01_00.1.hdmi-stereo

and you have a local monitor for the tunnel sink with name

    tunnel.mediacenter.local.alsa_output.pci-0000_01_00.1.hdmi-stereo.monitor

That name is exactly the same as what would be used for a tunnel source
for the remote monitor. When you record from the monitor source, you
actually get the audio that is being played to the tunnel sink, i.e.
nothing.

First I thought that the tunnel source for the remote monitor is not
getting created because of the name conflict, but actually module-
zeroconf-discover ignores all monitor sources. I don't know why. Maybe
because there *would* be name conflicts.

What to do about this then? One part would obviously be to modify
module-zeroconf-discover so that it doesn't ignore monitor sources, but
then the naming conflict has to be solved. Maybe the ".monitor" suffix
should be replaced with ".remote-monitor" when creating tunnel sources
for remote monitors. I don't think I'll work on this myself, so patches
welcome.

As a workaround, you should be able to load module-tunnel-source
manually for the remote monitor source.

-- 
Tanu

https://www.patreon.com/tanuk