[pulseaudio-discuss] using pulseaudio to listen to remote computers

[Colin Guthrie]

Hello Simon,

Firstly apologies for the very late reply to your email.

I will break with tradition and reply with a top post as I assume that
will be more convenient for you (forgive my ignorance if this is not the
case!)

PulseAudio does have some degree of automatic network transparency. If
you enable network access (currently done via the paprefs program) and
assuming there are no firewalling issues, running applications remotely
via SSH and X11 forwarding will also forward the sound.

This works because we inject configuration variables into the X11 root
window via properties (which can be examined via a "xprop -root | grep
PULSE" command). These are then forwarded by SSH with it's X11
forwarding capabilities. When the remote application is run, it is
visually presented locally via this X11 forwarding but in addition, any
audio applications using libpulse (which includes ALSA applications on a
typical setup) will read the connection string from the X11 window
properties and then establish a direct connection (which is separate to
the SSH tunnels) back to your local system. Thus sounds "just work". The
fact that PA is not tunnelled through SSH directly like X11 is a problem
that would be very nice to solve. Maybe with Wayland coming along,
someone will find a more generic way to teach SSH forwarding
capabilities and we can utilise that for PulseAudio more robustly.

I've more information on this configuration on an article I wrote a long
time back under the heading "Remote X11 Application":
http://colin.guthr.ie/2009/08/sound-on-linux-is-confusing-defuzzing-part-2-pulseaudio/



Regarding VNC clients or similar, I'm not too sure what the current
state there is regarding audio support, so I cannot really offer any
real comments there.

I hope this information helps.

All the best

Col

'Twas brillig, and Simon Eigeldinger at 22/07/12 23:15 did gyre and gimble:
> I am simon and i am blind. i have a linux and a windows machine over
> here. unfortunately the remote control clients just allow to be graphics
> to be transfered so the user can see whats happening on the computer.
> as a blind person i often experience the problem of being not able to
> use remote control software cause they are not able to transfer the
> sound with the vnc or other remote control software.
> So i currently wonder if PulseAudio could help there. I know that ubuntu
> 12.04 uses pulseaudio as its default sound server and now i wonder if i
> just ccould listen at this server and play the sounds back which my
> software speech plays there.
> 
> or does someone have a better solution.
> 
> i saw there is a test build of pulseaudio for windows so i wonder if it
> would work enough to listen at the linux machine but also listen at the
> windows machine too.
> 
> 
> 
> 
> Sorry for that thorn appart e-mail. its quite late *smile*.
> 
> 
> greetings,
> simon
> 


-- 

Colin Guthrie
gmane(at)colin.guthr.ie
http://colin.guthr.ie/

Day Job:
  Tribalogic Limited http://www.tribalogic.net/
Open Source:
  Mageia Contributor http://www.mageia.org/
  PulseAudio Hacker http://www.pulseaudio.org/
  Trac Hacker http://trac.edgewall.org/