[pulseaudio-discuss] pulseaudio-discuss Digest, Vol 5, Issue 52

[Arun Raghavan]

On Tue, 2011-09-27 at 20:44 +0530, Sriram Gopalan wrote:
[...]
> > > 3) However, when we attempt the followings, it does not work. We cannot hear
> > > any audio, whereas the same works on my Ubuntu 10.10 desktop
> > > #arecord | aplay
> >
> > Are you saying that this doesn't work, or is the silence expected? Are
> > you sure you're recording from the alsa hardware card and not from the
> > pulse virtual alsa device? (I'm sorry for using the wrong terminology
> > here)
> [Sriram] silence is not expected. I would expect a ramping up echo.

Really depends on the relative level between capture and playback.

[...]
> > > 3) However, when we attempt the followings, it does not work. We
> > > cannot hear any audio, whereas the same works on my Ubuntu 10.10
> > > desktop
> > > #arecord | aplay
> > > #gst-launch alsasrc ! alsasink
> > > #pactl load-module module-loopback
> >
> > Incidentally, why are all the tests with alsasrc/alsasink and not
> > pulsesrc/pulsesink?
> 
> [Sriram] I will try pulsesrc and pulsesink as well. I have not done that

It's best if you test one piece at a time. Something like:

gst-launch-0.10 audiotestsrc ! pulsesink

and

gst-launch-0.10 pulsesrc ! wavenc ! filesink location=record.wav
paplay record.wav

Make sure the correct device is selected in each case (you can tweak
this with the device property on pulsesink/pulsesrc), and that your
mixer controls are correctly initialised -- for custom hardware, you
might need to provide PulseAudio with additional information about the
mixer path. This wiki page might help a bit with that:

http://pulseaudio.org/wiki/WritingProfiles

Cheers,
Arun