On 2015-01-31, 16:29 GMT, you wrote:
I think *probably* ALSA. IIRC, PulseAudio should resample streams to
rate the card can play, but it gets the information as to what streams
the card can play from ALSA, I think. 'pulseaudio -k; pulseaudio -
vvvvv' output might have some interesting nuggets in it (you may need
to create a ~/.pulse/client.conf with 'autospawn = no' as the content
to disable auto-respawning; remember to delete it afterwards).
Does it work if you play, say, a 48KHz stream in mplayer and then
start playing a 44.1KHz stream in Totem or Rhythmbox *at the same
time*? That should force resampling.
Also, just for the sake of completness, what happens when you
play a soundfile with
$ gst-launch playbin uri=file:///usr/share/sounds/alsa/Front_Center.wav
(or gst-launch-1.0 or gst-launch-0.10, if you have both)