Description of problem:
I'm using liveCD on usb stick from:
https://fedoraproject.org/wiki/Test_Day:2011-02-22_Nouveau
Test is specified here:
https://fedoraproject.org/wiki/QA:Testcase_nouveau_xv

Version-Release number of selected component (if applicable):
kernel-2.6.38-0.rc5.git5.1.fc15.x86_64
xorg-x11-drv-nouveau-0.0.16-19.20110216git42c16ff.fc15.x86_64

How reproducible:
always

Steps to Reproduce:
1. run gstreamer-properties
2. select Video tab
3. set default output plugin: X Window System (X11/XShm/Xv)
4. click test
  
Actual results:
X Window System (X11/XShm/Xv): Could not initialise Xv output

In terminal:
[liveuser@localhost ~]$ gstreamer-properties 
Gtk-Message: Failed to load module "pk-gtk-module"

** (gstreamer-properties:3469): WARNING **: AT-SPI: Accessibility bus not found - Using session bus.


(gstreamer-properties:3469): Gtk-WARNING **: Unknown property: GtkDialog.has-separator

(gstreamer-properties:3469): Gtk-WARNING **: Unknown property: GtkDialog.has-separator
gstreamer-properties-Message: Skipping unavailable plugin 'artsdsink'
gstreamer-properties-Message: Skipping unavailable plugin 'esdsink'
gstreamer-properties-Message: Skipping unavailable plugin 'sunaudiosink'
gstreamer-properties-Message: Skipping unavailable plugin 'glimagesink'
gstreamer-properties-Message: Skipping unavailable plugin 'sdlvideosink'
gstreamer-properties-Message: Skipping unavailable plugin 'v4lmjpegsrc'
gstreamer-properties-Message: Skipping unavailable plugin 'qcamsrc'
gstreamer-properties-Message: Skipping unavailable plugin 'v4lsrc'
gstreamer-properties-Message: Skipping unavailable plugin 'esdmon'
gstreamer-properties-Message: Skipping unavailable plugin 'sunaudiosrc'
gstreamer-properties-Message: Error running pipeline 'X Window System (X11/XShm/Xv)': Could not initialise Xv output [xvimagesink.c(1435): gst_xvimagesink_get_xv_support (): /GstPipeline:pipeline0/GstXvImageSink:xvimagesink1:
No port available]

Expected results:
It should work I think :)

Additional info: