Comment 4 for bug 131222

I can report behavior on my MBP, gutsy up to date.
In Ekiga the webcam works. But I have some cases in which it does not.

# gst-launch-0.10 v4l2src queue-size=2 ! ffmpegcolorspace ! xvimagesink
Setting pipeline to PAUSED ...
ERROR: Pipeline doesn't want to pause.
ERROR: from element /pipeline0/v4l2src0: Could not negotiate format
Additional debug info:
gstbasesrc.c(2062): gst_base_src_start (): /pipeline0/v4l2src0:
Check your filtered caps, if any
Setting pipeline to NULL ...
FREEING pipeline ...

and...

# mencoder tv:// -tv driver=v4l2:width=320:height=240:device=/dev/video0 -ovc lavc -o webcam.avi
MEncoder 2:1.0~rc1-0ubuntu11 (C) 2000-2006 MPlayer Team
CPU: Genuine Intel(R) CPU 1500 @ 2.00GHz (Family: 6, Model: 14, Stepping: 8)
CPUflags: Type: 6 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1
Compiled with runtime CPU detection.
success: format: 9 data: 0x0 - 0x0
TV file format detected.
Selected driver: v4l2
 name: Video 4 Linux 2 input
 author: Martin Olschewski <email address hidden>
 comment: first try, more to come ;-)
v4l2: ioctl get standard failed: Invalid argument
Selected device: Built-in iSight
 Capabilites: video capture streaming
 supported norms:
 inputs: 0 = Camera;
 Current input: 0
 Current format: UYVY
v4l2: ioctl set format failed: Device or resource busy
v4l2: ioctl set mute failed: Invalid argument
v4l2: 0 frames successfully processed, 0 frames dropped.
Segmentation fault (core dumped)

finally (maybe this is right...)

#cat /dev/video0
cat: /dev/video0: No such device