This is the output from mplayer. Getting slower till frame 582 and than "v4l2: select timeout" messages appear every second :

tom@neo:~$ mplayer tv://dev/video0 
MPlayer svn r34540 (Ubuntu), built with gcc-4.6 (C) 2000-2012 MPlayer Team
mplayer: could not connect to socket
mplayer: No such file or directory
Failed to open LIRC support. You will not be able to use your remote control.

Playing tv://dev/video0.
The filename option must be an integer: video0
Struct tv, field filename parsing error: video0
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: your device driver does not support VIDIOC_G_STD ioctl, VIDIOC_G_PARM was used instead.
Selected device: USB Camera (046d:08d9)
 Capabilities:  video capture  read/write  streaming
 supported norms:
 inputs: 0 = zc3xx;
 Current input: 0
 Current format: unknown (0x4745504a)
tv.c: norm_from_string(pal): Bogus norm parameter, setting default.
v4l2: ioctl enum norm failed: Inappropriate ioctl for device
Error: Cannot set norm!
Selected input hasn't got a tuner!
v4l2: ioctl set mute failed: Invalid argument
v4l2: ioctl query control failed: Invalid argument
v4l2: ioctl query control failed: Invalid argument
==========================================================================
Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
libavcodec version 53.35.0 (external)
Mismatching header version 53.32.2
Selected video codec: [ffmjpeg] vfm: ffmpeg (FFmpeg MJPEG)
==========================================================================
Audio: no sound
Starting playback...
Could not find matching colorspace - retrying with -vf scale...
Opening video filter: [scale]
Movie-Aspect is undefined - no prescaling applied.
[swscaler @ 0x7f6706665120]using unscaled yuv422p -> yuyv422 special converter
VO: [vdpau] 640x480 => 640x480 Packed YUY2 
V:   0.0 582/582 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 584/584 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 586/586 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 588/588 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 590/590 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 592/592 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 594/594 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 596/596 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 598/598 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 599/599 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 601/601 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 603/603 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 605/605 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 607/607 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 609/609 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 611/611 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 613/613 ??% ??% ??,?% 0 0 
v4l2: select timeout
V:   0.0 615/615 ??% ??% ??,?% 0 0 
v4l2: select timeout


MPlayer interrupted by signal 2 in module: video_read_frame
V:   0.0 616/616 ??% ??% ??,?% 0 0 
v4l2: select timeout
v4l2: ioctl set mute failed: Invalid argument
v4l2: 578 frames successfully processed, 2612 frames dropped.

Exiting... (Quit)


Tom