pi@raspberrypi ~/Desktop $ ffmpeg -t 10 -f video4linux2 -s 176x144 -r 30 -i /dev/video0 -f avconv -i /dev/dsp1 -f mpeg webcam.mpeg
ffmpeg version 0.8.2-6:0.8.2-1+rpi1+b1, Copyright (c) 2000-2011 the Libav developers
  built on Jun 27 2012 01:07:05 with gcc 4.6.3
*** THIS PROGRAM IS DEPRECATED ***
This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.
[video4linux2 @ 0x8c7220] Cannot find a proper format for codec_id 0, pix_fmt -1.
/dev/video0: Input/output error
pi@raspberrypi ~/Desktop $