title: avconv or FFMPEG command to have multiple pictures slices from a direct webcam on pc
body: <p>I have found the command</p>
  
  <pre><code>ffmpeg -i rtsp://10.2.69.201:554/ch0_0.h264 -f image2 -vf fps=fps=1/120 img%03d.jpg
  </code></pre>
  
  <p>but it fail if I'm not on network. I tryed on my on computer but I have bind error.
  I would like to have a command like or a mix of these one:</p>
  
  <pre><code>ffmpeg -f v4l2 -s 640x480 -i /dev/video0 output.mpg
  </code></pre>
  
  <p>Thanks for your help. This is appreciated if that possible</p>