Re-encoding the audio of a video file

Sometimes I’ve problems adding videos to Youtube or Flickr, when the upload is done the image looks perfect but I get no audio. After some troubleshooting I’ve found it has to do with the way my camera, a Canon SD1100 IS, is internally encoding the audio track (uncompressed PCM format).

In case you get into a similar issue here you have an easy way of re-encoding the audio of a file to MP3 leaving the video untouched:

$ mencoder input.avi -o output.avi -of avi -oac mp3lame -ovc copy -lameopts q=0