Digital camera Casio Exilim EX-S600
The camera uses the Microsoft ISO MPEG-4 Video V1.1 (also known as M4S2) codec. There is no trouble playing the clips, but VirtualDub cannot use the standard codec. You have to install ffdshow with a version newer than ffdshow-20050803.
You can also use the Xvid codec to better compress the video.
However, the sound is nice and well compressed, and you will lose in quality if you try to compress it in mp3.