With current mencoders, vcodec=mpeg4 generates files with an AVI
signature of FMP4, which can't apparently be read on windows, even with
the Divx plugin.
The after the fact fix is to binary replace s/FMP4/DX50/ inside the files (2 instances to change), and the files then do play with media player if you have divx installed.
The better fix is to add -ffourcc DX50 on the mencoder command line. Why this isn't a default, I have no idea.
So, to compressed video from camera video clips, you can use one of the following commands:
Original: 37600170 video_mjpeg_orig.avi Divx 5 (i.e. mpeg4 for ffmpeg) 4968830 video_divx_dx50_1000.avi 7836424 video_divx_dx50_1600.avi Msmpeg4v2 (works out of the box on windows) 5057246 video_mp42_1000.avi 7943084 video_mp42_1600.aviWhile size is about the same, in my opinion, the 1000kbps divx5 video looks at least as good as the 1600kbps msmpeg4v2, while the 1600kbps divx5 video looks quite good
You can download the files and compare them for yourself by going here (if they aren't visible in your browser window already)
For now, it seems to mean that one can choose between good quality or windows compatibility. If someone know how to make this better on windows, let me know