To convert an .flv to an avi that will play on most windows machines:

 ffmpeg -i bungee-short.flv -an -b 400 -s 320x240 -vcodec wmv2 bungee-short.avi

-an means no audio. Use -ab 56 to include audio at 56 kbit.

The problem is, that doesn't play on OpenCV. To covert to DivX, which OpenCV is happy with:

  ffmpeg -i bungee-short.flv -an -b 400 -vcodec mpeg4 -y -vtag DIVX bungee-short.divx400.avi

Does a very good job of converting to QuickTime (for Cinelerra):

 ffmpeg -i bungee-short.flv -an -b 400k -vcodec h264 out4.mov

Generally the bitrate will never even come close to 400k. The problem is, at larger frame sizes h264 is just too slow. In this case, use mpeg4. It's *much* faster to encode and decode and comes within 20% of h264.

If you need a movie that works on older software you can use the much slower to encode, lower quality Sorenson codec: "-vcodec svq1".