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

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".