Here's a preliminary, but functioning version of my "reencode" module. It will convert videos to flv, so the flashvideo module will display it. It's a new module, however, contains changes to both ffmpeg and flashvideo modules. Currently, the user must manually setup reencoding for each item. Converting on upload, as well as a maintenance task to catch videos that already exist. I'm thinking transcode is likely a better name, so I might rename it. Note: suprsidr provided a new G2flv.swf.
This is mainly in response to: