Originally Posted by VGeorgie

You've really ever only needed Flash CS4 which comes with a good converter, or On2 Flix Pro or Sorenson Squeeze for Flash or anything else that supports VP6 format. FFmpeg does not, so forget it and the shareware proggies that use it. FFmpeg supports only an extremely old FLV format that doesn't match quality with the latest that Flash Player can do.

Or you could use x264 and encode in H.264 format, but the usual caution applies: not everyone has updated beyond Flash 9 version 3, which is the minimum version for playing H.264 videos.