FFmpeg/DivX_to_FLV

ffmpeg [1] is the best choice for making flash video sites (.flv files). To install it run:

# emerge media-video/ffmpeg

The syntax is simple:

# ffmpeg -i inputfile.avi flashfile.flv

Note that .flv files do not support a sample rate of 48000. Flash video can have a sample rate of 44100, 22050 and 11025. Set the audio sampling frequency with -ar freq (usually -ar 44100). If the original file has something other than the valid rates the program gives error and quits.

The other options you may want to consider:

-ab audio bitrate     # audio bitrate the default is 64k
-ar sampling freq     # audio sampling frequency
-b  video bitrate     # defaults to 200k, which is kind of low
-s  WxH               # frame size
-ac number            # audio channels (1: mono, 2: stereo (default))

Another useful option is -sameq. This makes the video the same quality as the original, but tends to make flash video files twice the size as original mpeg's. This is bad when it comes to serving files, but it may be worth it if you really want your flash video to have high quality.

See Also

http://en.linuxreviews.org/HOWTO_Convert_video_files#Using_FFMPEG