Xvid encoder will create H.263 video files.
The quality scale goes from 1 to 31.
Highest quality encode:
ffmpeg -i source.y4m -vcodec libxvid -qscale:v 1 xvid.mp4
Trace: • dvd_id • ubuntu • ffplay • bwdif • chips • theora • vmgi • vtsi • dart • xvid