[MPlayer-users] Mencoder encoding greenish bar on top?

[Toni Rasanen]

A few .avi files I (some stargate episodes not seen here,
season four) with AC3 audio track (codec id 2000), which,
when re-encoded (to reduce file size), produce a greenish
coloring on top of encoded video. It's there whole video
length, being two, maybe three macroblocks in height and
taking full width of video, but when looking carefully,
it's transparent enough so that correct video can be seen
behind it. Mplayer has no problems playing those vids, and
as far as I can tell, encoded audio seems to be correct.
That greenish bar just is annoying. Has someone encountered
this kind of behavior?