[MPlayer-users] a/v sync problem and corrupted AVI written by mencoder

[Matthias Welwarsky]

Hi all,

I'm trying to rip a DVD to a Mpeg4/MP3 AVI file with mencoder. The process 
seems to complete all right, and I can playback the file with mplayer or 
xine.

However, when I look at the file content with VirtualDub, I can see several 
oddities:

First, VirtualDub complains about the audio being VBR. I used the following 
commandline to rip the DVD:

mencoder dvd://1 -alang en -ovc lavc -lavcopts vcodec=mpeg4:vhq:vbitrate=800 
-vop crop=640:274:0:44,scale -zoom -xy 640 -oac mp3lame -lameopts 
abr:br=128:vol=1 -o output.avi

Obviously I told mp3lame to encode 128kbit/s CBR, so why doesn't it comply?

Second, looking at the structure of the AVI, I can see that the MOVI chunk's 
internal structure is damaged. One of the frames has a wrong length header 
and so the chain is broken. This will break all players that don't use the 
index chunk for playback. Mplayer and xine are fine, but it's a bug in 
mencoder nevertheless.

I'm using MPlayer-1.0pre3 and lame 3.94beta, compiled from source
System: SuSE 9.0, gcc 3.3.1

-- 
Matthias Welwarsky
Fachschaft Informatik FH Darmstadt
Email: matze at stud.fbi.fh-darmstadt.de

"all software sucks equally, but some software is more equal"