[MEncoder-users] Re-encoding mpeg-2 to Xvid problem.

[Emery Guevremont]

Hello everyone,

I've done a lot of research on this mailing list and google, but I still 
haven't found an answer to my problem. I recently set up a job on my 
mythtv box so I can re-encode my mpeg-2 recording to Xvid, but I can't 
seem to get a consistantly decent avi file size after the re-encoding.

Let's say I re-encode a mpeg-2 file, and its size is 4Gb, well lately 
I've only been able to reduce my 4Gb mpg file to a 2Gb avi file. Now 
here's the command I've been using.

/usr/bin/mencoder -quiet Reindeer_Games.mpg -oac mp3lame -ovc xvid 
-xvidencopts pass=1:bitrate=687 -o /dev/null
/usr/bin/mencoder -quiet Reindeer_Games.mpg -oac mp3lame -ovc xvid 
-xvidencopts pass=2:bitrate=687 -o Reindeer_Games.mpg.avi

I've played around a lot with the bitrate option, and at one point I was 
able to use 800 for bitrate and reduce a 4Gb mpg to a 700Mb avi for my 
recordings. But one day I increased my bitrate to 1300, but I quickly 
saw that it was too high of a bitrate for mencoder to significantly 
shrink with. So I slowly started decreasing my bitrate down to 800 and 
now 687 and I'm still not able to get the results I used to get when I 
first started re-encoding with a bitrate of either 687 or 800.

The strange thing is, if I rerun the same command on my new avi file 
(let's say Reindeer_Games.mpg.avi) with this command:

/usr/bin/mencoder -quiet Reindeer_Games.mpg.avi -oac mp3lame -ovc xvid 
-xvidencopts pass=1:bitrate=687 -o /dev/null
/usr/bin/mencoder -quiet Reindeer_Games.mpg.avi -oac mp3lame -ovc xvid 
-xvidencopts pass=2:bitrate=687 -o Reindeer_Games.mpg.avi.avi

then I'll be able to shrink my avi down to something like 700Mb.

Anyone understand what I'm saying and what I need to do to fix this?