[MPlayer-users] variable bitrate for the video?

[Wendy Tromp]

> Hm? Bitrate should be variable by default with most of the codecs. What
> codec are you trying? Normally you have to specify parameters to make the
> bitrate constant.

I realise now that 2-pass encoding is for variable bitrates, but I don't
quite get how that works. I know that the first pass is for getting
information about the movie and that in the second pass this information is
used. I am now doing the following commands:

mencoder -ovc lavc -lavcopts
vcodec=mpeg4:vhq:vpass=1:vbitrate=1200:v4mv -passlogfile=/mnt/log.log -oac
mp3lame -lameopts br=192 movie.avi -o movie_encoded.avi

and

mencoder -ovc lavc -lavcopts
vcodec=mpeg4:vhq:vpass=1:vbitrate=1200:v4mv -passlogfile=/mnt/log.log -oac
mp3lame -lameopts br=192 movie.avi -o movie_encoded.avi

Now this results in a movie of about 10 megs per minute, and decent quality,
but I actually have no idea what I am doing. I am very curious about the
vbitrate part, what it does, and when it is useful to specify it. Does it
indicate the minumum bitrate or the maximum or what?

can anyone help me with this?
Wendy