[MPlayer-users] vbitrate without frameno.avi

[D Richard Felker III]

On Wed, Feb 18, 2004 at 05:10:10PM +0100, Matthias Czapla wrote:
> Hi!
> 
> So its now dprecated to use frameno.avi. Ok, but how is one supposed to know
> the needed vbitrate to get a file with a specific size? Luckily I dont need
> VBR MP3 so I thought I can just do

Even with VBR mp3 you can do this. The bitrate is very predictable
over the length of a whole movie, and you can measure it during
vpass=1 and then adjust the vbitrate slightly during vpass=2 if you
need to...

> 700 * 1024 * 1024 * 8 / movie_length_in_seconds
> to get the overall bitrate available and subtract the MP3 bitrate from the
> result to obtain the vbitrate for -lavcopts. But this does not work - the
> resulting file 745 Mill. Bytes instead of the desired 733.

AVI files have a good bit of overhead, at least 32 bytes per frame...
This is likely a large part of the problem. Maybe you messed up your
calculations too...? When mencoder finishes, it prints the final
actual audio and video bitrates. Do they match what you asked it to
use?

Rich