[FFmpeg-devel] [PATCH] Maximum bitrate FAQ

Stefano Sabatini stefano.sabatini-lala
Mon Sep 3 21:14:29 CEST 2007

On date Saturday 2007-09-01 15:08:29 +0200, Michael Niedermayer encoded:
> Hi
> On Sat, Sep 01, 2007 at 12:59:58PM +0200, Stefano Sabatini wrote:
> > Hi all.
> > 
> > Suggested log: add a discussion for the FAQ: "How can I encode a video
> > without going over a maximum bitrate?"
> > 
> > The given reply is likely somehow incorrect, so improvements and
> > suggestions will be appreciated.
> please test and mention -mbd rd -flags trell and large -lmax
> (testing is so you see yourself what effect they have on the over/underflows
> ... they should have a good one but i think the text will be better if the
> author has used the options himself instead of repeating what someone else
> says ...)

I tested -mb rd and -mb bits getting in some cases an output size 5%
littler, with an encoding time increase of about 30%, in other cases a
less significant improvement; I got similiar results with -flags trell.

For what regards -lmax: I really can't figure out what does it mean,
I tried several values getting the best result (lower bitrate) at 10k,
increasing -lmax the bitrate seems to grow when the quality seem to
stay the same.

I feel like I'd have to understand libavcodec/ratecontrol.c ;-).

Anyway here it is another patch.

Stefano Sabatini
Linux user number 337176 (see http://counter.li.org)
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