[MPlayer-dev-eng] samples which look bad when encoded with lavc 2-pass needed

Michael Niedermayer michaelni at gmx.at
Mon Jul 22 01:48:28 CEST 2002


Hi

On Monday 22 July 2002 00:07, Arpi wrote:
[...]
> Hmm. I don't think that divx4's (xvid use the same) 2pass code is better...
> i've hacked it too much to know it's shit. Imho your code is far better,
> _but_:
> - no one experienced with good values - defaults aren't the best imho
i know, the defaults are mostly just randomly choosen without much testing, 
ill fix these (vqmin should be the lowest bugfree quantizer depending upon 
the used codec, ...)

> - imho it should change bitrate much more agressively, so decrease more for
> simple scenes and increase much for complex parts. i know (at leats i think
> i know :)) that it's just a parameter, i even read it somewhere which one
> :)
vqcomp

the, new, planned (and not yet written) ratecontrol code, should allow more 
precisse control so that texture complexity or amount of motion could affect 
the bitrate independantly

[...]
>
> anyway i also experienced - and read on -users too - a possible bug:
> when the input media is too low quality, so there are parts where the
> maximum reachable bitrate (due to high qmin or missing data) is under the
> wanted one (calculated by 2pass algo), it doesn't (or at least it seems it
> doesn't) distribute these 'free' bits for the remaining part of the movie.
someone should upload such a file

[...]

Michael



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