[Ffmpeg-devel] MPEG 2 Quality Issues

Guillaume POIRIER poirierg
Fri Dec 1 09:45:34 CET 2006


On 12/1/06, V?ctor Paesa <wzrlpy at arsystel.com> wrote:
> Hi,
> >
> > ffmpeg -i TestforMPG-Short.avi -vcodec mpeg2video -minrate 7000k
> > -maxrate 7000k -b 7000k -bufsize 5000k -bf 2 -flags +qprd+ildct -flags2
> > +ivlc+sgop -mbd rd -sc_threshold 10000000 -lmin 1 -mblmin 1 -lmax
> > '340*QP2LAMBDA' -f vob -ab 192 ffmpeg.mpg
> >
> > Feel free to add +trell.
> >
> > You must know that every encoder around WILL activate qprd. You can
> > detect it by using -debug 16, if macroblocks have differents values then
> > qprd is activated.
> >
> > Always try to use the largest bufsize for rc, the bigger buffer is, the
> > more rc will be efficient.
> >
> I noticed that ffmpeg -h offers no help for mbd, rd:
> -mbd               <int>   E.V..
>    rd                      E.V..
> Since you have just suggested them, could you please explain in
> a few words what they do?

MEncoder man page has all the details:

              Macroblock decision algorithm (high quality mode),
encode each macro block in all modes and choose the best.  This is
slow but results in better quality and file size.
                 0    Use mbcmp (default).
                 1    Select the MB mode which needs the fewest bits (=vhq).
                 2    Select the MB mode which has the best rate distortion.

An association of men who will not quarrel with one another is a thing
which has never yet existed, from the greatest confederacy of nations
down to a town meeting or a vestry.
 -- Thomas Jefferson
(when interviewed about MPlayer ML flamewars)

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