[MPlayer-dev-eng] mencoder problem

[Michael Niedermayer]

Hi

On Friday 17 May 2002 12:53, Arpi wrote:
> Hi,
>
> > video options:
> > -lavcopts vcodec=mpeg4:vhq:vbitrate=*:keyint=1000 -vop
> > scale=352:144,crop=72 0:296
>
> for such low resolution and high bitrates, you should allow lower qscales,
> so add vqmin=2 (or =1)
> it was discussed SEVERAL TIMES at -users in past week.
and now it will be disscused several times on -dev
tommorow we'll disscuss it on cvslog ....

> libavcodec is just too good ;)
> so it simply cannot use all bits you give it as it don't need such many
> bits to encode all that :)
>
> Michael: is it safe to set vqmin=1 by default?
no :( and neither is vqmin=2 allways save :(((
it depends on the used format though for mpeg4 vqmin=1 might be ok, but there 
is little quality difference (no encoder uses qscale=1 afaik)

[...]
> > -vpass 1 and -vpass 2  generate same files (diff show no differences)
>
> i doubt - unless all qscale is 3 or the stream is very linear, no low/high
> motion scene changes, or it is too short to get advantage of long-term vbr
i guess all frames are encoded with qscale=3

[...]

Michael

PS: RTFM DOCS/tech/libavc-rate-control.txt ;))))