[MPlayer-users] bitrate ignored with lavcodec

[Michael Niedermayer]

Hi

On Thursday 09 May 2002 10:56, marcogi at libero.it wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> ,
>
> I,m try to converting mpeg2 captured video to mpeg4 using mencoder
> (09042002 cvs). I use 3-pass mode:
>
> rm frameno.avi
> cat mpeg2files*.mp2|mencoder -ovc frameno -lameopts abr:br=112 -o
> frameno.avi - cat mpeg2files*.mp2|mencoder -v -oac copy -vop
> pp,scale=352:264 -npp tn:100:200:1000 -ovc lavc -lavcopts
> vcodec=mpeg4:vbitrate=570:vpass=1 -o /dev/null - cat
> mpeg2files*.mp2|mencoder -v -oac copy -vop pp,scale=352:264 -npp
> tn:100:200:1000 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=570:vpass=2 -o
> mpeg4file.avi -
>
> I get a low bitrate mpeg4 video (about 340-400 Kbit/sec) indipendently
> bitrate I set. Using vbitrate=700 I got aproxymately same file size and
> bitrate.
> I made many tests using various bitrates and even using vhq and/or v4mv
> options, but problem was still present. From mplayer manual seems that
> defaults for lavcopts I not specify are ok.
try -lavcopts vqmin=2

i guess that lavc encodes all frames at quantizer=3 (highest quality for 
vqmin=3) and so it can never reach a higher bitrate, in that case though the 
resulting file should be good quality

[...]

Michael