[MPlayer-users] File size inverse prop. to bitrate?

[Michael Niedermayer]

Hi

On Wednesday 01 May 2002 10:49, marcogi at libero.it wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> Last day happened something strange to me.
>
> I used 3-pass to encode mpeg2 files to divx4:
>
> rm frameno.avi
>
> cat mpeg2file[01]*|~/work/mplayer/mencoder -ovc frameno -lameopts
> vbr=3:q=5 -o frameno.avi -
>
> cat mpeg2file[01]*|~/work/mplayer/mencoder -v -oac copy -vop
> pp,scale=352:264 -npp tn:100:200:1000 -ovc lavc -lavcopts
> vcodec=mpeg4:vhq:vbitrate=565:vme=5:vb_strategy=1:vqcomp=0.6:vpass=1 -o
> /dev/null -
>
> cat /mnt/media/sttng[01]*|~/work/mplayer/mencoder -v -oac copy -vop
> pp,scale=352:264 -npp tn:100:200:1000 -ovc lavc -lavcopts
> vcodec=mpeg4:vhq:vbitrate=565:vme=5:vb_strategy=1:vqcomp=0.6:vpass=2 -o
> divx4file.avi -
>
> Well, divx4file.avi I got was about 160MB.
> Then I tryed to encode at 550 bitrate using the same audio from
> frameno.avi:
>
> cat mpeg2file[01]*|~/work/mplayer/mencoder -v -oac copy -vop
> pp,scale=352:264 -npp tn:100:200:1000 -ovc lavc -lavcopts
> vcodec=mpeg4:vhq:vbitrate=550:vme=5:vb_strategy=1:vqcomp=0.6:vpass=1 -o
> /dev/null -
>
> cat mpeg2file[01]*|~/work/mplayer/mencoder -v -oac copy -vop
> pp,scale=352:264 -npp tn:100:200:1000 -ovc lavc -lavcopts
> vcodec=mpeg4:vhq:vbitrate=550:vme=5:vb_strategy=1:vqcomp=0.6:vpass=2 -o
> divx4file.avi -
>
> This time I got a 200MB file. Is this normal?
RTFM
 vb_strategy=X    strategy to choose between
                                 I/P/B frames :
                                   0 allways use max B
                                   1 avoid B frames in high
                                     motion / scene change (can
                                     lead to filesize miss
                                      ^^^^^^^^^^^^^^^^^^^
                                     prediction)
                                     ^^^^^^^^^^
                                 default = 0

> btw, where all lavc options are explained? I did not find nothing in ffmpeg
> docs.
manual page of mencoder

> And, again, how tn and vb/hb vop filters thresholds work?
mplayer -npp help

[...]

Michael