[MPlayer-users] to use b-frames with mencoder

[Corey Hickey]

Betto Pinguino wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> hi, first at all sotty for my bad english
> a stupid question but b-frames with lavc are active by default or isn't?
> because in docs documents:
> 
> vmax_b_frames 0-4 (maximum number of B frames between non B frames)
>         0 no b frames (default)
>         0-2 is a sane range for mpeg4
> 
> and i think that is not active by default...but then there is this
> command line:
> 
> vb_strategy 0-1 for pass 2
>         0 allways use the max number of B frames (default)
>         1 avoid B frames in high motion scenes (this will cause bitrate
>           misprediction)
> 
> so if i use this line i use or not b-frames?
> 
> mencoder -oac copy -o /mnt/divx/file_finale.avi -ovc lavc -lavcopts
> vcodec=mpeg4:vbitrate=10000:vhq:vpass=2:keyint=50 -vop
> scale=592:352,pp=0x20000 -mc 1 /mnt/divx/film.vob
> 
> very very thanks
> 

The default is for vmax_b_frames to be 0, so unless you specify
vmax_b_frames to be something else, the value of vb_strategy doesn't
matter (since the maximum number of B frames is still zero). The line
you provided does not include vmax_b_frames, so no B frames will be
used.

A few notes:
1. vbitrate=10000 is extremely high (about as much bitrate as in a DVD,
which kind of defeates the purpose of re-encoding). You'll get very big
files.
2. Don't forget to crop out any black borders: -vop crop=<something>
3. Read DOCS/tech/encoding-tips.txt

-Corey