[MPlayer-users] Efficiently cutting black border above and adding below

[Alexander Roalter]

Thomas Heuving wrote:
> Hello,
> I have a MGEG2-Video which I want to burn on DVD. The format is
> correct, but there are subtitles below the picture (in a black
> border) which aren't shown entirely on a TV screen. Therefore I want
> to cut a part of the black border above the picture and to add the same
> amount of black border below.
> I can do that with 
> 
> mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=dvd -ofps \
> 30000/1001 -vf crop=720:456:0:24,expand=720:480:0:0,harddup -lavcopts \
> acodec=ac3:abitrate=128:dc=10:vcodec=mpeg2video:vrc_buf_size=1835:\
> vrc_maxrate=9000:vbitrate=2600:keyint=15:trell:mbd=2:aspect=4/3 \
> -af-adv force=1 -srate 48000 -af lavcresample=48000,volnorm -o \
> "$newfile" "$file"
> 
> but this will recode the whole file. Is there any way to do it more
> efficiently?
I don't think there is a way to do it more efficiently. Maybe someone 
knows a way how to do it if you shift your picture by a multiple of 16 
since then the macroblocks could be reused, but only on a different 
position (though I deem there's no such program around).

OTOH I don't know how this is a problem. I reckon you're playing a 
non-anamorphic widescreen video on a widescreen TV set, which (in Zoom 
mode) clips the subtitles found in the black bars. Modern Widescreen TVs 
should offer an option to shift the output when doing zoom (at least my 
$500 TV-set does).

Still I think you're stuck with reencoding, but hey, with mpeg2 this 
won't take *that* much time.

-- 
cheers,
Alex