[MPlayer-dev-eng] [PATCH] (mencoder) lavc option "notch_matrix"

Michael Niedermayer michaelni at gmx.at
Sun Oct 19 21:26:39 CEST 2003


Hi

On Sunday 19 October 2003 21:04, Steven M. Schultz wrote:
[...]
> > btw, does anyone know why this matrix is supposed to be better then the
> > default? did anyone do any tests? PSNR?, double blind subjective?
>
> 	Comparing the tables they give to the default MPEG-2 tables
> 	it looks like the high frequencies are quantized very differently.
> 	"Roll off" isn't the right term but that's what comes to mind.
>
> 	I've used the Kvcd tables as well as the TMPGEnc tables in
> 	mpeg2enc (mpeg2 encoder from mjpegtools).   Not double blind
> 	testing but the resulting video was fine to me (not having golden
> 	eyeballs, using an older TV set, etc ;)).
>
> 	The difference in bitrate was a big surprise.   Using "-K kvcd"
> 	with mpeg2enc the average reduction in bitrate (as reported by
> 	mplex) was 20% (depends on the -q or quality setting - sometimes
> 	the savings was closer to 12%, other times 25%).   The TMPGEnc
> 	tables split the difference between the default and Kvcd tables -
> 	usually around 10-15% savings over the default tables.   Much
> 	depends of course on the source of the material being encoded.
yes, but thats meaningless, i mean just use 99 or 255 for all enries, dunno 
which is tha largest which doesnt overflow, and u get a nice reduction of 
bitrate at the same q but the quality will also suffer seriously

[...]
-- 
Michael
level[i]= get_vlc(); i+=get_vlc();		(violates patent EP0266049)
median(mv[y-1][x], mv[y][x-1], mv[y+1][x+1]);	(violates patent #5,905,535)
buf[i]= qp - buf[i-1];				(violates patent #?)
for more examples, see http://mplayerhq.hu/~michael/patent.html
stop it, see http://petition.eurolinux.org & http://petition.ffii.org/eubsa/en



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