[MPlayer-users] mencoder options for NTSC television
Martin Collins
martin at mkcollins.org
Tue Jan 14 18:29:38 CET 2003
On Tue, 14 Jan 2003 10:20:58 -0600
Lance Simmons <lance at lsimmons.net> wrote:
> 1. NTSC resolution: one message when I use mencoder says
>
> Supported sizes: 48x32 => 768x480
>
> Does that mean that the height and width I choose have to preserve
> that ratio?
No. NTSC is 640x480 so you could try that. Some of that width may be
useless though. Keep both dimensions divisible by 16 for the encoder.
> 2. vbitrate: higher is better, right?
Up to a point, and from the point of view of quality. Lower bitrate
means smaller files but lower quality.
> How do I decide what vbitrate to use? I've been using 16000,
> and the results look good.
I'm sure they do :-) I have found going much above 3000 is pointless
for PAL. Do some experiments. Add vpass=1 to your -lavcopts then run
TOOLS/countquant.pl < divx2pass.log
after encoding something. You have maximum quality when q=2 is 100%
Aim for 95% as you get diminishing returns bitrate / filesize.
> What's the benefit of going lower?
Smaller files.
> 3. postprocessing: what kind of postprocessing is best? How do I
> decide whether to crop or not? Where in the documentation is there
> a clear description of what the various postprocessing options do?
Nowhere, at least in rc2. doc/mplayer/tech/vop.txt is the closest.
I am currently using:
-vop eq=7:14,pp=lb,unsharp=l3x3:1.5
Any -vop options will slow down your encoding.
Martin
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