[MPlayer-users] Re: mencoder/crop => image distortion
Steven M. Schultz
sms at 2BSD.COM
Mon Jul 28 22:13:18 CEST 2003
On Mon, 28 Jul 2003, D Richard Felker III wrote:
> No, you mkisunderstood entirely. You don't want either. I was just
No, I understood. My question was perhaps not completely formed
though.
Although you may not want either noise or black borders which
is worse?
For example if I have to have a 720x480 size (for a DVD) and that
the edges have noise (either from the VCR/tape or whatever) which
of the two choices (blacken or crop) is less bad? Scaling a
cropped image can degrade the picture so is that better than using
a few extra bits?
Are there any firm numbers showing the effect of cropping vs
blackening vs crop&scale?
> saying that usually the first 2-4 pixels of the actual image have a
> lot of noise, so it's usually good to crop them off along with the
Junk from the original film source I think - at least in some
cases.
> black borders, especially if that helps you get a size that's nice
> multiples of 16.
Many of the DVDs made from analog sources (old TV/Tape shows) I've
seen are NOT 'borderless' - so they're obviously not cropping at all
(in fact one can see all sorts of "noise" in the area that TVs don't
display due to overscan). I was surprised they didn't blacken the areas
instead of encoding all the noise. With a higher bitrate limit and
the ability to use two ~4GB layers perhaps they're not overly
concerned about a few bits here and there?
Steven Schultz
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