[MPlayer-users] Re: mencoder/crop => image distortion

[Steven M. Schultz]

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