Levels(0,1,128,0,255) - why does it work like that with U and V?

[Sharc]

Originally Posted by rgr

Look post #2.

This doesn't make any sense to me. Which codec produced such mess? Certainly not regular DV, unless the camera or capture device is broken, or some weird script has been applied.

[rgr]

Originally Posted by Sharc

This doesn't make any sense to me. Which codec produced such mess? Certainly not DV, unless the camera or capture device is broken, or some weird script has been applied.

This is a rip from a DV camcorder.

[Sharc]

Originally Posted by rgr

Yes, I noticed that it doesn't work. White (YUV 255,127,127) stops being white (UV -> ~120). The image becomes greenish overall.

For presenting visible colors YUV data need to be transformed to RGB by using a set of equations, for example following ITU specs ITU-BT.601-7 or ITU-BT.709-6, or according to the matrix used by Avisynth, etc. So the viewable color (what you eventually see on the PC monitor or TV) depends on the matrix (=set of equations) which is applied to the YUV data.
White is RGB(255,255,255). It is represented by YUV(235,128,128) using Avisynths's standard matrix, or YUV(255,128,128) using the ITU- "studio" matrices.
In either case your YUV(255,~120,~120) produces out-of-gamut RGB which get clipped in one or several of the R,G,B components (depending on the matrix), means distorted colors - which you apparently observed as becoming "greenish" in your case.

For example, if you use the ITU 601 "studio" matrix the YUV(255,120,120) would be transformed to RGB(244,263,241), but the green (263) would usually be clipped at 255 (8bit), so finally RGB(244,255,241).
If you use the standard Avisynth 601 matrix (limited range YUV-> full range RGB) the YUV(255,120,120) would be transformed to RGB(266,288,262), but all 3 components would usually be clipped at 255 (8bit), so finally RGB(255,255,255) which is just plain WHITE, loosing any structure or picture details.

You may also want to take a look at "Gavino's classic" here:
https://forum.doom9.org/showthread.php?t=154731

[Sharc]

Originally Posted by rgr

This is a rip from a DV camcorder.

How did you rip this?