How to adjust the luminance of a specific vertical section of a frame?

[Rolletus]

Hi,

Does anyone know if there is an existing function for Avisynth that can be used to adjust the brightness of a specific vertical section of the frame?

One option that came to mind is to try using ColorYUV(off_y = XXX) on a specific part of the frame, but perhaps there is already a ready-made implementation for this?

I’ve attached a screenshot and a short AVI clip showing the problem I’m trying to fix.


[Attachment 93471 - Click to enlarge]

[jagabo]

LWLibavVideoSource("example-1.avi") 

left = Crop(0,0,112,-0)
mid = Crop(110,0,64,-0).ColorYUV(off_y=-3)
right = Crop(174,0,-0,-0)

StackHorizontal(left, mid, right)

Using Overlay() and an alpha mask you could smooth out the edges.

[Sharc]

Alternatively consider shifting the superblacks (y~10...13) up by ~3...4 steps.

[Rolletus]

LWLibavVideoSource("example-1.avi") 

left = Crop(0,0,112,-0)
mid = Crop(110,0,64,-0).ColorYUV(off_y=-3)
right = Crop(174,0,-0,-0)

StackHorizontal(left, mid, right)

Using Overlay() and an alpha mask you could smooth out the edges.

Thanks! I have to study overlay & masking (Crop-approach was something I was familiar with, but using only that alone leaves visible lines)

[Rolletus]

Alternatively consider shifting the superblacks (y~10...13) up by ~3...4 steps.

Thanks for noticing that . My capturing method is able to capture wider than 16-235. Also, if I have understood it right, levels over 16-235 causes problems only if I would do RGB -> YUV conversion somewhere at the process? (usually I try to keep captures in 16-235 range).

[jagabo]

Y levels below 16 will all be crushed to 0, and levels above 235 will all be crushed at 255 upon a limited range YUV to full range RGB conversion. Note that TVs convert YUV to RGB that way for display so super black and super white details will be lost (there will be no visible detail in those areas).