VHS capturing - luma/chroma crosstalk? What do you think?

[Pinto007]

An S-VHS deck is no panacea. (...) They don't work well with tapes recorded at lower speeds.

If I may add - I agree totally (as I've brought up in post #6)

I don't agree. I have some LP recordings made on AKAI VHS, and Panny S-VHS plays them a lot better than AKAI! So don't mislead other users.

[rgr]

Some horizontal jitter is expected even after a line TBC. The TBC can't tell why a line is shorter or longer than normal. All it can do it stretch or compress it to the right length. For example a line may be short because the video head was spinning at the right frame rate for half the line then too fast for the second half. If the line is then stretched evenly the left half will be too long and the right side will still be too short and only line up at the far right.

I noticed in The Mask capture there is ghosting a few pixels to the right in image. I came up with a function to reduce that:

function DeGhost(clip source, int shift, float strength)
{
   ygain = int(strength*256.0) - 256
   shifted = source.Crop(0,0, -shift, -0).AddBorders(shift, 0, 0, 0)
   shifted = shifted.ColorYUV(gain_y=ygain, cont_u=ygain, cont_v=ygain)
   Overlay(source, shifted, mode="Subtract")
   ColorYUV(gain_y=256+ygain, cont_u=256+ygain, cont_v=256+ygain)
}

ffVideoSource("capture-3.mov") 
ConvertToYV12()
Crop(8,60,-8,-72)
DeGhost(last, 6, 0.15)  # reduce ghosting
vInverse()  # clean up a little residual comb artifacts
Spline36Resize(width/2, height)  # reduce dot crawl artifacts
TemporalDegrain(SAD1=100, SAD2=75, sigma=4)  # reduce noise
MergeChroma(Santiag(), aWarpSharp(depth=20))  # antialias luma, sharpen chroma
TurnRight().nnedi3(dh=true).TurnLeft()  # restore width
Sharpen(0.2, 0.0)  # a little horizontal sharpen

Sample attached.

Never use aWarpSharp2 - it changes the geometry of objects.

[Sharc]

Never use aWarpSharp2 - it changes the geometry of objects.

Bad general advice (and 10 years late anyway). The filter is applied on the smeared VHS chroma only. The benefit by far outweights any 'geometric deformation' which in this case is actually desired.

[rgr]

Never use aWarpSharp2 - it changes the geometry of objects.

Bad general advice (and 10 years late anyway). The filter is applied on the smeared VHS chroma only. The benefit by far outweights any 'geometric deformation' which in this case is actually desired.

Overall, this is very good advice.
https://www.diffchecker.com/image-compare/KrM6LOCz/
https://www.diffchecker.com/image-compare/i3Eur9Oj/

[dubster]

Note - Sharc said "chroma". Your "diffchecker" images include luma sharpening, so you're not comparing the kind of change Sharc talked about.

[rgr]

Note - Sharc said "chroma". Your "diffchecker" images include luma sharpening, so you're not comparing the kind of change Sharc talked about.

Yes, my mistake. However, I'm curious if this actually works for chroma.

[Sharc]

Note - Sharc said "chroma". Your "diffchecker" images include luma sharpening, so you're not comparing the kind of change Sharc talked about.

Yes, my mistake. However, I'm curious if this actually works for chroma.

It is very effective. Use it with mergechroma(....) and watch the chroma using UtoY() and VtoY(). Also see the last comment here:
https://forum.doom9.org/showthread.php?p=2030758#post2030758