Color correction?

[resonator]

Hi!

I have a HK dvd which is non-anamorphic (and combed as hell) but has pretty nice colors, and I have an anamorphic dvd as well, but it's lacking the original Cantonese audio track, so I'm trying to merge both for a decent copy. The anamorphic dvd is PAL, I resized the picture and speeded it down (and cut a few frames here and there in order to sync it to the unaltered 5.1 track) to 23.976 fps.

However, the anamorphic source has an ugly green tint, which I'd like to get rid of.

Here are 2 pics:

http://www.estatemusic.net/SCREENS/genx_ger_01.jpg

http://www.estatemusic.net/SCREENS/genx_hk_01.jpg

Any ideas on how to "color correct" the top picture?

[trevlac]

I'm a bit of a novice, but here is how I'd approach it.

step #1: Get white white

The white dress is a nice guide. The green source seems to have white offset towards yellow.

Just a quick YUV primer here ... If you map U&V on a graph, U is the horizontal, and V is the vertical. At the origin (0,0) is where white and black should be, because U&V should both be 0 for white/black. Next thing to know is take your graph, make it a circle with 0,0 at the center, and map colors around it. Red starts a little left of the top (11:30), and around goes magenta, blue, cyan, green, yellow. Each about 60 degrees appart.

So, yellow is in the upper left quadrant, down close to the horizontal (U) axis. For this pic, the U needs to be shifted to the right.

The following will move white to the right and down just a bit.
colorYUV(off_u=15, off_v=-2)

These values are a compromise. It looks like you white stays a bit yellow, but blacks start to move past the center into blue. If you increase the u offset to make the dress more white, the blacks will turn blue. I moved the v down a hair because the white dress looked a bit too red after U was moved.

The result of the above will be too dark. Next, drop the black down a bit (with bright) to cover the fact it contains blue, and increase the contrast to brighten the entire picture.

Tweak(bright=-10,cont=1.7)

step #2: Fix the colors

It seems to me that red is too low and blue maybe a bit.
To fix red alone, i made a version of Tweak that allows you to target a given color.

TweakColor(sat=1.7,startHue=80,endHue=140)

This increases the saturation of red alone. Look on the forum for TweakColor for more info.

warnings/more info

• You can put the bright and cont parms in tweakcolor.
• This is not easy to do. The more you try to get it perfect, the more you can mess up another frame.
• I would not touch blue unless you have alot of blue. Increasing blue will make black blue.
• You can also kill green/yellow a bit, but this might mess up a scene with green
• You can change the hue a bit with: TweakColor(hue=5,startHue=120,endHue=260) but you could get contors if you are not careful. This would make the skin tone a little better.
• !! Please check on a TV if you are going to view on a TV

[dbzgundam]

To be honest, I prefer the top pic...

[resonator]

trevlac: Interesting take, gonna try that tonight. Thanks!

dbzgundam: Don't you mind the completly unnatural skin tone?

[dbzgundam]

Originally posted by resonator
trevlac: Interesting take, gonna try that tonight. Thanks!

dbzgundam: Don't you mind the completly unnatural skin tone?

It looks like the scene had lighting to make it look that way, rather than it being off.

Also, even if the color is off, the above image seems like an overall better transfer/encode.

[HighInBC]

a MUCH easier way to wake your whites white:

http://forum.doom9.org/showthread.php?t=96042