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31st May 2004, 23:30 | #1 | Link |
Registered User
Join Date: Oct 2001
Location: Vienna
Posts: 75
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Color correction?
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? |
1st June 2004, 19:37 | #2 | Link |
budala
Join Date: Oct 2003
Location: U.S.
Posts: 545
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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
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2nd June 2004, 04:13 | #3 | Link |
Hates all his encodes
Join Date: Sep 2003
Posts: 166
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To be honest, I prefer the top pic...
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3rd June 2004, 21:13 | #5 | Link | |
Hates all his encodes
Join Date: Sep 2003
Posts: 166
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Quote:
Also, even if the color is off, the above image seems like an overall better transfer/encode.
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