How to color correct a video like this?

[Hypersonic1]

I can't seem to improve the image.

[Cornucopia]

What's your reference?

Scott

[Hypersonic1]

I'm not sure what you mean. I know I can't use a white balance tool. It won't do much to correct the image.

[theewizard]

do you have another image / frame another video ?

to show what the color is supposed to look like ? aka reference

[Hypersonic1]

No, I am not sure how it should look like. I just know that some types of lighting negatively affects the color accuracy of the camera.

[Cornucopia]

The lighting (both lamp type and default white point), the WB setting on the cam, the color(s) of the walls and other reflectors, all affect the look.
Skin tone might have been a reference, but there's only a very small sliver. Hair color? Emergency exit sign should be standardized, but not sure about that one.

Scott

[manono]

Post a sample of the video.

[LMotlow]

Post a sample of the video.

There's a a sample in post #5 but it's been through some bad processing and isn't an original.

No, I am not sure how it should look like. I just know that some types of lighting negatively affects the color accuracy of the camera.

That "sample" is not an original capture. It's VHS or other analog tape capture to a lossy DV codec, , and re-encoded (as interlaced?) to another lossy codec. That will also affect what you can do with it because you don't have the original color data. And who wants to fool with the distortion your re-encoding caused? The lighting is indoor fluorescent, which also affects the color. Don't you have a piece of the unprocessed original capture? Second question, do you know what the terms "unprocessed" and "original" refer to?

[Hypersonic1]

Post a sample of the video.

There's a a sample in post #5 but it's been through some bad processing and isn't an original.

No, I am not sure how it should look like. I just know that some types of lighting negatively affects the color accuracy of the camera.

That "sample" is not an original capture. It's VHS or other analog tape capture to a lossy DV codec, , and re-encoded (as interlaced?) to another lossy codec. That will also affect what you can do with it because you don't have the original color data. And who wants to fool with the distortion your re-encoding caused? The lighting is indoor fluorescent, which also affects the color. Don't you have a piece of the unprocessed original capture? Second question, do you know what the terms "unprocessed" and "original" refer to?

Yes, I know what you mean. Actually, it was uncompressed 422 encoded to lossy H.264. I was worried about the large file size. How long should the video be because even a few seconds is large?

[raffriff42]

The blue channel is hosed.

[Attachment 43948 - Click to enlarge]

One thing to try, is faking it:

[Attachment 43949 - Click to enlarge]

In Avisynth,

MergeRGB(
\   ShowRed,
\   ShowGreen,
\   Grayscale.ShowBlue )

Still leaves lots of secondary issues - blown out highlights, fringing, shading. Good luck with all that.

[Hypersonic1]

Here is the original.

One thing to try, is faking it:

Doesn't that just make the image black and white?

[raffriff42]

Doesn't that just make the image black and white?

Nope. You copy grayscale (luminance) information to the blue channel and leave the other two channels alone. The result is posted above and while it's not pretty, it's not grayscale. I show the AviSynth script I used, but the same thing can be done with many other programs.

BTW here's the blue channel alone - overloaded by the fluorescent lights (I guess) and beyond color correction:

[Attachment 43954 - Click to enlarge]

[Hypersonic1]

So there is nothing that I can do?

[manono]

Thanks, LMotlow. Don't know why I didn't notice the link 2 posts above mine.

Since I work almost entirely with black and white sources, I've had next to no experience with the AviSynth filter GamMac. But it does seem to make a big improvement and I'm sure it can be tweaked to give better results. Notice the huge gamma boost to the blues.

ConvertToRGB24()
GamMac()
ConvertToYV12()

[jagabo]

From the earlier mp4 file. The guy's a bit too purple, over saturated, and needs a little more adjustment...

brights = ColorYUV(off_u=61, off_v=-5)
darks = ColorYUV(off_v=-2)
bmask = ColorYUV(gain_y=100, off_y=-40, gamma_y=50).GreyScale()

Overlay(darks, brights, mask=bmask)

[jagabo]

I initially assumed the walls were white but that made the guy look even more purple. So I used the sign on the wall as my white reference.

[manono]

Right, I also noticed GamMac at default settings made the guy's clothes (and the ceiling) purple-looking. I didn't check on saturation. I was only trying to demonstrate that something can be done with it, and if it were my video I'd have made it look much better. And you demonstrated that not only can something be done, but that it can come out looking decent. Nice work.

[jagabo]

I was only trying to demonstrate that something can be done with it

Same here. He can fine tune the mask, adjust the saturation, levels, etc. to get the look he wants.

[Hypersonic1]

Unfortunately, I don't understand the v's and y's. I wish I could use Premiere instead of Avisynth.

[LMotlow]

I was only trying to demonstrate that something can be done with it

Same here. He can fine tune the mask, adjust the saturation, levels, etc. to get the look he wants.

Won't be easy. Make adjustments for one segment of the clip, other segments get wacky. It ain't easy trying to out-guess and out-distort the camera's auto controls. Besides the lighting problem and color reflecting off the walls, the camera's autocolor and autowhite change levels, gamma, and color balance at least 3 times during the clip. Compromise is all you can do, thanks to the camera's automatic "features".

Jagabo's sample is neat work, even if the sign on the wall isn't white (it's cyan) and the guys look purple (because there's too much blue), but reduce blue and you're almost back where you started with yellow-green. Hospital hallway walls sre almost always really white or off-white, maybe with a very pale institutional-green tint, but you'll never get there with that lighting reflected off the semi-gloss surface. Jagabo's fix is about as clean as it will get, even if you tweak it in Premiere.

Those camera features are the work of evil spirits. When Hollywood shoots scenes like this they bring their own lights and expose manually with compensating filters, and then the lab guys apply an LUT color correction scheme. It takes a little more than Premiere Pro, which is fine for amateurs. What it takes is a few million bucks.

[poisondeathray]

Unfortunately, I don't understand the v's and y's. I wish I could use Premiere instead of Avisynth.

If you want something close to jagabo's result use the channel mixer in PP . I just "eyeballed" this but effect => channel mixer (RR 105, GG 100, BR 25, BG 25, BB 120) . Adjust it how you want


Or you can do the channel swap similar to RR42's approach in AE . You can do a weighted channel repair (you might not want 50-50) using shift channels , to reconstruct the B from the R and G instead of greyscaling it e.g. blue to red, blue to green, original blue . To toggle just adjust opacity layers . (or you still have the option to greyscale the blue). Same thing in avisynth could be done using merge() with the weights, and mergergb()


A third approach is to use the color cast removal, eye dropper technique . Similar to photoshop where you pick a white, middle grey, and black point and it will shift the RGB curves. You can do that in color finesse for example in AE . CC Color Neutralizer in AE is basically very similar


A fourth is to selectively desaturate a range . For example the hue/saturation filter affecting "yellows"


You can mix and match the approaches to maybe get slightly better results . But the key thing to remember is you will never get something looking completely normal because the blue channel is crushed and missing so much information

[Hypersonic1]

I am trying to add that code, but I am getting the error:
Avisynth open failure:
Script error: Invalid arguments to function "ColorYUV"

video = AviSource("c:\videos\test.avi")

brights = ColorYUV(off_u=61, off_v=-5)
darks = ColorYUV(off_v=-2)
bmask = ColorYUV(gain_y=100, off_y=-40, gamma_y=50).GreyScale()
Overlay(darks, brights, mask=bmask)

video = ConvertToYV12(video, interlaced=true)
video = AssumeBFF(video)
video = QTGMC(video,Preset="Placebo",EZDenoise=1.5)
return video

[jagabo]

Remember, when you don't specify a stream by name the stream "last" is used. You have created a stream called video. But all your ColorYUV calls are trying to use stream last.

[manono]

Keep it simple, especially if you don't fully understand what you're doing and/or are using bits and pieces of scripts you saw in different places. This might work:

AviSource("c:\videos\test.avi")

brights = ColorYUV(off_u=61, off_v=-5)
darks = ColorYUV(off_v=-2)
bmask = ColorYUV(gain_y=100, off_y=-40, gamma_y=50).GreyScale()
Overlay(darks, brights, mask=bmask)

ConvertToYV12( interlaced=true)
AssumeBFF()
QTGMC(Preset="Placebo",EZDenoise=1.5)

[Hypersonic1]

I changed it, but it still says invalid arguments to function "ColorYUV" on line 2 (if the white space is removed).

[Hypersonic1]

AviSource("c:\videos\a.avi")
ConvertToYV12(interlaced=true)
brights = ColorYUV(off_u=61, off_v=-5)
darks = ColorYUV(off_v=-2)
bmask = ColorYUV(gain_y=100, off_y=-40, gamma_y=50).GreyScale()
Overlay(darks, brights, mask=bmask)
AssumeBFF()
QTGMC(Preset="Placebo",EZDenoise=1.5)

It works now. I had to convert to YV before using ColorYUV. However, it would only let me choose YV12; YV16 didn't work.

[manono]

That's why I said 'might', in case your original video wasn't already YV12 (or YUY2?). You never said, we didn't have a source video to use for testing, and all we had to go on was an already YV12 MP4. I'm glad you got it going.

[Hypersonic1]

You never said, we didn't have a source video to use for testing, and all we had to go on was an already YV12 MP4.

Post #11 is uncompressed 422.

Thanks for your help.

[aedipuss]

what f'ing good is the 08.avi? looks like a couple seconds of a drunk walking away down a plain hall. no color references available at all.

[manono]

Post #11 is uncompressed 422.

Damn, that's twice I missed the videos you uploaded. I apologize. Had I seen and downloaded that one I would have moved the 'ConvertToYV12(Interlaced=True)' line where it was supposed to go in the script. But you figured it out yourself.

what f'ing good is the 08.avi? looks like a couple seconds of a drunk walking away down a plain hall. no color references available at all.

That's the whole point of this thread - to try and make something decent of that lousy source. And something decent was made.