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-   -   Is Color-Correcting This Tape Possible? (https://www.digitalfaq.com/forum/video-restore/10146-color-correcting-tape.html)

stiltzkin 11-25-2019 12:10 AM

Is Color-Correcting This Tape Possible?
 
7 Attachment(s)
Hello all,

I'm coming to you for help to see what I might be able to do with part of a tape from 1985 I've been working on. I'm not sure if it's even possible to get much out of this, but I've seen some seriously impressive restoration work on this forum so I wanted to give it a shot. I'm also pretty new to this whole process and I'd like to learn.

First, I should list my setup:
Panasonic AG-7650P -> S-Video + XLR -> Diamond VC500 -> Avisynth/VirtualDub

Here's a sample a little over 1 minute in duration in Lagarith format:
https://drive.google.com/open?id=1qg...67hfe3TZypnlcC

I'm also attaching an x264-encoded sample to this post in case anyone just wants to take a cursory look at this without needing to download a 700MB file.

The only thing I've done to this is cuts to include the segments best illustrating the problems I'm going to show in this post - this is otherwise raw with no cropping, colorspace conversion, etc. If I've done something I shouldn't have, let me know.

On to the problems I see with this video:

The segment I'm posting here was filmed indoors, and this camera performed very poorly in low light, like a lot of handheld cameras in the 80s. All things considered, I think the image quality is not that bad; fairly stable, few dropouts/artifacts, and there's a good amount of detail. The problems are largely with color. I've been able to make some decent progress fighting heavy shadows with ContrastMask, here are some examples with those corrections plus deinterlacing and denoising with QTGMC:

http://www.digitalfaq.com/forum/atta...1&d=1574662981

http://www.digitalfaq.com/forum/atta...1&d=1574662981

From the second sample, you can see another problem with the low-light performance, which is that almost no color information was captured in many shots. The man in the hat looks almost as if he's been filmed in grayscale.

The man next to him in the costume has a bright red shirt on, but it's hard to even make this out. Skin tones are basically non-existent:

http://www.digitalfaq.com/forum/atta...1&d=1574662981

This looks more workable - with more lighting in the shot, we get some actual color, although there's a bad greenish-yellow cast here:

http://www.digitalfaq.com/forum/atta...1&d=1574662981

Any views through windows or of objects touched by sunlight have a very heavy blue/violet cast:

http://www.digitalfaq.com/forum/atta...1&d=1574662981

I'm not sure what to call this - chroma bleed? Even if it's not technically chroma bleed, I was able to address it to some degree with FixChromaBleedingMod:

http://www.digitalfaq.com/forum/atta...1&d=1574662988

This helped erase some of the blue cast from the papers on the desk, the side of the calculator, and to some extent on the wall, although the results are a little uneven. I probably need to play with the threshold and blending more.

I've been attempting to color-correct this tape in Premiere (using Avisynth for the few filters I mentioned above, then export to Lagarith with VirtualDub) simply because I find it a lot easier to use the Lumetri color tools, but in the posts I've seen from Sanlyn (I wonder if saying his name summons him to a forum post? :wink2:) it looks like he's using VirtualDub's color tools, which I'm not familiar with. Either way, I've not had much luck. I can't get the skin tones to look natural without wrecking the rest of the color in the frame.

Ideas? Thoughts? Hate mail? Would greatly appreciate your input on this. Thanks so much.

lordsmurf 11-25-2019 12:12 AM

Please edit the post to attach images directly to the post.

In the meantime, I'll read over this quickly. :)

stiltzkin 11-25-2019 12:27 AM

Images fixed, sorry about that.

stiltzkin 11-25-2019 12:47 AM

4 Attachment(s)
I should also mention that one other interesting path I explored was colorizing this video using deep learning, using DeOldify. At first glance, the results are pretty incredible in certain shots, injecting life back into skin tones:

http://www.digitalfaq.com/forum/atta...1&d=1574664101

http://www.digitalfaq.com/forum/atta...1&d=1574664101

Blue cast, be gone!
http://www.digitalfaq.com/forum/atta...1&d=1574664101

http://www.digitalfaq.com/forum/atta...1&d=1574664101

But of course, this is not a real video restoration method - this is a computer discarding all of the original color information and deciding with a classifier what it might have looked like. It gets many things wrong, the colors are often cartoonishly intense, and there's a ton of flicker introduced as the model has trouble deciding what things are in the frame. I'm just including this here because I thought it was interesting, and it gives a reference point for more natural color in certain shots.

traal 12-03-2019 04:45 PM

The "before" images have blacks all the way down to 0,0,0. Before capturing, you may need to adjust the Brightness and Contrast levels to get a good histogram. In my experience with the VC500, I have to increase brightness (always) and reduce contrast (sometimes) to prevent clipping at the low and high ends of the histogram.

stiltzkin 12-03-2019 04:48 PM

Quote:

Originally Posted by traal (Post 65113)
The "before" images have blacks all the way down to 0,0,0.

Thanks for pointing this out. Is there a good way to get a live view of the histogram from the capture card while I'm making adjustments? I've been using AmaRecTV to record.

sanlyn 12-03-2019 09:18 PM

The VirtualDub capture guide shows how to adjust levels and check with the YUV histogram. http://www.digitalfaq.com/forum/vide...-settings.html. In particular see posts #3 and #4. If you don't have legal luma and chroma levels during capture, your color work in RGB will be severely limited.

If you intend to do any post-processing or restoration and repair, you're crippling your effort if capturing to lossy codecs. It also looks as if you'll have to do some serious basic corrections in YUV before going to RGB for further color work.

stiltzkin 12-03-2019 09:36 PM

Quote:

Originally Posted by sanlyn (Post 65116)
The VirtualDub capture guide shows how to adjust levels and check with the YUV histogram. http://www.digitalfaq.com/forum/vide...-settings.html. In particular see posts #3 and #4. If you don't have legal luma and chroma levels during capture, your color work in RGB will be severely limited.

If you intend to do any post-processing or restoration and repair, you're crippling your effort if capturing to lossy codecs. It also looks as if you'll have to do some serious basic corrections in YUV before going to RGB for further color work.

Hey, thank you for the link, I appreciate it. I actually already tried to follow your guide when I was first setting this up, and there's nothing wrong with your instructions, but it seems like I cannot use VirtualDub to capture. It simply does not work in Windows 10. No video preview is ever shown, no matter what options I select. I realize Win10 is a terrible operating system for video work, but it's what I have to work with. Short of reinstalling my base operating system, I tried setting up a Windows 7 VM and attaching the VC500 to it, but I cannot get the drivers in a happy state. The only program that has worked for me for capture is AmaRecTV. Maybe someone else with Win10 and a similar setup can share secrets of how to make this work?

I'm not capturing to lossy formats - I made a point to ensure I was capturing in Lagarith - which to my knowledge is a lossless compression method?

traal 12-04-2019 03:51 AM

I'm using VirtualDub v1.10.4 32-bit version under Windows 10 with the VC500 capture card, 32-bit drivers. The live histogram works but flickers. I find I need to feed the VC500 a real video signal before I start the histogram, otherwise VirtualDub hangs.

stiltzkin 12-04-2019 04:34 PM

I'm trying this yet again, in a Windows XP VM this time. I have the drivers installed, and the card is recognized and passed through to the OS, and yet I still cannot get a video preview.

I'm using this VirtualDub from LordSmurf.

I've tried 1.9.10 and also VirtualDub2 build 243803; the version doesn't seem to make any difference.

Back in Win10 on the host system, I've tried installing ffdshow and copying in the .vdf file as mentioned in this post. Again, no change.

This is quite frustrating.


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