Quantcast Multicamera VHS video restoration filtering? - digitalFAQ Forum
  #1  
05-24-2020, 01:25 AM
babydealshunter babydealshunter is offline
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Hi,

I'm attempting to digitize and improve on a recording of a music recital that spliced from 3 different cameras/angles into 1 continuous 2 hour VHS tape. I was hoping for some insight on how to approach filtering 3 different angles intertwined into a 2 hour tape and specific filter settings for each camera angle. I attached a short clip which happens to contain all 3 camera views which is representative of the 2 hour recital that switches between the 3 views for each song.

The capture was done with JVC HM-DH40000U (all NR settings OFF) via S-video to ATI AIW 9700 PRO AGP using VirtualDub in WinXP with HuffyUV (filtered results saved using Lagarith)

VirtualDub was used for the original capture. I previewed the histogram before capture and boosted the brightness (155) and lowered the contrast (100) since it was clear the entire tape had extremes at both ends of luminosity.

Using VirtualDub, I used:
Gradation Curves filter (Y/U/V mode) [exported the settings, attached the .amp file]
Color Mill Saturation (Dark -13, Middle -20, Light -70)
Brightness/Contrast (Bright -3%, Contrast 106%)
Color Equalizer (R -2, B -4)
Dynamic Noise Reduction (12)
Crop/Resize with letterbox

Additionally, I blended the second cut (overexposed with yellow color cast) with internal HSV filter (Hue +2, S -69%, V -35%)

I elected to blend filters because I thought splitting and reintegrating all the different cuts would be extremely tedious. Though if that is the recommended workflow, I'll roll up my sleeves and get to work

I didn't intend to use so many filters. I just played around with a bunch of filters to try to make incremental improvements over several days. And when I attempted to replicate the changes in another existing filter in attempt to consolidate into few filters, the result often was worse.

I've been reading up on AVIsynth, haven't tried it yet as I'm not sure how to approach using it on a capture than switches between 3 scenes that need different settings. That's why I stuck with VirtualDub and used blended filters

I'm looking for suggestions on:
1) Specific alternate filtering settings
2) Alternate workflow to address correcting 3 different camera scenes interspersed in a 2 hour video
3) How do I remove that streak frames 87 and 88? It happens frequently in the first third of the capture and infrequently in the last 2/3rds

I've attached sample from original capture, my multilayered virtualdub filtering attempt, and the gradation curves export file (my other filter settings are written above)


Attached Files
File Type: avi Pianocap.avi (19.04 MB, 11 downloads)
File Type: avi pianocap-blended.avi (18.67 MB, 6 downloads)
File Type: txt Pianocap.amp.txt (1.3 KB, 2 downloads)
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  #2  
05-25-2020, 12:38 AM
Winsordawson Winsordawson is offline
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The streak you see on frame 87 and 88 can be removed in Avisynth with RemoveDirtMC(). Regarding the filter choices, I know that the brightness/contrast filter is quite destructive in Premiere Pro due to the way it crushes your blacks and whites. For that reason, it is not recommended. If you see this happening in the YC waveform while applying this filter in VirtualDub, I would advise not to use it either. It is better to control the blacks and whites separately, such as with Color Mill.

If each of the camera shots have a different color cast, you are going to spend a considerable amount of time correcting each scene. This might be easier to do in a NLE because you can splice each scene wherever you like and apply a color correction to it. Doing that in Avisynth will be tedious.
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06-02-2020, 01:58 PM
babydealshunter babydealshunter is offline
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Quote:
Originally Posted by Winsordawson View Post
The streak you see on frame 87 and 88 can be removed in Avisynth with RemoveDirtMC(). Regarding the filter choices, I know that the brightness/contrast filter is quite destructive in Premiere Pro due to the way it crushes your blacks and whites. For that reason, it is not recommended. If you see this happening in the YC waveform while applying this filter in VirtualDub, I would advise not to use it either. It is better to control the blacks and whites separately, such as with Color Mill.

If each of the camera shots have a different color cast, you are going to spend a considerable amount of time correcting each scene. This might be easier to do in a NLE because you can splice each scene wherever you like and apply a color correction to it. Doing that in Avisynth will be tedious.
Thanks for your suggestions! I was able to remove the streak using the RemoveDirtMC and I think I made some improvements in the color using ColorMill.

I noticed that when a bright area has a dark area adjacent to the right, the dark area seems to have a black patch/halo. I took a screen grab and and pointed out what I am seeing. It's not as pronounced in this screencap, but other areas of the video where the black halo is more noticeable. It's always to the right of the bright spot, and it only occurs when the adjacent area is dark. Is there a way to restore the details lost in the black area or blend it so that it's less noticeable?


Attached Images
File Type: jpg pianocap.jpg (34.6 KB, 3 downloads)
Attached Files
File Type: avi beforeafter.avi (27.30 MB, 1 downloads)
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  #4  
06-03-2020, 01:36 PM
Winsordawson Winsordawson is offline
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Sanlyn may be able to offer his expertise as to the cause and solution of that problem. What I will note is that you can reduce the color bleeding (as seen in the shirt collar) by playing with the MergeChroma and aWarpSharp2 functions. The latter requires only progressive input so you have to use SeparateFields and Weave like this:

Code:
SeparateFields()

MergeChroma(aWarpSharp2(depth=20).aWarpSharp2(depth=20))

Weave()
The video you attached is 4:2:0. If the original is not then you might have to convert it to a compatible YUV format. Play with the values to see what works. You can start with a high depth to see the change and then reduce it to a level so that it does not affect the rest of the image.

Regarding color, I know you are dealing with multiple shots that may be exposed differently. Just keep in mind that according to the Histogram in Avisynth (Histogram("levels"), the whites are a bit underexposed. The boy's shirt should probably be close to white when it is tinted blue. The white level needs more green and even more red to compensate. I would download ColorPic to help check the colors. It is free.
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  #5  
06-03-2020, 06:38 PM
sanlyn sanlyn is offline
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Quote:
Originally Posted by babydealshunter View Post
VirtualDub was used for the original capture. I previewed the histogram before capture and boosted the brightness (155) and lowered the contrast (100) since it was clear the entire tape had extremes at both ends of luminosity.

Using VirtualDub, I used:
Gradation Curves filter (Y/U/V mode) [exported the settings, attached the .amp file]
Color Mill Saturation (Dark -13, Middle -20, Light -70)
Brightness/Contrast (Bright -3%, Contrast 106%)
Color Equalizer (R -2, B -4)
Dynamic Noise Reduction (12)
Crop/Resize with letterbox

Now that we have no idea what the originals looked like, all I can say here is that the color work is not very good and there's not much we can advise from your filtered results except that you should submit unfiltered samples that are longer than a blink. You should also find out what the colors black, gray, and white are made up from in RGB colors. https://www.rapidtables.com/web/color/RGB_Color.html


Your samples have been converted to RGB, which doesn't help at this end, and didn't help you, either.


You won't get far with this video in VirtualDub. You need Avisynth.
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