Damaged sections on tapes

[SkyBlues2021]

I've recently been encoding some of my captures. However I have some videos that I'm not sure if anything can be done to improve them? Some sections in the videos were badly overexposed. Two of the videos have sections with a rolling line that moves from the top down. Any help would appreciated. Thanks.

[Selur]

For the damages try something like Spotless(radT=3, ablksize=64) should help to at least lessen the error,..

[SkyBlues2021]

Thanks Selur. That looks great. How would I place Spotless(radT=3, ablksize=64) in a script? Would I target just the damaged frames. Thanks.

[Selur]

Would I target just the damaged frames.

Personally, I first would look how it behaves when run on all frames (it's probably fine).

How would I place Spotless(radT=3, ablksize=64) in a script?

Assuming you are using Avisynth (I use Vapoursynth):
a. save the spotless-script from https://forum.doom9.org/showthread.php?t=181777 into an .avsi or .avs file (avsi = will be autoloaded when placed in Avisynths plugins folder)
b. make sure you either load the dependencies manually or autoload them.
c. call the script for example with:

SpotLess(RadT=3,BlkSz=64)

somehwere behind you deinterlacing (and before any resizing) in your script.
d. try if it's okay to lower RadT and/or BlkSz. Values for BlkSz to try would be 32, 16, 8, 4. 3 and 64 might be a bit strong to apply it on a whole file.

[Sharc]

The overexposure in tape 12 looks like being baked into the source (tape). You can try to tweak a bit, but I doubt one can recover any details from the overexposed parts

[SkyBlues2021]

Thanks Selur. That seems a really powerful tool, I didn't think anything would touch those lines. So far I have only used your values in the scripts and they seem to give great results. I've added my script snips just to check that my placement in the script of SpotLess is correct? I've added 3 new clips with the same damage and then after applying SpotLess.
Is it better to divide the video and apply the SpotLess filter only to the damaged sections? Thanks.

[Selur]

I've added my script snips just to check that my placement in the script of SpotLess is correct

Placement seems okay to me
(things are probably a bit faster if you place Spotless between crop and addBorders, sicne it would then run on a smaller image)

Is it better to divide the video and apply the SpotLess filter only to the damaged sections?

Spotless will do some denoising, but as a side effect. If the settings cause problems in other scenes, only running Spotless on a restricted range can help, if it does not splitting the source into xy sections would be too much trouble for my liking.

[SkyBlues2021]

Thanks Sharc. I know it's probably a lost cause. I hoped that maybe I could try to improve it slightly. However, the results may not be worth the effort? I think we messed about with the camera setting at the time, possibly a backlight setting and ended up with creating this mess.

[jagabo]

Those spotless settings are causing pretty significant damage to moving portions of the picture. Note the boy's face and hat:


[Attachment 74682 - Click to enlarge]

Lowering the blksz to 8 or so will help with that.

[SkyBlues2021]

Thanks Selur & jagabo. I've put the SpotLess between crop & add borders. I've lowered the blksz to 8. I'm guessing I need to play with the values without creating too much distortion?

[Selur]

Those spotless settings are causing pretty significant damage to moving portions of the picture.

That's what I suspected.
Yes, try adjusting the temporal radius (should be <=3 and the block size, I suspect 16 might be okay)

[SkyBlues2021]

Thanks Selur. I will try that and post tomorrow.

[SkyBlues2021]

I've uploaded the clip using BlkSz=16 which looks good also without having the damage on his cap. I will divide the videos as I believe this problem was on the end parts on two of my tapes. I will do a few tests and see if I need to reduce the values when there is more movement.

[jagabo]

The time base errors are seem to be limited mostly to the top 1/4 of the frame. You could protect the bottom 3/4 with something like:

LWLibavVideoSource("clip tape 18 damaged tape 2.avi") 
AssumeTFF()

before = QTGMC()
after = before.Spotless(radT=3, blksz=16) 
Overlay(before, after.Crop(0,0,width,144)) # use only the top 144 lines of the spotless clip

[SkyBlues2021]

Thanks jagabo. I've added your script to the clip and probably made a mess of it. I wasn't sure if my placement is correct? Thanks.

[jagabo]

Thanks jagabo. I've added your script to the clip and probably made a mess of it. I wasn't sure if my placement is correct? Thanks.

Looks right to me. Note that the Spotless settings don't remove all of the errors. Given that there's not much motion at the top of the frame you could go back to using blksz=64 to fix more of the errors.

[SkyBlues2021]

Thanks jagabo. I thought that the blksz=64 seemed to work well on #6 post (Tape 17 damaged section 2) as there was little motion, just my son sitting. Do you think it's best to use the script you gave me post in #14 on this, replacing blksz=16 with blksz=64 as there is little motion?
I think on Tape 17 damaged section 2 the error seems to come down lower so should I use 288 as my value? I've uploaded the 144 line script & mp4.

Overlay(before, after.Crop(0,0,width,288))

Thanks.

[jagabo]

Thanks jagabo. I thought that the blksz=64 seemed to work well on #6 post (Tape 17 damaged section 2) as there was little motion, just my son sitting. Do you think it's best to use the script you gave me post in #14 on this, replacing blksz=16 with blksz=64 as there is little motion?

That's probably ok with that clip.

I think on Tape 17 damaged section 2 the error seems to come down lower so should I use 288 as my value? I've uploaded the 144 line script & mp4.

Overlay(before, after.Crop(0,0,width,288))

I don't think I have that clip. But yes, you can do that to cover more of the damage. Another possibility is to use heavy filter for the top part of the frame and lighter filter for the rest:

before = QTGMC()
heavy = before.Spotless(radT=3, blksz=64) 
light = before.Spotless(radT=3, blksz=16) 
Overlay(light, heavy.Crop(0,0,width,288))

Generally, use the lowest value of radT that gives the desired result.

[SkyBlues2021]

Thanks jagabo. I've uploaded the original damaged clip. The 288 lines script and mp4 and also the 288 lines heavy light script and mp4. Both look so much better than the original. Which do you think is the better of the two to use? I can't believe that you could get such good results with such a poor clip. Thank you.