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Help Correct Bad Frame Rate Conversion
#1
Hello again Fanres.

So I have some Video Footage that is PAL 25fps that has been converted from NTSC 29.976.
There are the usual signs like blending between shots.
This is video footage shot in the early 90's and not from a film source.

Does anybody know of any techniques to return it back to its original form?
Preferably by an AVIsynth plugin / script.

I understand it maybe impossible but there are wizards around these parts Wink
Thanks again for your time folks.
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#2
If the original footage was interlaced NTSC (60i) converted to PAL (50i) then I'm not sure there's much that can be done to 'unblend' it. It's always worth separating the fields to see the extent of the damage (ie to check if individual fields are being blended vs. full frames).
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Thanks given by: CSchmidlapp
#3
In theory I think it might be possible to create some kind of temporal deconvolution filter to reverse this kind of frame blending as far as possible, similar to how Debilinear does it spatially for images that have been upsized with Bilinear resizing. Just as Debilinear needs to know the exact original resolution and subpixel shift, that filter would need to be very precisely aligned for good results. That is, it would need to reliably *know* how much percent of picture A and B a frame and the surrounding frames consist of and then do some weird (?) math to make guesses about how each individual picture looked.

In practical terms, I am not sure how well it would work. And I haven't seen such a piece of software anywhere so far.
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Thanks given by: CSchmidlapp
#4
Try SRestore().
New members, please don't PM me for links to my projects until you have participated for a while and become active members of the forum.
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Thanks given by: CSchmidlapp
#5
(2018-05-03, 07:25 PM)zoidberg Wrote: If the original footage was interlaced NTSC (60i) converted to PAL (50i) then I'm not sure there's much that can be done to 'unblend' it. It's always worth separating the fields to see the extent of the damage (ie to check if individual fields are being blended vs. full frames).

60i to 50i seems to be exactly the case here, Its a making of featurette on a PAL DVD
I de-interlace the 50i to 25p progressive and I see the frame blending.
I figured it was pretty burnt in and would need some wizadry Smile

(2018-05-03, 11:12 PM)TomArrow Wrote: In theory I think it might be possible to create some kind of temporal deconvolution filter to reverse this kind of frame blending as far as possible, similar to how Debilinear does it spatially for images that have been upsized with Bilinear resizing. Just as Debilinear needs to know the exact original resolution and subpixel shift, that filter would need to be very precisely aligned for good results. That is, it would need to reliably *know* how much percent of picture A and B a frame and the surrounding frames consist of and then do some weird (?) math to make guesses about how each individual picture looked.

In practical terms, I am not sure how well it would work. And I haven't seen such a piece of software anywhere so far.

It was something like this I was wondering existed. I found very little about anybody else attempting to solve the problem. Some of the anime conversion crowd we're close but they seem like a set of different problem's entirely.

(2018-05-04, 01:05 AM)Chewtobacca Wrote: Try SRestore().

This looks promising, will give it a whirl.
Do you think I should de-interlace from 50i to 25p and apply this, or try an the untouched file?

Once again thanks everyone Smile
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#6
(2018-05-04, 12:06 PM)CSchmidlapp Wrote: 60i to 50i seems to be exactly the case here, Its a making of featurette on a PAL DVD I de-interlace the 50i to 25p progressive and I see the frame blending.I figured it was pretty burnt in and would need some wizadry Smile
Is there a chance the featurette was included on an NTSC release? You'd be surprised how cheaply you can get older DVDs on eBay these days (assuming it's not some super rare title).
You will definitely see the blending when deinterlacing to 25p. Try SeparateFields:
Code:
separatefields()
This will split the frames into fields (and double the frame count/frame rate)
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Thanks given by: CSchmidlapp
#7
CSchmidlap, this is how you use SRestore().

Code:
WhateverSource()
WhateverDeinterlacer()# Choose your favorite.
SRestore()

Read the documentation for SRestore() carefully and adapt it to your situation.  You can separate the fields to analyse your video, but don't call SeparateFields() before calling SRestore().  I'm away from home and can't take a look at your video, but the above is what you have to do. Good luck!
New members, please don't PM me for links to my projects until you have participated for a while and become active members of the forum.
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Thanks given by: CSchmidlapp
#8
(2018-05-04, 12:06 PM)CSchmidlapp Wrote: This looks promising, will give it a whirl.
Do you think I should de-interlace from 50i to 25p and apply this, or try an the untouched file?

Deinterlace to 50p before using srestore. Don't use selecteven or selectodd.
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Thanks given by: CSchmidlapp
#9
If that doesn't work out the way you want, you could always try finding an NTSC DVD or a Blu Ray with that footage in the correct format. Chances aren't overwhelmingly big, but not non-existent either. (sorry for being Captain Obvious)
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Thanks given by: CSchmidlapp
#10
(2018-05-04, 02:00 PM)zoidberg Wrote: Is there a chance the featurette was included on an NTSC release? You'd be surprised how cheaply you can get older DVDs on eBay these days (assuming it's not some super rare title).
You will definitely see the blending when deinterlacing to 25p. Try SeparateFields:
Code:
separatefields()
This will split the frames into fields (and double the frame count/frame rate)
(2018-05-04, 06:12 PM)TomArrow Wrote: If that doesn't work out the way you want, you could always try finding an NTSC DVD or a Blu Ray with that footage in the correct format. Chances aren't overwhelmingly big, but not non-existent either. (sorry for being Captain Obvious)

The video is a 'Universal Soldier' featurette and behind the scenes footage. Ive had a look around and it is contained on various other discs (DVD and Bluray) but is in PAL format on them all.
There are a few videos in my collection that have been converted from various sources that Id like to try and restore, so thought Id cut my teeth with this Smile

(2018-05-04, 03:27 PM)Chewtobacca Wrote: CSchmidlap, this is how you use SRestore().

Code:
WhateverSource()
WhateverDeinterlacer()# Choose your favorite.
SRestore()

Read the documentation for SRestore() carefully and adapt it to your situation.  You can separate the fields to analyse your video, but don't call SeparateFields() before calling SRestore().  I'm away from home and can't take a look at your video, but the above is what you have to do. Good luck!

Thanks again bud, I will post my results when I get chance to experiment.
I'm getting conflicting advice on where to call SRestore though so I will try all Smile

(2018-05-04, 03:49 PM)IcePrick Wrote: Deinterlace to 50p before using srestore. Don't use selecteven or selectodd.

I remember you doing something similar (but way more complicated!) with your 'The Killer' custom.
I gather to had to go back from 60i to 50i using a similar method, then de-interlace to 25p and then to 24p?
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