Question: Long horizontal scratches on VHS tape

[bisonrav]

I have a short clip of 20 year old VHS tape (about 10 minutes) I'm trying to restore. This is my first ever restoration project, although I've done initial research and understand (for example) how AVISynth works in broad terms, I'm certainly missing fine detail, so please be patient.

Transfer is no problem as I've access to good kit on loan including a time base corrector. I haven't physically got this at the moment so can't post captures, the aim at present is to be forearmed so that when I do the transfer I get everything I need.

The problem I have is that there appears to be some physical damage to the tape, like a bit of grit has got between the tape and the heads at some point. The result to the image is a horizontal scratch in a fairly stable vertical position right along the length of the tape. Image damage is maybe 4 or 5 lines high, and is a mixture of dark spots and distorted underlying image, the effect is a bit like a magnifying glass over the image displaying a mix of picture and noise.

The other factor is that I have a poor digitisation of the same tape done by someone else, which doesn't show the damage. This is a non-widescreen format (not certain of the resolution) but has vertical black bars on either side of the image which is horizontally compressed, like it was generated as a widescreen image but then squashed into a non-widescreen width. Also the colour is way off.

I'm considering using the AVISynth scratch remover plug in, but fear the width of the damage is too great to repair reasonably. Another thought was to rescale and fix up the older digitisation as best as possible and overlay the new capture with information from that using AVISynth. And then there are the crazy night thought ideas of individually fixing up each frame using a pixel editor, thankfully I haven't found a tool that would let me do that (my partner has a copy of Apple Final Cut on her old macbook and claims that allows frame editing on a pixel level). Or ironing the tape. It's amazing how seductive truly dumb ideas can be.

I am prepared to spend money on this, within reason, because this is as much a matter of interest in what can be done as for the result itself. I don't want to be spoonfed fixes either, for the same reason. But ideas would be very welcome indeed, really just to give me places to look.

[guns1inger]

Post a short clip if you can

[bisonrav]

I'll do that when I have a capture, should have the kit over the weekend.

[lordsmurf]

I've have to see a clean uncompressed/lossless capture.

[2Bdecided]

Since the scratch is at a fixed location, a manual mask and one of the automatic video inpaiting tools for AVIsynth might be a good place to start.

Replacing the bad area with the other transfer would probably be better, if you can make it match stably.

The doom9 AVIsynth forum is the place to ask about AVIsynth tricks.

Cheers,
David.

[bisonrav]

Thanks for the initial comments. I'm going to have a look at what I can do with the older transfer today in terms of cleaning it up a bit, and will post some clips when I've done transfers.

[bisonrav]

OK, this is a capture of the damaged portion - just to add this is just via a USB capture device, not the kit I'll be using ultimately. Ideas very welcome. Having captured it and fiddled a bit with avisynth, I can't help feeling there's a lot to learn here, lol

[bisonrav]

Discovering that the logoaway filter in virtualdub with an XY fill with 100% Y does a remarkable job off hiding the worst of the damage. But you sort of think there must be a method where if a pixel is black or white it could take the colour of surrounding pixels or something.

[lordsmurf]

I need a 720x480 NTSC (or 720x576 PAL) interlaced AVI, uncompressed or lossless, capture. Maybe an MPEG-2 I-frame or IP GOP at same res. What you've posted doesn't help.

Because the sample size is too small, my quick test just now made the video really blurry -- something that would not happen on the higher res proper Full D1 version. It needs denoise, chrome fix, etc -- not just hiding of the scratches.

I need to know what the whole video looks like, too. Can the video be broken into small pieces and authored separate, or does this have to be one lone recording on the final DVD? For a problem like this, you'll need to just mask and/or crop. But ideally, only on the damaged part. Some of the work may require you convert to progressive, so an interlace/non-interlace mix stream may prove trouble for later software. Need more details on the whole project workflow. Also know I don't check back on old threads very often. You may need to PM me here, or find me at the other video help forum I use.

Logoaway is just going to make it a blurry mess, that won't work.

[bisonrav]

OK, thanks. The best thing to do I suspect is to get my ducks in a row in terms of assembling the necessary kit so I can get the higher resolution scans - this was really just a quick pass using what I had around me so I could try out the software tools and start understanding what the options were.

If you're interested in seeing the shape of the video and what happened using the delogo, the trial is up at

http://www.youtube.com/watch?v=1NGHKWv1X00

The lead in section is very noisy and has another (lower down) scratch which is an interesting point of comparison with the delogoed one, then 30 seconds or so in the video settles down. I don't think it's bad at all, because the scratch can be contained within about 10 lines and is vertically in a very stable position, but if there are better techniques so much the better.

You can also compare this to the original capture that someone else did, http://www.youtube.com/watch?v=UN4faK43_J0 - this isn't a bad representation of what comes off the tape when you play it.

One quick question about video capture boards - the strong recommendation seems to be for ATI AIW, I can find plenty of boards on ebay for example, but my main pc is Vista and the word seems to be that the ATI drivers for Vista are limited possibly to just display only, and the HD cards seem hard to get in the UK. I don't really care about the TV tuner part, but does anyone know if for example the 8500DV card is usuable? Otherwise are there any alternatives around for capture available easily in the UK at reasonable prices which support Vista?

[lordsmurf]

Your biggest issue the VCR -- it doesn't look to be a high end S-VHS deck, so you're getting a crappy picture.

You don't want the HD cards.

Video capture systems need to be build around Windows XP -- Vista and 7 screwed up too much stuff for audio/video.

[bisonrav]

Yes, the VCR issue is understood and being dealt with. Could probably load XP onto my desktop, will have to look at what else is on there. Would the 8500DV card be OK if I did that?

I was also looking at a Canopus advc 100 running into an old Macbook via firewire for acquisition, how would that be?

[lordsmurf]

1st Q: Yes
2nd Q: It works, but it's still DV compression. For something this messy, your capture may be blocky and colors more off than they are already. I'd suggest uncompressed YUV or lossless AVI.