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  1. I am working with a VHS tape from 1984. There have been several issues capturing the video, but here is where I am at now. A few scenes have a line of static through the image, fine tuning the tracking I can adjust this down but get clipping at the top. I now have 2 very low compression (Apple Intermediate Codec) 480i captures from the tape. One with the line mid video, and one with it at the bottom with distortion at the top.

    I have searched and searched (I'm sure I'm using the wrong keywords!) but I can't find a way to merge or combine the 2 identical videos (on either Mac or PC with a codec change) into 1. Essentially I have a complete copy of the video if I could replace the static in each one with good data from the other. I have a quad core Mac and a quad core PC, so I am up for any tools that can get the job done.

    Re-capping the VHS is out of the question as the tape is coming apart with each viewing (oxide shedding)

    Thanks for any suggestions and I hope it makes sense!
    Last edited by punkxdead; 28th Nov 2010 at 13:59.
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  2. If you can get an AIC codec for Windows it could easily be done with AviSynth. Crop() part of one video and Overlay() it over the other. You may have to adjust for brightness or color differences due to automatic gain during capture.

    v1 = DirectShowSource("video1.ext").Crop(0, 96, -0, 48) #leave just the good part
    v2 = DirectShowSource("video2.ext")
    Overlay(v2, v1, 0, 96) #overlay the good part of v1 over v2
    Here's a sample of the result using two different videos (so it's obvious what's overlaid):

    Click image for larger version

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    Last edited by jagabo; 28th Nov 2010 at 17:48.
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  3. Member edDV's Avatar
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    Probably the tape was recorded on a deck that was out of alignment. A good VCR service tech could adjust VCR guides and tape tension to play the tape properly. After capture, the VCR would need to be aligned to standard.
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  4. Originally Posted by jagabo View Post
    If you can get an AIC codec for Windows it could easily be done with AviSynth. Crop() part of one video and Overlay() it over the other. You may have to adjust for brightness or color differences due to automatic gain during capture.]
    I think I was over complicating it by looking for something like layers in Photoshop with a filter, but I think your idea will work great and be so much simpler! There is no Windows port for AIC, but I can recompress (I know...) to another near lossless codec like Apple ProRes or Avid's DNxHD that is cross-platform. Crop out and overlay the good 80 lines or so and try to get good color match.

    Originally Posted by edDV View Post
    Probably the tape was recorded on a deck that was out of alignment. A good VCR service tech could adjust VCR guides and tape tension to play the tape properly. After capture, the VCR would need to be aligned to standard.
    Its just a relatively short segment that is giving me grief. The tape was used before it began its life as a tape for family home videos, it was then recorded on by two different camcorders from 1984-1990 at varying speeds. The original camcorder was one that had the camera that sits on your shoulder with cords that hooked to the recorder that you carried by a handle, like a portable VCR. I honestly don't remember the model after all these years!

    Thanks for the feedback, I feel like I'm heading in the right direction now!
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  5. Originally Posted by punkxdead View Post
    Crop out and overlay the good 80 lines or so and try to get good color match.
    Overlay() supports an alpha mask so if you can't get a perfect color match you can soften the transition with an alpha mask:

    Click image for larger version

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    Last edited by jagabo; 28th Nov 2010 at 19:37.
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  6. Originally Posted by jagabo View Post
    Overlay() supports an alpha mask so if you can't get a perfect color match you can soften the transition with an alpha mask:
    Works great! I hadn't used avisynth in years (2004?) since I switched primarily to Mac back then. I had forgotten how powerful it is! Thanks Again!
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  7. Can we see short clips or still shots of the sources and the result?
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  8. I just tested the overlay idea with some short samples, haven't tried the alpha mask to blend yet. It was shot in low light under poor conditions, so the saturation levels have always been that bad. Since there were other issues with the source in general, I found me a Panasonic AG-1980 a couple of days ago. Despite my fears I recapped the tape using s-video and tbc with better results. My fears were founded in that the tape did get stuck halfway through, and I had take the cover off, remove the tape restart the capture mid way. There are now even more oxide particles that have flaked off everywhere, but the overall capture is better. I'm still working through all the video, and it all still needs a lot of work.

    P.S. I know the quality is bad


    Source 1 - Large Line of Static in Lower Half
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    Source2 - Line Moved with Head Tracking - Notice the Grainy Top Half and Discoloration at the Bottom
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    Quick and Dirty Overlay - Needs Work
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  9. Even the quick hack looks pretty good!
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