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  1. I'm capturing VHS tapes of TV shows I recorded around 25 years ago. I have a JVC HR-S3500U and a VC500 capture device. I'm also using a Panansonic ES10 as a pass-thru device. I'm using S-Video cables and capturing at 720x480. I'm mostly using Avisynth and VDub. I'm mostly happy with the results I've been getting.

    Some of the captures have this double image or halo. What is it and is there anyway to fix it with what I have? The tapes were recorded from OTA TV mostly.

    Thanks for the help.
    Image Attached Files
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  2. Multipath reception? This is close:
    Code:
    function ShiftRight(clip v, int pixels)
    {
        Crop(v,0,0,-pixels,-0)
        AddBorders(pixels,0,0,0)
    }
    
    #call with:
    src = last
    Overlay(last, ShiftRight(last, 8), mode="subtract", opacity=0.15).ColorYUV(gain_y=40)
    MergeChroma(last, src)
    Play with shift, opacity and gain.
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  3. Originally Posted by jagabo View Post
    Multipath reception? This is close:
    Code:
    function ShiftRight(clip v, int pixels)
    {
        Crop(v,0,0,-pixels,-0)
        AddBorders(pixels,0,0,0)
    }
    
    #call with:
    src = last
    Overlay(last, ShiftRight(last, 8), mode="subtract", opacity=0.15).ColorYUV(gain_y=40)
    MergeChroma(last, src)
    Play with shift, opacity and gain.
    That helps. I'll try to adjust it more later.
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  4. It's not a great fix. It works pretty well in some places, not so well in others.
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  5. Could also be magnetic image transfer since the tape had been wrapped around itself for ages, magnetic image signal on one part of the tape could transfer to another part of the tape wrapped above/below it.
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  6. Another problem is the strong oversharpening halos from the VHS deck -- and the subtraction maks them worse. Dehalo_alpha() can reduce them but it damages the picture.

    Code:
    LWLibavVideoSource("Cap.avi") 
    AssumeTFF()
    ConvertToYV12(interlaced=true)
    QTGMC(preset="fast")
    src = last
    
    Dehalo_Alpha(rx=7.0, ry=1.0, darkstr=0.8, brightstr=0.8)
    Overlay(last, ShiftRight(last, 8), mode="subtract", opacity=0.15).ColorYUV(gain_y=40)
    MergeChroma(last, src)
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  7. Member Cornucopia's Avatar
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    Originally Posted by babygdav View Post
    Could also be magnetic image transfer since the tape had been wrapped around itself for ages, magnetic image signal on one part of the tape could transfer to another part of the tape wrapped above/below it.
    You are thinking of pre- and post- echo due to bleedthrough of the magnetism in the layers. But while that's true of audio tape, this doesn't happen the same way with helical-scanned analog video tape (and doesn't happen at ALL with digital tape). A true bleedthrough of another earlier or later frame would have its sync, vertical interval, everything be shifted. And in doing so, it wouldn't maintain sync - it can only sync to one signal and anything else that comes through is garbage. It's not like the frames would overlay exactly the amount of the spool wind (which changes throughout).

    Good try though.
    Very likely multipath, as was mentioned.

    Scott
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