Problem with VHS video before capturing

Discussion in 'Video Cameras' started by Beemer, Aug 25, 2006.

  1. Beemer

    Beemer Guest

    I have a French dialogue PAL vhs video which when played displays a few
    flickering horizontal lines at the BOTTOM of the screen. This does not
    seem to be a tracking problem. Could it be that the video vhs premastering
    has done some incorrect framing from the French TV system SECAM to PAL
    conversion (if that is what was done). There is no Macrovision.

    Could there be another reason for the lines. I want to remove this before
    capturing to DV MPEG2

    Beemer
     
    Beemer, Aug 25, 2006
    #1
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  2. Beemer

    G Hardy Guest

    VHS always has that crap at the bottom. You can't see it on TV because
    (unless the tracking is bad) it lies in the overscan area.

    If you make a DVD if it and view it on the same TV as the VHS, you won't see
    the static on that, either.

    Google for "overscan" for a better explanation than I'm capable of...

    :eek:)
     
    G Hardy, Aug 25, 2006
    #2
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  3. Beemer

    Beemer Guest

    | | > I have a French dialogue PAL vhs video which when played displays a few
    | > flickering horizontal lines at the BOTTOM of the screen. This does not
    | > seem to be a tracking problem. Could it be that the video vhs
    | premastering
    | > has done some incorrect framing from the French TV system SECAM to PAL
    | > conversion (if that is what was done). There is no Macrovision.
    | >
    | > Could there be another reason for the lines. I want to remove this
    before
    | > capturing to DV MPEG2
    |
    | VHS always has that crap at the bottom. You can't see it on TV because
    | (unless the tracking is bad) it lies in the overscan area.
    |
    | If you make a DVD if it and view it on the same TV as the VHS, you won't
    see
    | the static on that, either.
    |
    | Google for "overscan" for a better explanation than I'm capable of...
    |
    | :eek:)
    |
    |
    Can a captured file be resized e.g. by Prem Pro to cut this off?

    Beemer
     
    Beemer, Aug 26, 2006
    #3
  4. Yes
     
    Laurence Payne, Aug 26, 2006
    #4
  5. Beemer

    G Hardy Guest

    ....but if you're planning to go back to TV you shouldn't bother as you'll
    lose picture detail for no (visible) benefit. Chopping off any dross that
    would normally be hidden by overscan is only really useful if you intend to
    show the video on a device unaffected by overscan. This includes web-based
    videos and DVDs that will be played back on a computer.

    Note that as plasma/LCD TVs are not subject to the technology limitations of
    CRT TVs, there's no reason why they need to use overscan - but many of them
    do.
     
    G Hardy, Aug 26, 2006
    #5
  6. But many of them don't. Particularly when playing a DVD.
     
    Laurence Payne, Aug 26, 2006
    #6
  7. Beemer

    G Hardy Guest

    Why the difference with DVD? (Asking out of ignorance.)

    The only reason I knew that many LCDs do unnecessarily still incorporate
    overscan is because I googled for it. I did a wedding where I'd zoomed in
    for an establishing shot, but when I came to edit, I wanted to zoom out, so
    I reversed the clip. Unfortunately, that meant I had a bloke crossing the
    road backwards right at the edge of the image. It was in overscan, so under
    normal circumstances, wouldn't be seen, but I knew the B&G have an LCD TV.
     
    G Hardy, Aug 26, 2006
    #7
  8. Beemer

    Jukka Aho Guest

    Not to mention that resizing any normal camcorder-shot video in the
    vertical direction is likely to throw interlacing completely out of
    whack, leading to stuttering images and whatnot when watching the
    material on a real tv.

    If something _must_ be done to the offeding area, masking it with black
    is an option, of course.
     
    Jukka Aho, Aug 26, 2006
    #8
  9. Beemer

    G Hardy Guest

    Not to mention that resizing any normal camcorder-shot video in the
    I work with MSP which, up until version 7.3 at least, was OK with resizing
    vertically. It performed its resize on each field separately, then combined
    the result into a new field-based frame.

    I've not investigated fully, but MSP8 seems to have a problem with field
    order when changing the speed of a DV clip, which means it might be possible
    it would struggle with the field order for resizing too. I'll report back
    when I've had a chance to look into it.
     
    G Hardy, Aug 27, 2006
    #9
  10. Beemer

    Jukka Aho Guest

    Yes, some programs allow graceful handling of interlaced material, which
    is nice. Some others, though, treat everything as if it was progressive
    frames, which leads to the above-mentioned problems. Then there are
    those which don't really keep track of the interlaced/non-interlaced
    status of the video, but may have checkboxes for interlaced processing
    in the option panels of individual filters and tools, which the user
    needs to manually select at appropriate times in order to get usable
    results. (VirtualDub is one of those.)
     
    Jukka Aho, Aug 27, 2006
    #10
  11. Beemer

    G Hardy Guest

    What about Premiere Pro which the OP uses?

    MSP is a fairly cheap "pro" editor, so if that can gracefully handle field
    order on resize/respeed, I'd have thought the other big names would do so
    too...

    Mind you, as Mitch Hennessey says - "Assumption makes an 'Ass' out of 'U'
    and ''umption'."
     
    G Hardy, Aug 27, 2006
    #11
  12. Beemer

    Jukka Aho Guest

    It might, but I'm not sure about that. Even if it does, I don't see the
    point in this case. Cropping and resizing the clip would make good,
    healthy parts of the picture (that were originally visible) go
    off-screen, in the overscan area. It would affect the original framing
    and composition in unpredictable ways. In other words, it's just a Bad
    Idea.

    Masking the offending area, on the other hand (or just leaving it alone
    since it's probably wholly within the overscan area and thus invisible
    on a normal tv, anyway), would cause none of that.
     
    Jukka Aho, Aug 27, 2006
    #12
  13. Yeah, I'd go for masking. Trouble is, these days you have to accept
    it WON'T be played on a "normal TV".
     
    Laurence Payne, Aug 27, 2006
    #13
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