Combining VHS/analog video with DV footage: What frame size should I capture at?

Discussion in 'Amateur Video Production' started by Yvan, Aug 28, 2007.

  1. Yvan

    Yvan Guest

    I'm working on a video project which requires that I combine DV
    footage (captured from my minidv camera via firewire) along with
    footage that's captured from VHS tapes using an old Osprey 100 video
    capture card.

    All of my DV footage will be at the 720x480 frame size. Is it
    necessary that the I capture my VHS/analog video footage at 720x480 as
    well? Or would it be best that I capture at 640x480 and then just
    scale up during the editing? I have lots of analog video clips that I
    need to capture, so I figured now would be the ideal time to ask this
    question (before I get too deep into it).

    I ask because the VFW driver for my Osprey capture card has the
    ability to switch to CCIR601 and capture at 720x480. But when I
    capture video at this size and then play it back, -- I can't help but
    notice some strangeness in the way the video looks during scenes where
    there's high motion (ie: choppy).

    I understand that I'm dealing with 2 entirely different video formats,
    and that standard VHS has less lines of resolution than DV. On that
    note, -- am I distorting the VHS/analog-captured video by capturing it
    at 720x480, and introducing problems that would be difficult to mask/
    correct during the editing?

    Thanks in advance,
    - Yvan
    Yvan, Aug 28, 2007
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  2. Yvan

    Ken Maltby Guest

    Interesting question, I don't see any real problem in
    principal with either way. Much would be dependent
    on how your editing program handles different video
    on the timeline. The highest potential for issues would
    be in the decode to the editor's native format.

    What I would expect is that capture to 720x480 should
    work out best/ have less potential for problems. I was
    an early advocate for 1/2 D1 capture for VHS source
    analog video, and there can be some benefit to the smaller
    format, in terms of bits per pixel, but the only real way to
    be sure would be to do a test run using both methods.

    If there is going to be any distortion applied when going
    from VGA (640x480) to 720x480, it would be applied at
    either stage, it shouldn't matter where it takes place. You
    might want to find out which step uses the best scaling
    algorithm, in your setup, i.e. Cubic over Bilinear.

    Ken Maltby, Aug 28, 2007
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  3. Almost certainly because the field order is inverted. DV uses the
    opposite field order from most other capture formats. You should be
    able to find an option in your editing software to "invert field


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    Steve Roberts, Aug 28, 2007
  4. Yvan

    Ken Maltby Guest

    Good point, but that is one of the things to check for
    and correct when adding material to a timeline anyway.

    Ken Maltby, Aug 28, 2007
  5. Yvan

    PTravel Guest

    I would capture to whatever is native for your editor. For example,
    Premiere Pro treats DV-25 as native. When I need to include analog clips, I
    capture them to 720x480 using the DV-25 codec. That way I don't have to
    render within the editor to work with the clips, and everything is seamless.
    PTravel, Aug 28, 2007
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