Plz explain Video/Film mode to me

Discussion in 'Archived Threads 2001-2004' started by Henry Carmona, Nov 8, 2001.

  1. Henry Carmona

    Henry Carmona Screenwriter

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    Plz help, how do i know when to use these options?
    I have a Toshiba 50H81, thanks.
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    [​IMG] "Charlie don't surf."
     
  2. John Kotches

    John Kotches Cinematographer

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    The best explanation comes from our website, Secrets of Home Theater and High Fidelity, on this page:
    DVD Benchmark Progressive Scan feature article.
    The best mode is probably "auto" if it exists, lacking that, most DVDs of movies are film mode, most concert DVDs are in video mode.
    There is no hard and fast answer. Switching between the two will tell you which is best for a particular viewing.
    Of course if you feed a progressive signal from a progressive scan DVD player, all your woes are solved anyway.
    Regards,
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    John Kotches
    Contributing Writer
    Secrets of Home Theater and High Fidelity
     
  3. Henry Carmona

    Henry Carmona Screenwriter

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    THanks for your help John
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    [​IMG] "Charlie don't surf."
     
  4. Allan Jayne

    Allan Jayne Cinematographer

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    To me, video mode vs. film mode has to do with the TV's built in doubler that converts broadcasts, VHS tape playback, and regular (non-progressive) DVD video to progressive scan.
    The easiest thing to do is try it both ways to see what looks better, the difference may be unnoticeable some of the time. More detail requires a technical explanation.
    Top notch doublers automatically switch between film mode (3-2 pulldown optimizing) and video mode (for sources other than film). But not all doublers that switch automatically are top notch.
    Some of the more noticeable problems with doublers in general are:
    (1) In video mode the entire image is not quite as sharp.
    (2) The entire image gets a little less sharp when something starts moving.
    (3) Edges of moving objects are feathered or serrated, or slight ghosting of faster moving objects is seen.
    These are things to look for in the store before buying.
    More on doublers: http://members.aol.com/ajaynejr/viddoubl.htm
    [Edited last by Allan Jayne on November 09, 2001 at 07:38 AM]
     
  5. John Kotches

    John Kotches Cinematographer

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    Alan,
    As I think about this more (and I'm not a video expert)
    that Video vs. Film mode is a valid concern for a DVD player, I don't see the TVs internal de-interlacing solution as being able to perform a 3:2 pulldown.
    By the time you get the interlaced signal to the television the inverse telecine is complete. All you have left are the 30fps (x2 fields) to reassemble into a progressive 60fps signal. You can't feed an interlaced signal to a TV at 24fps, as the TV can't sync.
    How would a TVs "line doubler" detect a 3:2 cadence from a 30frame/60field input? Seems to me, it couldn't be done.
    Regards,
     
  6. Stephen Tu

    Stephen Tu Screenwriter

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  7. John Kotches

    John Kotches Cinematographer

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    Stephen,
    Thanks for the explanation.
    So the penalty is exacted of yet another A/D and D/A conversion, with varying results as a function of both convertors.
    Yikes.
    Let's just go digital all the way and forget all this conversion nonsense [​IMG]
     
  8. Seth Paxton

    Seth Paxton Lead Actor

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    Video mode assumes that the 60 fps signal will be created from an originally 30 fps signal (aka video source).
    Film mode assumes that the 60 fps will be made from a 24 fps signal that has been 3:2 pulled down into a 30 fps signal for TV viewing.
    Putting the set in video mode simply line doubles. Therefore your mismatched frames from 3:2 pulldown will stay together when they really don't need to.
    Putting it in film mode forces it to assume that the frames are made from the 3:2 pulldown process and will therefore store and reassemble correct frames from odd/even fields in different frames (when applicable, some frames stay correct in 3:2).
    One reason for not having AUTO is simply the processor/memory requirements. At least having a selection option still allows the TV to do the appropriate type of deinterlacing with a little help from the user. [​IMG]
    A BIG reason for going with a progressive player in situations like this is that the source never has to be undigitized before deinterlacing. If the TV or an outboard source does it then it still gets sent out over analog video (yes, even VGA, YPbPR are analog sources going to digital TVs). This means that it has to be redigitized, analyzed, and put back into analog form for CRT scanning (with exceptions for DLP and LCD based sets, if their video display subsections can take a digital video stream as a source).
    If you do it in the player all this back and forth is avoided AND the MPEG stream has a FLAG to indicate if the source was video or film. The player can shuffle the still digitized fields around and match them up as appropriate. Keep in mind that film will still be in a 3:2 configuration, but rather than mixing fields from 2 seperate frames (thus the tearing artifacts, etc) you will simply be getting frame A 3 times, then frame B 2 times, 3, 2, etc. for a total of 60 frames in one second. (3 x 24 = 72 fps, 2 x 24 = 48 fps, so if you do half at a 3 rate and half at a 2 rate you end up compromising in the middle...at 60 fps!).
     

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