Layer change issuses

Discussion in 'DVD' started by Amitai, Oct 27, 2004.

  1. Amitai

    Amitai Auditioning

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    I've noticed the layer-changing points in all three films, and it bothers me. Is it supposed to be this noticeable? When it happens, the scene freezes for a little less than a second and then continue normally (in all 3 films). In Empire I think there's also a very subtle audio "tick" sound when it happens.
    In addition, I have the zone 2 version, and the layer chaging points are in 60:36, 55:42, and 60:08, respectively, while in the zone 1 version, according to some web pages I've been to, it's 63:08, 58:02, and 62:38, respectively. However, it happens in my copies in the exact same scenes as it does in the zone 1 version (e.g. right after Tarking says: "terminate her, immediately!" in ANH) so it seems as if my copy is missing about 2.5 minutes of each film!!! How could it be? It's very disturbing
     
  2. Adam Barratt

    Adam Barratt Cinematographer

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    Layer changes are often visible on conventional DVD players, depending on the layer change's position in the film or video content. They are quite normal.

    Some DVD players offer faster laser tracking, drives and faster buffering to reduce the length of a layer change, and some discs have been authored without visible layer changes (most Superbit titles, for example). Generally speaking, though, you will see a small pause on most players (DVD-ROM/PCs excluded) and this is often stated on the disc's packaging.

    The audio 'tick' is probably the result of your amplifier/processor detecting the soundtrack following the layer change pause, and is also quite common.

    As for the differing layer change times, your R2 discs appear to be using the PAL video system (common in Europe) while R1 discs use NTSC (the format used in North America). PAL operates at 25 frames per second compared to NTSC's roughly 30 frames per second.

    Due to the conversion process used to transfer film (which generally runs at 24 frames per second) to these different formats' frame rates (25fps and 30fps), PAL versions of the same film material run slightly more quickly (4% to be precise) than an NTSC equivalent. If you compare the running times of the three films you list, you will see that each R2 version is 4% shorter than the R1 version.

    This accounts for your missing minutes: you aren't losing any of the film, it's just being played back at a higher speed.

    And welcome to the forum; I'm sure you will find this community an invaluable resource!

    Adam
     
  3. Amitai

    Amitai Auditioning

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    Thank you for all this information! you helped me alot! If I'd known about this PAL speedup issue before buying the Star Wars trilogy DVDs, I'd invest a little more money and buy the region 1 version... Well, too late now, but I don't know if it matters so much because I never noticed that the films run faster anyway...
    By the way, you say that NTSC runs at 30fps, which means that it runs FASTER than PAL! I'm guessing there's another factor that causes the NTSC to play the films at 24fps (or close to that).
     
  4. Andre Bijelic

    Andre Bijelic Stunt Coordinator

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    NTSC video runs at 30 frames-per-second or 60 fields-per-second. Films shot at 24fps are transferred to NTSC video by repeating one of the fields every so often to compensate for the different frame rate. So even though video runs at a higher frame rate, the correct running time is maintained.

    PAL transfers, on the other hand, are simply done at 25fps, resulting in the 4% speed up.
     
  5. Jonathan Kaye

    Jonathan Kaye Second Unit

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    Funny you should say that. I am so familiar with the soundtrack score to these films, that the various PAL VHS iterations of the original trilogy always sounded "wrong". Thank heavens for DVD, is all I can say![​IMG]
     
  6. Drew Salzan

    Drew Salzan Second Unit

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    Ideally, the layer change should be placed between a fade out/fade in section of a film. This makes it far less noticeable. The worst placement I've ever seen is in the 1959 version of Imitation of Life; it occurs midway through the actress's descent down a flight of stairs. You have to see it to believe it. What was the authoring engineer thinking?
     
  7. Amitai

    Amitai Auditioning

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    Incidentally, can someone please tell me the correct layer-switch point of Star Wars episode II (region 1 NTSC)? My player performs the switch at 66:29 (chapter 28), but I read on a website that it's supposed to be at 66:26...
     

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