Dumb questions re: viewing DVDs on a Mac...

Discussion in 'Archived Threads 2001-2004' started by Allan Mack, Aug 13, 2002.

  1. Allan Mack

    Allan Mack Supporting Actor

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    Please excuse my ignorance in the followinhg questions.

    I'm currently using an old DVD-less beige PowerMac G3, and am considering getting a new PowerMac G4 with ComboDrive (DVD-ROM and CD-RW). The monitor will be a Sony Trinitron CRT.
    1. How does the DVD Player that comes with it handle anamorphic DVDs? Does it downconvert it to letterbox just like a 4:3 TV would if it didn't have a 16:9 mode?
    2. Is there a setup menu just like on a standalone DVD player which allows you to select 4:3 or 16:9 output? If so, would the images come out tall and skinny in 16:9 output, requiring me to adjust the vertical size manually on the monitor?
    3. What about 2:3 pulldown? Is this even necessary with the Mac's DVD Player?
    4. In general, does the image on a computer screen look better than on a HDTV, albeit with a much smaller screen?[/list=1]

      Please excuse the ignorance of my questions. I only have experience with TVs and standalone DVD players. I just wanted to know how DVDs look on a Mac equipped with a DVD player...
     
  2. Ken Chan

    Ken Chan Producer

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    You should get the full resolution on anamorphic DVDs. DVD pixels are not square, so there's always some kind of stretching to display it on a computer, which does have square pixels. (TVs are analog, so it's a little different.)
    (Note that playing on a 4:3 TV does not automatically mean downconverting; some TVs can do the "squeeze trick" and show all the lines in an anamorphic disc.)
    If you play it in a window, the window is 16:9. If you choose full screen, it will scale it up to fit the screen. So on a 4:3 monitor, it will look like it does on a 4:3 TV, but progressive and without throwing away lines. Of course, there are widescreen monitors, including Apple's HD Cinema display.
    The player does seem to do the inverse-telecine to display a better progressive picture. You can tell the difference when playing some supplements, which were originally shot on video; with those, you can sometimes see the "zipper effect".
    In general, computers show progressive pictures with full resolution, but the color response on monitors is different from TV, so it just looks different. You may want to calibrate the monitor using Avia, Video Essentials, or even THX OptiMode, but you may find that makes regular computer stuff look odd.
    //Ken
     
  3. Joseph S

    Joseph S Cinematographer

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  4. Allan Mack

    Allan Mack Supporting Actor

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    Thanks, Ken.

    I guess I'm having trouble understanding how the Mac's DVD player can output full resolution of an anamorphic widescreen DVD on a 4:3 computer display without performing the 16:9 "anamorphic squeeze". I guess the DVD players on computers are a completely different beast than standalone players because of the much higher resolution of computer monitors compared to NTSC TV displays.
     
  5. Ken Chan

    Ken Chan Producer

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    A TV always displays (approximately) 480 horizontal scanlines; its "squeeze" effectively reduces the gap between each one. When played on a computer, the screen's dimensions and pixel spacing never changes. Consider that more and more computers (especially Macs) are switching to LCDs, so -- unlike a CRT -- it's physically impossible to move those pixels closer together. But the nice thing is, you don't have to.

    Computers screens have more than enough resolution to display a DVD image. NTSC DVD is 720x480, while a typical computer display is 1024x768. Now, as I mentioned before, DVD pixels aren't square, so there is always some kind of stetching or squeezing to make the picture look right, but unlike a TV, you actually get more (or fewer) pixels. For example, a full size window (as opposed to full-screen) for a 4:3 DVD will often have a window that's 720x540; i.e. it's stretched vertically, so there's no loss of resolution, although there might be some fuzziness because of the stretching.

    With 16:9, the math is not quite as neat. They can keep the same horizontal resolution, but then you end up with 720x405, which means throwing away some resolution (about 15%, as opposed to 25% for DVD players that do 4:3 letterbox). Or you can keep the full vertical resolution and stretch horizontally. At a minimum, that's 853x480. If you were to stretch to fill a 1024x768 screen, you'd go to 1024x576, and there's no reason to throw out resolution if you're stretching.

    //Ken
     

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