Wobbly effect with letterbox picture

Discussion in 'Digital Video' started by speekez, Dec 18, 2007.

  1. speekez macrumors 6502

    Joined:
    Nov 19, 2003
    #1
    I have a 720x480 Quicktime movie created from a screengrab of a slideshow I did. The resulting Quicktime is very high and looks good.

    In iDVD, I burn a playable DVD of this movie. When I play it on my tube TV, there's a bit of letterbox effect going on because of the aspect ratio (which is fine, I like it) with black appearing above and below the 720x480 movie. The one thing I notice though is that the horizontal edge of the image seem to pulse and shimmy slightly. Perhaps it's because it's a tube TV and a few years old. I don't notice this effect if playing the DVD on my Apple LCD. I don't have a nice LCD screen to play it on to test.

    See illustration:

    http://www.pixentral.com/show.php?picture=1pmoAZxFAdAWWGN1NbLvCaamWNn86

    Anyone know what causes this?
     
  2. bimmzy macrumors regular

    bimmzy

    Joined:
    Dec 29, 2006
    Location:
    London
    #2
    mmm interesting.... well sort of.

    I think it's probably the interlacing of the half length lines inherent in PAL and NTSC.. You will see the effect acutely on an old crt style TV. :rolleyes:

    Its normal so don’t worry! :D
     
  3. alex1 macrumors newbie

    Joined:
    Dec 19, 2007
    #3
    Yup it's interlacing, but I think you might be able to lessen it or remove it.

    If you have Final Cut Pro and DVD-Studio pro (Final Cut Studio 1 or 2) you can eliminate it. If not, learn to live with it.

    If you have FCStudio 1 or 2, use a 24p timeline. DVD's use a 60i format but recognize a 23.97 pulldown (24p) and so if you edit and burn a DVD in 24p (hopefully from a 24p source) it will look very much like a big budget movie from the Blockbuster. I-movie and I-DVD I'm not sure if they handle 24p at all. but look for settings and see if it does, then give it a whirl.
     

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