Quality Loss Converting PAL to NTSC

Discussion in 'Digital Video' started by Col, Feb 8, 2007.

  1. Col macrumors newbie

    Sep 29, 2006
    Sydney, Australia
    Hey Mac-Experts,
    I have been creating iMovie projects down in Australia from PAL sources. I discovered accidentally that if I send the PAL iMovie project directly to iDVD (using the 'Create iDVD Project' button in the iDVD window (far right of screen) and have iDVD set to NTSC in Preferences, it converts it on the fly when creating the disc.
    As I live and have freinds in both Australia and the USA I am thinking of converting all future projects to NTSC so I can play them anywhere on anyone's TV (pretty well all Aussie DVD players/TVs do both nowadays).
    I think I see a loss of quality, but my current aussie TV is total garbage, so I don't know if I am imagining it.
    Is my decision to convert all going to come back and bit me in the bum once I get a decent TV?
    In other words, does anyone know if the quality is greatly diminished by doing this? I know that PAL inherently has more resolution, so there is definitely some loss, but is it compounded greater than that?
    Is there some other program I should be using instead that is better?

  2. Mydriasis macrumors 6502


    Mar 17, 2005
    Yes, there is a big difference between PAL and NTSC its not just resolution and frame rate but also color space and other details.

    Most software converters are, well, less than perfect. For the best results you'll want to stick to format the footage was captured in. Only convert if you have to.
  3. lostless macrumors 6502

    Oct 22, 2005
    To gi ve minor details of what the last guy said, PAL is 50 fields per second, interlaced into 25 video frams per second. NTSC is 60 fields and 30 frames per second. tryng to fit 50 fields into 60 fields isnt quite an easy thing to do, as you may end up with duplicate frames causeing some choppyness during the conversion. Thank God its easier to convert PAL to NTSC, since no frames are actually lost during the conversion.
    A great program to use is a program called JES Deinterlacer. Look it up. It actually reconizes individual fields and will resemble new frames in NTSC to get the smoothest possible image. Kind of like NTSC 3:2 pulldown for film (puting 24 progressive FPS into 30 interlaced FPS). Use the Standard conversion mode to do PAL to NTSC conversion. Just note in the PAL to NTSC convertion, some vertical resolution will be lost.
    If you dont know what I mean by fields and frames and interlacing, htt://www.100FPS.com explains what they are.
    Hope my explanation helpls
  4. lucasedf macrumors newbie

    Feb 22, 2009
    I've read about JES Deinterlacer in another topic, and tried using it (I'm also trying to convert a PAL into NTSC so it will play in a PS3), but it doesn't let me add the files I want to convert... it is a .img file, so do I have to convert it into another format before using JES Deinterlacer?

    I appreciate any help with this.

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