Anyone know about DVD players, why does mine....

Discussion in 'Blu-ray & DVD Players & Recorders' started by pixel, Apr 25, 2003.

  1. pixel

    pixel
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    During a film if the camera moves fast across the screen the picture seams to shake as it’s moving…why is this? :confused:
     
  2. Gary Lightfoot

    Gary Lightfoot
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    shake or jerk?

    If you're watching an NTSC movie output to yor tv as PAL then you'll see jerking - NTSC fits 24 frames of film into 60 fields of tv but reproducing the frames 3 2 3 2 3 2 3 2 3 2 3 2 etc. That won't work on 50hz UK tvs, so you see the jerking.

    On PAL disks, they speed the film up by 4% to get 25 frames per second, and that fits into 50 quite nicely by reproducing each frame twice.

    Gary.
     
  3. pixel

    pixel
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    Sorry it jerks is this because my TV does'nt support progressive scan?
     
  4. StooMonster

    StooMonster
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    No.

    Your jerking could be caused by all sorts of things -- oh er misses.

    Gary is assuming that you are talking about movies and not television shows, but "jerking" during pans is to do with changing formats as Gary says.

    I'm trying to be very simple here, not totally laboriously correct...

    Movies are 24 frames per second (FPS)

    NTSC video (e.g. Simpsons, Friends, Buffy, etc) is 30fps displayed in 60 fields per second (due to interlacing)

    PAL video (e.g. The Office, Phoenix Nights, etc) is 25fps displayed in 50 fields per second (due to interlacing)

    Problems like “jerking” highlight the difficulties in changing from one format to another.

    For example, putting movies on to an NTSC (region 1) DVD, 24fps has to go into 60 fields per second; this is done by a process called 3:2 pull down – it can make pans very jerky.

    Putting movies on to a PAL (region 2) DVD, 24fps has to go into 50 fields per second; this is done by speeding up film 4% – it makes the movie play faster.

    Putting NTSC video onto PAL DVD or for broadcast in UK, 30fps has to go into 50 fields per second; and for PAL video onto NTSC DVD or for US broadcast, 25fps has to go into 60 fields per second.

    It all gets a bit complicated.

    Even more so, as Gary suggests, when you may be watching an NTSC DVD output to PAL on your screen. Then 24fps goes into 60 fields which is then converted by DVD player into 50 fields; which could result in all sorts of difficulties.

    If this “jerking” is with NTSC movies (region 1); check that your DVD player is outputting the right signal, and that your screen is multi-format and can accept an NTSC signal anyway.

    StooMonster
     
  5. nathan_silly

    nathan_silly
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    Don't rule out 100hz processing/insufficient video memory buffer.
     
  6. pixel

    pixel
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    I'm watching Region 2 PAL DVD on a when it happens...it happens with all my Region 2 PAL DVD's

    By the way I have a Toshiba SD520e DVD muiti region player and a Toshiba 36ZP18Q Picture frame TV 36" widescreen.
     
  7. StooMonster

    StooMonster
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    Can you borrow another DVD player to test with your screen?

    Or use your DVD player on another screen?

    You could then easily identify which of the two is causing the problem -- the it will be easier to work out exactly what the problem is, and find a solution.

    StooMonster
     

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