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"Shifting" effect in some DVD's video... Explain pls :)

Discussion in 'Archived Threads 2001-2004' started by Serega_M, Jan 21, 2002.

  1. Serega_M

    Serega_M Agent

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    Hi people,
    Always wanted to know one thing. On some DVD's in my collection (for example - Ilsa series from AB, Ginger Snaps - Canadian CC, and some others) there are occasional effedt of this kind during the playback. Some "shifts" is going one in the picture - for example - in Ginger Snaps theer is a scene where camera moves to the actors face which lies on the table in the pool of blood - the motion is not so fast but not so slow as well - and parts of actor's face shifts from their places. Or - there is a panoramic view in Ilsa movie - on the background there are some hills and in the foreground - the watch-tower of the concentration camp. So - this watch-tower shifts in the picture!!! Such things are rare - but they are annoyingly distracting. So - the question is - what the hell is that? Is it the faults in encoding/authoring of the disk - or something else? Anyone explain? [​IMG] Thanks in advance [​IMG]
     
  2. Ike

    Ike Screenwriter

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    I'd give the discs a cleaning-sometimes when my discs are dirty or scratched, the "skips" can manifest themselves in picture shifts.

    If that doesn't work, I'd say it's a flaw with the discs. Since I'm not familiar with the paticular discs you listed, I can't check and see if it's a mastering problem. Maybe someone with these discs can answer you more detailed.
     
  3. Todd Phillips

    Todd Phillips Second Unit

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    I'm not sure if this is what you describe, but it may be caused by missing or damaged frames in the source film which would show up as jumps or skips in the DVD transfer.
     
  4. Ike

    Ike Screenwriter

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    Does the picture pixelate when it moves?
     
  5. TimW

    TimW Agent

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    It's probably the interlacing of the signal.

    When you have camera movement, you get those little jaggies because the image is unable to keep up. The lines of resolution are being alternated instead of shown at the same time.

    Tim
     
  6. mark_d

    mark_d Second Unit

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    Don't know what the TV standard is in Russia, but if you are used to PAL and you only see this problem on NTSC discs (American, Canadian, Japanese imports), I suppose it could be 3:2 pulldown artifacts that you see.

    If you are intersted in finding out more, DVDFile.com had an excellent explanation a while back, which I guess you may be able to find if you search their site.

    Mark
     
  7. mark_d

    mark_d Second Unit

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  8. Serega_M

    Serega_M Agent

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    Hi, Mark and all the others...
    In Russia the TV standard is SECAM [​IMG])) But really - all TV-sets sold here can show SECAM, PAL & in some cases even NTSC without any problems. And there is no pixelation during these shifts. Also - almost all of the disks of my collection - are Region 1 - therefore - NTSC. And only on the several of them I can see such strange effect. Hmm... My idea is - that possible it is some kind of MPEG-2 encoding glitch which wasn't eliminated on the authoring stage - but possible it is something more. Sadly - my TV is just 16x9 Philips without progressive mode. But the player (Pioneer DV-737) has progressive output for NTSC coded disks. I just think - maybe when I'll have a progressive display - these effect will dissappear? I dunno... Strange thing.
     
  9. NeilEdwards

    NeilEdwards Stunt Coordinator

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    This is what happens when you play a NON-Anamorphic DVD. My setup is a 16:9 TV with a progressive DVD player. With an Anamorphic DVD, the scan lines are always in sync with the picture. This will also happen with any progressive scan vs interlaced scan.

    What is funny is when someone shakes their head left to right, and their eye doesn't move.
     
  10. Serega_M

    Serega_M Agent

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    Hi, Neil
    Actually - all of the DVD's I have mentioned with this strange effect - in fact and for sure are ANAMORPHIC [​IMG] More than that - they were produced in 2001 - 4 years after the launch of DVD - with the modern compression and authoring methods (at least Ilsa movies - they were produced by Crest National, and Ginger Snaps by some Canadian factory, forgot the name [​IMG]) Also - your explanation doesn't explain why this effect is visible only on selected disks from my not so small collection, while all of the rest are playing fine without any kinda of image distortion or such "shifts"...
     
  11. Joseph Young

    Joseph Young Screenwriter

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    Serega,
    TimW's reference of interlacing of the signal seems accurate based on my experiences.
    I am using the lowest of the low end DVD players, so bad in fact that I won't mention it here. [​IMG] However my television is no slump. It does not support progressive scan though. Blurry (inferior resolution) televisions can actually mask much of the pixel smudging you described, giving the impression of a 'cleaner' signal.
    Needless to say, my amateur assumption is that the player itself determines in part how effeciently the video data is assembled on the screen.
    Progressive scan, given you have a compatible television (HDTV, Sony XBR for instance) will give you an amazing picture without much of the 'static pixel' issues described above.
    I could be wrong though. [​IMG]
    Joseph
     
  12. Jeff Ulmer

    Jeff Ulmer Producer

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    I know exactly the effect you are talking about, and I get the feeling others here may not from the replies. If I read you right, a section of the frame "floats" unnaturally while the rest remains fairly stationary. This is not limited to any one kind of transfer: How Green Was My Valley, a 4:3 film has a lot of this. I have yet to see an explanation of it, but I suspect it is due to image stabilisation filtering, though that is just a guess.

    Edited to add that this effect is cleary visible on my progressive setup.
     
  13. Joshua Clinard

    Joshua Clinard Screenwriter

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    I noticed this for the first time last week when watching a DVD. I cannot remember what DVD, but I remember it was when someone leaned over, it kind of jumped, well his head jumped, but the rest of his body was not in sync. I will go over the DVD's I have watched this week, and let yall know the Title, and the scene.
     
  14. Gunnar Syren

    Gunnar Syren Stunt Coordinator

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    I have seen this effect, too. The effect reminds me somewhat of a bad matte shot where the camera has not been locked down properly, so the non-matte part jiggles as bit whereas the matte is still. Although in this case the effect occurs when something moves (or the camera pans).

    The first time I noticed it was on an old color film, so I thought that it might have been a three strip technicolor print with one color slightly out of sync. But since then I have seen it on b&w films also, so that theory went out the window...
     
  15. Serega_M

    Serega_M Agent

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    Hi again, people [​IMG]
    Jeff, yes - you are right - I am seeing this effect as you have described (probably much better than I had [​IMG]) - and this is really crappy if you can see it on your Progressive setup. And now to Gunnar - yes - seems that we are talking about the same crap, but in my case - I have seen this effect while camera panning (or just the object which moves in the static camera position (a little jumping-horse in Ginger Snaps turns left-right-left-right)) and in the absolutely static frame - where NOTHING should shifts from its place - but some objects DO! The mystery for me is why it is celarly visible on some selected transfers, and most of the disks looks allright... For me it is a clear indication of the encoding/authoring glitch - but maybe I am wrong... [​IMG]
     

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