Jittery movement during side-scrolling on VCD. Why?

Discussion in 'Computers' started by John_Berger, Aug 8, 2003.

  1. John_Berger

    John_Berger Cinematographer

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    Now, I want to state here and now that this is a technical question regarding interlacing and encoding; so I would appreciate it if the admins would not be as paranoid and thread-lock-trigger-happy as they have been lately.

    I am converting some of my more-watched movies to VCD with various tools, in this case TMPGenc being the primary tool since it provides very nice results when high quality motion estimation is used, in order to keep the original media safely tucked away while I have a movie in the background to give me some noise. (You guess what the source media is.) Don't ask why I'm not using DVD-R at the moment. It's a long story.

    The only thing that's happening that is of any concern (and even then it's a very MINOR annoyance) is that during side-scrolling the image is jittery on those sections of the screen that are displaying a lot of movement. Action scenes to or away from the camera angle have no problems. It's only with genuine side-to-side motion.

    I'm assuming that this is due to interlacing or something during the encoding process.

    I've actually seen this before with some of my DV captures from my camcorder after converting them to DVD. It's very rare, but I've seen it. These VCDs that I'm creating are being used in my stand-alone DVD player in my computer room. That being the case, should I have the source de-interlaced before encoding to VCD or is this something that I just have to deal with? What would be the results of deinterlacing before encoding when the results are being viewed on a regular TV?

    If this thread gets locked (even though I'm only discussing general interlacing and encoding issues) I would appreciate e-mail from anyone who knows.
     
  2. Ken Chan

    Ken Chan Producer

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    You need to do inverse telecine and encode the VCD as NTSC Film, 24 fps. Luckily, TMPGEnc has a very nice built-in tool for "IVTC".

    A simple deinterlace won't help, because you'd still get the 2/3 cadence, which is more commonly described as "judder" than "jitter" (if that is what I'm guessing you're seeing). This technical lingo....

    //Ken
     
  3. John_Berger

    John_Berger Cinematographer

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    Thanks, Ken. I'll try that.
     
  4. John_Berger

    John_Berger Cinematographer

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    Worked like a champ, Ken! Thanks! [​IMG]
     

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