how is laserdisc video analog?

Discussion in 'Playback Devices' started by Christ Reynolds, Apr 27, 2004.

  1. Christ Reynolds

    Christ Reynolds Producer

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    i'm doing a presentation to a class, and i need to know how laserdisc video is analog in nature. i did a search here but didnt come up with much. i've seen bob niland's article, but it seems to cover audio and video, and niether specifically. i couldnt find much in the LD faq either, unless i am looking in the wrong places. from what i understand, pulse width modulation is involved. i'm not sure how, though. any help is much appreciated. images and diagrams would be great, and the more technical the info, the better.

    CJ
     
  2. alan halvorson

    alan halvorson Cinematographer

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    Have you looked in The Laserdisc FAQ ? It's no longer maintained, but it does have a lot of laser disc information.
     
  3. alan halvorson

    alan halvorson Cinematographer

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    But maybe this page How Laserdiscs Are Produced will be more useful. The The Laserdisc FAQ doesn't seem to contain what you're looking for.
     
  4. Allan Jayne

    Allan Jayne Cinematographer

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    What is encoded on LD is the composite video waveform, not individual luminance and color pixels.

    Video hints:
    http://members.aol.com/ajaynejr/video.htm

    Swamped by email? Reply with quick off the cuff snippets, follow up with details later.
     
  5. Christ Reynolds

    Christ Reynolds Producer

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    great, thanks for the links, i will check them out now.

    CJ
     
  6. JohnnyG

    JohnnyG Screenwriter

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    IIRC, the short answer is that the reflectivity of the substrate is modulated. It's not on/off pits like on CD/DVD, but varies. So, the amount of light that bounces of the disc is measured and creates a purely analog waveform.
     

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