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DVD and VCD

  1. Feb 7, 2005 #1
    What is the difference in quality between DVD and VCD? I don't notice that the main difference in image clearence quality.
     
  2. jcsd
  3. Feb 7, 2005 #2

    chroot

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    It's a huge difference.

    VCD has a resolution of 352 x 288, while DVD has a resolution of 720 x 480.

    - Warren
     
  4. Feb 9, 2005 #3
    Some people are very insensitive to difference in quality of image, and two two resolution appears the same to them. But most people can still detect the pixel quality difference between the Cd and DVD resolution.
     
  5. Feb 16, 2005 #4

    NoTime

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    Maybe not so huge.

    A standard tv has a displayable resolution around 300 x 250.

    Computer monitors are better but can have mapping artifacts and thruput errors as the data is resized to fit the presentation window.
    High resolution data can actually end up looking worse than low resolution here.

    Also those are max resolutions.
    Actual resolutions will depend on the source data resolution as well as encodeing choices.
    They may be much lower.
     
  6. Feb 20, 2005 #5
    Well, on my TV, I can't tell much of a difference. On my LCD computer montior though, set to its native resolution, I can tell a HUGE difference.
     
  7. Feb 21, 2005 #6

    chroot

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    NoTime,

    The NTSC standard has 525 lines of vertical resolution, of which 480 are typically active video. The horizontal resolution is not specified by the NTSC standard, because it's an analog signal. Typical sets are nowhere as bad as 300 x 250, however.

    - Warren
     
  8. Feb 21, 2005 #7

    NoTime

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    The first 25 lines or so, of the 525, are vbli and form the black bar if your picture "Rolls"
    Something that is rarely seen nowadays with the digital sync filters.
    In addition you have what is called overscan (where the 480 comes from).
    The 525 is also split into two fields which are alternately displayed.
    The effective resolution, what you can actually discern, works out to 250 on a good day. More like 200 in practice.

    The color comb filter has a theoretical max of 350 horizontal.
    To the best of my knowledge a top of the line comb filter peaks out around 300. Cheaper comb filters make around 200 to 250 horizontal.

    You can do slightly better horizontal using the s-vhs input which bypasses the comb filter (about 400) or even better with RGB input.

    I thought I was being really optimistic with that 300x250.
     
  9. Feb 21, 2005 #8

    NoTime

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    Newer computers, properly configured, work quite nicely.
    Get one that is two or three years old or operating without DMA.
    The results can look pretty rude. :eek:
     
  10. Feb 22, 2005 #9
    VCD's are essentialy compressed DVDs. VCD's have a lower bitrate which means there is less "information" that makes up the picture so a low bitrate VCD could sometimes become pixelated. This is because of the size difference. DVD's are around 4.2GB but a typical VCD would be around 1.4GB so you can see why the VCD's are lower in quality and have a lower resoltion.
     
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