Jagged Lines

Discussion in 'Amateur Video Production' started by J, Sep 24, 2004.

  1. J

    J Guest

    Ive been lurking and posting here for a few weeks and finally took my
    first stab at creating a DVD. Im using Nero Express which seems
    pretty easy to use. Im very happy with the process but the final
    result was a tad less than what I thought it would be. I captured the
    DV through a firewire (400) connection and captured it in DV Type 1

    On my DVD, there seems to be jagged lines between objects of different
    colors. The jagged lines are most noticable between white and any
    darker color. Is there something I can do to make the DVD sharper?
    Overall the quality is good and the jagged lines appear more
    pronounced while the object is moving.

    Thanks for any help.

    J, Sep 24, 2004
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  2. J

    david.mccall Guest

    Are you seeing these lines while watching on the computer or on a TV?

    If you are seeing them on the computer, but not on TV, then you are
    seeing what is called interlacing.

    In an effort to reduce the flicker of a TV picture they adopted interlacing.
    Simply put, it divides each frame into 2 fields. One field contains the
    "odd lines" and the other contains the even lines. At the time television
    was being designed, there was no way to store a full frame image (or
    even a field for that matter).As the electron beam scanned in every other
    the TVs at home scanned out in perfect sync. What you saw on TV was
    truly live, right down to the level of each scanline. This caused the
    picture to
    be perceived as a solid image, because a half picture gets scanned out 60
    times a second (50 times a second in PAL).

    So, what you are seeing as jagged lines is the difference between the
    of a moving object in 2 different positions 1/60th of a second apart. The
    effect of interlaced scanning is far smoother motion on the TV,
    the side effect on a computer screen is those jagged lines. A computer shows
    you both fields at once, instead of sequentially as on a TV. If you intend
    mostly view your video on a computer then you could use a deinterlacer to
    remove these motion artifacts. A simple deinterlaceing application will just
    remove half of the scanlines thus reducing the resolution by half. A smart
    deinterlacer will keep all of the resolution in portions of the picture that
    have motion, and reduce the resolution only in areas where there is motion.

    david.mccall, Sep 24, 2004
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  3. J

    Jon Milner Guest

    The DVD compressor built into Nero maybe isn't doing a good job, creating
    compression artifacts around the edge of objects. You have to expect some of
    this because the data rate of DVD is quite a bit lower than mini-DV. So you will
    lose quality.

    I like the results I get with a cheapo program called Ulead Movie Maker 3
    because I can set the compression level to variable and max the quality
    settings. This takes more time to render the DVD files, but the quality is
    pretty good. The one time I tried an earlier version of Nero to do the
    compressing, I thought the results were borderline terrible, with all kinds of
    MPEG artifacts around the edges of moving objects.
    Jon Milner, Sep 25, 2004
  4. J

    DeepOne Guest

    If he's seeing them on the TV, then the field order may have been set
    incorrectly during MPEG encoding. DV video is supposed to be bottom
    (B) field first.
    DeepOne, Sep 25, 2004
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