someone please explain software deinterlacing to me - Mandrake

This is a discussion on someone please explain software deinterlacing to me - Mandrake ; I have mythtv box, running FC4 and xine v0.99.4. I'm using it to play VOB dvd video files. I have this connected to a hitachi 42" 1080p LCD via the VGA output. If I burn the DVD and play it ...

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Thread: someone please explain software deinterlacing to me

  1. someone please explain software deinterlacing to me

    I have mythtv box, running FC4 and xine v0.99.4. I'm using it to play VOB dvd
    video files. I have this connected to a hitachi 42" 1080p LCD via the VGA
    output.

    If I burn the DVD and play it in my standalone sony DVD player, the DVDs look
    fine.

    However, when I play the videos on the mythtv box using Xine, I get some
    bizarre scanline artifacts. The problem is most noticable when there is fast
    motion and appears as brief flashes where I can see alternating scan lines. A
    good example would be a drummer playing the drums in a music video -- the
    drum sticks get a sort of on-off pattern when moved quickly.

    I think I understand how interlacing works, but what I don't understand is
    why the problem exists and is so darn annoying with the software DVD player,
    yet the sony player has no such problem. Some videos and movies are clearly
    much worse than others.

    I tried to enable software deinterlacing by toggling the 'D' key in Xine.
    Software deinterlacing eliminates the scanline artifacts, but instead I get
    severe motion blurring. Let's say for example if a person was running across
    the screen, their movement will appear blurred and/or jumpy.

    I've confirmed that at all times (with or without software deinterlacing)
    that CPU utilization on the box is less than 20%.

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  2. Re: someone please explain software deinterlacing to me


    wrote in message
    news:fg41rb125o2@news3.newsguy.com...
    >I have mythtv box, running FC4 and xine v0.99.4. I'm using it to play VOB
    >dvd
    > video files. I have this connected to a hitachi 42" 1080p LCD via the VGA
    > output.
    >
    > If I burn the DVD and play it in my standalone sony DVD player, the DVDs
    > look
    > fine.
    >
    > However, when I play the videos on the mythtv box using Xine, I get some
    > bizarre scanline artifacts. The problem is most noticable when there is
    > fast
    > motion and appears as brief flashes where I can see alternating scan
    > lines. A
    > good example would be a drummer playing the drums in a music video -- the
    > drum sticks get a sort of on-off pattern when moved quickly.
    >
    > I think I understand how interlacing works, but what I don't understand is
    > why the problem exists and is so darn annoying with the software DVD
    > player,
    > yet the sony player has no such problem. Some videos and movies are
    > clearly
    > much worse than others.
    >


    You can get a much more complete answer from one of the dvd newsgroups, but
    here is the simple version.
    Interlaced means that in the first pass, lines 1,3,5,7 etc are refreshed,
    and in the second pass, 2,4,6,8 are refreshed.
    Progressive means that lines are refreshed 1,2,3,4...
    Broadcast TV is interlaced to give better tracking for motion. They have
    traded resolution for rapid frame changes.When you freeze frame, you can see
    how bad the resolution really is, yet it looks ok because it is moving.
    Computer monitors are progressive scan, to give the detail needed when the
    screen does not change that much frame to frame.
    In the old days, 640x480 was progressive, but higher resolutions were
    interlaced, and that produced a noticeable flicker on the screen.

    As I understand it, modern video cards and monitors can not easily display
    interlaced signals, so the video is 'de-interlaced'. Often this is done by
    discarding the even (or odd) numbered scan lines. In effect, you are
    discarding half of the video information.

    The problem arises from a fusion of technologies which were never intended
    to meet.

    There may be a solution to this which I am not aware of. Again, check witht
    he dvd newsgroups.


    > I tried to enable software deinterlacing by toggling the 'D' key in Xine.
    > Software deinterlacing eliminates the scanline artifacts, but instead I
    > get
    > severe motion blurring. Let's say for example if a person was running
    > across
    > the screen, their movement will appear blurred and/or jumpy.
    >
    > I've confirmed that at all times (with or without software deinterlacing)
    > that CPU utilization on the box is less than 20%.
    >
    > -----------------------------------------------------------
    > Posted using Android Newsgroup Downloader:
    > .... http://www.sb-software.com/android
    > -----------------------------------------------------------



  3. Re: someone please explain software deinterlacing to me

    invader@nospamforme.com writes:

    >I have mythtv box, running FC4 and xine v0.99.4. I'm using it to play VOB dvd
    >video files. I have this connected to a hitachi 42" 1080p LCD via the VGA
    >output.


    >If I burn the DVD and play it in my standalone sony DVD player, the DVDs look
    >fine.


    >However, when I play the videos on the mythtv box using Xine, I get some
    >bizarre scanline artifacts. The problem is most noticable when there is fast
    >motion and appears as brief flashes where I can see alternating scan lines. A
    >good example would be a drummer playing the drums in a music video -- the
    >drum sticks get a sort of on-off pattern when moved quickly.


    Probably because the system cannot keep up with the changes in the scene.
    The system is I believe set up on a delta compression-- ie it is changes
    from one scene to another that are saved. When a scene changes rapidly or
    radically, there are a huge number of changes that have to be incorporated,
    and the system makes the tradeoff of keeping in sync with displaying all
    the changes. Now, on a dedicated system, this decoding is usually done very
    fast in hardware. On a software system, it depends critically on the
    efficiency of the encoding process if it can get the decoding done in time.



    >I think I understand how interlacing works, but what I don't understand is
    >why the problem exists and is so darn annoying with the software DVD player,
    >yet the sony player has no such problem. Some videos and movies are clearly
    >much worse than others.


    I do not believe this is an interlacing problem it is a decoding problem.


    >I tried to enable software deinterlacing by toggling the 'D' key in Xine.
    >Software deinterlacing eliminates the scanline artifacts, but instead I get
    >severe motion blurring. Let's say for example if a person was running across
    >the screen, their movement will appear blurred and/or jumpy.


    >I've confirmed that at all times (with or without software deinterlacing)
    >that CPU utilization on the box is less than 20%.


    It is probably mainly memory limited. Ie, if it has to grab stuff off the
    disk.


  4. Re: someone please explain software deinterlacing to me

    > Probably because the system cannot keep up with the changes in the scene.
    > The system is I believe set up on a delta compression-- ie it is changes
    > from one scene to another that are saved. When a scene changes rapidly or


    I did a little bit of googling around and found that I should be using the
    deinterlacing that is part of the tvtime plugin rather than whatever
    deinterlacing xine has internally.

    I switched to this method (using tvtime's greedyh algorithm) and I think the
    results are better. It's using about half again as much CPU (close to 25-
    30%), so it's definitely doing more work. I'll know more tonight after I've
    had a chance to watch something on it, but so far the results look good.

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