A Brief Look at De-Interlacing Modes

The process of taking interlaced content and displaying it in a non-interlaced form is often referred to as de-interlacing (for obvious reasons). There are two basic methods of de-interlacing, commonly known as "bob" and "weave."

Bob de-interlacing is more technically referred to as linear interpolation and it simply fills in the missing lines of resolution by interpolating between the resolution lines that are available. This interpolation form of de-interlacing is particularly useful if there are a lot of solid colors on the screen and if the decoder screws up and decides to combine two fields from different frames.

Weave de-interlacing, as the name implies, simply combines alternating lines of resolution from two separate interlaced fields. Using either method individually is generally not the best way of doing things, but thanks to the decent amount of power in today's PCs more sophisticated algorithms can be implemented to dynamically switch between bob and weave on a per pixel basis within a frame (usually referred to as adaptive per pixel de-interlacing).

NVIDIA's PureVideo supposedly takes adaptive per pixel de-interlacing one step further with what they call Spatial-Temporal de-interlacing. The idea here is that normal per pixel adaptive de-interlacing uses data from fields within a single frame to essentially fill in the blanks. NVIDIA's Spatial-Temporal de-interlacing can use data from fields in other frames to improve de-interlacing quality. We'll have to see if this ends up improving quality or not in our tests later in the article.

Frame Rate Conversion and You NVIDIA's PureVideo Driver and Encoder
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  • Cybercat - Monday, December 20, 2004 - link

    Oh, nevermind, that's for PCI Express 6800s, which are apparently the only cards that use the NV41 core. AGP 6800s use the NV40 core.
  • Novaoblivion - Monday, December 20, 2004 - link

    For anyone who wants it the link on Nvidia's site seems to working I just downloaded it.
  • Cybercat - Monday, December 20, 2004 - link

    http://nvidia.com/page/purevideo_support.html

    How does the 6800 have acceleration support if it's also based on the NV40 core?
  • skunkbuster - Monday, December 20, 2004 - link

    "At the same time, ATI sent us information on how to enable hardware acceleration of WMV9 on their cards before the forthcoming WMP10 update."


    would someone care to share this with the rest of us ?
  • KnightBreed - Monday, December 20, 2004 - link

    I hope nVidia plans to add support for decoding MPEG4-AVC HP at some point. Whether it's this product line or next, MPEG4 will be important for next generation optical media (whether it's HD-DVD or Blu-Ray).
  • LoneWolf15 - Monday, December 20, 2004 - link

    What makes me truly upset is that so far, the sites reviewing PureVideo has not take a stand for the consumers that own the 6800 and were promised the full PureVideo featureset by nVidia. Rather, sites are reviewing the tech, and ducking the issue, as if they are more concerned about continuing to receive nVidia products for review than they are for us. Who's looking out for the little guy?

    P.S. Anandtech's review states that the 6800 Standard has a fully functional video processor --this isn't fully true, as the AGP version according to nVidia's website, does not.
  • jamawass - Monday, December 20, 2004 - link

    Great review. Even though Nvidia doesn't always win the deinterlace test, it wins on picture quality in most tests.Looks like a 6600 Nvidia will be replacing my ATI as the next video card in my htpc.
  • Aquila76 - Monday, December 20, 2004 - link

    That is so retarded that it doesn't fully work on the 6800GT/Ultra. Why would they cripple their high end cards? I guess since they aren't very available it doesn't really matter. Hope they add the rest of the functionality to new revs of these cards.
  • GnomeCop - Monday, December 20, 2004 - link

    wow I guess they will get away with touting this feature on the AGP 6800Ultra/GTs , even though it doesn't fully work after all.
  • jg123 - Monday, December 20, 2004 - link

    I don't see a link on Nvidia's website for a trial mentioned in this article.

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