Category Archives: Codec Technology

Microsoft Video-1 Based on DCT?

I recently learned that Wikipedia has an entry for Microsoft Video-1. The entry makes two assertions of which I was heretofore unaware:

  1. the codec was licensed from Media Vision and is based on a codec called MotiVE
  2. the codec was based on the discrete cosine transform (DCT)

I can accept assertion #1 but I have trouble with the second. I just don’t see it. Per my understanding Video-1 falls into the category of vector quantizer. I did a quick Google search for “media vision motive cosine” to search for supporting details. This page supports the DCT claim. But it also claims that Duck TrueMotion 1 is a vector quantizer (nope). Here is another page that mentions the MotiVE connection but pegs Video-1 as a vector quantizer.

At least the Wikipedia article links to my Video-1 description so interested parties can investigate the details for themselves.

Video Coding Concepts: Frame Types

This article is maintained in Wiki format at http://wiki.multimedia.cx/index.php?title=Frame_Types.

Ultimately, encoded video data needs to be decoded to 2-dimensional arrays of pixel values and presented to the user (or perhaps transcoded to a different format). All of these frames look complete to the user. But the frames often can not stand by themselves. They usually need information from other frames in order to make their presentation complete.

Let’s talk basic video frame terminology. First, there is the intraframe. This is also known as a keyframe. An intraframe is one that can stand on its own. It requires no other frames. It carries with it all the information needed to be decoded.

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