[vorbis] Lossless video codec

[Chrissy and Raul]

MJPEG collects individual frames as if there were not related to each other. 
  That is the same for I-only MPEG.  This is useful, but not essential to 
editing (clever access to P and B frames can be done, including on-the-fly 
editing).  C-Cube has solutions for IBP single-frame editing.

For a lossless video compressor we can exploit relationships between pixels 
and do run-length coding plus huffman coding.  The relationships and 
potential lossless compression techniques are the following:

Intra Frame
1) Horizontal run-length coding
2) Vertical run-length coding
3) Differential horizontal coding
4) Differential vertical coding
5) 2D run-length coding (zig-zag? spiral?)
6) 2D differential coding (zig-zag? spiral?)

Inter Frame
7) Motion estimation with skipping and differential coding.  Most images can 
be predicted from its predecessors and, if available, from its successors.

MPEG does reference frames and then predicted frames.  The reference frames 
are coded completely, the predicted frames only code differences between the 
reconstructed reference frame and the predicted frame.  DCT coding, without 
throwing away coefficients can reduce information content.  Again, the trick 
here is not to step on any patents.

Has anybody put together a video compression patent minefield?
Is Huffman coding patent-free?  Is DCT patent free?

RAUL LOPEZ

>From: Ralph Giles <giles at snow.ashlu.bc.ca>
>Reply-To: vorbis at xiph.org
>To: Anthony Arcieri <bascule at holly.ColoState.EDU>
>CC: vorbis at xiph.org
>Subject: Re: [vorbis] Lossless video codec
>Date: Wed, 13 Sep 2000 22:47:18 -0700 (PDT)
>
>On Wed, 13 Sep 2000, Anthony Arcieri wrote:
>
> > I know this probably transcends the scope of the current aims of Ogg
> > video, but one thing I'd consider extremely useful is a lossless video
> > compressor.
>
>I don't really know how it compares to the codec you mention, but I've
>been pushing mng (the animation successor to png) for this. It supports a
>series of png images, a lossless 'delta png' mode, and mjpeg, among its
>other talents.
>
>  -r
>
>--
>giles at ashlu.bc.ca
>
>
>
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