[theora-dev] Updated VP3 Document

Mike Melanson melanson at pcisys.net
Mon Mar 1 10:00:04 PST 2004

On Mon, 1 Mar 2004, Timothy B. Terriberry wrote:

> Especially the one about Theora no longer having the opposite
> orientation that VP3 has (at least in the CVS version).

        That does seem important...which versions of Theora have which

> The other comment I'd make is that the DCT tokens are coded in terms of
> Huffman codes. The fact that the VP3 code re-derives the Huffman codes
> corresponding to a set of histograms every time you run it is mostly
> irrelevant. The histograms are fixed (in VP3), and so the codes are
> fixed. In Theora, the codes are specified in the bitstream directly, not
> in terms of a histogram.

        Okay, this is good stuff. I will remember to incorporate this when
I revise that section (next on the list, naturally, hopefully tonight).

> Also, I don't remember if anyone ever asked before, do we have
> permission to incorporate pieces of this document (with attribution)
> into our own Theora bitstream spec.?

        Hmm, I thought I was writing the Theora bitstream spec...:)
Anyway, sure, go ahead and use it with attribution. I noticed that there
is still a reference in the doc for the GNU Free Documentation License. I
thought I got rid of it, but it's on my TODO list now. The rest of my
documents are GFDL; then again, no one cares about those. If this spec is
useful to you, go ahead and use it.

	-Mike Melanson
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