[theora-dev] More Missing Pieces

Mike Melanson melanson at pcisys.net
Sun Feb 23 20:15:44 PST 2003

        I am making good progress on understanding, documenting, and
re-implementing VP3. I have found some more deadwood in the decoder code
and I just wanted to verify that it really has no place:

* Version 3.3 tables: There are 2 sets of VLCs: One for v3.1 and one for
v3.3. The v3.1 set is always selected. Are the v3.3 tables in production,
or will they ever be?

* DC Search Points: VP3 seems determined to predict DC from *something*.
To that end, DCT_decode.c:ReconRefFrames() has code to search through
surrounding fragments in a last ditch effort to find valid fragments from
which to predict DC. While the code is there, DCSearchPointCount is set to
0 (while a legitimate calculation was commented out) which effectively
short-circuits the DC search code. So, no DC searching in this version?
Will it be back in another version?


	-Mike Melanson

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