[Theora-dev] FPGA implementation

Andrey Filippov theora at elphel.com
Wed Jan 19 15:36:12 PST 2005


> Yes, it becam obvious when I went to the next level of my manual parsing -
> decoding Theora packets.

Trying to reimplement "decoder" (capable of just filling COEFFS array) I
found difference between the documentation and how theora-experimental
works (I did not hack main branch, but it shoul probably be the same as
the video is decoded). The only way I could make my decoder parse data
with the same result was when I noticed that regular decoder uses
different Huffman group calculation, so my program matched the results
only after the following chdnge.

//   HG=(ti>0)?((ti>4)?((ti>13)?((ti>26)?4:3):2):1):0;
     HG=(ti>0)?((ti>5)?((ti>14)?((ti>27)?4:3):2):1):0;

And I carefully checked that in my program ti=0 for DC, 1 - for AC1,...
ti=63 for the last AC63.

Could it be an error in the Theora_I_spec.pdf (page 95)?
Or am I missing something again?

Andrey





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