[theora-dev] dead DCSearchPoints code

Ralph Giles giles at xiph.org
Sat Jun 14 09:08:39 PDT 2003


In reviewing the code, derf came across the DCSearchPoints array in  
QuadCodeDisplayFragments(), encode.c:696. It looks like it specifies a 
search order for nearby coded fragments for prediction if there isn't a 
nearest neighbor. However, the upper search bound is defined as *0*, so 
the search loop (line 917) is never executed and it always falls back 
to the last coded fragment.

This table and supporting code is duplicated on the decode side in 
dct_decode.c around lines 1022 and 1191.

Derf thought this code was similarly bypassed in VP3 as well. I enabled 
it and tested a couple of files, but it didn't make an appreciable 
difference in efficiency. Therefore it seems reasonable to just take it 
out as dead code. I wanted to ask what you knew about it first, and 
make sure we're not breaking lossless VP3 transcode.


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