[theora-dev] MMX patch to speed up Theora decoding

Chih-Chung Chang jochang at gmail.com
Sun Mar 25 11:33:54 PDT 2007


Attached is a patch against 1.0alpha7 to speed up Theora decoding. It
is about 15~20% faster in my test. It consists of following things:

* MMX loop filter based on Rudolf Marek's patch in
* MMX IDCT based on Rudolf Marek's patch in
and the code in http://svn.xiph.org/trunk/vp32/CoreLibs/CDXV/Vp31/dx/win32/
* change FiltBoundingValue to ogg_int16_t and reduce it to 256
entries. (It is safe if I read the spec correctly)
* comment out unused idct_short__c, remove unused LoopFilterLimitValuesV2

An --enable-mmx option is added to configure (you need to run
autogen.sh to enable it after patch). Compile time switch is used
instead of a runtime one because it seems easier to me :)

Chih-Chung Chang
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