[FFmpeg-devel] [PATCH] SPARC VIS simple_idct

Balatoni Denes dbalatoni
Tue Aug 21 22:35:13 CEST 2007


Here is a patch to add sparc vis optimized simple_idct. Speedwise it is about 
halfway between the C and the mlib version, slightly on the faster side. 
Although the mlib version is faster, this is more accurate - and I honestly 
don't know why it is not faster on the sparc than it is, it should be 
according to my estimates, but it is not.
Also, although it's the same algorithm as simple_idct, it might be less 
accurate on rare occasions, because of the primitive slow split 8+8 bit 
multply operation in VIS. I am hoping the idct won't overflow, too.

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