These are only supposed to be called once per row, not once per macroblock.
~1.5% faster according to oprofile.
Originally committed as revision 19213 to svn://svn.ffmpeg.org/ffmpeg/trunk
~8% faster VC-1 decoding.
Possible future optimization: clear blocks after use instead of before, and for
DC-only blocks, only clear the DC coefficient.
Originally committed as revision 19205 to svn://svn.ffmpeg.org/ffmpeg/trunk
Includes mmx2 asm for the various functions.
Note that the actual idct still does not have an x86 SIMD implemtation.
For wmv3 files using regular idct, the decoder just falls back to simple_idct,
since simple_idct_dc doesn't exist (yet).
Originally committed as revision 19204 to svn://svn.ffmpeg.org/ffmpeg/trunk
