[FFmpeg-devel] [PATCH] Fix bit-exactness of MMX avg_no_rnd_pixels

Michael Niedermayer michaelni
Wed Apr 15 19:27:10 CEST 2009

On Wed, Apr 15, 2009 at 12:41:01PM -0400, David Conrad wrote:
> Hi,
> As I found in VC1, the MMX versions of avg_no_rnd_pixels are not identical 
> with their C counterparts. The problem is that the C versions use 
> (a+b+1)>>1 to average the interpolated pixels with the existing pixels, 
> while the MMX versions use the same (a+b)>>1 used for interpolation.
> This fixes the problem by adding an OP_AVG macro to always use (a+b+1)>>1 
> where needed.

probably ok

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The bravest are surely those who have the clearest vision
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notwithstanding go out to meet it. -- Thucydides
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