[FFmpeg-devel] [PATCH] Move VC1 loop filter to DSPContext

David Conrad lessen42
Wed Apr 1 20:44:13 CEST 2009

On Apr 1, 2009, at 1:37 PM, Michael Niedermayer wrote:

> On Wed, Apr 01, 2009 at 04:23:26AM -0400, David Conrad wrote:
>> Hi,
>> First patch moves VC1's loop filter function as is to DSPContext, the
>> second splits it according h/v and size for faster/easier simd
>> implementations.
>> Since these functions require 16 bit arithmetic, there isn't really  
>> a speed
>> advantage to having size 16 functions in simd. I kept them for  
>> consistency
>> and because it's a bit uglier to use size 8 x2 in  
>> vc1_loop_filter_iblk.
> The changes to files maintained by me are ok, assuming it has been  
> verified
> that the vc1 loop filter is bitexact relative to the binary codec
> (i would not want incorrect code to be optimized)

The loop filter is identical to the VC1 spec and the one in the  
reference implementation.
The file I have that uses the loop filter is bitexact to the binary  
codec for I and P frames, but not B frames.
Of the files I have that do not use the loop filter, three are  
bitexact and one is not bitexact for any frame.
The two files that aren't bitexact are from HDDVD rips, so I'll create  
a roundup ticket since there's probably some weird feature or  
something being used.

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