[FFmpeg-devel] [PATCH] MMX VP3 Loop Filter

[David Conrad]

On Oct 11, 2008, at 6:03 AM, Michael Niedermayer wrote:

> On Sat, Oct 11, 2008 at 04:53:24AM -0400, David Conrad wrote:
>> On Oct 8, 2008, at 1:59 AM, David Conrad wrote:
>>
>>> On Oct 7, 2008, at 5:43 AM, Jason Garrett-Glaser wrote:
>>>
>>>>> Here's an 8-bit version. However, checking for the C fallback  
>>>>> negates
>>>>> the
>>>>> small speedup on my Penryn compared to the 16-bit version.
>>>>
>>>> Most of the code is still 16-bit.  Are you sure this can't be done
>>>> x264-style with emulation of extra bits and 8-bit math (reference  
>>>> for
>>>> an example of how to do this: common/x86/deblock-a.asm in x264  
>>>> tree)?
>>>> This would eliminate the need for all unpacks, all packs, and all
>>>> multiplication, and probably increase speed dramatically.  I  
>>>> strongly
>>>> suspect that it can be done, as the deblocking formulas seem very
>>>> similar to those used in H.264.
>>>
>>> It seems like you're right; the only difference between  
>>> DEBLOCK_P0_Q0 and
>>> VP3 is a *3 vs. a *4 in H.264.
>>> I don't quite fully understand x264's implementation, so it'll take
>>> another bit to adapt it.
>>
>> And here's an entirely 8-bit implementation. ~3 cycles faster than  
>> the last
>> patch I posted.
>
>> I'm not sure the best way to avoid the duplication of ff_pb_1/3/7
>> constants; there aren't enough registers to pass the address of all  
>> of the
>> constants I need.
>
> try MANGLE()

Done.

> [...]
>> +\
>> +    "movd     "#flim", %%mm5 \n\t" \
>> +    "punpcklbw  %%mm5, %%mm5 \n\t" \
>
> you could pass the thing from mm5 at the end of the bounding_values  
> array,
> this also would make filter_limit unneeded, avoid the *0x02020202  
> and the
> punpcklbw

Done.

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