[FFmpeg-devel] [PATCH] SSE dct32() [Was: r23095 - in trunk/libavcodec: ...]

Måns Rullgård mans
Sat Jun 5 12:24:43 CEST 2010

Vitor Sessak <vitor1001 at gmail.com> writes:

> Moving discussion to -devel...
> On 05/31/2010 09:59 PM, Vitor Sessak wrote:
>> On 05/14/2010 05:52 PM, Michael Niedermayer wrote:
>>> On Fri, May 14, 2010 at 08:39:48AM +0200, Vitor Sessak wrote:
>>>> Michael Niedermayer wrote:
>>>>> On Tue, May 11, 2010 at 03:56:45PM -0400, Alex Converse wrote:
>>>>>> On Tue, May 11, 2010 at 3:52 PM, michael<subversion at mplayerhq.hu>
>>>>>> wrote:
>>>>>>> Author: michael
>>>>>>> Date: Tue May 11 21:52:42 2010
>>>>>>> New Revision: 23095
>>>>>>> Log:
>>>>>>> float based mp1/mp2/mp3 decoders.
>>>>>> Thanks
>>>>> :)
>>>>> btw, any volunteers to try to hook it up to our split radix dct and or
>>>>> simd optimize it?
>>>> Without rdft or dct simd, our split radix code is slower. Ugly hack
>>>> to test
>>>> it attached.
>>> if dct32() is faster then it should be used by our generic dct code.
>>> at least for the plain C case
>> I've given a try at a SSE dct32(). It is much faster than current C
>> code. The only problem is that current code in mpegaudiodec.c expect two
>> arguments, one input (which is destructed) and one output. ITOH,
>> ff_dct_calc() does everything in-place, what does not glue well with the
>> current mpegaudiodec.c code. Can you (or anyone else that knows
>> mpegaudiodec.c well) fix it?
> I've given a try of making mpegaudiodec.c use the same buffer for dct
> input and output and it is not trivial. It is much easier (and has no
> measurable slowdown) to make ff_dct_calc() take both an input and an
> output pointer as in attached patch.

No change needed to asm?

M?ns Rullg?rd
mans at mansr.com

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