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

[Michael Niedermayer]

On Sat, Jun 05, 2010 at 07:35:29AM +0200, Vitor Sessak wrote:
> 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.
>
> -Vitor

>  avfft.c     |    2 +-
>  binkaudio.c |    2 +-
>  dct.c       |   40 +++++++++++++++++++++++-----------------
>  fft-test.c  |    6 ++----
>  fft.h       |   11 +++++++++--
>  wmavoice.c  |    4 ++--
>  6 files changed, 38 insertions(+), 27 deletions(-)
> 91cf0cde9a50a47a8df3fbd171b35535abe00d16  dct_inout.diff

ok if tested and no slowdown is confirmed

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Frequently ignored awnser#1 FFmpeg bugs should be sent to our bugtracker. User
questions about the command line tools should be sent to the ffmpeg-user ML.
And questions about how to use libav* should be sent to the libav-user ML.
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