[FFmpeg-devel] [PATCH] SSE RDFT

[Vitor Sessak]

On 06/24/2010 11:37 PM, M?ns Rullg?rd wrote:
> "Ronald S. Bultje"<rsbultje at gmail.com>  writes:
>
>> Hi,
>>
>> On Thu, Jun 24, 2010 at 5:20 PM, Jason Garrett-Glaser
>> <darkshikari at gmail.com>  wrote:
>>> 2010/6/24 M?ns Rullg?rd<mans at mansr.com>:
>>>> Michael Niedermayer<michaelni at gmx.at>  writes:
>>>>> btw, speaking of yasm, a not too long while ago i realized that configure
>>>>> simply compiles without yasm optimizations if yasm isnt installed
>>>>> i noticed it just because x264 doesnt and warns, we should do the same
>>>>> this issue alone weighs heavier than any difference between inline and
>>>>> yasm. Because loosing the optimizations without the user knowing is really
>>>>> bad.
>>>>
>>>> Done.
>>>
>>> This is not sufficient.  From years of experience with x264, people
>>> will NEVER NOTICE the configure warning, and will proceed to compile
>>> obliviously.  They will then complain incessantly about slow it is.
>>>
>>> This is doubly important with more and more of ffmpeg's asm being in
>>> yasm -- particularly the upcoming VP8 decoder, where we are going to
>>> market ourselves on speed.
>>>
>>> I suggest that configure fail with an error (telling the user to
>>> install yasm or disable asm) if the following conditions are true:
>>>
>>> 1) architecture is x86 or x86_64
>>> 2) --disable-mmx is not set
>>> 3) --disable-yasm is not set
>>
>> This is probably a good idea.
>>
>> Note how libvpx has some script that translated from yasm to bla*asm,
>> similar to mru's iphone script, maybe we need something like that for
>
> It's David's script.  I don't touch rotten fruit.
>
>> the future? (Wild idea, reject if not practical.)
>
> Not needed.  Yasm is available for all targets we support.

Even PPC? I remember Loren once sent a Altivec-optimized FFT that was 
never committed because of some bikeshed about asm syntax...

-Vitor