[FFmpeg-devel] [PATCH] SSE RDFT

Måns Rullgård mans
Thu Jun 24 23:37:00 CEST 2010

"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.

M?ns Rullg?rd
mans at mansr.com

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