[FFmpeg-devel] [PATCH] SSE RDFT

Jason Garrett-Glaser darkshikari
Thu Jun 24 23:20:19 CEST 2010

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

Dark Shikari

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