[FFmpeg-devel] [PATCH] fix --enable-runtime-cpudetect --disable-amd3dnow compilation

Ronald S. Bultje rsbultje
Sun Sep 5 04:28:07 CEST 2010


On Sat, Sep 4, 2010 at 6:59 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> id rather see dsputil gain support to have things disabled at compiletime
> that arent relevant for some target cpu.

That's not quite the same thing. Swscale should always do runtime CPU
detection, but the user should be able to disable compilation of all
MMX (i.e. all SIMD) or all SSE4 or all >=SSSE3 or all >=SSE2
functions, etc. We already have HAVE_SSSE3, HAVE_SSE and HAVE_MMX2
(and the relevant --disable-.. configure flags). Isn't that enough?
Why doesn't swscale use this same system that dsputil uses, or if you
dislike that, why don't they at least use the same system?

Also, on x86-64, all <SSE2 functions should be disabled for functions
that have a SSE2 implementation, since every x86-64 CPU has SSE2. I've
been meaning to file a bug report for this but have forgotten so far.


More information about the ffmpeg-devel mailing list