[FFmpeg-devel] runtime-cpu-detect bug in swscale

Michael Niedermayer michaelni at gmx.at
Tue Apr 5 03:16:35 CEST 2011

On Fri, Mar 04, 2011 at 10:15:57PM +0000, Darren Horrocks wrote:
> swscale doesnt ever actually do any runtime detection at all when
> runtime cpu detection is enabled, it simply passes whatever is passed
> to -sws_flags, which could be nothing at all making swscale default to
> the C implementation.
> i have uploaded a patched libswscale.dll (win32 build), the patch its
> self, and a pre-patched swscale.c file:
> http://www.bizzeh.com/ffmpeg/free/swstest/
> the patch has been tested, an unpatched swscale gained roughly 79fps
> during an encode with no flags and around 190fps with mmx2 set in the
> sws_flags. the patched swscale dll gained 190fps without any flags set
> at all since it detected the capabilities of the processor before
> choosing.
> could anyone else test this patch and submit it to trunk if its usable?

patch applied and pushed


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I do not agree with what you have to say, but I'll defend to the death your
right to say it. -- Voltaire
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