[FFmpeg-devel] manually hacked configure options increase h264 decoding speed significantly

madshi madshi at gmail.com
Thu Oct 20 11:56:59 CEST 2011

> 2011/10/20 Michael Niedermayer <michaelni at gmx.at>
> a patch that autodetects their availability in configure
> and uses them in mem.c if available is welcome

> The existing autodetection has to be fixed, and its a
> bit hard for me to do this without a mingw system to
> test. Could you look into why it fails ?

I wish I could do these things. Unfortunately I'm a
mingw noob and haven't really looked into how the whole
ffmpeg configuration system works at all. So I wouldn't
really know where to start. I'm sorry...  :-(

Just thought I'd bring this to your attention because
HAVE_EBP_AVAILABLE alone already makes quite a
big difference.

FWIW, my current configure line looks like this:

configure --enable-shared --disable-static --enable-pthreads
--extra-cflags='-march=i686 -mfpmath=sse -mmmx -msse -DPTW32_STATIC_LIB'

After reading Hendrik's comment, I should probably add
"--arch=x86 --cpu=i686". Seems that would take care
of the CLZ and CMOV options. But it doesn't change

Best regards, Mathias.

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