On Mon, Mar 14, 2016 at 10:04:59PM -0400, Ganesh Ajjanagadde wrote: > This is ~2x faster for y not an integer on Haswell+GCC, and should > generally be faster due to the fact that anyway powf essentially does > this under the hood. Made an inline function in lavu/internal.h for this > purpose. > > Note that there are some accuracy differences, that should generally be > negligible. In particular, FATE still passes on this platform. > > Results in ~ 7% speedup in aac encoding with -march=native, Haswell+GCC. > before: > ffmpeg -i sin.flac -acodec aac -y sin_new.aac 6.05s user 0.06s system 104% > cpu 5.821 total > > after: > ffmpeg -i sin.flac -acodec aac -y sin_new.aac 5.67s user 0.03s system 105% > cpu 5.416 total > > This is also faster than an alternative approach that pulls in powf, gets rid > of > the crufty NaN checks and other special cases, exploits knowledge about the > intervals, etc. > This of course does not exclude smarter approaches; just suggests that > there would need to be significant work on this front of lower utility than > searches for hotspots elsewhere. > > Reviewed-by: Reimar Döffinger <reimar.doeffin...@gmx.de> > Reviewed-by: Ronald S. Bultje <rsbul...@gmail.com> > Signed-off-by: Ganesh Ajjanagadde <gajja...@gmail.com> > --- > libavcodec/aacenc_utils.h | 6 +++++- > libavutil/internal.h | 16 ++++++++++++++++ > 2 files changed, 21 insertions(+), 1 deletion(-)
Tested on mingw-wine, linux x86_64 & x86_32 and mips qemu [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB The real ebay dictionary, page 1 "Used only once" - "Some unspecified defect prevented a second use" "In good condition" - "Can be repaird by experienced expert" "As is" - "You wouldnt want it even if you were payed for it, if you knew ..."
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