Jason Garrett-Glaser <[email protected]> writes: > On Tue, Jul 24, 2012 at 8:05 AM, John Stebbins <[email protected]> > wrote: >> On 06/25/2012 02:42 PM, Mans Rullgard wrote: >>> >>> Module: libav >>> Branch: master >>> Commit: 82992604706144910f4a2f875d48cfc66c1b70d7 >>> >>> Author: Mans Rullgard <[email protected]> >>> Committer: Mans Rullgard <[email protected]> >>> Date: Sat Jun 23 19:08:11 2012 +0100 >>> >>> x86: fft: convert sse inline asm to yasm >>> >>> --- >>> >>> libavcodec/x86/Makefile | 1 - >>> libavcodec/x86/fft_mmx.asm | 139 >>> ++++++++++++++++++++++++++++++++++++++++--- >>> libavcodec/x86/fft_sse.c | 110 ---------------------------------- >>> 3 files changed, 129 insertions(+), 121 deletions(-) >>> >> >> Hi, >> >> This commit is causing some strange interaction with libx264 in HandBrake >> under certain conditions. x264 is encoding at about 1/10th it's normal rate >> after updating to this commit. >> >> A little more background. When doing ac3 passthru HandBrake encodes a >> single packet of silence data to ac3 that is uses for filling any gaps that >> it detects in the audio. Encoding of this packet happens before any other >> encoding or decoding starts. For some crazy reason, if we encode this >> silence, we get the x264 slowdown. If we do not encode the silence, the >> speed is ok. I ran gprof on the code to see where all the time is being >> spent and it is all in x264. So it's not like there is some run-away loop >> somewhere that is bringing everything to it's knees. I'm guessing some cpu >> state must not be getting cleared or restored properly somewhere. >> >> John > > Could it have anything to do with denormals/NaN?
Does x264 use floating-point SSE instructions anywhere? -- Måns Rullgård [email protected] _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
