[FFmpeg-cvslog] r14698 - in trunk/libavcodec: Makefile dsputil.h fft.c i386/fft_3dn.c i386/fft_3dn2.c i386/fft_mmx.asm i386/fft_sse.c

[Måns Rullgård]

Mike Melanson <mike at multimedia.cx> writes:

> Loren Merritt wrote:
>> I have no idea what's special about those configurations. For that matter, 
>> why didn't all the other mdct codecs and all the other configurations 
>> change? And how could anyone expect md5 matches for floating-point codecs?
>
> Well, it's an encoding test. Plus, the test parameters specify bit 
> exactness:
>
>    ffmpeg -y -flags +bitexact -dct fastint -idct simple -ab 128k -ac 2 
> -f s16le -i input -acodec wmav1 output.asf

The bitexact flag doesn't change the way the FPU works.  Different
FPUs give slightly different results, and this is allowed.  All that
flag does is prevent use of code with explicitly different results
from the reference (to gain some speed, usually).

> And it always worked before, and cross platform, before your change.

That was luck.

-- 
M?ns Rullg?rd
mans at mansr.com