[Ffmpeg-cvslog] CVS: ffmpeg/libavcodec ac3enc.c, 1.31, 1.32 ac3tab.h, 1.7, 1.8

Justin Ruggles jruggle
Sun Apr 23 21:26:38 CEST 2006

Michael Niedermayer wrote:
> Hi
> On Sun, Apr 23, 2006 at 02:23:20AM +0100, M?ns Rullg?rd wrote:
>>Rich Felker <dalias at aerifal.cx> writes:
>>>On Sat, Apr 22, 2006 at 11:37:28PM +0200, Michael Niedermayer wrote:
>>>>On Sat, Apr 22, 2006 at 11:21:19PM +0200, Benjamin Larsson CVS wrote:
>>>>>Update of /cvsroot/ffmpeg/ffmpeg/libavcodec
>>>>>In directory mail:/var2/tmp/cvs-serv11932/libavcodec
>>>>>Modified Files:
>>>>>	ac3enc.c ac3tab.h 
>>>>>Log Message:
>>>>>Patch to generate the ac3 window, based on code by Justin Ruggles.
>>>>btw, by how much does the binary get smaller due to this?
>>>I suspect it gets larger.. ;)
>>Yes, ac3enc.o gets 40 bytes larger stripped.  Nothing that worries me,
>>and this is done to avoid typos in the tables anyway, right?
> its done to break the regression tests due to FPU rounding/optimization
> differences ... yeah why didnt i realize this before ...

Is this way really much different than the way the sin & cos tables are
generated?  Granted, there is a bit more adding and multiplying, but is
any FPU *that* inaccurate?  If you want to be that careful about using
floating-point when you need bitexact-ness, why not hardcode the sin &
cos tables as well?

The binary size is a good reason to revert though, unless, like Benjamin
said, the code is put somewhere it can be reused by other codecs.


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