[Ffmpeg-devel] ac3enc.c modifications

Måns Rullgård mru
Fri May 20 00:56:07 CEST 2005

Rich Felker <dalias at aerifal.cx> writes:

> On Thu, May 19, 2005 at 09:53:33PM +0200, Michael Niedermayer wrote:
>> both float and int should be supported, there are people with cpus
>> where float IS faster then int
> This is only possible if the cpu has a horribly botched integer
> implementation.

Or a damn good floating point unit.  Have you ever used an IBM Power
or Digital Alpha CPU?  A 300 MHz IBM Power3 (Power5 is the latest) I
ran some tests on beat a 1 GHz Pentium3 at floating point math, as did
a 500 MHz Alpha a few generations older than the P3.

> However I have no objection to supporting both if it can be done
> without bloat or slowdown for the integer case, but i'm seriously
> doubtful that float is ever faster than a well-optimized integer
> implementation, especially when the final output will be integers.

Dividing by a variable on Alpha is sometimes faster to do in floating

M?ns Rullg?rd
mru at inprovide.com

More information about the ffmpeg-devel mailing list