[FFmpeg-devel] [RFC] remove table_4_3_value with CONFIG_SMALL

Måns Rullgård mans
Thu Oct 15 10:59:33 CEST 2009

Reimar D?ffinger <Reimar.Doeffinger at gmx.de> writes:

> On Tue, Oct 13, 2009 at 01:53:06PM +0200, Reimar D?ffinger wrote:
>> On Tue, Oct 13, 2009 at 01:18:02PM +0200, Michael Niedermayer wrote:
>> > > Either way, should the code that generates the tables be updated to use
>> > > the same formula?
>> > 
>> > as you prefer ...
>> Ok, I propose then this patch, to be applied in two parts.
>> It generally replaces "pow(2," by "exp2f(" and "pow(.., 4.0/3.0)" by
>> ".. * cbrtf(..)".
>> make test passes on x86_64 at least, with and without --enable-small.
> Hm... It didn't play any files right though, attached version plays the
> files ok, though the CRC is not the same with and without
> --enable-small.
> Speed is probably about 4 times slower, though on a regular desktop
> system the overall speed difference for mp3 decoding is not measurable
> (the usual caveat about benchmarks by me apply).

It will totally murder performance on anything without an FPU.  Those
are also the systems most likely to need CONFIG_SMALL, so this is not

M?ns Rullg?rd
mans at mansr.com

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