[FFmpeg-devel] [PATCH] unscaled float 2 int conversion

Michael Niedermayer michaelni
Fri May 16 12:39:40 CEST 2008


On Fri, May 16, 2008 at 12:44:39PM +0300, Siarhei Siamashka wrote:
> On Friday 16 May 2008, Michael Niedermayer wrote:
> > Ohh well, why do i always have to do the work? You could have safed me
> > some time by just saying that you wont do the benchmarks.
> >
> > PS: yes i dont give a damn what you or anyone else thinks, either
> > i see benchmarks or people can go talking to their next wall.
> > It would have taken you less time to disable MMX*/SSE* and write
> > a benchmark than explaining why its better not to.
> >
> > P3
> > gcc-4.4 -O3 -fno-math-errno
> > 145658 dezicycles in conv_cast, 16368 runs, 16 skips
> > 52531 dezicycles in conv_lrint, 16377 runs, 7 skips
> > 57978 dezicycles in conv_bias, 16380 runs, 4 skips
> 
> [...]
> 
> By the way, how adequate is the distribution of input values in your
> test? Is the percentage of cases when value clipping is actually 
> needed in this test similar to the percentage of clipping on real 
> audio files?
> 
> Because it affects benchmark results *very* much...

ahh you spoted it as well, sorry :(
 in[i]= i + i*i*0.3 - 32780;
instead of
 in[i]= i - i*i*0.3 - 32780;
what was i meant to write
possibly 0.3 should be changed to 0.25 even
but it doesnt change much anymore ...

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No snowflake in an avalanche ever feels responsible. -- Voltaire
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