[FFmpeg-devel] [PATCH] avfilter, swresample, swscale: use fabs, fabsf instead of FFABS

Ganesh Ajjanagadde gajjanag at mit.edu
Thu Oct 15 12:34:15 CEST 2015


On Wed, Oct 14, 2015 at 6:50 AM, Hendrik Leppkes <h.leppkes at gmail.com> wrote:
> On Wed, Oct 14, 2015 at 12:37 PM, Ganesh Ajjanagadde <gajjanag at mit.edu> wrote:
>> On Wed, Oct 14, 2015 at 5:01 AM, Matt Oliver <protogonoi at gmail.com> wrote:
>>> On 14 October 2015 at 09:46, Ganesh Ajjanagadde <gajjanag at mit.edu> wrote:
>>>
>>>> On Tue, Oct 13, 2015 at 9:12 AM, Ganesh Ajjanagadde <gajjanag at mit.edu>
>>>> wrote:
>>>> > On Tue, Oct 13, 2015 at 4:02 AM, Clément Bœsch <u at pkh.me> wrote:
>>>> >> On Tue, Oct 13, 2015 at 09:25:03AM +0200, Paul B Mahol wrote:
>>>> >> [...]
>>>> >>> What about fmax/FFMAX?
>>>> >>
>>>> >> Feel free to try that out (it looks OT regarding the patch), but fmax()
>>>> >> looks glibc specific
>>>>
>>>> Seems they are actually ISO:
>>>> http://en.cppreference.com/w/c/numeric/math/fmax
>>>>
>>>> Can someone check availability on all of our platforms of interest
>>>> (e.g Microsoft)?
>>>>
>>>
>>> fmax and fmin are only available on msvc using 2013 or newer. Currently the
>>> only msvc version without fmax/fmin that FFmpeg supports is 2012 which uses
>>> the C99 to C89 converter.
>>
>> And does that converter handle fmin, fmax, fmaxf, etc?
>> Does it need patches?
>> Bottom line: are they safe to use at the moment?
>>
>
> No, they are not.
>
> One thing I don't understand - why are we bothering with something
> that at best comes out as "same speed" from tests performed? (low
> number of runs are irrelevant as they are not statistically
> significant).

Because if you actually bothered to run my random numbers benchmark
instead of posting with no basis claiming "statistical
insignificance", or for that matter matter bothered to actually check
the libc link, or even looked at Clement's asm test - you would
finally understand.

Also, what needs to be done to get fmax, fmin, etc into the converter?

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