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

[Hendrik Leppkes]

On Thu, Oct 15, 2015 at 12:34 PM, Ganesh Ajjanagadde <gajjanag at mit.edu> wrote:
> 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?
>

The converter doesn't provide any functions, just alters the syntax if
needed. Functions not available cannot be fixed that way, sorry.

- Hendrik