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

[Ganesh Ajjanagadde]

On Thu, Oct 15, 2015 at 6:37 AM, Hendrik Leppkes <h.leppkes at gmail.com> wrote:
> 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.

Thanks for clarifying. I am still confused: how do we have llabs then?
Per MSDN, this was not present in MSVC 2012, and was added in MSVC
2013 (looks like a similar case to fabs, fabsf).

>
> - Hendrik
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