[FFmpeg-devel] [PATCH 06/11] avutil/half2float: adjust conversion of NaN

[Timo Rothenpieler]

On 11.08.2022 00:37, Mark Reid wrote:
> On Wed, Aug 10, 2022 at 3:28 PM Timo Rothenpieler <timo at rothenpieler.org>
> wrote:
> 
>> On 11.08.2022 00:18, James Almer wrote:
>>> Then maybe the current implementation should be moved back to exr (it
>>> used to be internal to exr until Paul made it standalone), so this lavu
>>> module can match the existing hardware implementations of IEEE-734 half
>>> floats for the purpose of relevant pixel format support.
>>
>> That doesn't seem necessary to me.
>> The values produced before and now are both correct, just different.
>> But there is no functional difference in the values it produces.
>>
>> Duplicating the entirety of that code just for that seems extremely
>> unnecessary.
>>
> 
> openexr does note the intel implementations difference here
> https://github.com/AcademySoftwareFoundation/Imath/blob/main/src/Imath/half.h#L288

It's actually quite curious how that came to be.
My natural idea would be that our current and EXRs code does it right.

But all hardware as well as gccs software emulation agrees. Makes me 
wonder if it's fully intentional and according to some spec. But I 
couldn't find anything on the matter.