[FFmpeg-devel] [PATCH v2] Change cube faces order to match Youtube's

[Paul B Mahol]

On 3/14/18, Hazem Ashmawy <hazem.s.ashmawy at gmail.com> wrote:
> So I'm still looking into using bilinear instead of nearest. Most of
> the online discussions are in the context of computer graphics and
> using things like openGL shaders.
>
> One solution I found and may try to implement is to add padding pixels
> around each face tile in the input frame. This should help in handling
> sampling near cube edges and corners. However, I'm not sure about the
> complexity of this or its effect on the performance. WDYT?

Either that or doing it hard way, by picking different pixels for each face.
Anyway that (padding) solution doesn't sound that bad, and is much simpler than
above mentioned alternative.

>
> Meanwhile this is a hacky/lazy way to use bilinear, but I can barely
> notice any improvements
> over using nearest by my bare eyes, are there any systematic way to
> evaluate the quality?

Not realy. One could compare with another projection conversion utility,
there are at least two freely available AFAIK.

> https://github.com/HazemSamir/FFmpeg/commit/fcd82b9782b5f32072d9b0516b275fe3d4f4a163
>
> On 3/12/18, Paul B Mahol <onemda at gmail.com> wrote:
>> On 3/12/18, Hazem Ashmawy <hazem.s.ashmawy at gmail.com> wrote:
>>> On 3/12/18, Paul B Mahol <onemda at gmail.com> wrote:
>>>> On 3/12/18, Hazem Ashmawy <hazem.s.ashmawy at gmail.com> wrote:
>>>>> Sorry about that! Here is github branch
>>>>>
>>>>> https://github.com/FFmpeg/FFmpeg/compare/master...HazemSamir:panorama_youtube
>>>>
>>>> Good, now can you look at how to use bilinear instead of nearest
>>>> interpolation
>>>> for cubemap to equirectangular conversion.
>>>>
>>>> Nearest is extremly ugly.
>>>>
>>> Sure, will look into that. Just to take that into my consideration,
>>> why didn't you use it at the first place? Were there any obstacles?
>>
>> It was non-trivial to do.
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