On 1/31/2017 12:40 PM, Aaron Colwell wrote:
> 
> 
> On Tue, Jan 31, 2017 at 2:12 AM Vittorio Giovara <vittorio.giov...@gmail.com 
> <mailto:vittorio.giov...@gmail.com>> wrote:
> 
> On Sat, Jan 28, 2017 at 4:13 AM, James Almer <jamr...@gmail.com 
> <mailto:jamr...@gmail.com>> wrote:
>> On 1/27/2017 11:21 PM, Aaron Colwell wrote:
>>> On Fri, Jan 27, 2017 at 5:46 PM James Almer <jamr...@gmail.com 
>>> <mailto:jamr...@gmail.com>> wrote:
>>>
>>> yeah. I'm a little confused why the demuxing code didn't implement this to
>>> begin with.
>>
>> Vittorio (The one that implemented AVSphericalMapping) tried to add this at
>> first, but then removed it because he wasn't sure if he was doing it right.
> 
> Hi,
> yes this was included initially but then we found out what those
> fields were really for, and I didn't want to make the users get as
> confused as we were. As a matter of fact Aaron I mentioned this to you
> when I proposed that we probably should have separated the classic
> equi projection from the tiled one in the specification, in order to
> simplify the implementation.
> 
> 
> Like I said before, it is not a different projection. It is still 
> equirectangular and those parameters just crops the projection. It is very 
> simple to just verify that the fields are zero if you don't want to support 
> the cropped version.
>  
> 
> 
>>>> I know you're the one behind the spec in question, but wouldn't it be a
>>>> better idea to wait until AVSphericalMapping gets a way to propagate this
>>>> kind of information before adding support for muxing video projection
>>>> elements? Or maybe try to implement it right now...
>>>>
>>>
>>> I'm happy to implement support for the projection specific info. What would
>>> be the best way to proceed. It seems like I could just place a union with
>>> projection specific structs in AVSphericalMapping. I'd also like some
>>
>> I'm CCing Vittorio so he can chim in. I personally have no real preference.
> 
> The best way in my opinion is to add a third type, such as
> AV_SPHERICAL_TILED_EQUI, and add the relevant fields in
> AVSphericalMapping, with a clear description about the actual use case
> for them, mentioning that they are used only in format. By the way,
> why do you mention adding a union? I think four plain fields should
> do.
> 
> 
> I don't think it is worth having the extra enum value for this. All the 
> cropped fields do is control how you generate the spherical mesh or control 
> the shader used to render the projection. If players don't want to support it 
> they can just check to see that all the fields are zero and error out if not. 
> 
> I was suggesting using a union because the projection bounds fields are for 
> equirect, and there are different fields for the cubemap & mesh projections. 
> I figured that the enum + union of structs might be a reasonable way to 
> organize the projection specific fields.
> 
>  
> 
> 
> Please keep me in CC.
> 
> 
> Will do.
> 
> Aaron

You didn't CC him, so doing it now in case you also didn't BCC him.

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