[vlc-devel] [PATCH 1/6] decoder: add code to send 3d metadata to the output modules to be handled

[Steve Lhomme]

On 20/08/2018 17:19, Rémi Denis-Courmont wrote:
> Le maanantaina 20. elokuuta 2018, 15.28.31 EEST Steve Lhomme a écrit :
>> For stereoscopy we don't have filters that would crop the source (SBS,
>> TB) or decimate one eye so calling
>> vout_display_SendEventPicturesInvalid() when the stereo changes would be
>> useless. The converters chain would end up being the same as before the
>> call.
> We should have them.
>
> We made an explicit and carefully weighed special exception for colorimetry
> that it was OK for display plugins to ignore it.
>
> But we never made a blanket rule that any other new properties could be
> ignored, at least not that I'd remember. Accordingly, orientation cannot be
> ignored - it is either supported directly in the display plugin, or handled by
> conversion/filtering.

We also don't have 360 to flat filters so platforms without either D3D11 
or OpenGL working display the picture

> However, in the specific case of stereoscopy, I suspect that any such filter
> will expose latent bugs with cropping and SAR again.

There are 3 formats we should support: Side By Side, Top-Bottom and 
Frame Sequential. The easiest filter is the frame sequential decimator. 
It just drops every other frame. The other two appear like a crop of 
half the picture but displayed twice the size (horizontally or 
vertically). That can be achieved with an added factor in the SAR. If it 
works as expected I may even use that to display SBS/TB in D3D11 since 
it will place the picture correctly for me when displayed in 2D.

Also since it depends on the display mode chosen by the user so it may 
fall in the interactive category.