[vlc-devel] [PATCH 01/12] vlc_input: add title angles

[Rémi Denis-Courmont]

Le tiistaina 5. toukokuuta 2020, 19.07.44 EEST Francois Cartegnie a écrit :
> Le 03/04/2020 à 10:21, Rémi Denis-Courmont a écrit :
> >> We can add this helper in the player API then (like it's already done for
> >> few complicated things that are only done from control/interfaces).
> > 
> > And the point of that is what exactly? At this point, we're telling
> > everybody to treat angles as video tracks. Might as well skip the reverse
> > abstraction and treat angles as video tracks from the ground up then.
> 
> Angle control can't be done using different ES.
> The switch not only changes video, but any other associated stream. And that
> decision must done at demux level.
> 
> That's exactly the same issue as when adaptive quality/alternative
> selection patches which have been rejected and ended up with unusable
> streams exposing countless ES to the user.

For network feeds, you have the problem that the other pseudo-tracks are not 
sent and received. The data for deselected tracks is not available. In fact, 
it would be more correct to treat different network qualities as titles (though 
that implies tying audio and video quality) than tracks.

I don't think that's even remotely close to the situation with angles on local 
optical media. Either angles are interleaved and they are very much the same 
as multiple tracks, or they are not and they are more like title (because 
seeking disc is slow). I'm guessing the earlier, otherwise I don't see how 
audio would work.


And in the end, the point is that we should not force LibVLC app vendors (and 
the VLC GUI) to handle million different media-specific variants of track/title 
selection.

-- 
レミ・デニ-クールモン
http://www.remlab.net/