Re: WebVR and DRM

On Mon, Jul 10, 2017 at 10:07 PM, Brandon Jones <bajones@google.com> wrote:

> Jim: when I say limited layouts I'm referring to the format of the source
> video. Things like Equirectangular 360, side by side stereo, etc. Nothing
> to do with lens distortion. All it really means is that we'll have to
> dictate which layouts we can support, which will inevitably end up being a
> lowest common denominator set. This will prevent your app from taking
> advantage of whatever experimental packings Facebook or Google come up with
> unless they become standardized.
>
Facebook actually uses a center viewpoint adjusted variant of octahedral
mapping. Cubemapping would be an appropriate layer also for the reduction
in texel density distortion. Cubemapping can be extended for less
distortion by normal bending. Paraboloid mapping (often dual but not
always) is another popular option. Spherical mapping is sometimes used with
some capturing solutions (conical reflectors) if you want to preserve
source fidelity around a central focus. If you're going to "support" one
projection, I'd suggest you get busy supporting the dozen or so popular
projections plus the dozens and dozens of less popular projections and
variants, because somebody (who might not even know about WebVR yet) might
find them useful. Please also consult ongoing projection research of which
there's the odd paper every year or so, it's always a good idea to have to
hardcode all the different possibly useful things into an API. That's why
we invented programmable APIs in the first place isn't it? How isn't this a
gigantic technological retardation?