Need query for stereoscopic displays (or stereoscopic video planes.)

[MetaHubbe]

Over at MediaCapabilities, we (Meta Quest Browser) are discussing adding support for querying if the browser can handle stereoscopic videos. (w3c/media-capabilities#249) The prevailing wisdom is that MediaCapabilities should provide answers which are independent of the output device, and then have some other query for testing what the output device can do. For HDR, this is the dynamic-range and video-dynamic-range queries. We would like to have something similar for stereoscopic outputs and stereoscopic video surfaces.

Perhaps something like:

(stereoscopic-capable: yes) and (video-stereoscopic-capable: yes) ?

[frivoal]

While this certainly does seem like an important distinction to capture, I am not sure how practical it is to do so before we have some shared understanding about how being displayed on a stereoscopic display changes for the web page.

• Do authors have some control over depth inside the web page which gets rendered in 3d thanks to the stereoscopic capabilities of the display, or they need themselves to render two separate views, one intended for each eye?
• do some image/video formats show up in 3d on their own, or does the author need to do something to make it so?
• etc

As part of a broader project to expose stereoscopic capabilities to the web, this would make a lot of sense to me. In isolation, I'm a lot less sure what authors could do with it.

[MetaHubbe]

Right now, there is little or no difference. Browsers on VR- and 3Dtv-devices generally display web pages as flat surfaces. I think that will change in the future, but probably one step at a time. The steps I can see are:

• stereoscopic video support
• stereoscopic image support
• stereoscopic canvas / webgl support (quering this can be done with getContext, so probably doesn't need support here.)
• stereoscopic css support (this means each element would have it's own depth)

In an ideal world, each of these steps could be implemented separately, and their support would be signalled to the web page separately so that the web page can choose weather to use stereoscopic assets or not.

There are existing standards for stereoscopic images and videos, canvas and css will need new standards for stereoscopic support AFAIK.

Right now, we are mostly interested in stereoscopic video, but it makes sense to look forward and make sure that whatever come with doesn't immediately fall apart when new capabilities are added.

Maybe the css query should be more like (sterescopic-capable: feature) where feature is one of image, video, canvas or css ?