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Re: [presentation-api] Consider use cases for Presentation API v2 with VR capable displays

From: Louay Bassbouss via GitHub <sysbot+gh@w3.org>
Date: Wed, 01 Nov 2017 08:22:53 +0000
To: public-secondscreen@w3.org
Message-ID: <issue_comment.created-341031495-1509524572-sysbot+gh@w3.org>
Thx @toji  feedback from my side: 

> For both of those reasons we feel the Presentation API is not appropriate for launching VR content on most headsets. The other use case called out in the original post seem appealing, however! It's not entirely clear to the WebVR group what would need to be done to support them.

This is correct but there are two implementation modes 1-UA and 2-UA. in 1-UA mode both pages (sender and receiver pages) are rendered on the controller device but the video output of the receiver page will be captured and displayed on the receiver display. In case of VR the 1-UA mode could implemented in a way that both sender and receiver pages are displayed on the same HMD. But the receiver page will still be loaded via URL and there are two page contexts as you mentioned.  IMO I see more potential for collaboration between WebVR API and RemotePlayback API for 360° videos but this requires native 360° video playback in the browser. 

> Certainly using the Presentation API from within VR to begin displaying content on an external screen would be nice. It seems to me, though, that such use should generally work with the API as specced today without change?

I agree with you this can be done without any changes. The only thing needed is the capability detection which is not currently supported in the API, but there an issue #348 for this. In VR case you don’t need to offer all TVs in your network if your application is looking only for VR displays. 

>  This normally requires a user gesture, but the Presentation API could provide the appropriate permissions to bypass that requirement.

The Presentation API requires user gesture only to start a presentation in this case on the HMD. The Presentation API doesn’t say anything about available APIs and their restrictions on the receiver UA. But in most Presentation API use cases, it doesn’t make sense to require use gesture on the receiver page otherwise this will break the use experience (imagine a user starts a receiver page that plays a video on TV via Presentation API and he still need to press the play on the Remote control in order to play the video). 

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Received on Wednesday, 1 November 2017 08:22:54 UTC

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