Apple Patents Complicating W3C's Open Screen Protocol

Written by Michael Larabel in Standards on 19 August 2021 at 02:16 PM EDT. 24 Comments
The W3C has been working on the "Open Screen Protocol" as part of their Second Screen Working Group. This effort has been about having a web standard so web pages can drive secondary screens to display web content. Unfortunately, the plans are currently being complicated by a number of software patents issued to Apple.

The Open Screen Protocol was published as a working draft earlier this year and is intended to allow web content / web-sites to interact with secondary screens such as for controlling Internet-connected TVs, HDMI dongles, smart speakers, and other secondary Internet-connected devices.
This spec defines a suite of network protocols that enable two user agents to implement the Presentation API and Remote Playback API in an interoperable fashion. This means that a Web developer can expect these APIs to work as intended when connecting two devices from independent implementations of the Open Screen Protocol.

The Open Screen Protocol is a specific implementation of these two APIs, meaning that it does not handle all possible ways that browsers and presentation displays could support these APIs. The Open Screen Protocol specifically supports browsers and displays that are connected via the same local area network. It allows a browser to present a URL, initiate remote playback of an HTML media element, and stream media data to another device.

The Open Screen Protocol is intended to be extensible, so that additional capabilities can be added over time. This may include additions to existing Web APIs or new Web APIs.

The working draft of the Open Screen Protocol can be found on

Unfortunately, these efforts are being thwarted now by a number of Apple patents. The W3C announced today they have needed to form a patent advisory group (PAG) for their Second Screen Working Group to work through these issues. The W3C has a policy in place for establishing a patent advisory group when learning of patents that may be essential to their efforts but not available under a royalty-free license.

The patent advisory group has posted a list of patents currently causing problem for the Open Screen Protocol and all held by Apple. Among these patents are around host configured for interoperation with coupled media player device, synchronizing media presentation at multiple recipients, network media device, and others.

The patent advisory group will try to resolve the issues or otherwise suggest to the working group to consider re-designing portions affected by the patented claims, or even terminating/rescinding work on the specification. More details on the PAG's approach via the W3C patent policy.
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