Microsoft, Google, Hookflash and others Co-Author Real-Time Communications Specification

There is a growing industry interest in the Object Real-Time Communications API (ORTC) as a foundation for real-time communications among mobile, tablet, and desktop devices. Today, the W3C ORTC Community Group reached an important milestone by issuing an updated draft specification authored by Microsoft, Google, Hookflash and others.

Developed within the W3C ORTC Community Group, which now numbers more than 50 participants, the new ORTC API Editor’s draft is now considered complete enough for implementations to gain experience with it, so that a “call for implementations” will go out.

ORTC leverages JavaScript to enable plugin-free real-time communications among web browsers, mobile devices and cloud technologies in a way that is familiar to website developers. The ORTC API is well suited to a “mobile first, cloud first” world because it supports advanced video features such as scalable video coding and simulcast. These advanced video technologies have proven difficult to support in an interoperable way within SDP in WebRTC 1.0. By contrast, utilizing these advanced video technologies within a JavaScript object API is more straightforward.

The specification has matured rapidly since the W3C Community Group was formed in the fall of 2013. For the last few months, the Community Group has been releasing monthly Editor’s drafts. Over the last two months, the specification has taken important steps forward with this new ORTC-based approach to WebRTC. Microsoft and Google joined Hookflash and others as new authors.

In May 2014, a proposal for the integration of ORTC objects within the W3C WebRTC 1.0 specification was made to the WebRTC Working Group, and implementations that are adding partial ORTC support to the existing WebRTC 1.0 API have been announced. The new draft will enable implementations of the full ORTC specification, which enables real time communications without a dependency on Session Description Protocol (SDP) and the Offer/Answer state machine. In either approach, compatibility with the existing WebRTC 1.0 API can be maintained, either by partially implementing ORTC alongside the WebRTC 1.0 API, or by supporting the WebRTC 1.0 API on top of the full ORTC API via a “shim.”

The “call for implementations” is also expected to reenergize work on ORTC-related open source projects. These include projects to enable use of the ORTC API on mobile devices (ortclib) as well as server-side development (ortc-node). The MS Open Tech team has been supporting this work through the release of prototype implementations that help demonstrate ORTC’s potential. The prototype has recently been updated to work work with ORTC objects as per latest specification and take into account the latest API changes. In addition, other major browsers including Internet Explorer and Chrome are considering ORTC support in upcoming releases.

We look forward to moving forward with our colleagues in the ORTC Community Group to help the industry build on this great momentum and make it easier for developers to build interoperable RTC applications for the open web.

For more information, see:

  • W3C ORTC Community Group home page linking to participants, mailing lists, and documents
  • The history page summarizes how ORTC developed from then converged with WebRTC
  • Google presentation outlining their vision of how ORTC and WebRTC will converge (about minute 46)
  • blog with news from the ORTC Community Group and information about various companies’ implementation plans.


Michael Champion, Senior Program Manager
Doug Mahugh, Senior Technical Evangelist
Microsoft Open Technologies, Inc.