Media Working Group Charter

The mission of the Media Working Group is to develop and improve client-side media processing and playback features on the Web.

Join the Media Working Group.

Start date 22 May 2019
End date 31 May 2021
Chairs Mounir Lamouri (Google)
Jer Noble (Apple)
Team Contacts François Daoust (0.2 FTE)
Meeting Schedule Teleconferences: topic-specific calls may be held
Face-to-face: we will meet during the W3C's annual Technical Plenary week; additional face-to-face meetings may be scheduled by consent of the participants, usually no more than 3 per year.

Scope

Standardization efforts to develop media foundations for the Web, such as the HTMLMediaElement interface and Media Source Extensions, have helped turn the Web into a major platform for media streaming and media consumption. Building on the experience gained through implementation, deployment and usage of these technologies, and on incubation discussions within the Web Platform Incubator Community Group, the Media Working Group will extend media foundations with new standardized technologies to improve the overall media playback experience on the Web.

The scope of the Media Working Group is:

The following features are out of scope, and will not be addressed by the Media Working Group:

Success Criteria

In order to advance to Proposed Recommendation, each specification is expected to have at least two independent implementations of each of feature defined in the specification.

Each specification should contain a section detailing all known security and privacy implications for implementers, Web authors, and end users.

Each specification should contain a section on accessibility that describes the benefits and impacts, including ways specification features can be used to address them, and recommendations for maximising accessibility in implementations. The latest versions of the Media Accessibility User Requirements and Framework for Accessible Specification of Technologies (FAST) documents notably provide media related advice to ensure that specifications developed by the Working Group meet the needs of users with disabilities.

To promote interoperability, the working group will follow a test as you commit approach:

All normative spec changes are generally expected to have a corresponding pull request in web-platform-tests, either in the form of new tests or modifications to existing tests, or must include the rationale for why test updates are not required for the proposed update.

Typically, both pull requests (spec updates and tests) will be merged at the same time. If a pull request for the specification is approved but the other needs more work, add the 'needs tests' label or, in web-platform-tests, the 'status:needs-spec-decision' label. Note that a test change that contradicts the specification should not be merged before the corresponding specification change.

If testing is not practical due to web-platforms-tests limitations, please explain why and if appropriate file an issue with the 'type:untestable' label to follow up later.

Deliverables

Draft state indicates the state of the deliverable at the time of the charter approval.

Normative Specifications

The Working Group will deliver the following W3C normative specifications:

Media Capabilities

This new specification provides APIs to allow websites to make an optimal decision when picking media content for the user. The APIs expose information about the decoding and encoding capabilities for a given format but also output capabilities to find the best match based on the device’s display.

Draft state: Adopted from the Web Platform Incubator Community Group

Picture-in-Picture

This new specification defines APIs to allow websites to create a floating video window always on top of other windows so that users may continue consuming media while they interact with other content sites or applications on their device.

Draft state: Adopted from the Web Platform Incubator Community Group

Media Session

This new specification enables web developers to show customized media metadata on platform UI, customize available platform media controls, and access platform media keys such as hardware keys found on keyboards, headsets, remote controls, and software keys found in notification areas and on lock screens of mobile devices.

Draft state: Adopted from the Web Platform Incubator Community Group

Media Playback Quality

This new specification extends media playback interfaces defined in HTML to add new features that can be used to detect the user perceived playback quality.

Draft state: Adopted from the Web Platform Incubator Community Group

Autoplay Policy Detection

This new specification provides APIs to allow websites to determine the document-level autoplay policy and whether autoplay will succeed for a given media element in a page.

Draft state: Adopted from the Web Platform Incubator Community Group

Media Source Extensions

This existing specification extends the HTMLMediaElement interface defined in HTML to allow JavaScript to generate media streams for playback. The scope of this revision is the same as that of the W3C Recommendation published in November 2016, limited to the generation and control of media streams. This revision updates the W3C Recommendation to address maintenance issues against the specification and add the codec switching feature incubated in the Web Platform Incubator Community Group since then. Additional features that are strictly in the scope of this specification may be considered.

Draft state: Adopted from the Web Platform Incubator Community Group

Encrypted Media Extensions

This existing specification extends the HTMLMediaElement interface defined in HTML to control playback of encrypted content. This revision updates the W3C Recommendation published in September 2017 to address maintenance issues against the specification and add four minor features incubated in the Web Platform Incubator Community Group since then, namely: Persistent Usage Record sessions, HDCP Detection, Encryption scheme capability detection and an API to find existing sessions. The inclusion of other features is considered out of scope for this group and would require rechartering.

Draft state: Adopted from the Web Platform Incubator Community Group

Potential Normative Specifications

The following features have been identified as potential normative specifications and may be adopted as normative specifications by the Working Group if there is consensus in the group that they are ready to move to the Recommendation track:

Audio Focus API
An API to allow web applications to manage their audio focus, to improve the audio-mixing of websites with native apps so they can play on top of each other or play exclusively.
Encoders/Decoders API
An API to expose media encoding/decoding capabilities to Web applications.
DataCue
An API to support metadata event tracks, carried either in-band or out-of-band and synchronized to audio or video media, which are used to support use cases such as ad insertion or presentation of supplemental content alongside the audio or video. This includes the possible adoption of the Sourcing In-band Media Resource Tracks from Media Containers into HTML document to specify the handling of in-band events.
Stream format specifications and accompanying registries
Notes described in Other Deliverables define optional features for Media Source Extensions and Encrypted Media Extensions. The Working Group may move them to the Recommendation track.

The Working Group will not adopt these features until they have matured through the Web Platform Incubator Community Group or another similar incubation phase. If additional normative specifications need to be added to the Charter before the Charter expires, the Working Group will recharter with changes.

Other Deliverables

The Media Working Group will maintain non-normative stream format specifications for Media Source Extensions and Encrypted Media Extensions, develop new stream format specifications, and update corresponding registries. It will maintain the following Notes in particular:

Other non-normative documents may be created such as:

  • Use case and requirement documents;
  • Test suite and implementation report for the specifications;
  • Primer or Best Practice documents to support web developers when designing applications.

Timeline

Milestones
Specification FPWD CR PR Rec
Media Capabilities Q3 2019 Q2 2020 Q1 2021 Q1 2021
Picture-in-Picture Q3 2019 Q4 2020 Q2 2021 Q2 2021
Media Session Q3 2019 Q4 2020 Q2 2021 Q2 2021
Media Playback Quality Q1 2020 Q4 2020 Q2 2021 Q2 2021
Autoplay Policy Detection Q1 2020 Q4 2020 Q2 2021 Q2 2021
Media Source Extensions Q1 2020 Q4 2020 Q2 2021 Q2 2021
Encrypted Media Extensions Q1 2020 Q4 2020 Q2 2021 Q2 2021

Note: The actual production of some of the deliverables may follow a different timeline. Schedule changes will be documented on the group home page.

Coordination

For all specifications, this Working Group will seek horizontal review for accessibility, internationalization, performance, privacy, and security with the relevant Working and Interest Groups, and with the TAG. Invitation for review must be issued during each major standards-track document transition, including FPWD and at least 3 months before CR, and should be issued when major changes occur in a specification.

Additional technical coordination with the following Groups will be made, per the W3C Process Document:

W3C Groups

Accessible Platform Architectures (APA) Working Group
The Media Working Group will coordinate with the APA Working Group to help ensure its deliverables support accessibility requirements, particularly with regard to interoperability with assistive technologies, and inclusion in the deliverables of guidance for implementing the group's deliverables in ways that support accessibility requirements. The Media Working Group will also review updates made to media related requirements in accessibility documents such as the Media Accessibility User Requirements and Framework for Accessible Specification of Technologies (FAST) documents.
Audio Working Group
The Audio Working Group develops a client-side API to synthesize, process and render audio streams directly in script.
CSS Working Group
The CSS Working Group develops and maintains CSS. This includes work on the CSS Object Model. The Media Working Group expects to coordinate with the CSS Working Group on the definition of the screen interface of the Media Capabilities deliverable.
Media and Entertainment Interest Group
The Media and Entertainment Interest Group discusses media-related technologies on the Web, and identifies possible use cases and requirements for Media Working Group deliverables. The Interest Group also maintains liaisons with external media organizations that develop or reference media technologies and that may want to bring specific requirements to the Media Working Group.
Second Screen Working Group
The Second Screen Working Group develops the Remote Playback API that extends the HTMLMediaElement interface to allow rendering of media on secondary devices. The Picture-in-Picture specification developed by the Media Working Group follows a similar design.
Timed Text Working Group
The Timed Text Working Group develops specifications for media online captioning.
Web Real-Time Communications Working Group
The Web Real-Time Communications Working Group develops APIs to capture, encode, process, transfer, decode and render media.

External Organizations

Web HyperText Working Group (WHATWG)
The WHATWG maintains the HTMLMediaElement interface that some of the Media Working Group deliverables extend.
External media groups
As noted above, through the Media and Entertainment Interest Group (or directly, when needed), the Media Working Group expects to liaise with external organizations that develop or reference media technologies (e.g. ATSC, CTA, HbbTV Consortium, IETF, IPTVF-J, ITU-T, MPEG, SMPTE). See the Media and Entertainment Interest Group charter for a list of candidate groups.

Participation

To be successful, this Working Group is expected to have 6 or more active participants for its duration, including representatives from the key implementors of this specification, and active Editors and Test Leads for each specification. The Chairs, specification Editors, and Test Leads are expected to contribute half of a working day per week towards the Working Group. There is no minimum requirement for other Participants.

The group encourages questions, comments and issues on its public mailing lists and document repositories, as described in Communication.

The group also welcomes non-Members to contribute technical submissions for consideration upon their agreement to the terms of the W3C Patent Policy.

Communication

Technical discussions for this Working Group are conducted in public: the meeting minutes from teleconference and face-to-face meetings will be archived for public review, and technical discussions and issue tracking will be conducted in a manner that can be both read and written to by the general public. Working Drafts and Editor's Drafts of specifications will be developed on a public repository and may permit direct public contribution requests. The meetings themselves are not open to public participation, however.

Information about the group (including details about deliverables, issues, actions, status, participants, and meetings) will be available from the Media Working Group home page.

Most Media Working Group teleconferences will focus on discussion of particular specifications, and will be conducted on an as-needed basis.

This group primarily conducts its technical work on GitHub issues. The public is invited to review, discuss and contribute to this work.

The group may use a Member-confidential mailing list for administrative purposes and, at the discretion of the Chairs and members of the group, for member-only discussions in special cases when a participant requests such a discussion.

Decision Policy

This group will seek to make decisions through consensus and due process, per the W3C Process Document (section 3.3). Typically, an editor or other participant makes an initial proposal, which is then refined in discussion with members of the group and other reviewers, and consensus emerges with little formal voting being required.

However, if a decision is necessary for timely progress and consensus is not achieved after careful consideration of the range of views presented, the Chairs may call for a group vote and record a decision along with any objections.

To afford asynchronous decisions and organizational deliberation, any resolution (including publication decisions) taken in a face-to-face meeting or teleconference will be considered provisional. A call for consensus (CfC) will be issued for all resolutions (for example, via email and/or web-based survey), with a response period from one week to 10 working days, depending on the chair's evaluation of the group consensus on the issue. If no objections are raised on the mailing list by the end of the response period, the resolution will be considered to have consensus as a resolution of the Working Group.

All decisions made by the group should be considered resolved unless and until new information becomes available or unless reopened at the discretion of the Chairs or the Director.

This charter is written in accordance with the W3C Process Document (Section 3.4, Votes) and includes no voting procedures beyond what the Process Document requires.

Patent Policy

This Working Group operates under the W3C Patent Policy (Version of 5 February 2004 updated 1 August 2017). To promote the widest adoption of Web standards, W3C seeks to issue Recommendations that can be implemented, according to this policy, on a Royalty-Free basis. For more information about disclosure obligations for this group, please see the W3C Patent Policy Implementation.

Licensing

This Working Group will use the W3C Software and Document license for all its deliverables.

About this Charter

This charter has been created according to section 5.2 of the Process Document. In the event of a conflict between this document or the provisions of any charter and the W3C Process, the W3C Process shall take precedence.