[PROPOSED] Media Working Group Charter

This document is a draft charter proposed for discussion and review by the W3C Advisory Committee. It is available on GitHub. Feel free to raise issues.

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.

Charter Status See the group status page and detailed change history.
Start date When approved
End date Start date + 2 years
Charter extension See Change History.
Chairs Chris Needham (BBC)
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:

Out of Scope

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

  • The definition of any new codecs for audio and video
  • The definition of adaptive streaming mechanisms (but the group will develop mechanisms that enable/ease the implementation of such mechanisms within Web applications)

Deliverables

Updated document status is available on the group publication status page.

Draft state indicates the state of the deliverable at the time of the charter approval. Expected completion indicates when the deliverable is projected to become a Recommendation, or otherwise reach a stable state. Adopted Draft, Exclusion Draft and Exclusion Draft Charter are defined in the W3C Process Document (section 4.2, Content of a Charter).

Normative Specifications

The Working Group will deliver the following W3C normative specifications:

Media Capabilities

This 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.

Expected completion: [Q1–4 yyyy].

Draft state: Working Draft.

Adopted Draft: Media Capabilities, https://www.w3.org/TR/2022/WD-media-capabilities-20221117/, 17 November 2022.

Exclusion Draft: Media Capabilities, https://www.w3.org/TR/2020/WD-media-capabilities-20200130/, 30 January 2020. Exclusion period began on 30 January 2020; ended on 28 June 2020.

Exclusion Draft Charter: https://www.w3.org/2019/05/media-wg-charter.html.

Picture-in-Picture

This 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.

Expected completion: [Q1–4 yyyy].

Draft state: Working Draft.

Adopted Draft: Picture-in-Picture, https://www.w3.org/TR/2022/WD-picture-in-picture-20221219/, 19 December 2022.

Exclusion Draft: Picture-in-Picture, https://www.w3.org/TR/2020/WD-picture-in-picture-20200130/, 30 January 2020. Exclusion period began on 30 January 2020; ended on 28 June 2020.

Exclusion Draft Charter: https://www.w3.org/2019/05/media-wg-charter.html.

Media Session

This 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.

Expected completion: [Q1–4 yyyy].

Draft state: Working Draft.

Adopted Draft: Media Session Standard, https://www.w3.org/TR/2022/WD-mediasession-20220920/, 20 September 2022.

Exclusion Draft: Media Session Standard, https://www.w3.org/TR/2020/WD-mediasession-20200130/, 30 January 2020. Exclusion period began on 30 January 2020; ended on 28 June 2020.

Exclusion Draft Charter: https://www.w3.org/2019/05/media-wg-charter.html.

Media Playback Quality

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

The group expects to work with the WHATWG to integrate the specification in the HTML specification, and does not plan to work on or publish the specification once integration in HTML has been completed.

Draft state: Editor's Draft

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.

Expected completion: [Q1–4 yyyy].

Draft state: Working Draft.

Adopted Draft: Autoplay Policy Detection, https://www.w3.org/TR/2023/WD-autoplay-detection-20230127/, 27 January 2023.

Exclusion Draft: Autoplay Policy Detection, https://www.w3.org/TR/2022/WD-autoplay-detection-20220315/, 15 March 2022. Exclusion period began on 15 March 2022; ended on 12 December 2022.

Exclusion Draft Charter: https://www.w3.org/2021/07/media-wg-charter.html.

Media Source Extensions

This 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.

Expected completion: [Q1–4 yyyy].

Draft state: Working Draft.

Adopted Draft: Media Source Extensions™, https://www.w3.org/TR/2022/WD-media-source-2-20220921/, 21 September 2022.

Exclusion Draft: Media Source Extensions™, https://www.w3.org/TR/2021/WD-media-source-2-20210930/, 30 September 2021. Exclusion period began on 30 September 2021; ended on 27 February 2022.

Exclusion Draft Charter: https://www.w3.org/2021/07/media-wg-charter.html.

Encrypted Media Extensions

This 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 three minor features incubated in the Web Platform Incubator Community Group since then, namely: HDCP Detection, Encryption scheme capability detection and a means to avoid creating duplicate sessions within the same origin (building on alternatives to finding existing sessions). The inclusion of other features is considered out of scope for this group and would require rechartering.

Draft state: Editor's Draft

WebCodecs

This specification defines interfaces for encoding and decoding of audio, video, and images.

Expected completion: [Q1–4 yyyy].

Draft state: Working Draft

Adopted Draft: WebCodecs, https://www.w3.org/TR/2023/WD-webcodecs-20230130/, 30 January 2023.

Exclusion Draft: WebCodecs, https://www.w3.org/TR/2021/WD-webcodecs-20210408/, 08 April 2021. Exclusion period began on 08 April 2021; ended on 05 September 2021.

Exclusion Draft Charter: https://www.w3.org/2019/05/media-wg-charter.html.

Audio Focus

This specification allows 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.

Draft state: Editor's Draft

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:

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.
Registration specifications
Notes described in Registries define optional features for WebCodecs, Media Source Extensions, 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.

Registries

To enhance interoperability among implementations and users the Media Working Group develops and maintains registries for WebCodecs, Media Source Extensions, and Encrypted Media Extensions:

The Media Working Group may re-publish registries published as Notes on the Registry track.

The Media Working Group also develops and maintains non-normative codec-specific or format-specific registrations for each of these registries, published on the Note track. These include:

Other Deliverables

Other non-normative documents may be created such as:

  • Use cases and requirements documents;
  • Test suites and implementation reports for the specifications;
  • Code samples, Primers or Best Practices documents to support web developers when designing applications.

Success Criteria

In order to advance to Proposed Recommendation, each normative specification is expected to have at least two independent interoperable implementations of every feature defined in the specification, where interoperability can be verified by passing open test suites, and two or more implementations interoperating with each other. In order to advance to Proposed Recommendation, each normative specification must have an open test suite of every feature defined in the specification.

There should be testing plans for each specification, starting from the earliest drafts.

To promote interoperability, all changes made to specifications in Candidate Recommendation or to features that have deployed implementations should have tests. Testing efforts should be conducted via the Web Platform Tests project.

Each specification should contain sections detailing all known security and privacy implications for implementers, Web authors, and end users, including analysis of fingerprinting surface introduced and suggested mitigation strategies, as applicable. For features that allow detection and/or negotiation of capabilities, the group will document architectural alternatives, particularly ones that minimize fingerprinting surface, and seek horizontal review as it makes its choice(s) among the alternatives. Where features are imported by reference to other specifications, analysis and mitigation of their privacy and security issues will be included in the referencing specification.

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.

Coordination

For all specifications, this Working Group will seek horizontal review for accessibility, internationalization, 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. The Working Group is encouraged to engage collaboratively with the horizontal review groups throughout development of each specification. The Working Group is advised to seek a review at least 3 months before first entering CR and is encouraged to proactively notify the horizontal review groups when major changes occur in a specification following a review.

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.
GPU for the Web Working Group
The GPU for the Web Working Group develops interfaces between the Web Platform and modern 3D graphics and computation capabilities present on native system platforms, including processing of media streams for processing or rendering on the GPU.
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.
WebTransport Working Group
The WebTransport Working Group develops APIs that enable data transfer between browsers and servers with support for multiple data flows, unidirectional data flows, out-of-order delivery, variable reliability and pluggable protocols. One of the use cases for these APIs is streaming of media, using WebCodecs for media encoding and decoding.
Web Real-Time Communications Working Group
The Web Real-Time Communications Working Group develops APIs to capture, encode, process, transfer, decode and render media.
Open UI Community Group
The group researches components and controls across the web and also looks to native paradigms to bring interoperability for design systems, frameworks and the web platform. The Open UI CG is looking at ways to enable style-able and extensible video/audio controls for features that the Working Group develops.

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.

Participants in the group are required (by the W3C Process) to follow the W3C Code of Ethics and Professional Conduct.

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 5.2.1, Consensus). 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, GitHub issue 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 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 5.2.3, Deciding by Vote) and includes no voting procedures beyond what the Process Document requires.

Patent Policy

This Working Group operates under the W3C Patent Policy (Version of 15 September 2020). To promote the widest adoption of Web standards, W3C seeks to issue Web specifications 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 3.4 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.

Charter History

The following table lists details of all changes from the initial charter, per the W3C Process Document (section 4.3, Advisory Committee Review of a Charter):

Charter Period Start Date End Date Changes
Initial Charter 22 May 2019 31 May 2021 none
Chair update 29 April 2021
  • Mounir Lamouri steps down as co-Chair
  • Chris Needham appointed co-Chair
Extended 19 May 2021 30 June 2021 End date adjusted
Rechartered 1 July 2021 31 May 2023
  • Adjusted boilerplate text to match latest charter template
  • Added WebCodecs to the list of deliverables
  • Dropped Persistent usage record sessions feature from EME description
  • Updated milestones and coordination list
Rechartered When approved Start date + 2 years
  • Adjusted boilerplate text to match latest charter template
  • Added Registries section to highlight registries and registration deliverables
  • Replaced milestones table with expected completion dates
  • document changes