"webm" Initialization Data Format

W3C Editor's Draft

This version:
Latest published version:
Latest editor's draft:
Joey Parrish (Google Inc.)
Greg Freedman (Netflix Inc.)
Former editors:
Mark Watson (Netflix Inc.) (Until September 2019)
David Dorwin (Google Inc.) (Until September 2017)
Jerry Smith (Microsoft Corporation) (Until September 2017)
Adrian Bateman (Microsoft Corporation) (Until May 2014)


This specification defines the "webm" Initialization Data format for use with the Encrypted Media Extensions [ENCRYPTED-MEDIA]. This format is commonly used with the WebM Stream Format [EME-STREAM-REGISTRY].

Status of This Document

This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at https://www.w3.org/TR/.

This document was published by the Media Working Group as an Editor's Draft.

Comments regarding this document are welcome. Please send them to public-media-wg@w3.org (archives).

Publication as an Editor's Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

This document was produced by a group operating under the W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.

This document is governed by the 1 March 2019 W3C Process Document.

1. Format

The format is a single key ID of one or more bytes, as defined by the ContentEncKeyID [Matroska] element and [WebM-Encryption].

A. References

A.1 Normative references

Encrypted Media Extensions. David Dorwin; Jerry Smith; Mark Watson; Adrian Bateman. W3C. 18 September 2017. W3C Recommendation. URL: https://www.w3.org/TR/encrypted-media/
Matroska Specifications. Matroska. 9 January 2014. URL: https://matroska.org/technical/specs/index.html
WebM Encryption. Frank Galligan. The WebM Project. 4 March 2015. URL: https://www.webmproject.org/docs/webm-encryption/

A.2 Informative references

Encrypted Media Extensions Stream Format Registry. David Dorwin; Adrian Bateman; Mark Watson. W3C. URL: ../stream/index.html