"keyids" 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 "keyids" Initialization Data format for use with the Encrypted Media Extensions [ENCRYPTED-MEDIA].


It defines a stream format-independent format for specifying a list of key ID(s). This type can be used by applications to directly provide information necessary to generate a license request without using media data or constructing container-specific formats.

Status of This Document

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

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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.

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

1. Format

The format is a JSON object, encoded in UTF-8 as specified in the Encoding specification [encoding], containing the following member:

An array of key ID(s). Each element of the array is the base64url encoding of the octet sequence containing the key ID value.

See Using base64url.


Applications may encode the JSON string using the TextEncoder interface [encoding]

2. Example

This section is non-normative.

The following example will generate a license request for two key ID(s). (Line breaks are for readability only.)


A. References

A.1 Normative references

Encoding Standard. Anne van Kesteren. WHATWG. Living Standard. URL: https://encoding.spec.whatwg.org/
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/