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[encrypted-media] CDM implementations must support multiple keys per session

From: ddorwin via GitHub <sysbot+gh@w3.org>
Date: Sat, 24 Jan 2015 00:49:29 +0000
To: public-html-media@w3.org
Message-ID: <issues.opened-55351696-1422060569-sysbot+gh@w3.org>
ddorwin has just created a new issue for
https://github.com/w3c/encrypted-media:

== CDM implementations must support multiple keys per session ==
In Bug 25092, Mark says, "there are DRM systems which do not support
multiple keys or key ids for the same session" ([comment
8](https://www.w3.org/Bugs/Public/show_bug.cgi?id=25092#c8)) and
"there are CDMs that support only a single key or only a single key at
a time" ([comment
30](https://www.w3.org/Bugs/Public/show_bug.cgi?id=25092#c30)).

Such CDM implementations would break interoperability, especially for
some common use cases. For example, applications that use multiple
keys (i.e. different keys for audio and video) would either not
support clients with such CDMs or need key system-specific logic to
support them. In theory, such an application could use a separate
session per key, but that would introduce overhead. In addition,
applications may rely on a single session/license for tracking active
licenses.

Such CDM implementations also break the intended behavior and usage of
the keyStatuses attribute (see [Bug 25092 comment
33](https://www.w3.org/Bugs/Public/show_bug.cgi?id=25092#c33)).

Unless we have some baseline requirements, authors will have a
difficult time writing interoperable applications.

See https://github.com/w3c/encrypted-media/issues/23
Received on Saturday, 24 January 2015 00:49:30 UTC

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