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RE: [Bug 20944] New: EME should do more to encourage/ensure CDM-level interop

From: Paul Cotton <Paul.Cotton@microsoft.com>
Date: Mon, 11 Feb 2013 14:40:55 +0000
To: "David Dorwin <ddorwin@google.com> (ddorwin@google.com)" <ddorwin@google.com>, Adrian Bateman <adrianba@microsoft.com>, Mark Watson <watsonm@netflix.com>
CC: "public-html-admin@w3.org" <public-html-admin@w3.org>, "Sam Ruby (rubys@intertwingly.net)" <rubys@intertwingly.net>, "Maciej Stachowiak (mjs@apple.com)" <mjs@apple.com>
Message-ID: <AB5704B0EEC35B4691114DC04366B37F1F80A056@TK5EX14MBXC291.redmond.corp.microsoft.com>
I would like to encourage the EME Editors to respond to this bug with questions, request for clarifications, resolution, etc. as soon as possible.  At a minimum we should figure where this bug impacts the candidate FPWD and to decide if we should markup that part of the candidate to point to this bug.

Can we get this done this week?


Paul Cotton, Microsoft Canada
17 Eleanor Drive, Ottawa, Ontario K2E 6A3
Tel: (425) 705-9596 Fax: (425) 936-7329

-----Original Message-----
From: bugzilla@jessica.w3.org [mailto:bugzilla@jessica.w3.org] 
Sent: Monday, February 11, 2013 12:24 AM
To: public-html-media@w3.org
Subject: [Bug 20944] New: EME should do more to encourage/ensure CDM-level interop


            Bug ID: 20944
           Summary: EME should do more to encourage/ensure CDM-level
    Classification: Unclassified
           Product: HTML WG
           Version: unspecified
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Encrypted Media Extensions
          Assignee: adrianba@microsoft.com
          Reporter: roc@ocallahan.org
        QA Contact: public-html-bugzilla@w3.org
                CC: mike@w3.org, public-html-media@w3.org

The current EME draft makes no attempt to encourage interop at the CDM level.
For example, the current EME draft does not forbid or even discourage a UA vendor from promulgating a CDM that no other user-agent can support, and encouraging the creation of content for that CDM consumable only by that user-agent. Such an outcome would be antithetical to the mission of the W3C, and the W3C should not bless, appear to bless, or enable such scenarios.

I believe it is possible to fix this bug without making major changes to EME or CDM technology, without discarding existing EME/CDM requirements, and that it's worth making at least a good-faith effort to try. I believe this should be settled (at least to the point of committing to fix the bug) before EME progresses further, or any requirements we need to add to EME and CDMs are likely to be rejected as "too late".

My proposed fix is to have EME require CDMs to be registered in a central registry. To be registered, a CDM would have to meet the following conditions:

1) Documentation must be published describing the complete operation of the CDM, in enough detail to enable independent implementation in user-agents and to enable content deployment by content providers, except for some set of secret keys whose values may be withheld. (Similar to but weaker than IANA's "specification required" registry policy.)

2) If the CDM vendor offers functionality to third parties to decrypt content that can be decrypted by the CDM, then it must publish documentation describing how to implement the CDM using that functionality. (E.g. if a DRM platform vendor implements a CDM using that DRM platform, other consumers of that platform must also be able to implement the same CDM.)

These requirements are not the only possible fix, and may in fact be an inadequate fix, but I believe they're a lot better than nothing.

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Received on Monday, 11 February 2013 14:42:12 UTC

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