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Re: Custom and extending CDM to support other DRM systems

From: Emmanuel Poitier <emmanuel.poitier@enman.fr>
Date: Sat, 07 Feb 2015 17:13:05 +0100
Message-ID: <54D63991.40909@enman.fr>
To: János Barta <bartakok@gmail.com>, Mark Watson <watsonm@netflix.com>
CC: "public-html-media@w3.org" <public-html-media@w3.org>
Hi Janos,

all you mentioned make sense to me, and I hope to others as well. I hope
it will be considered by UAs and will be addressed accordingly for the
best interest of users and video service providers.

Le 01/02/2015 17:37, János Barta a écrit :
> Hi Emmanuel,
>
> On 2015.01.31. 17:26, Emmanuel Poitier wrote:
>> Mark,
>>
>> Le 30/01/2015 16:59, Mark Watson a écrit :
>>>
>>>
>>> On Fri, Jan 30, 2015 at 7:53 AM, Emmanuel Poitier
>>> <emmanuel.poitier@enman.fr <mailto:emmanuel.poitier@enman.fr>> wrote:
>>>
>>>     Matt,
>>>
>>>     Le 30/01/2015 16:14, Mark Watson a écrit :
>>>>
>>>>
>>>>     On Fri, Jan 30, 2015 at 6:58 AM, Glenn Adams <glenn@skynav.com
>>>>     <mailto:glenn@skynav.com>> wrote:
>>>>
>>>>
>>>>         On Fri, Jan 30, 2015 at 7:49 AM, Emmanuel Poitier
>>>>         <emmanuel.poitier@enman.fr
>>>>         <mailto:emmanuel.poitier@enman.fr>> wrote:
>>>>
>>>>             All,
>>>>
>>>>             I am currently looking after the information on how to
>>>>             extend the CDM to support other DRM systems, which is
>>>>             nowadays fixed and hardcoded for each browsers (IE with
>>>>             PlayReady, Chrome with Widevine, Safari with FairPlay).
>>>>             It would be nice to ensure the EME spec does provide
>>>>             information and also how browsers would support that in
>>>>             an agnostic manner to ensure a non fragmented market
>>>>             where the user does want to play a protected video
>>>>             content whatever the browser he is using.
>>>>
>>>>
>>>>         I doubt if anything has changed on this front, but this
>>>>         type of specification was ruled out of scope for EME. EME
>>>>         uses the term and concept "CDM" only in a notional manner,
>>>>         and does not specify any concrete interface to such a
>>>>         component.
>>>>
>>>>         It is likely that interface and any mechanism for
>>>>         adding/extending UA supplied CDMs will remain UA specific,
>>>>         that is, until some organization steps forward to
>>>>         standardize it (assuming UA vendors are willing to do
>>>>         that... a dubitable proposition).
>>>>
>>>>
>>>>     ​Yes, such an API is not really in scope of W3C, never mind
>>>>     just EME. Just as NPAPI for <object> was created by UA vendors
>>>>     any such cross-browser CDM API would need to come from the UA ​
>>>>     vendors. Of course, the open source implementations of EME have
>>>>     CDM APIs in their code, but a major point of EME was to bring
>>>>     DRM under UA control, so I would not expect UAs ever to support
>>>>     download of arbitrary user-installable CDMs - at least it's not
>>>>     clear to me how this could be done and simultaneously meet the
>>>>     privacy and security requirements of the specification. Whilst
>>>>     UAs can technically enforce many security and privacy
>>>>     properties through sandboxing I'm not sure they will be willing
>>>>     to host CDMs about which they have no knowledge whatsoever.
>>>>
>>>>     …Mark
>>>
>>>     I can understand this point, though a service provider
>>>     protecting their content will evaluate DRM systems based on the
>>>     UA CDM DRM support before using EME which is at the moment quite
>>>     split across browsers. Thanks anyway for your view on this issue.
>>>
>>>
>>> ​ What's your alternative and how does it address the security and
>>> privacy issues ?​
>>>
>>> …Mark
>>
>> I would see a separate working group who will be in charge of
>> offering a CDM description with security analysis based on the data
>> flow interfacing with the CDM. It may be a consortium composed of all
>> or the most used DRM providers to design a such component, so they
>> would have a complete knowledge and the necessary technical
>> constraints to ensure the required level of security delivered by the
>> CDM component within the EME feature. It does definitely require a
>> collaborative work to assure content protection and the legitimate
>> use of protected content in a generic manner to let users choose
>> their preferred way to use them.
>
>
> do we really need to have a standard CDM solution or wouldn’t it be
> better to focus on a standard, auditable layer amongst browser
> components and  CDM modules (as it is already available in case of
> Firefox), called CDM/DRM sandbox?
> In case of a Sandbox solution:
> -    CDM-Sandbox can be a “bridge” with well-defined, standard interfaces
> -    DRM specific CDM can be an independent/closed/proprietary module
> -    CDM will be downloaded and activated from the website of DRM
> provider based on user consent
> -    Decoupled Browser and DRM layers (-> Multi-DRM support)
> -    etc…
>
> I think the biggest issue is that there is no interest from the
> UI/Browser side to have a cross-platform solution. There is no doubt
> about their intention is to set their own CDM in stone (because of the
> additional incomes, e.g.  from licenses).
> I would like to believe that it is only my misinterpretation and they
> (Google/Microsoft/Mozilla/Opera/Apple…) are willing to make sacrifices
> in order to have a standard, sandbox based cross-CDM solution. We will
> see…
>
> Best regards,
> Janos BARTA
> 1. dia

Best regards,
-- 
Emmanuel Poitier- Chief Executive Officer (CEO)
Enman

Telephone:+33 (0)2 54 67 15 38	
	Mobile:+33 (0)780 381 124
Email:emmanuel.poitier@enman.fr 	
	Web site:http://enman.fr





Received on Saturday, 7 February 2015 16:13:52 UTC

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