Re: [MEDIA_PIPELINE_TF] Content protection proposal

On Dec 14, 2011, at 5:33 AM, Jan Lindquist wrote:

Hello Mark,

I do not agree with the assertion in the introduction that OIPF requires the web page to understand the commands set of every DRM. I believe the command set you have proposed is equivelent in nature that of OIPF.

As I understand it, the only calls available in OIPF have parameters of the form ( "type", "message" ) and the set of possible types is DRM-specific. The web page needs to know the command set of the DRM and needs to construct the message contents appropriately. This command set could include anything, but for the limited set I have been able to obtain information about it doesn't include passing of the actually DRM key exchange messages (these are stated in the OIPF architecture to flow directly between DRM client agent and DRM server over a DRM-specific protocol, which is what I'd like to avoid).


Can you explain how a WebPage will be aware of the DRM system that is available in the UA?

It won't. It will be aware of the DRM systems that the service supports, which I expect would be a small list. It would try each of those in preference order until one of them worked.

Actually, it's been pointed out to me that we do need an event to trigger the start of the key exchange. I think I will start with a plain onkeyneeded event with no parameters, and then the flow would progress as described. Potentially, that onkeyneeded event could contain a list of the DRM system ids in the intersection of those supported by the client and those suitable for the media, which would avoid the need for the try-and try-again code on the page. But that's just an optimization.

...Mark


Regards,
JanL

________________________________
From: Mark Watson [mailto:watsonm@netflix.com]
Sent: den 8 december 2011 20:03
To: public-web-and-tv@w3.org<mailto:public-web-and-tv@w3.org> WG
Subject: [MEDIA_PIPELINE_TF] Content protection proposal

All,

I have placed a more detailed proposal for the content protection mechanism we proposed at the Berlin workshop here: http://www.w3.org/2011/webtv/wiki/MPTF/Netflix_Content_Protection

I look forward to comments/discussion.

Best,

Mark