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

From: Mark Watson <watsonm@netflix.com>
Date: Mon, 18 Feb 2013 16:44:00 +0000
To: "<robert@ocallahan.org>" <robert@ocallahan.org>
CC: "<public-html-media@w3.org>" <public-html-media@w3.org>, Glenn Adams <glenn@skynav.com>
Message-ID: <FE5EB293-C25E-43B4-B249-EC30A3A4447C@netflix.com>

On Feb 17, 2013, at 3:36 PM, Robert O'Callahan wrote:

I told Glenn I'd follow up his comment https://www.w3.org/Bugs/Public/show_bug.cgi?id=20944#c2 on this list.

Glenn Adams wrote:
(In reply to comment #0)
> The current EME draft makes no attempt to encourage interop at the CDM
> level.

This is not a well defined statement in the sense that neither "interop" nor "at the CDM level" are defined concepts.

"Interop" is short for "interoperabilty" and the Wikipedia definition is pretty good.

By "interop at the CDM level" I mean the degree to which CDM support is uniform across user-agents, by which I mean both that each CDM should be supported in as many user-agents as possible, and each CDM should work in exactly the same way across user-agents. (There is probably also something to say about the content production side, but I know less about that.)

Common Encryption helps here. We don't expect all UAs to support a common CDM and that's ok, so long as the CDMs they do have support common encryption. There is some overhead on the server side to support multiple CDMs, but that is better than restricting content to a subset of devices or trying to force devices to support a particular CDM. The key point is that with common encryption we can use the same media file with different CDMs.

Received on Monday, 18 February 2013 16:44:31 UTC

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