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

https://www.w3.org/Bugs/Public/show_bug.cgi?id=20944

--- Comment #45 from David Dorwin <ddorwin@google.com> ---
As mentioned above, I think it would be more effective and beneficial to the
web platform to document the expected observable behavior and capabilities of
CDMs rather than the unique behavior of each CDM. Robustness
mechanisms/features and keys/secrets may vary, but we should be able to
document the observable capabilities. This will benefit application developers
(less key system-specific code [1], easier to support new key systems) and
users (more content on more clients).

This will also make behaviors more explicit and less dependent on proprietary
content metadata, such as PSSH boxes. As discussed in bug 17673, such headers
are a threat to EME interop. Ideally, custom PSSH boxes should not be necessary
for all/most (common) scenarios and a common CENC protection system [2] can be
used.

The spec currently specifies interoperable solutions for streaming and offline
playback. We should continue this model for specifying observable behavior.


[1] Ideally, key system selection code is the only part of the application that
needs to be key system-specific, as shown in the examples:
https://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/encrypted-media.html#example-selecting-key-system
[2]
https://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/cenc-format.html#common-system;
bug 24027

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Received on Tuesday, 27 May 2014 22:22:51 UTC