[encrypted-media] Consider providing guidance for implementations on platforms that do not expose key IDs

ddorwin has just created a new issue for 
https://github.com/w3c/encrypted-media:

= Consider providing guidance for implementations on platforms that 
do not expose key IDs =
EME may be implemented on top of platforms that have not yet been 
updated to expose the information necessary to support 
`MediaKeyStatusMap`. This should generally work fine, but applications
 may assume a non-empty list of key IDs and/or implementations may 
need to report output issues, expiration, etc. While the long-term 
goal is full support, we should consider (non-normatively) specifying 
a behavior to increase interoperability of and with such 
implementations.

I propose two non-normative notes:
1. Some implementations may not report key IDs.
* In such cases, we need to decide what the `MediaKeyStatusMap` should
 look like. It could either be empty or - for compatibility with the 
next item - always contain a single element with the ID "0".
2. Implementations that do not support reporting key IDs but need to 
report status (i.e. an error) via one of the `MediaKeyStatus` values 
should report the most appropriate status (from the application`s 
point of view) in key ID "0".

See https://github.com/w3c/encrypted-media/issues/32

Received on Tuesday, 10 February 2015 20:46:45 UTC