[encrypted-media] Get Supported Capabilities algorithm appears to conflict with RFCs specifying MIME types

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

== Get Supported Capabilities algorithm appears to conflict with RFCs 
specifying MIME types ==
Currently the algorithm "3.1.1.3 Get Supported Capabilities for 
Audio/Video Type" [1] has step:
3.8 If the user agent does not recognize one or more parameters, 
continue to the next iteration.

However, RFC2045 ("Multipurpose Internet Mail Extensions (MIME) Part 
One: Format of Internet Message Bodies"), which defines the basic 
rules for parsing MIME types, has the statement "MIME implementations 
must ignore any parameters whose names they do not recognize." This 
seems to imply that unrecognized parameters should always be ignored.

RFC2045 is not directly referenced from the spec. However, RFC6381, 
which is referenced in the algorithm, includes "The syntax in this 
document uses the BNF rules specified in [RFC2045] and [RFC2231]."

I also note that RFC6381 documents the "profiles" parameter (in 
addition to "codecs"). Since it is up to the implementation whether 
they support "profiles", it may affect cross-browser compatibility to 
skip capabilities with unrecognized parameters.

[1] 
http://w3c.github.io/encrypted-media/#get-supported-capabilities-for-audio-video-type

Please view or discuss this issue at 
https://github.com/w3c/encrypted-media/issues/373 using your GitHub 
account

Received on Saturday, 4 March 2017 00:38:55 UTC