1072719 - Provide way for GMPs to specify what profiles/levels they support

Status: RESOLVED WONTFIX

(Core :: Audio/Video: GMP, defect, P3)

Description

[Chris Pearce [:cpearce (Not reading bugmail)]]

We need to be able to tell what H.264 profiles/levels/constraints a GMP can play. Ditto for AAC.

We need this so that HTMLMediaElement.canPlayType() and MediaKeys.isTypeSupported() can accurately report what H.264/AAC levels/profiles we can play.

I describe the H.264 codecs parameters. 
http://blog.pearce.org.nz/2013/11/what-does-h264avc1-codecs-parameters.html

For example, avc1.4D401E is main, level 3. We've been identifying H.264 in GMPs .info file by the tag "h264", but web content actually identifies H.264 by a "codecs=avc..." string as in the previous example.

The naive implementation would be to enumerate them in the GMP's .info file. But for H.264, there are at least 17 levels and at least 3 profiles we care about. I don't know how many permutations of the constraint flags we need to care about. So there would be lots of permutations, so that's not an elegant solution...

Comment 1

[Chris Pearce [:cpearce (Not reading bugmail)]]

For the first Adobe/Windowns >= Vista release we can just assume that their decoder can play everything that WMF's decoder can play. So we don't need to be fancy in the short term. Long term, a better solution would be nice.

Comment 2

[Chris Peterson [:cpeterson]]

These bugs are fit and finish issues that might block EME uplift to Aurora.

Comment 3

[Bulk Bug Changes for mreavy's org]

Mass change P2->P3 to align with new Mozilla triage process.