1083658 - Send EME downscaling notification from CDM to JS

Status: RESOLVED FIXED

(Core :: Audio/Video, defect)

Description

[Chris Peterson [:cpeterson]]

If a CDM loses authority to decode HD video, it downscales HD input to SD output. The CDM needs a way to notify the web app so it can save bandwidth by switching from HD to SD stream.

Comment 1

[Chris Peterson [:cpeterson]]

cpearce says: Sounds like the preferred solution is to have MediaKeySession.getUsableKeyIds return info about whether downscaling is required for a particular key and send a keyschange event when downscaling happens.

Comment 2

[Chris Peterson [:cpeterson]]

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

Comment 3

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

Basically here we need to update MediaKeySession.usableKeyIds to be keyStatuses instead, and ensure that the CDM can use that API to report downscaling. We may need to add something to the MediaKeyStatus enumeration.

We need to sync up with Adobe before we implement this.

Comment 4

[JW Wang [:jwwang] [:jw_wang]]

Can we associate resolution with MediaKeyStatus? "output-not-allowed" doesn't really tell much.

Comment 5

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

JW: would you be able to take this? I'm being sidetracked helping out with MSE for the next couple of weeks.

I think we should go ahead and include a "downscaled" key status, as is being proposed here, even though it's not made it into the spec yet:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=25092

Comment 6

[JW Wang [:jwwang] [:jw_wang]]

sure.

Comment 7

[JW Wang [:jwwang] [:jw_wang]]

It looks like MediaKeySession.keyStatuses is not implemented at all. Is there already a bug for that?

[1] https://w3c.github.io/encrypted-media/#widl-MediaKeySession-keyStatuses

Comment 8

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

Yes. This bug covers implementing keyStatuses. :)

Comment 9

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

https://github.com/w3c/encrypted-media/commit/61450e0c5279772451360733b23161aa92ecb63e
adds "output-downscaled" to MediaKeyStatus.

Comment 10

[JW Wang [:jwwang] [:jw_wang]]

Attachment: 1083658_support_downscaling_notification-v1.patch

Add kGMPOutputDownscaled and kGMPInternalError to GMPMediaKeyStatus.

Comment 11

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

Comment on attachment 8557542 [details] [diff] [review]
1083658_support_downscaling_notification-v1.patch

Review of attachment 8557542 [details] [diff] [review]:
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Excellent. Thank! This can land right? Would be good if we can get this into Sunday night PST's Nightly.

Comment 12

[JW Wang [:jwwang] [:jw_wang]]

Try: https://tbpl.mozilla.org/?tree=Try&rev=03544966b624

Comment 13

[JW Wang [:jwwang] [:jw_wang]]

inbound:
https://hg.mozilla.org/integration/mozilla-inbound/rev/ae8394c92f28

Comment 14

[Phil Ringnalda (:philor)]

https://hg.mozilla.org/mozilla-central/rev/ae8394c92f28

Comment 15

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

https://hg.mozilla.org/releases/mozilla-beta/rev/c4b5f9a4cc0a

Comment 16

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

Attachment: Beta patch

Patch for beta branch as part of EME platform uplift.

Comment 17

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

Comment on attachment 8572336 [details] [diff] [review]
Beta patch

Requesting retroactive approval for Beta landing as part of EME platform uplift.

Comment 18

[Lawrence Mandel [:lmandel] (use needinfo)]

Comment on attachment 8572336 [details] [diff] [review]
Beta patch

Previously approved as part of the EME platform landing on Beta.