Intent to Ship: EME Encryption Scheme Query

[Xiaohan Wang (王消寒)]

Contact emails

jrum...@chromium.org, xhw...@chromium.org, joeyp...@chromium.org

Explainer

https://github.com/WICG/encrypted-media-encryption-scheme/blob/master/explainer.md

Spec

• Not in EME spec yet.

• Tag Review: https://github.com/w3ctag/design-reviews/issues/322

Summary

Provide applications the ability to query whether a specific encryption scheme is supported by EME.

Link to “Intent to Implement” blink-dev discussion

https://groups.google.com/a/chromium.org/d/msg/blink-dev/lMUKOaohUTY/e7jO087-AgAJ

Link to Origin Trial feedback summary

N/A. Did not do origin trial since the API change is trivial and straightforward.

Is this feature supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?

Yes. The API will be supported on all platforms. The actual encryption schemes supported on each platform could be different.

Demo link

N/A. But sample code are provided in this blog post:

https://developers.google.com/web/updates/2018/08/chrome-69-media-updates#encryption_scheme

Debuggability

N/A

Risks

Interoperability

Firefox: No public signals

Edge: Public support

Safari: Public support

Web developers: Positive

Compatibility

Compatibility risk is low.

Ergonomics

N/A

Activation

N/A

Is this feature fully tested by web-platform-tests? Link to test suite results from wpt.fyi.

https://crbug.com/905433 tracks the work to upstream existing layout test and add new test cases to WPT.

OWP launch tracking bug

http://crbug.com/838416

Entry on the feature dashboard

https://www.chromestatus.com/features/5184416120832000

[Philip Jägenstedt]

It looks like both spec and test work remains to be done here. Normally that blocks shipping a new feature, is that OK or are there reasons to make an exception here?

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[Xiaohan Wang (王消寒)]

For spec work, do you mean it needs to make into the EME spec, or we need to wait for the TAG review to be finished? For the former, AFAIK, there's no active working group for the next version of EME spec. joeyparrish@ may know more. For the latter, we are just waiting for the review.

For test, we should be able to get it done soon. +John Rummell 

The API change and implementation are pretty straightforward, and it's partially blocking some content providers from switching from Flash to HTML5, which could be the reason that we make an exception?

[Philip Jägenstedt]

I mean making it into a spec, that there's a page (probably https://w3c.github.io/encrypted-media/) where other implementers can find the requirements for implementing the feature. Otherwise, they'll need to reverse engineer our implementation in order to follow.

If the API is simple, would you be able to send a PR for the spec? If it can't be merged for process reasons, isn't there a fork of the EME spec where changes can still be made?

[Xiaohan Wang (王消寒)]

Currently all the EME (and other) incubation changes are at: https://github.com/WICG/

I am not familiar with the spec process on how to merge it into EME or a fork of EME. +joeyp...@chromium.org, our EME editor for insights.

[Mounir Lamouri]

The explainer for the change is fairly detailed and it may not take too long to put this into a spec inside the "encrypted-media-encryption-scheme" repo. The spec could just extend the EME spec.

The intent here isn't to have the change in an "official" spec but just a spec wording that will guarantee interop.

-- Mounir

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[Joey Parrish]

The official EME spec currently has no working group, so this will not be a part of the official EME spec yet.  But we should write spec text for it in the same repo as the explainer, so that others can implement it faithfully, as Philip points out.

[Joe Medley]

Would someone please review and update the Chrome Status numbers. If this is coming out from a flag, the shipping number should be noted. Also, if it's only in Chrome desktop, it's probably NOT in Opera Android as currently stated. Please fix that.

Joe Medley | Technical Writer, Chrome DevRel | jme...@google.com | 816-678-7195

If an API's not documented it doesn't exist.

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[Philip Jägenstedt]

We discussed this briefly in API owners meeting today, Chris, Daniel, Yoav and me.

Just wanted to say explicitly that what Joey says makes sense, to add something spec-like in https://github.com/WICG/encrypted-media-encryption-scheme, with the IDL and the basic algorithms to make it work. If expressing it as changes against the existing EME spec is easier, then just taking a snapshot of that and making a single change on top of it would be fine, so that it's easy to later port it over to the main spec when there's a WG to do it in.

Does that make sense?

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[Xiaohan Wang (王消寒)]

Philip: It makes sense to me. Thanks for the discussion! +Joey Parrish 

Joe: I updated the Chrome Status page to reflect that this is also available in Chrome on Android starting from M69 behind a flag. (CBCS is not supported on Android yet, but the query API is there.) I'll update it again once this ITS is approved and the feature is shipping by default.

[Joe Medley]

Great, thanks! 

Joe Medley | Technical Writer, Chrome DevRel | jme...@google.com | 816-678-7195

If an API's not documented it doesn't exist.

[Daniel Bratell]

We (API owners) have this as blocked on a published spec /spec fork/ spec patch. xhwang, do you know the current status on that?

/Daniel

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/* Opera Software, Linköping, Sweden: CET (UTC+1) */

[Xiaohan Wang (王消寒)]

Yes, it's blocked by the spec-ish doc, and WPT tests. We are coordinating efforts on both fronts.

[Yoav Weiss]

On Fri, Dec 14, 2018 at 5:59 PM Xiaohan Wang (王消寒) <xhw...@chromium.org> wrote:

Yes, it's blocked by the spec-ish doc, and WPT tests. We are coordinating efforts on both fronts.

Thank you. Note that you can start by writing that spec somewhere public (e.g. on your own GH repo, or in a public doc) and we can worry about the proper venue for this afterwards.

 

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[Alex Russell]

Hey all,

The OWNERS were hoping to find out if there has been progress on the spec issue. Any luck?

Regards

[Xiaohan Wang (王消寒)]

Joey will update the spec, but he's been busy with other work recently :|