Intent to ship: encryptionScheme in MediaKeySystemMediaCapability

[Alastor Wu]

Hello,

I intend to turn ON the preference media.eme.encrypted-media-encryption-scheme.enable by default for all platforms in Firefox 128, which will allows web developers to use encryptionScheme in MediaKeySystemMediaCapability for EME API.

Summary: The encryptionScheme is an optional attribute in MediaKeySystemMediaCapability, which is used to indicate the encryption scheme associated with the content type. Web developers can use that attribute to explicitly indicate what encryption scheme the user agent should support. We've implemented this feature for a long time, and it's time to turn it on by default.

Bug for Feature Implementation : https://bugzilla.mozilla.org/show_bug.cgi?id=1536102

Bug to turn on by default:  https://bugzilla.mozilla.org/show_bug.cgi?id=1899182

Standard: https://w3c.github.io/encrypted-media/#dom-mediakeysystemmediacapability-encryptionscheme

Platform Coverage: Available on all platforms.

Preference: media.eme.encrypted-media-encryption-scheme.enable

Other Browsers: Other browsers have shipped this feature.

Blink: https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/renderer/modules/encryptedmedia/media_key_system_media_capability.idl;l=10

Webkit : https://searchfox.org/wubkat/source/Source/WebCore/Modules/encryptedmedia/MediaKeySystemMediaCapability.idl#35

Web-platform-tests: https://wpt.fyi/results/encrypted-media/clearkey-check-encryption-scheme.https.html