Intent to Ship: MediaCapabilities.decodingInfo.encryptionScheme
Sangbaek Park
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Specification https://w3c.github.io/media-capabilities/#dom-keysystemtrackconfiguration-encryptionscheme
Summary Adds the encryptionScheme attribute to the KeySystemTrackConfiguration dictionary used in navigator.mediaCapabilities.decodingInfo(). This allows web applications to query whether a specific encryption scheme (such as 'cenc' or 'cbcs') is supported.
This feature is already approved by the W3C spec and the underlying backend implementation in Chromium already exists. This launch is purely to plumb the encryptionScheme property from the Blink IDL layer to the existing backend.
Blink component Blink>Media
Search tags media-capabilities, decodingInfo, encryptionScheme, eme, drm, cenc, cbcs
TAG review None. This is a trivial IDL plumbing update for a standard that is already shipped by other vendors.
TAG review status Not applicable
Risks Interoperability and Compatibility None. We are simply exposing the encryptionScheme property to match the W3C spec. Edge and Firefox have already implemented this and pass the relevant tests.
Gecko: Shipped WebKit: Not Supported Web developers: Positive
Debuggability N/A
Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)? Yes
Is this feature fully tested by web-platform-tests? Yes. The web-platform-tests were recently updated to robustly verify this plumbing.
As shown on the main WPT dashboard, Chrome Stable is currently lagging behind Edge and Firefox: https://wpt.fyi/results/media-capabilities/decodingInfoEncryptedMedia.https.html?label=master&product=chrome%5Bstable%5D&product=edge%5Bexperimental%5D&product=firefox%5Bexperimental%5D&product=safari%5Bexperimental%5D&aligned
However, the plumbing is already verified to work in Chrome Canary (where the feature flag is enabled), as shown here: https://wpt.fyi/results/media-capabilities/decodingInfoEncryptedMedia.https.html?label=experimental&label=master&aligned
This launch simply flips the flag to stable to catch up.
Requires code in //chrome? False
Tracking bug https://crbug.com/498284510
Link to entry on the Chrome Platform Status https://chromestatus.com/feature/4644898109259776