We introduce a mechanism that allows an application to opt-in to exposing certain information to other applications which are video-capturing it. This allows collaboration between capturing and captured applications.
For example, a VC application that's video-capturing a tab where a presentation application lives, could expose user-facing controls in the VC tab for navigating the presentation in the captured tab.
Display-capturing applications can offer the user improved functionality if they know what they are capturing, assuming the captured application collaborates. This is already possible using steganography. We offer a simpler, more reliable and more secure mechanism, by which an application may advertise select information - origin, handle, ID, etc.
Additionally, the mechanism we propose allows the captured application to select the audience - the entire web or select origins.
Finally, our mechanism offers some confidence in the capturer that certain parts of the message, if included, are not spoofed:
1. Only the top-level application can set the capture-handle, whereas steganography-based methods are exposed to messages being displayed by embedded content.
2. The browser provides the origin of the captured application (if it opts-in to exposing it).
Initial public proposalhttps://github.com/w3c/mediacapture-screen-share/issues/166
TAG review statusPending
Interoperability and Compatibility
NoneGecko: No official signal
. Some resistance voiced over the argument that this makes getDisplayMedia "too attractive" and could hinder adoption of getViewportMedia. (There are no current plans to deprecate getDisplayMedia.)WebKit: No official signal
, but they contributed ideas to early revisions and seemed generally positive.Web developers:
Google Meet very interested. Additional developers will be approached soon.
Link to entry on the Chrome Platform Statushttps://chromestatus.com/feature/4854125411958784