[mediacapture-screen-share] Specify track.label (#128)

jan-ivar has just created a new issue for https://github.com/w3c/mediacapture-screen-share:

== Specify track.label ==
Right now, this spec says nothing about what the `track.label` should contain:
const stream = await navigator.mediaDevices.getDisplayMedia({video: true});
console.log(stream.getVideoTracks()[0].label); // ???
Implementations [differ](https://jan-ivar.github.io/dummy/gdm.html) so we should specify this:
- Firefox says: `Specify track.label · Issue #128 · w3c/mediacapture-screen-share` or `Primary Monitor`
- Chrome says: `window:123:0` or `screen:2067749241:0`
- Safari and Edge say: ""

The Firefox behavior uses the window title or monitor name, which seems helpful for the visually impaired. OTOH it might be a privacy issue if a window title is longer than what is visibly shown in the actual shared video (e.g. a user carefully resized a window to conceal an account number in the title). Wrinkle: most desktop browser windows use a layout without title these days, so this might actually be new information and surprising.

How do we balance these benefits?

One solution may be to limit the label length to reveal only the part of the window title that is currently, or was previously, visible in the video, whichever is longer. This might be hard to calculate (fonts etc) on some OSes, and the length may grow over time.

Whatever we come up with, we should probably say something.

Please view or discuss this issue at https://github.com/w3c/mediacapture-screen-share/issues/128 using your GitHub account

Received on Friday, 13 December 2019 14:26:43 UTC