Opened 3 months ago

Last modified 3 months ago

#1411 assigned request

Screen sharing not working in gendispatch

Reported by: fluffy@… Owned by: alex@…
Priority: tbd Milestone: ietf-108
Component: incoming Keywords:
Cc: My Current Location:
My MAC Address: My OS:


The screen updates are not working for people in gendispatch - basically parts of screen are not updating so we can’t see stuff. Waiting a bit does not fix it. Example attached

Added by email2trac

Attachments (1)

Screen Shot 2020-07-30 at 7.30.44 AM.png (2.4 MB) - added by fluffy@… 3 months ago.
Added by email2trac

Change history (3)

Changed 3 months ago by fluffy@…

Added by email2trac

comment:1 Changed 3 months ago by Rick Alfvin

Owner: changed from < default > to alex@…
Status: newassigned

comment:2 Changed 3 months ago by alex@…

From what I've gathered on the Jabber room, this should now be fixed, correct?

It's not clear from the screenshot which browser the participant/chair was using to share the stream. It may be Safari, from the menu I see: in that case, Safari is known to only allow you to share the whole screen, and not a specific application. Not sure what happens when there are actually multiple screens connected, though: e.g., if you have a PDF viewer or Keynote on screen #1, and share screen #1, going fullscreen may move the application to screen #2, which would then be (partly?) unavailable to the browser for capturing. The same kind of issue can sometimes happen when sharing a single application from browsers that support it (Chrome, Firefox): also in that case, sharing a single application would instruct the browser abount boundaries on what to capture, and so moving the application around (e.g., to a separate screen) or putting it fullscreen (on the same screen or not) may cause similar issues if the screencapturing utilities the browser makes use of are impacted by the action.

At any rate, our only involvement in the process is invoking getDisplayMedia() from the JavaScript? application: this then shows a browser specific dialog to pick an app/screen/tab (each browser does it differently), and eventually we get access to a MediaStream? instance we can use in the PeerConnection?. As such, the broken video is what the browser itself is capturing, and so there may be different causes for that, possibly system-specific. Our suggestion would be to either share a single screen and ensure the content is always confined there, or share a single application and not move it from the screen where it is.

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