Bug 259823

Summary: Calling getDisplayMedia() the first time results in an error.
Product: WebKit Reporter: mawojtcz
Component: WebRTCAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Major CC: eric.carlson, jer.noble, js-webkit, mkrens, saghul, webkit-bug-importer, youennf
Priority: P2 Keywords: InRadar
Version: Safari 16   
Hardware: Unspecified   
OS: macOS 13   
Attachments:
Description Flags
repeated requests to navigator.mediaDevices.getDisplayMedia always results in error none

Description mawojtcz 2023-08-04 03:59:34 PDT 
When we call getDisplayMedia() the user sees the UI to allow screen or window sharing, user chooses screen sharing and then getDisplayMedia() rejects with the error:
"The request is not allowed by the user agent or the platform in the current context, possibly because the user denied permission."
After that, if we call the same API again, it works fine. If the user then closes Safari and starts it again, he/she will get the error again.

Here is a simple js fiddle for reproducing the issue:
https://jsfiddle.net/bazyl/zvfuh1n0/

steps:
1. run the js fiddle in Safari
2. press the "start screen share button"
3. you will see the safari UI to allow screen or window sharing, choose screen
4. at this point you should see a "SUCCESS" string beneath the button, but instead you will see "ERROR" and errors in the console
5. pressing the button again works fine - this time you get "SUCCESS"

This issue is not 100% reproducible, some users can't reproduce it at all, some others see it very often (about 50% of the time)

Also, it usually take a long time for getDisplayMedia() to resolve with the error (up to 1 minute).


This has been tested and seen on the following Safari versions on macOS:
Version 16.5.1 (18615.2.9.11.7)
Version 16.6 (18615.3.12.11.2)
Version 17.0 (19616.1.17.11.4)

This is affecting the webex web app (from web.webex.com)
Comment 1 Radar WebKit Bug Importer 2023-08-04 14:25:39 PDT 
<rdar://problem/113413459>
Comment 2 Eric Carlson 2023-08-04 14:28:33 PDT 
(In reply to mawojtcz from comment #0)
> Also, it usually take a long time for getDisplayMedia() to resolve with the
> error (up to 1 minute).

WebKit sets a 60 second watchdog timer when the system prompt is shown, so this suggests that ScreenCaptureKit.framework isn't calling WebKit's delegate after the user chooses a screen or window (see https://github.com/WebKit/WebKit/blob/main/Source/WebCore/platform/mediastream/mac/ScreenCaptureKitSharingSessionManager.mm#L380).

It would be extremely helpful for us to examine a sysdiagnose taken after such a failure. If it is possible to get one, please send it directly to me at eric.carlson@apple.com.
Comment 3 Michael 2023-10-01 14:46:11 PDT 
In my case I never get a prompt to share the screen and can consistently reproduce this.

navigator.mediaDevices.getDisplayMedia({
    video: true,
    audio: true,
  })

always results in: NotAllowedError: The request is not allowed by the user agent or the platform in the current context, possibly because the user denied permission.

Simple fiddle example: https://jsfiddle.net/9uLcgb0d/

This also does not work for example: https://www.webrtc-experiment.com/RecordRTC/

I've submitted Feedback + sysdiagnose under: FB13222093

Please let me know if I can help.

Version 17.0 (17616.1.27.111.22, 17616)
Comment 4 Michael 2023-10-01 14:49:36 PDT 
Created attachment 468007 [details]
repeated requests to navigator.mediaDevices.getDisplayMedia always results in error
Comment 5 mawojtcz 2023-10-03 03:53:23 PDT 
Hello, any update on this, please? We have sent sysdiagnose files over email to Eric as requested on Aug 23rd and also a screen recording with another sysdiagnose on Aug 30th and then resent them again on Sept 19th.
Comment 6 saghul 2023-10-09 06:04:40 PDT 
I can reproduce this 100% in macOS Monterrey with Safari 17. Not so on Sonoma.
Comment 7 Jacek Stypuła 2023-12-02 06:32:40 PST 
I have the same problem as Michael all the time, see https://bugs.webkit.org/show_bug.cgi?id=259823#c3 and https://bug-259823-attachments.webkit.org/attachment.cgi?id=468007.

Screen capturing does not work in any web app.

My system version is macOS 12.7.1 (21G920).
My Safari version is 17.1.2 (17616.2.9.11.12, 17616).