Screen share not working properly within SEB with Sonoma 14.5

[hlo250]

Discussed in #413

^{Originally posted by hlo250 June 6, 2024}
Ever since 14.5 was released, we've been having issues with sharing the screen properly within SEB.

When i click on share this screen, the screen that is shared is not the Safe Exam Browser screen, instead it shares my desktop. The only way to fix it, is to click on the presenter overlay "small" option and then turning it off, and then it finally shows the SEB.

Tested on previous versions of Sonoma and screensharing doesn't have any issues. Anyone have any ideas?

[danschlet]

What platform/software are you using for screen sharing?
In general, SEB blocks screen sharing (depending on its settings more or less strictly).
You might need to change settings in the Security pane in SEB settings which you're using for your exam: Allow screen capture/recording, Allow window capture (screen shots) and enable Block screen shots (Legacy). Also some process might be terminated by SEB which is responsible for screen sharing in your platform (you would find that in SEB's log files)

[hlo250]

@danschlet Using webrtc getdisplaymedia to share the screen. If we enable those settings, it allows screenshotting and recording, which we currently do not allow.

[rubenarturogarcia]

@danschlet this started to happen recently with Sonoma 14.5. We tested this with several screensharing applications (Meet, Teams) that use browser-based screensharing and it always shares the wallpaper / desktop as the image above. It seems that it is related to the new presenter overlay in 14.5? Does block Screenshotting work? It seems to allow screenshotting even when enabled.

[bhardwaj-manish]

We are facing a similar issue with SEB on macOS 14.5. When the screen is recorded using the Screen Capture API with the getDisplayMedia() method, SEB's screen is not recorded, only the desktop screen is recorded. However, mouse movements are visible. When we tried the screen recording on macOS 12.7.5, it worked fine.

After investigation, We found that the newer macOS version has added some new options in Safari to share either the whole screen or just a window, which were not present in older versions of Safari before 14.5 mac os. Since SEB also uses WebKit, this new change might be causing the issue.

Video track object returned by MediaStreamTrack: getSettings() method:

macOS v12.7.5:

{
    deviceId: "XXXXXXXXXXXXXXXXXXXXXXXXXXXX",
    frameRate: 30,
    height: 0,
    width: 0,
}

macOS v14.5:

{
    deviceId: "XXXXXXXXXXXXXXXXXXXXXXXXXXXX",
    displaySurface: "monitor",
    frameRate: 30,
    height: 0,
    width: 0,
}

As we can see above, displaySurface was not present in the video's settings in the older macOS version.

Current Solution (Not Suitable for our requirements)

By tweaking SEB configurations, We found that enabling the allowWindowCapture setting fixes the screen recording problem. This generates a possibility that this issue might be happening due to a mismatch between SEB and the new WebKit settings. It seems SEB's security settings are now stopping it from recording its own screen.

While enabling allowWindowCapture solves the screen recording issue, it also lets users take screenshots, which is not desirable for our requirements. Please let us know how we can achieve the same result without allowing our screen to be captured by users.

Device configurations in which the issue was faced:
macOS version: 14.5
SEB version: 3.3.3
Safari version: 17.5
Webkit version: 605.1.15