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VDM Screen Sharing Enhancements

Download of the corresponding VDMShare.exe is now part of VDM installation, which is available here.


Computer screen sharing is very pervasive and available via popular applications such as Microsoft Teams, Zoom, WebEx, GoToMeeting, just to name a few. While each solution appears to rely on similar built-in capabilities of the underlying operating system, they can be quite different in their implementations. In the past, any change to the underlying code caused a domino affect on our side, to keep up with the update. With this preview, we are getting closer to a “generic” solution that can enhance screen sharing with virtual display capabilities, while not prone to compatibility issued with future updates.

About screen sharing

Screen sharing solutions do have many features. Sharing options are likely to include the following:

  • Full monitor sharing, often called “screen sharing”.
  • Full desktop sharing.
  • Individual application window sharing.

Monitor and Desktop sharing is straightforward – anything that intersects with shared screen, is displayed to the audience, making multi-window demonstrations easy. The downsides of screen sharing are usually related to:

  • Screen formfactor.
  • Monitor resolution.
  • Available monitor real-estate outside the presentation screen.

Application window sharing usually does not allow any other window’s visual representation, at least not windows from other applications, to be transmitted making it safe from unwanted interferences. This option has it’s own challenges:

  • Can be quite cumbersome, as interruption of screen sharing is usually required to switch to another window.
  • Unintended closing of a shared window can interrupt the sharing process.
  • Not all windows can be shared.

Addition of Virtual Displays as a sharing option

In the past, Virtual Display Manager targeted screen sharing that was not to be distinguished from sharing physical monitors. While early on we were successful with some applications, GoToMeeting for example, support for Microsoft Teams and Zoom had challenges between corresponding version updates for these applications. By introducing “Display sharing”, which stands in-between monitor and application sharing, we did achieve improvements to the above challenges for both common screen sharing techniques.

In essence, when Virtual Display sharing is enabled, these displays appear as Display #1, Display #2, etc. within the sharing selector under Microsoft Teams and Zoom. A few notable benefits of this approach are:

  • Switching between these virtual displays can be accomplished in one step, thus preventing dropped sessions.
  • Presenters can use a portion of high-resolution screen without inconveniencing the audience by broadcasting high resolution content to low resolution monitors.
  • Presenter can take full advantage of available monitor’s real-estate, pre-staging different parts of the presentation on virtual displays and easily switching between them during the presentation.
  • Virtual displays act as shared screens, so they do show all windows overlapping that area, even the windows that are not visible within the sharing selector and thus could not be shared individually.
PIC.1 Preparing to share a single virtual display. Switching to another virtual display does not interrupt the sharing session. Best when consecutive sharing of several virtual displays is desired.
PIC.2. Enabling all virtual displays for sharing. Best when built-in selector from screen sharing application is used to start or stop the sharing process.
PIC.3. Virtual display sharing via Microsoft Teams. Notice the characteristic red boarder around the shared area.
PIC.4. Switching to virtual Display #4 momentarily moving the red border to the correct quadrant without interruption of sharing session.
PIC.5. Example of Display #4 selection via Microsoft Teams.

Things to consider for best experience

  • When using multiple monitors be aware that some screen sharing applications (noted first with Microsoft Teams) are sensitive to monitors powered by different graphics adapters, causing “black window” appearance once virtual display is switched to another virtual display covering screen from another graphics card. Re-sharing of the desired virtual display should fix the issue.
  • Some applications (Zoom specifically) will pause screen sharing when switched between virtual displays placed on different physical monitors – resume sharing to continue.
  • Virtual displays work flawlessly with fast changing content including video and animated presentations like Microsoft PowerPoint. Depending on the screen sharing application, window dragging across virtual display is not transmitted until the dragging process is over. This is not dependent on Virtual Display Manager.
  • Some applications that are screenshot protected and are either to be invisible to screen sharing or present themselves as “black windows“. This is a normal behavior and is independent from Virtual Display Manager.

Downloads and Installation

With current VDM 3.x release it is overed as a standalone application VDMShare.exe, included with VDM installation. The upcoming VDM 4.x is expected to have this feature integrated within the main VDM module.

  • Needs no installation, though it is reliant on Microsoft .Net Framework 4.5.2 or higher, which is available with most modern Microsoft Windows systems.
  • Requires current Virtual Display Manager installed and running. Version discrepancies to be self-diagnosed and user alerted about this requirement.
  • Will automatically sense changes to physical monitors or to Virtual Display Manager configuration, adjusting to current virtual display settings. Screen sharing is expected to adjust accordingly without dropping the sharing session.
  • Final version is expected to be integrated into Virtual Display Manager as a menu option.

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