OBS 28.1.1 Virtual Camera does not work with Webex

jondion

jondion

New Member
Hello, I have the same problem as mentioned above. Funny enough, I've been troubleshooting that for many hours as I upgraded earlier this week and then added an eGPU. So, I thought it was the eGPU while this actually my upgrade of OBS.

The issue I experience is that Webex displays a black screen/refuses to connect to the Virtual Camera at all. I don't even see the default preview when the camera isn't launched with the black and blue screen with the OBS logo. Thus I don't even need to have OBS launched to know it works or doesn't work. I've tried using the .bat file to uninstall the Virtual Cam plugin and reinstall it, but that didn't work. The only way I fixed it was to revert to 28.0.3. Then I did a few regressions like mention below.

If this helps, I did a few regressions tests the best way I can by downloading the different versions below. For each of the installs, I uninstalled OBS and selected both OBS and settings to wipe it. I also made sure that there were no obs-studio folder remaining. Then I downloaded the full installer from GitHub of the different version and installed it. After installation, I didn't even let it launch for the first time. I launched Webex to see if the blue and black default not started camera would show or not. Here are my results:
OBS-Studio-28.1.2-Full-Installer-x64 - broken
OBS-Studio-28.1.1-Full-Installer-x64 - broken
OBS-Studio-28.1-Full-Installer-x64 - broken
OBS-Studio-28.1-rc1-Full-Installer-x64 - broken
OBS-Studio-28.1-beta1-Full-Installer-x64 - works!
OBS-Studio-28.0.3-Full-Installer-x64 - works!

It seems like something changed from the 28.1-beta1 to 28.1-rc1 release that broke it. From the release logs, I see a few changes specific to Windows and virtual-cam:
  • Fixed a crash on resolution change of Windows Virtual Camera [Jim]
  • Fixed a crash related to Windows Virtual Camera [Jim]
I've tried looking at the code, but I don't have the tools to compile the virtual-cam dll to see which change broke it.

Since I don't start OBS, I can't find any logs. Unless there are logs I can get somewhere else related to virtual-cam.

Just as a test, I've also taken the obs-virtualcam-module64.pdb and obs-virtualcam-module64.dll from the 28.1-beta1 and replaced the ones from 28.1.2 to see if it would work and it does.

I'm not sure if this is of any help, but Webex says it uses Microsoft DirectShow to capture.

I've done these test on Windows 11 Enterprise 21H2 build 22000.1165 with the latest Webex.

Please let me know if I can test anything for you! I'm sorry I can't be of much help.
 
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