WindowsSDK Webinar video not visible to attendee when using CustomUI

Video elements do not render for attendees of webinar using the custom UI

Which version?

To Reproduce(If applicable)

  1. Start the demo application and enable CustomUI
  2. Choose Email Login and log in with Zoom account credentials
  3. Hit the Join button and enter a webinar ID for a webinar in progress with “No Registration Required”
  4. See that the host of the webinar is not visible in the meeting window
  5. Click the button for the thumbnail tab and see that the thumbnails are entirely blank

Device (please complete the following information):

  • Device Spec: PC
  • OS: Windows 10

Additional context
I’m building a custom ui for webinars on Windows

Using the sample app with CustomUI turned on, after joining an attendee can’t see the host or any panelists. The thumbnails section is blank.

If an attendee is promoted to a panelist the video renders correctly.

It looks like someone had the same problem with the mac SDK here:

But it looks like there’s been no movement on that yet but I wanted to log that the windows SDK seems to have the same issue.

Thanks for your help!

Hey @wcarle,

Thank you for using the dev forum!

I am sorry this issue is happening. That is strange that the user can only see the video stream after being promoted to a panelist.

Can you upgrade to the latest version of the SDK, and see if you are still experiencing the same behavior? Version 5.4.54524.1229

Note, the current version of the SDK and future versions of the SDK will be available on Zoom Marketplace instead of github.
To download the latest version, sign in to Zoom Marketplace. Navigate to “Build App” -> “SDK” -> “Download” -> “Windows”.


@Michael_Condon Thanks for the response, I was finally able to get around to upgrading to the latest SDK and am still seeing the problem. Attendees of webinars are only able to see the “active speaker” window and not any of the other participants when using the custom UI feature of the windows SDK.
It looks like there has been a similar ongoing discussion in the Mac SDK forum as well and it seems like it is still a known bug there as well: Webinar host and panelists not visible to attendee when using CustomUI - #5 by jon.lieblich

Hey @wcarle,

Yes, there has been lots of discussion around this. There are two things related to this. First, it is actually intended behavior that a participant-level user cannot access the other participant’s information in the meeting. This means that there is no way for a participant to render another participant’s video stream in a webinar using the SDK. A participant can only view the active speaker. This is not a bug, although I understand that this is not very convenient for the developer and user alike.

The second thing, is that in the past there has been a bug where not even the active speaker’s video could be rendered. If that is happening, that is indeed a bug.


Hey @Michael_Condon

We are having a similar situation where our Host is logging in, joining the webinar, and utilizing the Custom UI. When we promote attendees to speak, they no longer see the Host Video. We need them to see the Host Video while they are speaking. I noticed there is a Host setting in the regular zoom client that sets the attendee video layout… Is this available through the SDK?
(See Picture’s bottom right corner).


Hey @apdevuser,

This sounds like a bug, would you be able to share your code for handling this so we can investigate further?

This is not currently available for custom UI in the SDK.


I should have been a bit more clear. The attendees are using the regular Zoom Client and when they are allowed to speak, they are seeing the Active Speaker View. We need them to always be in the Gallery View so that the host video is always visible. How can this be achieved? (Our host user is controlling the meeting with a custom UI)

Hey @apdevuser,

Are they using the Zoom Windows SDK or the Zoom Windows application?


The host is using the Zoom Windows SDK and the Attendees/Panelists are using any one of your Zoom Applications: Windows, Mac, Android, IOS etc…

Hey @apdevuser,

I see, thank you for responding. I do not believe we have an interface for this in the SDK, but I am confirming with the engineers. If there is indeed no interface for this, I will submit a feature request for this.


Sounds great thank you very much!

1 Like

You are welcome :slight_smile: