Good-day folks,

I trust you're all doing well and staying safe from COVID-19. So I'm running a small one-man (for now) live stream production for my church using vMix and I have been successful in getting bi-directional audio & video between vMix and Zoom using the KB Article at https://www.vmix.com/knowledgebase/article.aspx/170/adding-zoom-calls-to-vmix-with-return-video-and-audio

My congregation has a need to do Q&A Sessions during our Zoom calls and we want to have this streamed to our YouTube audience simultaneously. So while this successful integration allows the two-way video and audio, I've noticed that the minute I cut to a Side by Side input from vMix (which includes the Zoom window captured over NDI) the video in Zoom immediately goes into an infinite loop (not sure how else to describe it).

What we're

Perhaps its my lack of understanding of video technology. But I'm willing to best someone on here has run into this problem before. If so, how did you resolve it?

Yes, we are able to send the External output from the vMix PC to the Zoom PC without any issues. The problem comes when I do a PIP or 2x2 Box Layout scene where one of the inputs used is the Zoom PC's Desktop Capture over NDI (i.e., Display 1). But it doesn't happen until I spotlight the Zoom PC's video in Zoom, then the infinite loop starts happening. So basically, I could ask all meeting participants to simply put their screens in Gallery View and then individually spotlight the Zoom PC's video if they want to see the vMix production. But we're trying to limit the user input to our production staff and not have to burden our audience with this task.

My simple brain is telling me that this is happening because since the Zoom PC isn't sending over just the individual Zoom participant videos or just the Zoom Video screen like it used to, but rather the entire computer's Display, the loop is being created when that output now shows up as an image and is recaptured as part of the Display 1 transmission over NDI to the vMix PC, then sent back to the Zoom PC - and I think this is how the loop is happening.

Now to figure out how to break it. Hope I explained better?

You have two options
#1 Zoom as Master:
vMix acts as a client and just grabs whatever happens in zoom and sends it out to FB, YT whatever.
#2 Zoom as Client:
vMix acts as master and sends the output into zoom. You have to do all the switching/mixing in vmix and just feed it into zoom and social.

A mixture of both will lead to problems.

You can send any input into Zoom that you want inc NDI ... perhaps have a look at the recent video Martin posted, you might find the answers to your questions ...

I try to think of my output to Zoom from vMIx more of a studio monitor in our studio. We wouldn't send the main TX output from vMIx to our floor monitor in the studio other wise we would be seeing the same effect that you are speaking about here.

We send an independent output to the floor monitor (sometimes using the new Add Input (mix) mini M/E) that way we can control what is being seen on the floor monitor and by our PTZ camera and likewise being sent back to zoom.

The other main difference is that we are using srt as our main presenter feed to drive the zoom call, this could also be vMix Call but we find we can't seem to get more than 1.5Mbps on the stream using vMix call, not sure why .. So I guess bottom line is that we don't send the main TX back to Zoom but only what we want to send.