And... maybe I DON'T need to delay the video.

Moving from old hardware old system to new.
One of the things we do on our show is zoom call-ins. This is handled via an NDI Local capture, and zoom running on a second USB soundcard. The soundcard is it's own input on my mixer, which we then mix-minus back to the zoom user.

Overall, I have my incoming mixer on a 400ms delay to vmix- so that vocals sync up with the video. This was the delay on the old system, so I'm using it on the new one. When I have a video file as an input on vmix- I have it go through vMix bus A, which is another input on the mixer. I run everything on Bus A at a -400ms delay (so...positive...?) so that it's in sync when played through the board like that. We have to take that route, so that in-studio guests get feedback of the video sound. In the past- I've always warned guests that the in-studio audio won't appear synced up, but it's always in sync on the recording or stream.

Now with the new hardware, upgraded vmix- I'm having a new problem. I am personally seeing a fairly major delay on my preview monitors from in-studio talent. But the final recording doesn't have any delay. It's synced perfectly. Also, my incoming zoom call APPEARS to be synced on preview- but the final recording shows that the audio is delayed for that zoom guest. I'm guessing it's delayed by 400ms, as that's the delay of the board.

What I'm struggling to figure out here is, why is my preview delay so obvious now- and what am I missing about this zoom non/delay on preview, horrible delay in export. I can honestly deal with the preview screen delays, if I must... but I can't figure out why zoom wouldn't be just as delayed (and therefore, just as synced on the finished product)

As a last ditch attempt to fix this myself, I went into the NDI capture settings, advanced, and tried to set a frame delay on the input. I was going to set it to 12 frames. That SHOULD sync everything back up. But the option is greyed out.

And it's greyed out on every input I have. How do I enable this? Or is there something else I should be doing to avoid this problem all together?