We are using vMix and some decent audio/video equipment to feed a Worship service to Zoom for remote participants.

We are using vMix to combine two USB video sources (1-webcam, 1-PTZ HuddlecamHD) and two sound sources (L-8 Audio board and M-Audio box) All feed into a higher-end laptop with GPU. That signal is fed to Zoom for transmission into the inner-webs.

When we first set the system up, we dialed in an 80ms delay in the two audio feeds to match sound and audio. All was well.

Over the past few weeks, we began to see the delay become a moving target, the worst being today when we finally got the image and audio to sync using a 525ms delay.

In my mind, the change and very long delay is the sign of something going on internally but I don't know where to begin to look. Hardware hasn't changed. Windows10 is current. Settings are essentially the same. No plug-ins in vMix

Can someone help me to understand where the delay comes from and how to begin to troubleshoot it? Very confusing to control sound mix to internal and external members when there's a 1/2 second sound delay.

Thanks

Paul