Trying to use vMix to build a stream to feed to Zoom, I can create the external virtual camera stream, which Zoom can get, but the image in Zoom comes out upside down. Trying to produce a stream from multiple NDI cameras and a USB3 digitizer from the video from another PC.

When I do the same thing in OBS, it works and the image is right side up, so it seems to be a vMix issue, but I can't see any place to tell vMix to do this.

When streaming directly from vMix to Facebook and/or YouTube, everything works out fine, so it doesn't seem to be an input issue, just something with generating the virtual camera output.

Any suggestions on what the issue could be?