QCamera video fails with Snap Camera

Given the new prevalence of video conferencing, and the strong desire to add some whimsy back into our lives, "Snap Camera" is relatively more important than it might otherwise have been. I feel it is rather important that Qt works well with it.

1. on macOS (tested on Mojave)
2. with "Snap Camera" installed, and a filter turned on
3. open example project "Camera Example" (widgets, not QML)
4. build and run
5. "image" version works okay
6. click "Video" tab
7. <--- black or garbage video
8. click "image" tab
9. <--- crash / hang
10. the console ("Application Output" in Qt Creator) is continuously being filled with information of dubious usefulness. seems to me that Qt libraries should not be using the console at all, even in debug mode, leave that for user apps?