Video is using a low resolution substream

[Dijon]

I  am running out of ideas  and need help.

My zoom video is hugely pixelated.

Using windows 10 with a network camera  supported by microsoft ONVIF driver. The camera appears in device manager as a detected camera and can be used by Zoom.

When I check the video with the Microsoft "Camera" app - everything looks perfect.

When I start zoom, it picks a substream which has a terrible quality. I don't know why and unfortunately I cant change it.

I also have the camera displaying video on a network controller, and it shows there OK all the time.

Unfortunately, my camera has a problem that even if I disable the substreams in the settings, and save the configuration, it reverts back to enabling the substreams.

My questions are:

1.  Why does zoom picks a substream why all other apps pick the main stream ?

2. How can I make zoom pick the main stream ?