I also think it would be interesting to test this. At some point the tracking and the video background could also come from two different cameras, so it might be interesting to have an API to specify the display resolution vs the tracking resolution in different ways.

Not sure what happens under the hood when we call `CameraDevice.selectVideoMode()` and `Renderer.setVideoBackgroundConfig()` with different resolutions.

The problem is that the downscale-before-tracking is probably going to require an interpolation on the CPU-side so it might lower the perfs.