Hi Koktail,
There is a limitation I have found with this implementation of preferring H.264 over H.265 streams. Some cameras that have both streams H.264 still don’t work for the main stream (possibly due to the resolution and bandwidth limitations?).
I believe it would likely be preferable to either change it, or add an additional setting, to set the preferred stream as the sub stream.
Would this be possible please?
Thank you kindly good sir 
