I ran the AMD cleanup utility to remove all the AMD video and sound stuff.
Let "windows update" install an old AMD driver, it picked one from 2022 that has no adrenaline control system
Driver Date 2/08/22 (in Australia that would be 2nd August, and different in the USA...)
Driver Version 31.0.12020.1
whatever the version means.
AMD High Definition Audio Device was missing.
Checked optional updates, and ther was an AMD audio package of some sort.
Installed that and suddenly we now have an AMD High Definition Audio Device.
Videos now working perfectly.
(have not reloaded the Jriver media Centre library yet)
After tuning all the Digital TV channels again, that is now working perfectly as well.
Hope this helps
So, to sum up, it may be that more recent AMD software is at least part of the problem.
Are we say moving away from supporting HDMI 1.4a or some such perhaps?
Why do older drivers work better than newer drivers??