One thing I'll throw out from a conversation I had with the previous RMP developer (he has since retired) is that RMP is only a graphical front end, and the actual playback is all controlled under the OS itself. When the OS developers change (break) something, the RMP developer is stuck waiting for the OS developers to make the changes. It seems to me the OS developers don't give much of a hoot about local playback, so it doesn't get much priority. It's the primary reason I now use an Nvidia Shield for the vast majority of my local playback, as it plays everything without transcoding and with a Gigabit Ethernet connection doesn't have any issues with my UHD rips. I still use Roku for most of my other online streaming, in particular HBO Max, which HBO can't seem to make work well on most platforms.
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