Hello GraffitiDecos
On a P7 MKV file you can take the EL/RPU HEVC 2nd layer, drop the EL (MEL or FEL) and convert the RPU from p7 to p8, and inject that new RPU file into the main HEVC HDR10 stream.. then remux that edited HEVC stream into a new MP4 with a Roku compatible audio file (EAC3 DD+ or AC3 DD). The Roku OS can play that directly... hypothetically.
I ended up buying a Dennon AV device, some speakers, and a Shield Pro. So, now I can play MKV files with DV and lossless audio.
Check out the scripts posted by quietvoid here: https://forum.doom9.org/showthread.php?t=183479
Good luck,
