UDP-x700 wont play MkV Atmos

[mow955]

The vast majority of lossless Atmos demos from https://thedigitaltheater.com/dolby-trailers/ are in the mkv format. 
I have no luck in getting my UBP-x700 player to play these from my hdd. I can play mkv separately , I can play Atmos separately, but not combined from a single mkv file. 

It’s been over a year since a firmware update was released, so I guess we won’t be getting any more. 
Has anyone got any help on this subject

[Marino.Manolo]

If you want to try...

The HD Audio (Dolby Digital Plus, Dolby TrueHD, DTS-HD High Resolution Audio, DTS-HD Master Audio, Dolby Atmos and DTS:X) is not output by bitstream. • Set [BD Secondary Audio] in [Audio Settings] to [Off] (page 21).

https://www.sony.com/electronics/support/res/manuals/4698/6014f2c77e20f44605ea8821bf88a55b/46984071M...

[mow955]

Have you managed to play stated files over usb? Or is it just a suggestion, rather than an answer?

I have set  up my system as stated in the manual, and every other conceivable variation.

This still gives me an unsupported audio format. 

[Marino.Manolo]

Only a suggestion...

[mow955]

Thanks. 
It’s unfortunate that there doesn’t seem to be any information on this. 
Would anyone have any knowledge of converting mkv to m2ts?

The x700 can play m2ts files with Atmos, but I cannot find a way to extract the audio from the mkv file, and then remux it back into a m2ts file.

I’m starting to wish I hadn’t bought this box