While Harmy’s MKVs are often known to push unexpected limits and challenge playback methods that generally seem otherwise capable, it would help greatly for us to first make sure what files you are actually working with. With Star Wars, for instance, did you get it from less controllable public sources like piratebay or our normal sources like the spleen or TP? Is it a 17GB+ sized MKV and is it called v2.5 or v2.7?

When you say you access your networked drive, are you doing so via DLNA, SMB, NFS, etc.? Does the computer access the networked drive in a different listed protocol than the TV/PS4 does? What model TV?

Would you happen to be capable of burning to a Blu-ray disc or connecting a computer straight to your TV (and A/V equipment)? Do you have a Roku, FireTV, Chromecast, etc.?

Anyway, just give us as many specifics like that about your situation as you can, so we can better know how to help you.