Try ni ug install boss sa imong laptop na CODEC.
CCCP - Combined Community Codec Pack
Pili lang 32bit/64bit platform depende sa imong OS gigamit.
OR if di mag work
Best other solution, sayon ra kaayo. I convert imong movie nga MKV to AVI using free decoder Handbrake.
https://handbrake.fr/
@TS: Your laptop should be capable of playing HD videos at high settings using HDMI smoothly. I suspected its the video player is the problem. Try lang sa 2 solution ako gi hatag and I hope it helps.