How To: MKV file doesn't Play on Ubuntu

I have downloaded movie in a .mkv file format, and when I try to play it on my Ubuntu, I just can heard the sound but the movie didn't played. After a couple of minutes google it, I found a way to make it clear.
First, add this repo,

sudo apt-add-repository ppa:strukturag/libde265
sudo apt-get update 

Install the corresponding GStreamer plugin directly,

sudo apt-get install gstreamer0.10-libde265 

For GStreamer 1.0 applications,

sudo apt-get install gstreamer1.0-libde265 

There is also a VLC plugin available,

sudo apt-get install vlc-plugin-libde265 

Try it and enjoy your .mkv file. If you have any problem don't hestitate to let me know and help you.