For Mkv Video On Linux Mint Link !free!: Install Hevc Codec

To play HEVC (H.265) encoded MKV videos on Linux Mint, you can install a comprehensive package of multimedia codecs or use a media player that includes them by default. Method 1: Install Multimedia Codecs (Recommended)

sudo add-apt-repository universe
sudo add-apt-repository multiverse
sudo apt update

sudo apt install ubuntu-restricted-extras -y

Step 2: Install the HEVC Codec Package