MPG, sometimes called MPEG, is a video file format popular for distributing content over the internet. It is the sister format to MP4 and MP3 because they share the same developer – Moving Picture Expert Group. MPG format uses either MPEG-2 or MPEG-1 compression, depending on the circumstance. Opening it is usually easy on any OS platform.
Windows Media Player, VLC Media Player Apple QuickTime Player, Cyberlink PowerDVD 17
HEVC MKV is a digital media format that uses HEVC codec, instead of the usual H.264, which is used on typical MKV files. HEVC MKV files are encoded at lower bitrates than H.264 MKV, making them smaller by up to 50%. However, software and hardware support for HEVC MKV files is quite limited as opposed to H.264 MKV, which ranks among the most popular media formats today.
VLC Media Player
MKV File Player