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
F4V is a filename extension for Flash Video (FLV) container format. It supports H.264 (MPEG-4 AVC) video codec compression standard, which is known to offer significant compression. FLV videos come in multiple formats apart from F4V, including F4P, F4A, and F4B. Also, it opens on Adobe Flash Player 6 or later and Windows Media Player.
Windows Media Player Adobe Flash Player 6 or later Media Monkey