H.264 is a video compression standard used for HD videos. In fact, it’s the most widely-used video codec today. As such, this codec can be incorporated into several container formats like MP4, 3GP, MOV, FLV, and others. Most of the time, it’s encoded with the Advanced Audio Coding (AAC) codec.
Apple QuickTime Player VLC Media Player Windows Media Player Apple iTunes
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