What Are They?
The F4V file format is an FLV MPEG-4 file Flash video file, that's been renamed to F4V. (Given .F4V extension).
The F4V format and the FLV format, are MPEG-4 video formats defined by Adobe. F4V files are containers for H.264 and MP3.
Before you can open or play an F4V format file, you must have the appropriate codecs installed. The video compression used is H.264. Audio compression is AAC or MP3.
If your media player can't open or play the file, you can download the necessary codecs to enable your media player.
Other choices are to look at VLC, the VideoLan Client, or check out mPlayer for your platform. On the windows platform, media player classic is available.
All have the necessary codecs to play F4V files.