FLV (Flash Video) is a video container format developed by Adobe Systems and comes with a .flv filename format. FLV is primarily used to stream audio, video, and text data such as subtitles. It supports MPEG-4 Part 10 (H.264) video codec and AAC sound.
RealPlayer, Apple QuicTime Player
VLC Media Player
Although not a format itself, Facebook has some technical requirements regarding the type of audio/video format it supports. While most file formats are supported, it’s best to use either MP4 or MOV. Also, the video compression codec should be in H.264 with AAC sound compression at 128kbps+. You can convert any video file type to Facebook using programs such as Wondershare UniConverter, VLC Media Player, Aiseesoft Video Converter Ultimate, and more.
VLC Media Player Windows Media Player Apple QuickTime Player 5KPlayer