MP3 is a standard audio format developed by Moving Picture Experts Group and uses MPEG-1 and MPEG-2 standardizations. MP3 uses lossy data compression, meaning that it loses quality over time. This sound format comes with a .mp3 filename extension and is today the most common audio format on websites and multimedia players.
Windows Media Player iTunes, Mplayer VLC Media Player
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