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 on sites like YouTube, Metacafe, and more. It supports MPEG-4 Part 10 (H.264) video codec and AAC sound.
RealPlayer, Apple QuicTime Player MPLayer VLC Media Player
Xvid is a cross-platform video codec for compressing video files. It can compress a video file at a more than 200:1 ratio. This, in return, makes it easier and quicker to transmit video files over the internet. Also, compressed videos take up less storage space. It compresses data using the MPEG-4 standard.
Roxio Toast 18 Eltima Elmedia Player Windows Media Player (Xvid codec) Apple QuickTime Player (Xvid codec)