FLV (Flash Video) is a file format used to deliver video over the Internet using Adobe Flash Player (also called Macromedia Flash Player) version 6, 7, 8, or 9. FLV content may also be embedded within SWF files. Notable users of the FLV format include Google Video, Reuters.com, YouTube and MySpace. Flash Video is viewable on most operating systems, via the widely available Macromedia Flash Player and web browser plug-in, or one of several third-party programs such as Media Player Classic (with the ffdshow codec installed), MPlayer, or VLC media player.

Delivery options
FLV files can be delivered in several different ways:

• Embedded in a SWF file using the Flash authoring tool (supported in Flash Player 6 and later)
  
• Streamed via RTMP to the Flash Player using the Flash Media Server (formerly called Flash Communication Server) , VCS ( Video Communication Server from Onlinelib VCS or the open source Red5 server
  
• Streamed via HTTP (supported in Flash Player 8 and later) by StroboScope, a crossover between progressive download and streaming, allowing random access in VOD FLV files while not requiring expensive servers and not requiring the commonly blocked RTMP ports.
  
• Progressively downloaded via HTTP (supported in Flash Player 7 and later.), very basic way of delivery (limited to playback of FLV files)
  
• Provided as a .FLV format flash file, for playback from local disk