FLV (Flash Video) is a file format used to deliver video over the Internet.

It uses a plug-in called Macromedia Flash Player (a multimedia and application player) or another third-party program. Google Video and YouTube both use FLV formats.

FLV files can be delivered:

• Embedded in a SWF file using the Flash program
• Streamed via RTMP to the Flash Player using the Flash Media Server. This is the best option for allowing advanced seek capabilities and automatic bandwidth detection.
• Progressively downloaded via HTTP (sometimes referred to as pseudo-streaming or progressive downloading)