File type: Flash Video
The FLV file extension is employed in identifying Flash Video files. Flash Video Exporter plug-in or other applications with support for the FLV format exports it. The FLV file extension is comprised of an interleaved audio, short header, metadata packets and video.
The video and audio data is then contained in a format that is similar to the standard SWF format of Flash. The FLV format is described to be an open format supported application not under Macromedia or Adobe. It is possible to export the FLV files from QuickTime Pro or from a number of other programs capable of exporting to the file format of QuickTime. The .FLV identifies the video files with Flash compatibility.
This video file had originally been supported and developed by Macromedia which has since been acquired by Adobe Systems.
The said is presently supported by other companies also and has gained popularity because it is used by YouTube in their videos.