FLV is a video file format developed by Adobe Systems. The name is an abbreviation of the full name Flash Video File. FLV format video files are Flash-compatible and usually contain various metadata (titles, audio, video, etc.). FLV-files are widely spread on the global network, in this format they make streaming video for YouTube, MySpace and other video hosting sites. Compared with similar formats, video files have a higher compression ratio. FLV files are easily converted to more common video formats.
F4V is a well-known flash video format developed by Adobe System. It is supported by Adobe Flash Player. Currently, approximately 80% of online videos are transmitted using Adobe Flash technology. Files with the F4V extension are called a container format. The F4V format, in comparison with other files of the FLV category, uses boxes to store information. In addition to devices with an operating system from Apple, these files can play almost all browsers that support flash video playback. F4V files resemble .FLV files, but use “blocks” to store data. Examples of blocks that are supported by the F4V format include meta block (metadata), moov block (file header), ftyp block (requested player tools), uda block (user data in free form), etc. The format container, in the development of which the ISO Media File Format was used, initially used the Quick Time Container Format from Apple. Compared to the old FLV format, the F4V format is fully compatible with the h.264 and ACC formats. This provides an opportunity to use other container formats.