F4V is a digital video file format developed by Adobe Systems, which is based on the ISO base media file format. It is a container format that is used to store video and audio data, along with metadata and other information about the video file. F4V files use the H.264 video codec and the AAC audio codec to compress video and audio data, respectively. This allows for high-quality video playback with relatively small file sizes, making it well-suited for online video streaming. The F4V format is similar to the FLV (Flash Video) format, which is also developed by Adobe Systems. However, F4V provides improved support for high-definition video and includes features such as support for AAC audio, which provides higher quality sound than the MP3 audio used in FLV files. F4V files can be played back on a variety of media players, including Adobe Flash Player, VLC, and QuickTime, and can also be converted to other more widely supported video formats like MP4 or AVI using compatible media conversion software. Overall, F4V is a versatile and widely used video file format that provides high-quality video playback and is well-suited for online video streaming and distribution.