AC3 is a sound file format. Its name is the abbreviation for Audio Codec 3. The format was developed by Dolby Laboratories, Inc as a modern and efficient sound compression technology. AC3 files feature Dolby Digital multi-channel surround sound. In this regard, they are widely distributed as a format for DVDs, movie theaters and game consoles. However, you can evaluate all the advantages of such files only if you have the appropriate acoustics for surround sound. An audio file of the specified format can include up to six sound channels, which creates a presence effect for the listener.
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.