Is a media container format designed for streaming over the Internet. Used on popular video hosting sites. Video is usually stored in h.263 and h.264 formats, audio is a in MP3 or other less popular codecs. FLV-file format is a bit stream, which provides high-quality image even at low bit rates.
Is a format of audio/video data, which is the most popular today. It can contain files encoded by different codecs, but they will be played in sync and create a unified image to the end user. AVI container supports function in multi-threaded mode, and allows different ratios of audio and video codecs.