Flash Video, or FLV, is a container file format used to deliver video via the Adobe Flash player. Deployed by leading video sites such as YouTube, Yahoo! Video, and many others, Flash Video is an open format which supports H.264, VP6 and Sorenson Spark formats.
MPEG video generally refers to a set of standards and methods for compressing audio and video data. The most important and widely used standards include MPEG-2, an older format currently used by over-the-air digital television providers (digital cable, satellite) and MPEG-4, which includes additional features for digital rights management and support of higher-efficiency standards used by streaming media, HD DVD and Blu-Ray. MPEG-4 supports interactivity and has the ability to crunch massive video files into pieces small enough to send over mobile networks. Within MPEG-4 standards are two very popular formats utilized for broadband video delivery: H.264 and MP4.