Moving Picture Experts Group. This is a working group of ISO/IEC for the development of international standards for compression, decompression, processing, and coded representation of moving pictures, audio and their combination. It has also extended into metadata. Four MPEG standards were originally planned but the accommodation of HDTV within MPEG-2 has meant that MPEG-3 is now redundant. MPEG-4 is very broad and extends into multimedia applications. MPEG-7 is about metadata and MPEG-21 describes a ‘big picture’ multimedia framework.