An overview of audio and video compression

MPEG-1 and MPEG-2, developed by the Moving Pictures Expert Group (MPEG) within the International Organization for Standardization, were the first international standards in the field of high-quality digital audio compression. MPEG-1 includes coding of stereophonic audio signals at high sampling rates aiming at transparent quality, whereas MPEG-2 also offers stereophonic audio coding at lower sampling rates. In addition, MPEG-2 introduces multichannel coding, with and without backwards compatibility to MPEG-1, to provide an improved acoustic image for audio-only applications and for enhanced television and video-conferencing systems. MPEG-2 audio coding without backwards compatibility, called MPEG-2 advanced audio coding (AAC), offers the highest compression rates. Typical application areas for MPEGbased digital audio are in the fields of audio production, program distribution and exchange, digital sound broadcasting, digital storage, and various multimedia applications.

Video compression is the process of converting digital video into a format that takes up less storage space or transmission bandwidth. Video compression (or video coding) is an essential technology for applications such as digital television (terrestrial, cable or satellite transmission), optical storage/reproduction, mobile television, video-conferencing, and Internet video streaming. Video compression standards make it possible for products from different manufacturers (e.g. encoders, decoders, and storage media) to interoperate. Anencoder converts video into a compressed format and a decoder converts compressed video back into an uncompressed format.

Recommendation H.264: Advanced Video Coding is a document published by the international standards bodies International Telecommunications Union–Telecommunication Standardization Sector (ITU-T) and International Organization for Standardization/International Electrotechnical Commission (ISO/IEC).