MPEG2

MPEG-2 is a standard for the compression of moving images and audio for digital television, DVDs, and other media. It is part of the Moving Picture Experts Group (MPEG) family and is defined as ISO/IEC 13818. First published in the mid-1990s, MPEG-2 was designed to provide higher quality video than MPEG-1 and to accommodate interlaced video and broadcast requirements.

Technically, MPEG-2 video uses block-based transform coding with discrete cosine transform, motion compensation, and the use of predictive frames (I, P, B). It allows several profiles, notably Simple, Main, and High, and several levels that cap resolution and bitrate. It supports both standard-definition and high-definition formats, as well as interlaced or progressive scanning. The standard supports variable bitrate encoding and can carry optional scalability features such as SNR and Spatial scalability.

The MPEG-2 specification also defines system encoding, including program streams for storage and transport streams for broadcast. A Program Stream is for stored content, while a Transport Stream is designed for error-prone networks like broadcasting. MPEG-2 video became the default video format on DVDs and is widely used in digital terrestrial television (DVB), satellite and cable TV (ATSC, DVB).

Audio in MPEG-2 is defined in Part 3 and includes various audio coding formats used in conjunction with MPEG-2 video in streams; later amendments and related standards added advanced audio coding such as AAC in related MPEG releases. The combined video–audio streams enable synchronized playback in broadcast and storage contexts.

Although many markets have shifted to more recent codecs like H.264/AVC and H.265/HEVC, MPEG-2 remains in use for legacy broadcasts, DVDs, certain streaming services, and standard-definition content due to widespread hardware support and existing infrastructure.