MPEG-2: The Codec Standard That Defined DVDs and Digital Television

MPEG-2 is a suite of digital video and audio compression standards developed by the Moving Picture Experts Group, ratified jointly by the ITU-T (as H.222/H.262) and ISO/IEC in 1995–1996. It defines both a video coding algorithm and a systems layer for multiplexing encoded audio, video, and metadata into transport streams. ## Video Coding MPEG-2 video uses DCT-based inter-frame coding with I-frames (independently coded), P-frames (predicted from prior frames), and B-frames (bidirectionally interpolated). It extended MPEG-1 to handle interlaced content and a wider range of resolutions and bitrates, making it the first codec suitable for broadcast-quality video. ## Where It Was Used - **DVD-Video**: Standardized on MPEG-2 video, making it the defining codec of the optical disc era. - **Digital broadcast television**: DVB (Europe), ATSC (North America), and ISDB (Japan) all adopted MPEG-2 transport streams as the underlying multiplex format. - **Blu-ray**: Uses MPEG-2 transport streams as its container even when the enclosed video is H.264 (AVC): The Video Codec That Enabled YouTube and Modern Streaming or VC-1 — MPEG-2 as infrastructure layer, not video codec. ## Succession H.264 (AVC): The Video Codec That Enabled YouTube and Modern Streaming (2003) superseded MPEG-2 for most new applications, offering roughly 2× the compression efficiency at equivalent quality. H.265 (HEVC): The Technically Superior Codec Killed by Patent Licensing and later AV1: The Royalty-Free Codec That Won the Web pushed further. However, backward compatibility with installed hardware has kept MPEG-2 alive in over-the-air digital TV broadcasting in many countries, and DVD-Video remains MPEG-2 by specification. MPEG-2's enduring legacy is less as a codec and more as a transport layer — its 188-byte fixed-size packet structure underpins broadcast infrastructure worldwide, a format that has outlived the video compression it was designed to carry.