MPEG-2

MPEG-2 (1994) is the designation for a group of audio and video coding standards agreed upon by MPEG (Motion Pictures Coding Experts Group). MPEG-2 is typically used to encode audio and video for broadcast signals, including [digital satellite]? and Cable? TV. MPEG-2 is also the coding format used by standard commercial DVD movies.

MPEG-2 is similar to MPEG-1, but also provides support for interlaced? video (the format used by broadcast TV systems.) MPEG-2 video is not optimized for low bit-rates (less than 1Mbps), but outperforms MPEG-1 at 3 Mbps and above. With some enhancements, MPEG-2 is also the current standard for HDTV transmission. A standards-compliant MPEG-2 decoder should be capable of playing back MPEG-1 streams.

MPEG-2 audio is a multi-channel extension of MPEG-1 audio (Layer 3, or MP3). MPEG-2 supports various audio formats, including MPEG-2 AAC?.

MPEG-2 consists of several standards (termed "Layers"), as follows:

Layer 1: Describes synchronization and multiplexing of video and audio.
Layer 2: Compression codec for interlaced and non-interlaced video signals.
Layer 3: Compression codec for perceptual coding of audio signals. A multichannel-enabled extension of MP3.
Layer 4: Describes procedures for testing compliance.
Layer 5: Describes systems for Software simulation.
Layer 6: Describes extensions for DSM-CC (Digital Storage Media Command and Control.)
Layer 7: Advanced Audio Coding (AAC?)
Layer 9: Extension for real time interfaces.
Layer 10: Conformance extensions for DSM-CC.