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. MPEG-2 also introduces and defines Transport Streams, which are designed to carry digital video and audio over unreliable media, and are used in broadcast applications. 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, defined in Part 3 of the standard, enhances MPEG-1's audio by allowing the coding of audio programs with more than two channels. Part 3 of the standard allows this to be done in a backwards compatible way, allowing MPEG-1 audio decoders to decode the two main stereo components of the presentation, or in a non backwards compatible way, which allows encoders to make better use of available bandwidth. MPEG-2 supports various audio formats, including MPEG-2 AAC?.
MPEG-2 consists of the following standards:
ISO/IEC 13818-1: Systems - describes synchronization and multiplexing of video and audio.
ISO/IEC 13818-2: Video - compression codec for interlaced and non-interlaced video signals.
ISO/IEC 13818-3: Audio - compression codec for perceptual coding of audio signals. A multichannel-enabled extension of MPEG-1 audio (MP3).
ISO/IEC 13818-4: Describes procedures for testing compliance.
ISO/IEC 13818-5: Describes systems for Software simulation.
ISO/IEC 13818-6: Describes extensions for DSM-CC (Digital Storage Media Command and Control.)
ISO/IEC 13818-7: Advanced Audio Coding (AAC?)
ISO/IEC 13818-9: Extension for real time interfaces.
ISO/IEC 13818-10: Conformance extensions for DSM-CC.