Sustainability of Digital Formats
 Planning for Library of Congress Collections

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Identification and description

Full name	Information technology -- Generic coding of moving pictures and associated audio information (formal name)MPEG-2, 4:2:2 Profile
Description	Permits the use of Intra-coded (I) frames, predicted (P) frames, and bidirectionally predicted (B) frames. The ISO/IEC specifications establish a conformance point for this bitstream at Main Level, with a broadcast-stream picture size of 720x576 pixels (non-square pixels), color sampling of 4:2:2, and a maximum data rate of 50 Mb/s. A separate SMPTE specification establishes High Level conformance, with a maximum picture size of 1920x1080, color sampling of 4:2:2, and a maximum data rate of 300 Mb/s.
Production phase	Generally a middle state (broadcast production) format; may be used as a final-state (end-user delivery) format.
Relationship to other formats
Subtype of	MPEG-2,
Used by	MPEG-2_422_layer_2, MPEG-2 422 Profile, with Layer II Audio Encoding

Local use

LC experience or existing holdings	See MPEG-2_family
LC preference	See MPEG-2_family

Sustainability factors

Disclosure	Open standard. Developed by ISO technical program JTC 1/SC 29 (WG11), aka the Motion Pictures Expert Group (MPEG), Coding of audio, picture, multimedia and hypermedia information. Supplementary specification from the Society of Motion Picture and Television Engineers (SMPTE).
Documentation	ISO/IEC 13818-2:2000. Information technology -- Generic coding of moving pictures and associated audio information: Video. For a complete list of the ISO/IEC MPEG-2 specifications, see MPEG-2. SMPTE 308M-1998. SMPTE Standard for Television -- MPEG-2 4:2:2 Profile at High Level.
Adoption	MPEG-2-422 (4:2:2 Profile) is used by broadcasters and cablecasters who seek richer color information than MPEG-2_MP (Main Profile), especially for footage that may be edited or repurposed.
Licensing and patents	See MPEG-2.
Transparency	See MPEG-2.
Self-documentation	See MPEG-2.
External dependencies	See MPEG-2.
Technical protection considerations	See MPEG-2.

Quality and functionality factors

Moving Image
Normal rendering	Good support.
Clarity (high image resolution)	See MPEG-2. At a given picture size, data rate, and encoding algorithm, MPEG-2_422 (4:2:2 Profile) will produce greater clarity than MPEG-2_MP (Main Profile) or MPEG-2_SP (Simple Profile).
Functionality beyond normal rendering	See MPEG-2.

File type signifiers

Tag	Value	Note
Filename extension	mpg, mpeg	There is no explicit MPEG-2 file format; MPEG-2 content "ready to be delivered" is exchanged in files with these extensions.
Internet Media Type	See note	See MPEG-2
Magic numbers	See note	See MPEG-2

Notes

General
History

Format specifications

• ISO/IEC 13818-2:2000. Information technology -- Generic coding of moving pictures and associated audio information: Video.
• SMPTE 308M-1998. SMPTE Standard for Television -- MPEG-2 4:2:2 Profile at High Level.
• See also MPEG-2.

Useful references