Sustainability of Digital Formats
 Planning for Library of Congress Collections

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Identification and description

Full name	Information technology -- Coding of audio-visual objects (formal name) MPEG-4, Visual Coding, Simple Profile
Description	See also MP4_FF_2 and MPEG-4_V. Intended to serve mobile audio-visual services and low-complexity video for the Internet; other uses include small camera devices that record to disk or memory chips.1 The Simple Profile permits the use of the following visual object type: • Simple: rectangular video, uses intra (I) and predicted (P) video object planes (VOPs, the MPEG-4 term for frames). The Simple Profile permits the use of three compression levels with bit rates from 64 kbps in Level 1 to 384 kbps in Level 3.
Production phase	Generally a final-state (end-user delivery) format.
Relationship to other formats
Subtype of	MPEG-4_V, MPEG-4, Visual Coding (Part 2)
Used by	MP4_FF_2_V, MPEG-4 File Format, V.2, with Visual Coding (All Profiles)

Local use

LC experience or existing holdings
LC preference

Sustainability factors

Disclosure	Open standard. See MP4_FF_2.
Documentation	See MP4_FF_2.
Adoption	Actual adoption not known to the compilers of this document. One indicator, however, is the specification for the video-capable iPod introduced by Apple in late 2005: MPEG-4 video up to 2.5 mbps, 480 x 480, 30 frames per sec., Simple Profile, associated with AAC_MP4_LC audio.
Licensing and patents	See MP4_FF_2.
Transparency	See MP4_FF_2.
Self-documentation	See MP4_FF_2.
External dependencies	See MP4_FF_2.
Technical protection considerations	See MP4_FF_2.

Quality and functionality factors

Moving Image
Normal rendering	Good support.
Clarity (high image resolution)	See MP4_FF_2 and MPEG-4_V. Other profiles will produce greater clarity than the Simple Profile at a given picture size, data rate, and encoding algorithm.
Functionality beyond normal rendering	See MP4_FF_2.

File type signifiers

Tag	Value	Note
Filename extension	mp4
Internet Media Type	See MP4_FF_2	**See MP4_FF_2
Magic numbers	See MP4_FF_2	**See MP4_FF_2
File type brand (ISO Base Media File Format)	See note	Indicated in file wrapper and relates to "brands" defined in ISO_BMFF. Wrapping MPEG-4_V bitstreams in MP4_FF_1 would occasion the use of mp41; in MP4_FF_2, use mp42. See Part 15 of the standard, pp. 2-9, 13.
Other	00000000, 00000001, 00000010	Profile and level indicators. For profile_and_level_indication for Simple Profile, levels 1, 2, and 3. From Annex G of ISO/IEC 14496-2:2004, pp. 454-55.

Notes

General
History

Format specifications

• See Disclosure under Sustainability factors.

Useful references