Sustainability of Digital Formats: Planning for Library of Congress Collections

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MPEG-4, Advanced Video Coding, Main Profile

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Format Description Properties Explanation of format description terms

Identification and description Explanation of format description terms

Full name Information technology -- Coding of audio-visual objects (formal name); MPEG-4, Advanced Video Coding (part 10), Main Profile
Description Main is the middle of the three original MPEG-4_AVC profiles (Baseline, Main, and Extended) in terms of complexity and the demands it places on a decoder. The Main Profile is constrained in several ways, but may include intra (I), predicted (P), and bidirectional (B) slice types (slice is the MPEG-4_AVC term for a single macroblock or a set of macroblocks that make up a portion of an individual picture.) For a discussion of additional constraints and the levels that may be used in this profile, see Appendix A in Part 10 of the standard, pp. 204-211.
Production phase Generally a final-state (end-user delivery) format.
Relationship to other formats
    Subtype of MPEG-4_AVC, MPEG-4, Advanced Video Coding (Part 10) (H.264)
    Used by MP4_FF_2_AVC_MP, MPEG-4 File Format, V.2, with AVC, Main Profile

Local use Explanation of format description terms

LC experience or existing holdings  
LC preference  

Sustainability factors Explanation of format description terms

Disclosure Open standard. See MPEG-4_AVC.
    Documentation See MPEG-4_AVC.
Adoption See MPEG-4_AVC.
    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 Explanation of format description terms

Moving Image
Normal rendering Good support.
Clarity (high image resolution) See MPEG-4_AVC. Depends in part on the level and encoding algorithm selected. The Main Profile will produce greater clarity than the MPEG-4_AVC_BP (Baseline Profile) at a given picture size and data rate but less than the MPEG-4_AVC_EP (Extended Profile). The clarity in all three of the original profiles is surpassed by the four FRExt (Fidelity Range Extension) profiles: MPEG-4_AVC_HP, MPEG-4_AVC_H10P, MPEG-4_AVC_H422P, and MPEG-4_AVC_H444P.
Functionality beyond normal rendering See MP4_FF_2.

File type signifiers and format identifiers Explanation of format description terms

Tag Value Note
Filename extension mp4
 
Internet Media Type See related format.  See MP4_FF_2.
Magic numbers See related format.  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_AVC bitstreams in MP4_FF_1 would occasion the use of mp41; in MP4_FF_2, use mp42.
Indicator for profile, level, version, etc. 77
For profile_idc; Annex A of Part 10 of the standard, pp. 204-05.

Notes Explanation of format description terms

General  
History  

Format specifications Explanation of format description terms


Useful references

URLs


Last Updated: Tuesday, 21-Feb-2017 08:55:46 EST