Sustainability of Digital Formats: Planning for Library of Congress Collections |
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Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact |
Full name | Information technology -- Coding of audio-visual objects (formal name); MPEG-4, Advanced Video Coding (part 10), Main Profile |
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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 |
LC experience or existing holdings | |
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LC preference |
Disclosure | Open standard. See MPEG-4_AVC. |
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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. |
Moving Image | |
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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. |
Tag | Value | Note |
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Filename extension | mp4 |
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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. |
Pronom PUID | See note. | PRONOM has no corresponding entry as of July 2022. |
Wikidata Title ID | See related format. | See MPEG-4, Advanced Video Coding (Part 10) (H.264). |
General | |
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History |
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