ISO/IEC 14496-12:2026
(Main)Information technology — Coding of audio-visual objects — Part 12: ISO base media file format
Information technology — Coding of audio-visual objects — Part 12: ISO base media file format
This document specifies the ISO base media file format, which is a general format forming the basis for a number of other more specific file formats. This format contains the timing, structure, and media information for timed sequences of media data, such as audio-visual presentations.
Technologies de l'information — Codage des objets audiovisuels — Partie 12: Format ISO de base pour les fichiers médias
General Information
- Status
- Published
- Publication Date
- 21-Apr-2026
- Technical Committee
- ISO/IEC JTC 1/SC 29 - Coding of audio, picture, multimedia and hypermedia information
- Drafting Committee
- ISO/IEC JTC 1/SC 29/WG 3 - MPEG Systems
- Current Stage
- 6060 - International Standard published
- Start Date
- 22-Apr-2026
- Due Date
- 02-Sep-2025
- Completion Date
- 22-Apr-2026
Relations
- Effective Date
- 13-Feb-2026
Overview
ISO/IEC 14496-12:2026 defines the ISO base media file format, a foundational standard in the field of information technology, particularly for the coding of audio-visual objects. Maintained by ISO and IEC, this standard establishes a general file structure for handling timed sequences of media data. It serves as the backbone for various derived formats, supporting the storage, transmission, and management of synchronised audio, video, and metadata.
The ISO base media file format provides the essential timing, structure, and media information necessary to represent complex audio-visual presentations. Its extensibility and adaptability make it a critical component in the development of multimedia systems, streaming services, and digital content distribution.
Key Topics
- File Structure and Organization
- Specification of file and binary structure for consistent interpretation across platforms
- Use of "boxes" to encapsulate different media data and metadata segments
- Timing and Synchronization
- Detailed handling of media timing, ensuring synchronisation of audio and video streams
- Support for time-based editing, fragmenting, and segmenting
- Media Types and Metadata
- Support for multiple track types (audio, video, subtitles, etc.)
- Integration of rich metadata, such as user data, copyright information, and descriptive labels
- Extensibility and Compatibility
- Designed to act as a base for other ISO/IEC media file formats (e.g., MP4, HEIF)
- Backward and forward compatibility options for future enhancements
- Delivery and Adaptation
- Structures for fragmented media, adaptive streaming, and progressive download scenarios
- Mechanisms for file delivery, hint tracks, and network streaming optimization
Applications
The ISO base media file format is at the heart of modern media systems, enabling interoperability and efficient handling of digital content. Typical applications include:
- Multimedia Player Support: Utilized as the underlying format for media player software, ensuring consistent playback across devices.
- Streaming Services: Serves as the basis for formats used in online video platforms, facilitating adaptive streaming, fast seeking, and low-latency delivery.
- Content Creation and Editing: Widely supported in professional video and audio editing tools, allowing frame-accurate editing and annotation.
- Storage and Distribution: Used in digital cameras, smartphones, and broadcasting for efficient storage, transfer, and archiving of media files.
- Derived Formats: Acts as the foundation for popular container formats like MP4 (.mp4), 3GP (.3gp), and others, ensuring broad compatibility in the digital media ecosystem.
- Adaptive Bitrate Streaming: Supports file fragmentation and segmenting, essential for protocols like MPEG-DASH and HLS.
Related Standards
The ISO base media file format is specified in ISO/IEC 14496-12:2026 and forms the technical foundation for numerous other standards and specifications, including:
- ISO/IEC 14496-14: Defines the MP4 file format for audio and video.
- ISO/IEC 15444-12: Related to JPEG 2000 image coding system.
- ISO/IEC 23008-12: Used in High Efficiency Image File Format (HEIF) and related systems.
- MPEG-DASH (ISO/IEC 23009): Streaming standard that uses the ISO base media file format for segmenting content.
- 3GPP (3GPP TS 26.244): Specifies file formats based on the ISO base for mobile multimedia storage and streaming.
By following ISO/IEC 14496-12:2026, organizations ensure interoperability, future-proofing, and consistent user experiences across a wide range of digital media applications. This standard supports the evolving needs of multimedia delivery and sets the stage for innovations in audio-visual technology.
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Frequently Asked Questions
ISO/IEC 14496-12:2026 is a standard published by the International Organization for Standardization (ISO). Its full title is "Information technology — Coding of audio-visual objects — Part 12: ISO base media file format". This standard covers: This document specifies the ISO base media file format, which is a general format forming the basis for a number of other more specific file formats. This format contains the timing, structure, and media information for timed sequences of media data, such as audio-visual presentations.
This document specifies the ISO base media file format, which is a general format forming the basis for a number of other more specific file formats. This format contains the timing, structure, and media information for timed sequences of media data, such as audio-visual presentations.
ISO/IEC 14496-12:2026 is classified under the following ICS (International Classification for Standards) categories: 35.040.40 - Coding of audio, video, multimedia and hypermedia information. The ICS classification helps identify the subject area and facilitates finding related standards.
ISO/IEC 14496-12:2026 has the following relationships with other standards: It is inter standard links to ISO/IEC 14496-12:2022. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
ISO/IEC 14496-12:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
International
Standard
ISO/IEC 14496-12
Eighth edition
Information technology — Coding of
2026-04
audio-visual objects —
Part 12:
ISO base media file format
Technologies de l'information — Codage des objets
audiovisuels —
Partie 12: Format ISO de base pour les fichiers médias
Reference number
© ISO/IEC 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO/IEC 2026 – All rights reserved
ii
Contents Page
Foreword .x
Introduction .xi
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 2
3.1 Terms and definitions .2
3.2 Abbreviated terms .8
4 ISO base media file organization . 9
4.1 File structure .9
4.2 Binary structure .9
4.2.1 Syntax conventions .9
4.2.2 Box definitions .10
4.2.3 Extensibility of box definitions .11
4.2.4 Data types and fields . 12
5 Typed ISO base media file organization .13
5.1 File structure . 13
5.2 File-type box .14
5.2.1 Definition .14
5.2.2 Syntax . .14
5.2.3 Semantics .14
5.3 Extended type box . . . 15
5.3.1 Definition . 15
5.3.2 Syntax . . 15
5.3.3 Semantics . 15
6 Common specifications for movie files, item files and segment files .16
6.1 Data offsets .16
6.2 Box order .17
7 Movie file organization .21
7.1 Files, segments, and streams .21
7.2 Presentation structure . 22
7.2.1 Box structure of a presentation . 22
7.2.2 Meta data and media data . 22
7.3 Structure-data . 22
7.3.1 Box . . 22
7.3.2 Interpretation of matrix values . 22
7.3.3 URIs as type indicators . . 23
7.3.4 Box order . 23
7.4 Time structure overview .24
7.5 Identifiers .24
7.6 Uniform resource locators (URLs) .24
8 Box structures .25
8.1 File structure and general boxes . 25
8.1.1 Media data box . 25
8.1.2 Free space box . 25
8.1.3 Progressive download information box . 26
8.1.4 Identified media data box . . 26
8.2 Movie structure .27
8.2.1 Movie box .27
8.2.2 Movie header box .27
8.3 Track structure . 29
8.3.1 Track box . 29
8.3.2 Track header box . 29
© ISO/IEC 2026 – All rights reserved
iii
8.3.3 Track reference box.32
8.3.4 Track group box . . 34
8.3.5 Track type box . 36
8.4 Track media structure .37
8.4.1 Media box .37
8.4.2 Media header box .37
8.4.3 Handler box . 38
8.4.4 Media information box . 39
8.4.5 Media information header boxes . 39
8.4.6 Extended language tag . 40
8.5 Sample tables . 40
8.5.1 Sample table box . 40
8.5.2 Sample description box .41
8.5.3 Degradation priority box .43
8.5.4 Sample scale box .43
8.6 Track time structures .43
8.6.1 Time to sample boxes .43
8.6.2 Sync sample box . 49
8.6.3 Shadow sync . 50
8.6.4 Independent and disposable samples box .52
8.6.5 Edit box . 53
8.6.6 Edit list box . 54
8.7 Track data layout structures . 56
8.7.1 Data information box. 56
8.7.2 Data reference box .57
8.7.3 Sample size boxes .59
8.7.4 Sample to chunk box . 60
8.7.5 Chunk offset box .61
8.7.6 Padding bits box .62
8.7.7 Sub-sample information box .62
8.7.8 Sample auxiliary information sizes box . 65
8.7.9 Sample auxiliary information offsets box.67
8.7.10 Sub-sample Reference Table Box. 68
8.8 Movie fragments . 69
8.8.1 Movie extends box . 69
8.8.2 Movie extends header box .70
8.8.3 Track extends box .71
8.8.4 Movie fragment box . 72
8.8.5 Movie fragment header box . 72
8.8.6 Track fragment box . 73
8.8.7 Track fragment header box . 73
8.8.8 Track fragment run box . . 75
8.8.9 Movie fragment random access box .76
8.8.10 Track fragment random access box . 77
8.8.11 Movie fragment random access offset box . 78
8.8.12 Track fragment decode time box . 79
8.8.13 Level assignment box . 80
8.8.14 Sample auxiliary information in movie fragments. 81
8.8.15 Track extension properties box . 82
8.8.16 Alternative startup sequence properties box . 82
8.8.17 Metadata and user data in movie fragments . 83
8.8.18 Redundant Sample Original Timing . 83
8.9 Sample group structures . 85
8.9.1 Overview . 85
8.9.2 Sample to group box . 85
8.9.3 Sample group description box . 87
8.9.4 Representation of group structures in movie fragments . 89
8.9.5 Compact sample to group box . 90
8.10 User data . 92
© ISO/IEC 2026 – All rights reserved
iv
8.10.1 User data box . 92
8.10.2 Copyright box . 93
8.10.3 Track selection box . 93
8.10.4 Track kind . 95
8.10.5 Label box . 95
8.11 Metadata support . 96
8.11.1 MetaBox . 96
8.11.2 XML boxes . . 98
8.11.3 Item location box . 98
8.11.4 Primary item box . 102
8.11.5 Item protection box . 102
8.11.6 Item information box . 103
8.11.7 Additional metadata container box . 105
8.11.8 Metabox Relation box . 105
8.11.9 URL forms for MetaBoxes . . 105
8.11.10 Static metadata . 106
8.11.11 Item data box . 107
8.11.12 Item reference box . 107
8.11.13 Auxiliary video metadata . 108
8.11.14 Item properties box . 108
8.11.15 Brand item property .110
8.11.16 Handler property .110
8.11.17 T.35 item . 111
8.12 File delivery format support . 111
8.12.1 Overview . 111
8.12.2 FD item information box . 112
8.12.3 File partition box . 113
8.12.4 FEC reservoir box .114
8.12.5 FD session group box . 115
8.12.6 Group ID to name box . . .116
8.12.7 File reservoir box .116
8.13 Sub tracks .117
8.13.1 Overview .117
8.13.2 Backward compatibility .117
8.13.3 Sub track box. 118
8.13.4 Sub track information box . 118
8.13.5 Sub track definition box .119
8.13.6 Sub track sample group box . 120
8.14 Segments . 120
8.14.1 Overview . 120
8.14.2 Segment type box . 120
8.14.3 Segment index box . 121
8.14.4 Subsegment index box . 124
8.14.5 Producer reference time box . 126
8.15 Entity grouping . 127
8.15.1 General . 127
8.15.2 Groups list box . 128
8.15.3 Entity to group box.128
8.15.4 Entity group definitions .129
8.16 Compressed boxes . 131
8.16.1 Overview and processing . 131
8.16.2 Processing model . 131
8.16.3 General syntax. 133
8.16.4 General semantics . 133
8.16.5 Original file-type box . 133
8.16.6 Compressed movie box .134
8.16.7 Compressed movie fragment box .134
8.16.8 Compressed segment index box .134
8.16.9 Compressed subsegment index box . 135
© ISO/IEC 2026 – All rights reserved
v
9 Hint track formats .135
9.1 RTP and SRTP hint track format . 135
9.1.1 Overview . 135
9.1.2 Sample entry format . 136
9.1.3 Sample format .138
9.1.4 SDP information . 140
9.1.5 Statistical information .141
9.2 ALC/LCT and FLUTE hint track format .141
9.2.1 Overview .141
9.2.2 Design principles .142
9.2.3 Sample entry format .143
9.2.4 Sample format . 144
9.3 MPEG-2 transport hint track format .147
9.3.1 Overview .147
9.3.2 Design principles .147
9.3.3 Sample entry format . 149
9.3.4 Sample format . 151
9.3.5 Protected MPEG 2 transport stream hint track . 153
9.4 RTP, RTCP, SRTP and SRTCP reception hint tracks . 153
9.4.1 RTP reception hint track . 153
9.4.2 RTCP reception hint track . 156
9.4.3 SRTP reception hint track . 158
9.4.4 SRTCP reception hint tracks . 159
9.4.5 Protected RTP reception hint track . 160
9.4.6 Recording procedure . 160
9.4.7 Parsing procedure . .161
10 Sample groups .161
10.1 Random access recovery points .161
10.1.1 Definition .161
10.1.2 Syntax .161
10.1.3 Semantics .161
10.2 Rate share groups . 162
10.2.1 Overview . 162
10.2.2 Rate share sample group description entry . 163
10.2.3 Relationship between tracks . 164
10.2.4 Bitrate allocation. 164
10.3 Alternative startup sequences . 165
10.3.1 Definition . 165
10.3.2 Syntax . . 165
10.3.3 Semantics . 166
10.3.4 Examples . 166
10.4 Random access point (RAP) sample group . 168
10.4.1 Definition . 168
10.4.2 Syntax . . 169
10.4.3 Semantics . 169
10.5 Temporal level sample group . 169
10.5.1 Definition . 169
10.5.2 Syntax . 169
10.5.3 Semantics . 169
10.6 Stream access point sample group . 169
10.6.1 Definition . 169
10.6.2 Syntax .170
10.6.3 Semantics .
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