ISO/IEC 14496-12:2008

INTERNATIONAL ISO/IEC
STANDARD 14496-12
Third edition
2008-10-15
Information technology — Coding of
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 2008
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©  ISO/IEC 2008
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ii © ISO/IEC 2008 – All rights reserved

Contents Page
Foreword .vii
Introduction.ix
1 Scope.1
2 Normative references.1
3 Definitions .2
3.1 Terms and definitions .2
3.2 Abbreviated terms.3
4 Object-structured File Organization.3
4.1 File Structure .3
4.2 Object Structure .3
4.3 File Type Box .4
5 Design Considerations .5
5.1 Usage.5
5.1.1 Introduction.5
5.1.2 Interchange .6
5.1.3 Content Creation .6
5.1.4 Preparation for streaming .7
5.1.5 Local presentation.7
5.1.6 Streamed presentation.7
5.2 Design principles.7
6 ISO Base Media File organization.8
6.1 Presentation structure .8
6.1.1 File Structure .8
6.1.2 Object Structure .8
6.1.3 Meta Data and Media Data .8
6.1.4 Track Identifiers.8
6.2 Metadata Structure (Objects) .9
6.2.1 Box.9
6.2.2 Data Types and fields.9
6.2.3 Box Order .10
6.3 Brand Identification.12
7 Streaming Support .13
7.1 Handling of Streaming Protocols .13
7.2 Protocol ‘hint’ tracks.13
7.3 Hint Track Format.14
8 Box Structures.14
8.1 File Structure and general boxes.14
8.1.1 Media Data Box.14
8.1.2 Free Space Box.15
8.1.3 Progressive Download Information Box.15
8.2 Movie Structure .16
8.2.1 Movie Box.16
8.2.2 Movie Header Box .16
8.3 Track Structure .17
8.3.1 Track Box .17
8.3.2 Track Header Box.18
8.3.3 Track Reference Box.20
8.4 Track Media Structure.20
8.4.1 Media Box.20
8.4.2 Media Header Box .21
© ISO/IEC 2008 – All rights reserved iii

8.4.3 Handler Reference Box .22
8.4.4 Media Information Box .22
8.4.5 Media Information Header Boxes.23
8.5 Sample Tables.24
8.5.1 Sample Table Box.24
8.5.2 Sample Description Box .25
8.5.3 Degradation Priority Box .29
8.5.4 Sample Scale Box.30
8.6 Track Time Structures.31
8.6.1 Time to Sample Boxes .31
8.6.2 Sync Sample Box.34
8.6.3 Shadow Sync Sample Box.34
8.6.4 Independent and Disposable Samples Box .35
8.6.5 Edit Box .36
8.6.6 Edit List Box .37
8.7 Track Data Layout Structures.38
8.7.1 Data Information Box .38
8.7.2 Data Reference Box.38
8.7.3 Sample Size Boxes .39
8.7.4 Sample To Chunk Box.40
8.7.5 Chunk Offset Box.41
8.7.6 Padding Bits Box .42
8.7.7 Sub-Sample Information Box .42
8.8 Movie Fragments .43
8.8.1 Movie Extends Box.43
8.8.2 Movie Extends Header Box.44
8.8.3 Track Extends Box.44
8.8.4 Movie Fragment Box .45
8.8.5 Movie Fragment Header Box .45
8.8.6 Track Fragment Box .46
8.8.7 Track Fragment Header Box.46
8.8.8 Track Fragment Run Box .47
8.8.9 Movie Fragment Random Access Box .48
8.8.10 Track Fragment Random Access Box.49
8.8.11 Movie Fragment Random Access Offset Box.50
8.9 Sample Group Structures .50
8.9.1 Introduction.50
8.9.2 Sample to Group Box .50
8.9.3 Sample Group Description Box.51
8.9.4 Representation of group structures in Movie Fragments .53
8.10 User Data .53
8.10.1 User Data Box .53
8.10.2 Copyright Box .54
8.10.3 Track Selection Box .54
8.11 Metadata Support.56
8.11.1 The Meta box.56
8.11.2 XML Boxes.57
8.11.3 The Item Location Box .57
8.11.4 Primary Item Box .58
8.11.5 Item Protection Box.59
8.11.6 Item Information Box.59
8.11.7 Additional Metadata Container Box.61
8.11.8 Metabox Relation Box .61
8.11.9 URL Forms for meta boxes.62
8.11.10 Static Metadata.63
8.12 Support for Protected Streams .63
8.12.1 Protection Scheme Information Box.64
8.12.2 Original Format Box .65
8.12.3 IPMPInfoBox.65
8.12.4 IPMP Control Box.66
iv © ISO/IEC 2008 – All rights reserved

8.12.5 Scheme Type Box.67
8.12.6 Scheme Information Box .67
8.13 File Delivery Format Support .67
8.13.1 Introduction.67
8.13.2 FD Item Information Box.68
8.13.3 File Partition Box .68
8.13.4 FEC Reservoir Box.70
8.13.5 FD Session Group Box .70
8.13.6 Group ID to Name Box .71
9 Hint Track Formats.72
9.1 RTP and SRTP Hint Track Format .72
9.1.1 Introduction.72
9.1.2 Sample Description Format.72
9.1.3 Sample Format.74
9.1.4 SDP Information .77
9.1.5 Statistical Information.77
9.2 ALC/LCT and FLUTE Hint Track Format .78
9.2.1 Introduction.78
9.2.2 Design principles.79
9.2.3 Sample Description Format.80
9.2.4 Sample Format.81
10 Sample Groups .83
10.1 Random Access Recovery Points .83
10.2 Rate Share Groups.84
10.2.1 Introduction.84
10.2.2 Rate Share Sample Group Entry.85
10.2.3 Relationship between tracks.86
10.2.4 Bitrate allocation .87
11 Extensibility .87
11.1 Objects .87
11.2 Storage formats .88
11.3 Derived File formats.88
Annex A (informative) Overview and Introduction .89
A.1 Section Overview.89
A.2 Core Concepts .89
A.3 Physical structure of the media .89
A.4 Temporal structure of the media .90
A.5 Interleave.90
A.6 Composition.90
A.7 Random access .91
A.8 Fragmented movie files .91
Annex B (informative) Patent Statements .93
Annex C (informative) Guidelines on deriving from this specification .94
C.1 Introduction.94
C.2 General Principles.94
C.3 Brand Identifiers .94
C.3.1 Introduction.94
C.3.2 Usage of the Brand.94
C.3.3 Introduction of a new brand .95
C.3.4 Player Guideline .95
C.3.5 Authoring Guideline.95
C.3.6 Example.95
C.4 Box layout and order.96
C.5 Storage of new media types.96
C.6 Use of Template fields .96
C.7 Construction of fragmented movies.97
© ISO/IEC 2008 – All rights reserved v

Annex D (informative) Registration Authority .98
D.1 Code points to be registered .98
D.2 Procedure for the request of an MPEG-4 registered identifier value .98
D.3 Responsibilities of the Registration Authority .99
D.4 Contact information for the Registration Authority .99
D.5 Responsibilities of Parties Requesting a RID.99
D.6 Appeal Procedure for Denied Applications .100
D.7 Registration Application Form .100
D.7.1 Contact Information of organization requesting a RID.100
D.7.2 Request for a specific RID .100
D.7.3 Short description of RID that is in use and date system was implemented.101
D.7.4 Statement of an intention to apply the assigned RID .101
D.7.5 Date of intended implementation of the RID.101
D.7.6 Authorized representative .101
D.7.7 For official use of the Registration Authority .101
Annex E (normative) File format brands.102
E.1 Introduction.102
E.2 The ‘isom’ brand.103
E.3 The ‘avc1’ brand.104
E.4 The ‘iso2’ brand.104
E.5 The ‘mp71’ brand.104
E.6 The ‘iso3’ brand.104
Annex F (informative) Document Cross-Reference .106
Bibliography .108

vi © ISO/IEC 2008 – All rights reserved

Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 14496-12 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information.
This third edition cancels and replaces the second edition (ISO/IEC 14496-12:2005) of which it constitues a
minor revision.
ISO/IEC 14496 consists of the following parts, under the general title Information technology — Coding of
audio-visual objects:
⎯ Part 1: Systems
⎯ Part 2: Visual
⎯ Part 3: Audio
⎯ Part 4: Conformance testing
⎯ Part 5: Reference software
⎯ Part 6: Delivery Multimedia Integration Framework (DMIF)
⎯ Part 7: Optimized reference software for coding of audio-visual objects
⎯ Part 8: Carriage of ISO/IEC 14496 contents over IP networks
⎯ Part 9: Reference hardware description
⎯ Part 10: Advanced Video Coding
⎯ Part 11: Scene description and application engine
⎯ Part 12: ISO base media file format
⎯ Part 13: Intellectual Property Management and Protection (IPMP) extensions
© ISO/IEC 2008 – All rights reserved vii

⎯ Part 14: MP4 file format
⎯ Part 15: Advanced Video Coding (AVC) file format
⎯ Part 16: Animation Framework eXtension (AFX)
⎯ Part 17: Streaming text format
⎯ Part 18: Font compression and streaming
⎯ Part 19: Synthesized texture stream
⎯ Part 20: Lightweight Application Scene Representation (LASeR) and Simple Aggregation Format (SAF)
⎯ Part 21: MPEG-J Graphics Framework eXtensions (GFX)
⎯ Part 22: Open Font Format
⎯ Part 23: Symbolic Music Representation
⎯ Part 24: Audio and systems interaction
⎯ Part 25: 3D Graphics Compression Model
viii © ISO/IEC 2008 – All rights reserved

Introduction
The ISO Base Media File Format is designed to contain timed media information for a presentation in a
flexible, extensible format that facilitates interchange, management, editing, and presentation of the media.
This presentation may be ‘local’ to the system containing the presentation, or may be via a network or other
stream delivery mechanism.
The file structure is object-oriented; a file can be decomposed into constituent objects very simply, and the
structure of the objects inferred directly from their type.
The file format is designed to be independent of any particular network protocol while enabling efficient
support for them in general.
The ISO Base Media File Format is a base format for media file formats.
It is intended that the ISO Base Media File Format shall be jointly maintained by WG1 and WG11.
Consequently, a subdivision of work created ISO/IEC 15444-12 and ISO/IEC 14496-12 in order to document
the ISO Base Media File Format and to facilitate the joint maintenance.
This technically identical text is published as ISO/IEC 14496-12 for MPEG-4, and as ISO/IEC 15444-12 for
JPEG 2000, and reference to this specification should be made accordingly. The recommendation is to
reference one, for example ISO/IEC 14496-12, and append to the reference a parenthetical comment
identifying the other, for example “(technically identical to ISO/IEC 15444-12)”.
© ISO/IEC 2008 – All rights reserved ix

INTERNATIONAL STANDARD ISO/IEC 14496-12:2008(E)

Information technology — Coding of audio-visual objects —
Part 12:
ISO base media file format
1 Scope
This part of ISO/IEC 14496 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 part of ISO/IEC 14496 is applicable to MPEG-4, but its technical content is identical to that of
ISO/IEC 15444-12, which is applicable to JPEG 2000.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 639-2:1998, Codes for the representation of names of languages — Part 2: Alpha-3 code
ITU-T Rec. X.667 (09/2004) | ISO/IEC 9834-8:2005, Information technology — Open Systems
Interconnection — Procedures for the operation of OSI Registration Authorities: Generation and registration of
Universally Unique Identifiers (UUIDs) and their use as ASN.1 Object Identifier components
ISO/IEC 11578:1996, Information technology — Open Systems Interconnection — Remote Procedure Call
(RPC)
ISO/IEC 14496-1:2004: Information technology — Coding of audio-visual objects — Part 1: Systems
ISO/IEC 14496-10, Information technology — Coding of audio-visual objects — Part 10: Advanced Video
Coding
ISO/IEC 14496-14, Information technology — Coding of audio-visual objects — Part 14: MP4 file format
ITU-T Rec.T.800 | ISO/IEC 15444-1, Information technology — JPEG 2000 image coding system: Core
coding system
ITU-T Rec.T.802 | ISO/IEC 15444-3, Information technology — JPEG 2000 image coding system: Motion
JPEG 2000
ISO/IEC 15938-1, Information technology — Multimedia content description interface — Part 1: Systems
ISO/IEC 23001-1, Information technology — MPEG systems technologies — Part 1: Binary MPEG format for
XML
IETF RFC 3711, “The Secure Real-time Transport Protocol (SRTP)”, BAUGHER, M. et al., March 2004
© ISO/IEC 2008 – All rights reserved 1

SMIL 1.0 “Synchronized Multimedia Integration Language (SMIL) 1.0 Specification”,

IETF RFC 2045, Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies,
FREED, N. and BORENSTEIN, N., November 1996
IETF RFC 2046, Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types, FREED, N. and
BORENSTEIN, N., November 1996
ITU-R Rec. TF.460-6, Standard-frequency and time-signal emissions (Annex I for the definition of UTC.)
3 Definitions
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
box
object-oriented building block defined by a unique type identifier and length
NOTE Called ‘atom’ in some specifications, including the first definition of MP4.
3.1.2
chunk
contiguous set of samples for one track
3.1.3
container box
box whose sole purpose is to contain and group a set of related boxes
3.1.4
hint track
special track which does not contain media data, but instead contains instructions for packaging one or more
tracks into a streaming channel
3.1.5
hinter
tool that is run on a file containing only media, to add one or more hint tracks to the file and so facilitate
streaming
3.1.6
movie box
container box whose sub-boxes define the metadata for a presentation (‘moov’)
3.1.7
media data box
box which can hold the actual media data for a presentation (‘mdat’)
3.1.8
ISO Base Media File
name of the files conforming to the file format described in this specification
3.1.9
presentation
one or more motion sequences, possibly combined with audio
2 © ISO/IEC 2008 – All rights reserved

3.1.10
sample
all the data associated with a single timestamp
NOTE 1 No two samples within a track can share the same time-stamp.
NOTE 2 In non-hint tracks, a sample is, for example, an individual frame of video, a series of video frames in decoding
order, or a compressed section of audio in decoding order; in hint tracks, a sample defines the formation of one or more
streaming packets).
3.1.11
sample description
structure which defines and describes the format of some number of samples in a track
3.1.12
sample table
packed directory for the timing and physical layout of the samples in a track
3.1.13
track
timed sequence of related samples (q.v.) in an ISO base media file
NOTE For media data, a track corresponds to a sequence of images or sampled audio; for hint tracks, a track
corresponds to a streaming channel.
3.2 Abbreviated terms
For the purposes of this International Standard, the following abbreviated terms apply.
ALC Asynchronous Layered Coding
FD  File Delivery
FDT File Delivery Table
FEC Forward Error Correction
FLUTE File Delivery over Unidirectional Transport
IANA Internet Assigned Numbers Authority
LCT Layered Coding Transport
MBMS Multimedia Broadcast/Multicast Service

4 Object-structured File Organization
4.1 File Structure
Files are formed as a series of objects, called boxes in this specification. All data is contained in boxes; there
is no other data within the file. This includes any initial signature required by the specific file format.
All object-structured files conformant to this section of this specification (all Object-Structured files) shall
contain a File Type Box.
4.2 Object Structure
An object in this terminology is a box.
Boxes start with a header which gives both size and type. The header permits compact or extended size (32
or 64 bits) and compact or extended types (32 bits or full Universal Unique IDentifiers, i.e. UUIDs). The
© ISO/IEC 2008 – All rights reserved 3

standard boxes all use compact types (32-bit) and most boxes will use the compact (32-bit) size. Typically
only the Media Data Box(es) need the 64-bit size.
The size is the entire size of the box, including the size and type header, fields, and all contained boxes. This
facilitates general parsing of the file.
The definitions of boxes are given in the syntax description language (SDL) defined in MPEG-4 (see reference
in clause 2). Comments in the code fragments in this specification indicate informative material.
The fields in the objects are stored with the most significant byte first, commonly known as network byte order
or big-endian format. When fields smaller than a byte are defined, or fields span a byte boundary, the bits are
assigned from the most significant bits in each byte to the least significant. For example, a field of two bits
followed by a field of six bits has the two bits in the high order bits of the byte.
aligned(8) class Box (unsigned int(32) boxtype,
optional unsigned int(8)[16] extended_type) {
unsigned int(32) size;
unsigned int(32) type = boxtype;
if (size==1) {
unsigned int(64) largesize;
} else if (size==0) {
// box extends to end of file
}
if (boxtype==‘uuid’) {
unsigned int(8)[16] usertype = extended_type;
}
}
The semantics of these two fields are:
size is an integer that specifies the number of bytes in this box, including all its fields and contained
boxes; if size is 1 then the actual size is in the field largesize; if size is 0, then this box is the last
one in the file, and its contents extend to the end of the file (normally only used for a Media Data Box)
type identifies the box type; standard boxes use a compact type, which is normally four printable
characters, to permit ease of identification, and is shown so in the boxes below. User extensions use
an extended type; in this case, the type field is set to ‘uuid’.
Boxes with an unrecognized type shall be ignored and skipped.
Many objects also contain a version number and flags field:
aligned(8) class FullBox(unsigned int(32) boxtype, unsigned int(8) v, bit(24) f)
extends Box(boxtype) {
unsigned int(8) version = v;
bit(24)   flags = f;
}
The semantics of these two fields are:
version is an integer that specifies the version of this format of the box.
flags is a map of flags
Boxes with an unrecognized version shall be ignored and skipped.
4.3 File Type Box
4.3.1 Definition
Box Type: ‘ftyp’
Container: File
Mandatory: Yes
Quantity: Exactly one
4 © ISO/IEC 2008 – All rights reserved

Files written to this version of this specification must contain a file-type box. For compatibility with an earlier
version of this specification, files may be conformant to this specification and not contain a file-type box. Files
...