ISO/IEC 23009-1:2022

INTERNATIONAL ISO/IEC
STANDARD 23009-1
Fifth edition
2022-08
Information technology — Dynamic
adaptive streaming over HTTP
(DASH) —
Part 1:
Media presentation description and
segment formats
Technologies de l'information — Diffusion en flux adaptatif
dynamique sur HTTP (DASH) —
Partie 1: Description de la présentation et formats de remise des
médias
Reference number
© ISO/IEC 2022
© ISO/IEC 2022
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ii
© ISO/IEC 2022 – All rights reserved

Contents
Foreword . vii
Introduction . viii
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 2
3.1 Terms and definitions . 2
3.2 Symbols and abbreviated terms . 7
3.3 Conventions . 9
4 Overview . 10
4.1 System description . 10
4.2 DASH Client model . 11
4.3 DASH data model overview . 12
4.4 Protocols . 15
4.5 Media stream and Representation properties . 16
4.5.1 Switching and Random Access Support . 16
4.5.2 Media stream access points . 16
4.5.3 Non-overlapping Segments and Subsegments . 17
4.5.4 Conforming Segment track . 18
4.6 Brands . 18
4.7 Schemes . 19
5 Media Presentation . 22
5.1 General . 22
5.2 Media Presentation Description . 22
5.2.1 General . 22
5.2.2 Schema . 23
5.2.3 Elements and Attributes added in revisions and amendments . 24
5.3 Hierarchical data model . 26
5.3.1 General . 26
5.3.2 Period . 33
5.3.3 Adaptation Sets . 39
5.3.4 Media content component . 50
5.3.5 Representation . 51
5.3.6 Sub-Representation . 62
5.3.7 Common attributes and elements . 63
5.3.8 Subsets . 70
5.3.9 Segments and Segment information . 71
5.3.10 Label and Group Label . 93
5.3.11 Preselection . 95
5.3.12 Initialization Set, Group and Presentation . 99
5.3.13 Resynchronization . 103
5.4 Media Presentation Description updates . 106
5.4.1 General . 106
5.4.2 MPD Reset . 108
5.5 MPD assembly . 108
5.5.1 General . 108
5.5.2 Syntax and semantics . 108
5.5.3 Processing . 109
5.6 Base URL Processing . 110
5.6.1 Overview . 110
5.6.2 Semantics . 111
5.6.3 XML syntax . 112
5.6.4 Reference resolution . 112
5.6.5 Alternative base URLs. 113
5.7 Program information . 113
5.7.1 Overview . 113
5.7.2 Semantics . 113
5.7.3 XML syntax . 114
5.8 Descriptors . 114
5.8.1 General . 114
5.8.2 Semantics of generic descriptor . 115
5.8.3 XML syntax of generic descriptor . 115
5.8.4 Specific descriptors . 116
5.8.5 Specific scheme definitions . 122
5.9 DASH metrics descriptor . 133
5.9.1 Overview . 133
5.9.2 Semantics . 133
5.9.3 XML syntax . 134
5.9.4 Metric reporting . 135
5.10 Events . 135
5.10.1 Overview . 135
5.10.2 MPD Events . 135
5.10.3 Inband Event Signalling . 139
5.10.4 DASH-specific events. 142
5.11 MPD Chaining . 146
5.11.1 General . 146
5.11.2 Regular Chaining . 146
5.11.3 Fallback Chaining . 147
5.12 Producer Reference Time . 148
5.12.1 General . 148
5.12.2 Semantics . 148
5.12.3 XML Syntax . 150
5.13 Leap seconds . 150
5.13.1 Overview . 150
5.13.2 Semantics . 151
5.13.3 XML-Syntax . 151
5.13.4 Leap second information updates . 152
5.14 Content Popularity Rate . 152
5.14.1 General . 152
5.14.2 Semantics . 153
5.14.3 XML syntax . 154
5.15 MPD patch framework. 155
5.15.1 Overview . 155
5.15.2 MPD Patch Location . 155
5.15.3 MPD patch document . 156
5.15.4 Processing Model . 158
5.15.5 Recommended Client Operation . 159
6 Segment formats . 159
6.1 General . 159
6.2 Segment types . 160
6.2.1 General . 160
6.2.2 Initialization Segment . 160
6.2.3 Media Segment . 160
iv © ISO 2022 – All rights reserved

6.2.4 Index Segment . 162
6.2.5 Bitstream Switching Segment . 162
6.2.6 Missing Content Segment . 162
6.3 Segment formats for ISO base media file format . 162
6.3.1 General . 162
6.3.2 Preliminaries: Refinements of generic concepts . 163
6.3.2.5 Resynchronization Point . 163
6.3.3 Initialization Segment format . 164
6.3.4 Media Segment types . 164
6.3.5 Self-Initializing Media Segment formats . 166
6.4 Segment formats for MPEG-2 transport streams . 166
6.4.1 General . 166
6.4.2 Preliminaries: Refinements of generic concepts . 167
6.4.3 Initialization Segment types and formats . 168
6.4.4 Media Segment types and formats . 169
6.4.5 Bitstream Switching Segment . 169
6.4.6 Index Segment . 170
6.4.7 Boxes used with MPEG-2 TS Index Segments . 172
7 Combined semantics of MPD and Segment formats . 172
7.1 Overview . 172
7.2 General . 173
7.2.1 Media Presentation timeline . 173
7.2.2 Segment Index . 174
7.2.3 Segment alignment . 174
7.2.4 Subsegment alignment . 174
7.3 Media Presentation based on the ISO base media file format . 174
7.3.1 General . 174
7.3.2 Media presentation timeline . 175
7.3.3 Authoring Rules for specific MPD attributes . 175
7.3.4 Sub-Representations . 176
7.3.5 Segment Timeline without Segment Index . 176
7.4 Media Presentation based on MPEG-2 TS . 176
7.4.1 General . 176
7.4.2 Media presentation timeline . 177
7.4.3 Authoring rules for specific MPD attributes . 177
7.4.4 Sub-Representations . 178
8 Profiles . 178
8.1 Definition . 178
8.2 Full profile . 180
8.2.1 General . 180
8.2.2 Media Presentation Description constraints . 180
8.2.3 Segment format constraints . 180
8.3 ISO Base media file format On Demand profile . 180
8.3.1 General . 180
8.3.2 Media Presentation Description constraints . 181
8.3.3 Segment format constraints . 182
8.4 ISO Base media file format live profile . 182
8.4.1 General . 182
8.4.2 Media Presentation Description constraints . 182
8.4.3 Segment format constraints . 183
8.5 ISO Base media file format main profile . 183
8.5.1 General . 183
8.5.2 Media Presentation Description constraints . 184
8.5.3 Segment format constraints . 184
8.6 MPEG-2 TS main profile . 185
8.6.1 General . 185
8.6.2 Media Presentation Description constraints . 185
8.6.3 Segment format constraints . 185
8.6.4 Comments and recommendations . 185
8.7 MPEG-2 TS simple profile . 186
8.7.1 General . 186
8.7.2 Media Presentation Description constraints . 186
8.7.3 Segment format constraints . 186
8.7.4 Recommendations . 187
8.8 ISO Base media file format extended live profile . 187
8.8.1 General . 187
8.8.2 Media Presentation Description constraints . 187
8.8.3 Segment format constraints . 188
8.8.4 Inband Events . 188
8.9 ISO Base media file format extended On Demand profile . 188
8.9.1 General . 188
8.9.2 Media Presentation Description constraints . 189
8.9.3 Segment format constraints . 190
8.10 ISO Base media file format common profile . 190
8.10.1 General . 190
8.10.2 Media Presentation Description constraints . 190
8.10.3 Segment format constraints . 191
8.11 ISO Base media file format broadcast TV profile . 191
8.11.1 General . 191
8.11.2 Media Presentation Description constraints . 191
8.11.3 Segment format constraints . 193
8.11.4 MPD Updates and Inband Event Streams . 193
8.12 DASH profile for CMAF content . 194
8.12.1 General . 194
8.12.2 CMAF content model for DASH profile definition . 194
8.12.3 CMAF to DASH Mapping Principles . 197
8.12.4 DASH profiles for CMAF content - Common constraints . 200
8.12.5 DASH CMAF Core Profile . 208
8.12.6 DASH CMAF Extended Profile . 208
8.12.7 Conformance Checking Considerations . 208
Annex A (informative) Example DASH Client behaviour . 210
Annex B (normative) MPD schema . 234
Annex C (normative) MIME type registration for MPD and other resources. 235
Annex D (normative) DASH Metrics . 242
Annex E (normative) Byte range requests with regular HTTP GET methods . 251
Annex F (informative) Guidelines for extending DASH with other delivery formats . 254
Annex G (informative) MPD Examples and MPD Usage . 256
Annex H (normative) Spatial Relationship Description . 284
Annex I (normative) Flexible Insertion of URL Parameters . 293
Annex J (informative) Open GOP resolution change . 307
Annex K (normative) DASH Service Description . 308
Bibliography . 319
vi © ISO 2022 – 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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of document should be noted. This document was drafted in accordance with the editorial
rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives or
www.iec.ch/members_experts/refdocs).
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. Details
of any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents) or the IEC list of patent
declarations received (see patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the World
Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see
www.iso.org/iso/foreword.html. In the IEC, see www.iec.ch/understanding-standards.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information.
This fifth edition cancels and replaces the fourth edition (ISO/IEC 23009-1:2020), which has been
technically revised.
The main changes are as follows:
— DASH profile for using Common Media Application Format (CMAF) are added;
— The concept Resynchronization is added in order to identify stream access points in Segments;
— MPD patching is updated to support explicit MPD updates of smaller size, not only as inband
messages;
— A client processing model for Event Streams and Timed Metadata tracks is introduced;
— Extensions are added to content protection for efficient signalling and to support robustness
levels.
— A descriptor is added in order to describe the minimum required device output protection security;
— More flexible bandwidth signalling is provided to signal variable bitrate encoding.
A list of all parts in the ISO/IEC 23009 series can be found on the ISO and IEC websites.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html and
https://www.iec.ch/national-committees.
Introduction
Dynamic adaptive streaming over HTTP (DASH) is intended to support a media-streaming model for
delivery of media content in which control lies primarily with the client. Clients may request data using
the HTTP protocol from standard web servers that have no DASH-specific capabilities. Consequently, this
document focuses not on client or server procedures but on the data formats used to provide a DASH
Media Presentation.
The International Organization for Standardization (ISO) and the International Electrotechnical
Commission (IEC) draw attention to the fact that it is claimed that compliance with this document may
involve the use of a patent.
ISO and IEC take no position concerning the evidence, validity and scope of this patent right.
The holder of this patent right has assured ISO and IEC that he/she is willing to negotiate licences under
reasonable and non-discriminatory terms and conditions with applicants throughout the world. In this
respect, the statement of the holder of this patent right is registered with ISO and IEC. Information may
be obtained from the patent database available at www.iso.org/patents or https://patents.iec.ch.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights other than those in the patent database. ISO and IEC shall not be held responsible for
identifying any or all such patent rights.
viii © ISO 2022 – All rights reserved

INTERNATIONAL STANDARD ISO/IEC 23009-1:2022(E)

Information technology — Dynamic adaptive streaming over
HTTP (DASH) —
Part 1:
Media presentation description and segment formats
1 Scope
This document primarily specifies formats for the Media Presentation Description and Segments for
dynamic adaptive streaming delivery of MPEG media over HTTP. It is applicable to streaming services
over the Internet.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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/IEC 13818-1, Information technology — Generic coding of moving pictures and associated audio
information — Part 1: Systems
ISO/IEC 14496-12, Information technology — Coding of audio-visual objects — Part 12: ISO base media file
format
ISO/IEC 23000-19, Information technology — Multimedia application format (MPEG-A) — Part 19:
Common media application format (CMAF) for segmented media
ISO/IEC 23091-2, Information technology — Coding-independent code points — Part 2: Video
ISO/IEC 23091-3, Information technology — Coding-independent code points — Part 3: Audio
IETF RFC 2397, The “data” URL scheme
IETF RFC 3629, UTF-8, a transformation format of ISO 10646
IETF RFC 3986, Uniform Resource Identifier (URI): Generic Syntax
IETF RFC 4122, A Universally Unique IDentifier (UUID) URN Namespace
IETF RFC 4337, MIME Type Registration for MPEG-4
IETF RFC 4648, The Base16, Base32, and Base64 Data Encodings
IETF RFC 5234, Augmented BNF for Syntax Specifications: ABNF
IETF RFC 5261, An Extensible Markup Language (XML) Patch Operations Framework Utilizing XML Path
Language (XPath) Selectors
IETF RFC 5646, Tags for Identifying Languages
IETF RFC 6381, The 'Codecs' and 'Profiles' Parameters for “Bucket” Media Types

IETF RFC 6838, Media Type Specifications and Registration Procedures
IETF RFC 7231, Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content
IETF RFC 7233, Hypertext Transfer Protocol (HTTP/1.1): Range Requests
IETF RFC 8141, URN Syntax
IETF RFC 8673, HTTP Random Access and Live Content
HTML 4.01 Specification, W3C Recommendation, 24 December 1999
W3C Canonical XML Version 1.1, W3C Recommendation, 2 May 2008
W3C Extensible Markup Language (XML) 1.0 (Fifth Edition), W3C Recommendation, 26 November 2008
W3C XLINK, XML Linking Language (XLink) Version 1.1, W3C Recommendation 06, May 2010
W3C Media Fragments URI 1.0 (basic), W3C Recommendation, 25 September 2012
3 Terms, definitions, symbols and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 23000-19 and the following
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1.1
access unit
unit of a media stream (3.1.29) with an assigned Media Presentation time
3.1.2
accessibility
degree to which a media content or certain media content components (3.1.22) are available to as many
people as possible
3.1.3
Adaptation Set
set of interchangeable encoded versions of one or several media content components (3.1.22)
3.1.4
asset
content including media and metadata together with the rights to use the content by the content
provider
2 © ISO 2022 – All rights reserved

3.1.5
associated Representation
Representation (3.1.38) which provides supplemental or descriptive information for at least one other
Representation
3.1.6
available Segment
Segment (3.1.40) that is accessible at its assigned HTTP-URL (3.1.17) and a possibly assigned byte range
that is the request with an HTTP GET results in a reply of the Segment and 2xx status code
3.1.7
Bitstream Switching Segment
Segment (3.1.40) that if present contains essential data to switch to the Representation (3.1.38) it is
assigned to
3.1.8
complementary Representation
Representation (3.1.38) which complements at least one dependent Representation (3.1.12)
3.1.9
continuous media
media with an inherent notion of time
EXAMPLES Speech, audio, video, timed text or timed metadata.
3.1.10
DASH metric
metric computed by the DASH Client and uniquely identified by a key
3.1.11
data URL
URL with a fixed scheme “data”
3.1.12
dependent Representation
Representation (3.1.38) for which Segments (3.1.40) from its complementary Representations (3.1.8) are
necessary for presentation and/or decoding of the contained media content components (3.1.22)
3.1.13
earliest presentation time
smallest presentation time (3.1.36) of any access unit (3.1.1) of a Media Segment (3.1.28) Or Subsegment
(3.1.50) for a media stream (3.1.29)
3.1.14
event
aperiodic sparse media-time related auxiliary information to the DASH Client or to an application
3.1.15
event stream
sequence of related events (3.1.14)
3.1.16
group
collection of Adaptation Sets (3.1.3) that are not expected to be presented simultaneously

3.1.17
HTTP-URL
URL with a fixed scheme of “http” or “https”
3.1.18
Index Segment
Segment (3.1.40) that primarily contains indexing information for Media Segments (3.1.28)
3.1.19
Initialization Segment
Segment (3.1.40) containing metadata that is necessary to present the media streams (3.1.29)
encapsulated in Media Segments (3.1.28)
3.1.20
Main Adaptation Set
Adaptation Set (3.1.3) In A Preselection (3.1.35) that contains the Initialization Segment (3.1.19) for the
complete experience
3.1.21
media content
single media content period (3.1.24) or contiguous sequence of media content periods
3.1.22
media content component
single continuous component of the media content (3.1.21) with an assigned media content component
type (3.1.23)
3.1.23
media content component type
single type of media content (3.1.21)
EXAMPLES Audio, video, or text.
3.1.24
media content period
set of media content components (3.1.22) that have a common timeline as well as relationships on how
they can be presented
3.1.25
Media Presentation
collection of data that establishes a bounded or unbounded presentation of media content (3.1.21)
3.1.26
Media Presentation Description
MPD
formalized description for a Media Presentation (3.1.25) for the purpose of providing a streaming
service
3.1.27
Media Presentation timeline
concatenation of the timeline of all Periods (3.1.34) which itself is common to all Representations
(3.1.38) in the Period
4 © ISO 2022 – All rights reserved

3.1.28
Media Segment
Segment (3.1.40) that complies with media format in use and enables playback when combined with
zero or more preceding Segments and an Initialization Segment (3.1.19) (if any)
3.1.29
media stream
encoded version of a media content component (3.1.22)
3.1.30
Media Subsegment
Subsegment (3.1.50) that only contains media data but no Segment Index (3.1.44)
3.1.31
message
part of an event (3.1.14) containing information that is exclusively handled by the event handler
3.1.32
MPD start time
approximate presentation start time of a Media Segment (3.1.28) signalled in MPD (3.1.26)
3.1.33
MPD duration
approximate presentation duration of a Media Segment (3.1.28) signalled in MPD (3.1.26)
3.1.34
Period
interval of the Media Presentation (3.1.24), where a contiguous sequence of a
...