IEC 62766-2-2:2016
(Main)Consumer terminal function for access to IPTV and open internet multimedia services - Part 2-2: HTTP adaptive streaming
Consumer terminal function for access to IPTV and open internet multimedia services - Part 2-2: HTTP adaptive streaming
IEC 62766-2-2:2016 specifies media formats for adaptive unicast content streaming over HTTP. Two HTTP adaptive streaming formats are specified. The first is based entirely on MPEG DASH. The second is the OIPF “HTTP adaptive streaming” (HAS) format, which is based upon 3GPP’s release 9 adaptive HTTP streaming (AHS) format, with some profiling and extensions to add the features of media components and support for MPEG-2 transport stream content segment format. The latter format was specified before MPEG DASH had been published. It is retained due to usage in some legacy applications.
Fonction des terminaux grand public pour l'accès aux services IPTV et multimédias de l'internet ouvert - Partie 2-2: Diffusion en flux adaptatif sur HTTP
L'IEC 62766-2-2:2016 spécifie les formats de médias pour une diffusion en flux adaptatif de contenu en monodiffusion sur HTTP. Deux formats de diffusion en flux adaptatif sur HTTP sont spécifiés. Le premier repose entièrement sur le format MPEG DASH. Le second est le format de "diffusion en flux adaptatif sur HTTP" (HAS) de l'OIPF, basé sur le format de diffusion en flux adaptatif sur HTTP version 9 de 3GPP, certains profils et extensions ajoutant les caractéristiques des composants médias et prenant en charge le format de segment de contenu du flux de transport MPEG-2. Ce dernier format a été spécifié avant la publication du format MPEG DASH. Il est maintenu en raison de son utilisation dans certaines applications existantes.
General Information
Standards Content (Sample)
IEC 62766-2-2 ®
Edition 1.0 2016-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Consumer terminal function for access to IPTV and open internet multimedia
services –
Part 2-2: HTTP adaptive streaming
Fonction des terminaux grand public pour l’accès aux services IPTV et
multimédias de l'internet ouvert –
Partie 2-2: Diffusion en flux adaptatif sur HTTP
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IEC 62766-2-2 ®
Edition 1.0 2016-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Consumer terminal function for access to IPTV and open internet multimedia
services –
Part 2-2: HTTP adaptive streaming
Fonction des terminaux grand public pour l’accès aux services IPTV et
multimédias de l'internet ouvert –
Partie 2-2: Diffusion en flux adaptatif sur HTTP
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.170; 35.240.95 ISBN 978-2-8322-3689-5
− 2 − IEC 62766-2-2:2016 IEC 2016
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 8
3.1 General . 8
3.2 Terms and definitions . 8
3.3 Abbreviated terms . 9
4 Adaptive streaming in the OIPF IPTV solution . 10
5 MPEG DASH based adaptive streaming . 11
5.1 General . 11
5.2 DASH usage for the TS systems layer format . 12
5.2.1 General . 12
5.2.2 PID allocation . 12
5.2.3 Protected TS content . 12
5.3 DASH usage for the MP4 systems layer format . 13
5.3.1 General . 13
5.3.2 Protected content . 13
5.4 Operational parameters . 14
5.5 Adaptation set audio/video source coding . 14
5.6 MPD requirements, audio description . 15
5.7 Key management of protected contents . 15
6 OIPF HTTP adaptive streaming . 15
6.1 General . 15
6.2 Media presentation . 16
6.2.1 Media presentation description . 16
6.2.2 Component element . 16
6.3 Segmentation constraints . 18
6.4 Signalling of content protection in the MPD . 20
6.5 Media presentation description updates . 20
6.6 Adaptive media formats . 20
6.6.1 General . 20
6.6.2 MPEG-2 transport stream systems layer . 20
6.6.3 MP4 file format systems layer . 22
6.7 Use cases . 23
6.7.1 Live streaming . 23
6.7.2 Trick play . 23
6.7.3 MPEG-2 TS seeking . 24
Annex A (normative) OIPF HAS MPD schema . 25
Annex B (informative) OIPF HAS component management . 26
Annex C (informative) Usage of the MP4 file format in OIPF HAS . 28
C.1 Audio/video synchronization . 28
C.2 Partial representations . 29
Annex D (informative) DASH usage with embedded CSPG . 31
Bibliography . 32
Figure 1 – Content segmentation for HTTP adaptive streaming . 10
Figure 2 – Example of the HAS MPD . 18
Figure A.1 – HAS MPD schema . 25
Figure B.1 – Component management example . 26
Figure C.1 – Example tfad-box . 29
Figure C.2 – Partial representation MP4 example . 30
Figure C.3 – Partial representation retrieval . 30
Table 1 – Role and accessibility descriptor values for audio description . 15
Table 2 – Component element and attributes . 17
Table C.1 – Example audio/video synchronization . 28
− 4 − IEC 62766-2-2:2016 IEC 2016
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CONSUMER TERMINAL FUNCTION FOR ACCESS TO IPTV
AND OPEN INTERNET MULTIMEDIA SERVICES –
Part 2-2: HTTP adaptive streaming
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62766-2-2 has been prepared by IEC technical committee 100:
Audio, video and multimedia systems and equipment.
The text of this standard is based on the following documents:
CDV Report on voting
100/2488/CDV 100/2658/RVC
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
This International Standard is to be used in conjunction with IEC 62766-1.
A list of all parts in the IEC 62766 series, published under the general title Consumer terminal
function for access to IPTV and open internet multimedia services, can be found on the IEC
website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
− 6 − IEC 62766-2-2:2016 IEC 2016
INTRODUCTION
The IEC 62766 series is based on a series of specifications that was originally developed by
the OPEN IPTV FORUM (OIPF). They specify the user-to-network interface (UNI) for
consumer terminals to access IPTV and open internet multimedia services over managed or
non-managed networks as defined by OIPF.
CONSUMER TERMINAL FUNCTION FOR ACCESS TO IPTV
AND OPEN INTERNET MULTIMEDIA SERVICES –
Part 2-2: HTTP adaptive streaming
1 Scope
This part of IEC 62766 specifies media formats for adaptive unicast content streaming over
HTTP.
Two HTTP adaptive streaming formats are specified. The first is based entirely on MPEG
DASH. The second is the OIPF “HTTP adaptive streaming” (HAS) format, which is based upon
3GPP’s release 9 adaptive HTTP streaming (AHS) format, with some profiling and extensions
to add the features of media components and support for MPEG-2 transport stream content
segment format. The latter format was specified before MPEG DASH had been published. It is
retained due to usage in some legacy applications.
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.
IEC 62766-1 , Consumer terminal function for access to IPTV and open Internet multimedia
services – Part 1: General
IEC 62766-2-1, Consumer terminal function for access to IPTV and open Internet multimedia
services – Part 2-1: Media formats
IEC 62766-3, Consumer terminal function for access to IPTV and open Internet multimedia
services – Part 3: Content metadata
IEC 62766-4-1 , Consumer terminal function for access to IPTV and open Internet multimedia
services – Part 4-1: Protocols
IEC 62766-5-1 , Consumer terminal function for access to IPTV and open Internet multimedia
services – Part 5-1: Declarative application environment
IEC 62766-6 , Consumer terminal function for access to IPTV and open Internet multimedia
services – Part 6: Procedural application environment
IEC 62766-7 , Consumer terminal function for access to IPTV and open Internet multimedia
services – Part 7: Authentication, content protection and service protection
__________
Under preparation. Stage at the time of publication: IEC/CDV 62766-1:2015
Under preparation. Stage at the time of publication: IEC/CDV 62766-4-1:2015
Under preparation. Stage at the time of publication: IEC/CDV 62766-5-1:2015
Under preparation. Stage at the time of publication: IEC/CDV 62766-6:2015
Under preparation. Stage at the time of publication: IEC/CDV 62766-7:2015
− 8 − IEC 62766-2-2:2016 IEC 2016
ISO/IEC 13818-1:2014, Information technology – Generic coding of moving pictures and
associated audio information – Part 1: Systems
ISO/IEC 14496-12:2012, Information technology – Coding of audio-visual objects – Part 12:
ISO base media file format
ISO/IEC 23001-7:2015, Information technology – MPEG systems technologies – Part 7:
Common encryption in ISO base media file format files
ISO/IEC 23009-1:2014, Information technology — Dynamic adaptive streaming over HTTP
(DASH) — Part 1: Media presentation description and segment formats
ISO 639 (all parts), Codes for the representation of names of languages
ETSI TS 101 154 V1.11.1 (2012-11), Digital Video Broadcasting (DVB); Specification for the
use of Video and Audio Coding in Broadcasting Applications based on the MPEG-2 Transport
Stream
3GPP TS 26.234 V9.3.0 (2010-06), Transparent end-to-end Packet-switched Streaming
Service (PSS) Protocols and codecs (Release 9)
3GPP TS 26.244 V9.2.0 (2010-06), Transparent end-to-end packet switched streaming
service (PSS), 3GPP file format (3GP) (Release 9)
3GPP TS 26.247 V10.1.0 (2011-11), Transparent end-to-end Packet-switched Streaming
Service (PSS), Progressive Download and Dynamic adaptive streaming over HTTP (3GP-
DASH) (Release 10)
Marlin Developer Community, Marlin adaptive streaming Specification – Simple Profile,
Version 1.0, July 2011, available at
Marlin Developer Community, Marlin adaptive streaming Specification – Full Profile,
Version 1.0, August 2011, available at
3 Terms, definitions and abbreviated terms
3.1 General
The terms and definitions specified in 3.2 apply to the OIPF HAS format specified in Clause 6.
Where MPEG DASH defines the same terms in ISO/IEC 23009-1 the DASH definitions apply
to the specification of DASH usage in Clause 5.
3.2 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62766-1 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.2.1
content
instance of audio, video, audio-video information, or data
Note 1 to entry: The content is as defined in IEC 62766-1.
3.2.2
component
element of a content item, for example an audio or subtitle stream in a particular language or
a video stream from a particular camera view
3.2.3
component stream
bit stream that is the result of encoding a component with a certain codec and certain codec
parameters
Note 1 to entry: Examples of parameters are bitrate, resolution.
3.2.4
content resource
content item that is provided in multiple representations to enable adaptive streaming of that
content item
Note 1 to entry: Such representations are multiple qualities, bitrates, camera views, etc.
3.2.5
period
temporal clause of a content resource
3.2.6
representation
version of a content resource within a period
Note 1 to entry: Representations may differ in the included components and the included component streams.
3.2.7
segment
temporal clause of a representation in a specific systems layer format (either MPEG-2TS or
MP4), referred to via a unique URL
3.3 Abbreviated terms
3GPP ETSI 3rd Generation Partnership Project
3GP-DASH 3GPP Dynamic Adaptive Streaming over HTTP
AAC Advanced Audio Coding
AAC LC AAC Low Complexity
ATSC Advanced Television Systems Committee
BBTS Broadband Transport Stream
CA Conditional Access
CAT Conditional Access Table
DAE Declarative Application Environment
DCF DRM Content Format
DRM Digital Rights Management
DVB Digital Video Broadcasting
ECM Entitlement Control Message
EMM Entitlement Management Message
ETSI European Telecommunications Standards Institute
GOP Group Of Pictures
IPMP Intellectual Property Management and Protection
− 10 − IEC 62766-2-2:2016 IEC 2016
IV Initialisation Vector
JPEG Joint Photographic Experts Group
MIPMP Marlin Intellectual Property Management Protocol
MP4 MP4 File Format
MPD Media Presentation Description
MPEG Moving Pictures Expert Group
nPVR Network Personal Video Recorder
NTP Network Time Protocol
OMA Open Mobile Alliance
PAE Procedural Application Environment
PAT Program Association Table
PDCF Packetised DRM Content Format
PF Protected Format
PID Packet Identifier
PMT Program Map Table
RAP Random Access Point
TCA Terminal Centric Approach
4 Adaptive streaming in the OIPF IPTV solution
Rather than providing a content asset as a single file or stream, in the case of HTTP adaptive
streaming, a service provides a content item in multiple bitrates in a way that enables a
terminal to adapt to (for example) variations in the available bandwidth by seamlessly
switching from one version to another, at a higher or lower bitrate, while receiving and playing
the content. This is achieved by encoding a content item in alternative representations of
different bitrates and segmenting these representations into temporally aligned and
independently encoded segments. This results in a matrix of segments, as depicted
generically in Figure 1.
A content item may consist of several components.
Service discovery procedures refer to a content resource. A content resource consists of one
or more time-sequential periods.
Content item
Nominal playback time
Nominal
Representation 1
Segment n Segment n+1 Segment n+2
data
(e.g. high bitrate)
size
Representation 2
Segment n Segment n+1 Segment n+2
(e.g. medium bitrate)
Representation 2
Segment n Segment n+1 Segment n+2
(e.g. low bitrate)
IEC
Figure 1 – Content segmentation for HTTP adaptive streaming
The Segments are offered for HTTP download from a URL that is unique per segment. After
completion of the download (and playback) of a certain segment of a certain representation, a
terminal may switch to an alternate representation simply by downloading (and playing) the
next segment of a different representation. This requires the terminal to have a description of
the available representations and segments and the URLs from which to download the
segments. This description is provided as a separate resource, the media presentation
description (MPD).
The media data in a segment are formatted in compliance with the media formats as defined
in IEC 62766-2-1. However, in the context of HTTP adaptive streaming, additional
requirements are put on the usage of these formats, especially regarding the systems layers.
Similarly, the retrieval mechanisms of segments are in compliance with 6.3.2.2 of
IEC 62766-4-1, with the usage in the context of HTTP adaptive streaming as defined in this
document.
IEC 62766-5-1 specifies the initiation of HTTP adaptive streaming from the DAE.
IEC 62766-6 specifies the initiation of HTTP adaptive streaming from the PAE.
This generic model of adaptive streaming is valid for both variants of adaptive streaming
format defined in this standard.
Clause 5 provides the specification of MPEG DASH based adaptive streaming within the OIPF
IPTV solution.
MPEG DASH can be applied also to the delivery of content to mobile devices via mobile data
networks. This is specified by 3GPP in specification 3GPP TS 26.247. Further details on the
use of 3GP-DASH within the OIPF IPTV solution, as an adaptive bit-rate streaming service to
mobile devices, is out of the scope of the present specification.
Clause 6 provides the equivalent specification based on the OIPF HAS format, which is
maintained only for legacy applications.
5 MPEG DASH based adaptive streaming
5.1 General
This clause specifies the preferred format for adaptive bit-rate streaming content, based on
MPEG DASH (ISO/IEC 23009-1).
One of the profiles defined by MPEG DASH is adopted for use for each of the systems layer
formats specified in IEC 62766-2-1, namely MPEG-2 TS and MP4 file format. Subclauses 5.2
and 5.3 specify the application of DASH to each of the OIPF systems layers.
Subclause 5.4 specifies constraints and recommendations for operational parameters with the
two selected DASH profiles.
Subclause 5.5 makes provisions and recommendations about audio and video source coding
within an Adaptation Set, including concerning the variations of audio-video coding
parameters that enable different bit-rate versions of the content to be provided.
Subclause 5.6 specifies constraints for key management of protected content.
− 12 − IEC 62766-2-2:2016 IEC 2016
MPEG DASH based adaptive bit-rate streaming content is also relevant for the “embedded
CSPG” concept described in Annex F of IEC 62766-7:— . Usage of MPEG DASH in this
scenario is described in Annex D.
5.2 DASH usage for the TS systems layer format
5.2.1 General
For MPEG-2 TS based content (system format TS, as specified in IEC 62766-2-1), the
MPEG-2 TS simple profile, as defined in 8.7 of ISO/IEC 23009-1:2014, is adopted, with the
additional restrictions and constraints as specified in this subclause. This constitutes the
definition of an interoperability point of the MPEG DASH MPEG-2 TS simple profile. This
interoperability point is identified with the URI “urn:oipf:dash:profile:ts:2012” and is called the
“OIPF MPEG-2 TS simple” interoperability point.
Additional constraints are placed on the use of the MPEG-2 TS simple profile regarding PID
value allocations to the component streams contained in the DASH segments. These are
specified in 5.2.2.
This document does not provide any adaptive bit-rate streaming method for use with the TTS
format.
5.2.2 PID allocation
The value of the id attribute in each component element, if present, shall be set equal to the
PID value of the TS packets that carry the component.
The following rules apply regarding TS PID values used in the segments belonging to
representations within an adaptation set:
• component streams of the same component shall be carried in TS packets that have the
same PID (in transport stream packet header) and the same stream_id (in PES packet
header);
• component streams of different components shall be carried in TS packets that have
different PIDs (in TS packet header).
The following depicts some examples:
• "audio in Spanish" and "audio in English" have different PIDs;
• "audio in English" and "audio description for hearing impaired in English" have different
PIDs;
• "audio description in English at 64 kbit/s" and "audio description in English at 128 kbit/s"
have the same PID;
• "video angle 1 in ITU-T Recommendation H.264 at 720x576" and "video angle 1 in H.264
at 320x288" have the same PID.
5.2.3 Protected TS content
5.2.3.1 General
The BBTS and PF protected formats are compatible with provision by adaptive bit-rate
streaming as specified in this subclause.
The following general requirements apply if segments are protected.
__________
Under preparation. Stage at the time of publication: IEC/CDV 62766-7:2015.
• The DRM related metadata (i.e. PMT containing CA descriptors, CAT, EMM streams or
ECM streams) in relation to a certain elementary stream shall be delivered as part of the
media segments that carry the samples of the elementary stream or the initialisation
segment.
• The DRM related metadata (i.e. ECM stream) of the CA system that applies to a certain
elementary stream shall have the same PID in all segments, in all representations, in
which it is included.
The following subclauses specify further specific details of DASH usage that apply to the
BBTS and PF formats.
The MPEG2-TS Simple profile defined in DASH guarantees that the OITF can play any
bitstream generated by the concatenation of consecutive segments from any representation
within the same adaptation set. The same guarantee shall apply to protected MPEG2-TS
segments. Note that BBTS and PF formats are conformant with ISO/IEC 13818-1. This
guarantee may be achieved by using the same crypto-period boundaries and control words
across different representations, in which case there is no further impact from adaptive
streaming on the CSP solutions specified in IEC 62766-7.
5.2.3.2 DASH usage for BBTS format
For the TCA, content items provided in the BBTS format shall include the DASH
ContentProtection element in the MPD, as specified in Clause 2 of Marlin adaptive
streaming specification – simple profile or Marlin adaptive streaming specification – full profile.
The ContentProtection element shall contain mandatory Marlin related information (i.e.
the @schemeIdUri attribute with specified URI signalling that the segments are protected by
Marlin).
5.2.3.3 DASH usage for PF format
Content items provided in the PF protected format for the CSPG-CI+ content protection
scheme, as defined in IEC 62766-7, shall include the DASH ContentProtection element in
the MPD, as specified for ISO/IEC 13818-1 (MPEG-2 transport stream) in 5.8.5.2 of
ISO/IEC 23009-1:2014.
The @value attribute shall be set to the required representation of the appropriate DVB
CA_system_id. The DVB CA_system_id usage is specified in IEC 62766-7.
5.3 DASH usage for the MP4 systems layer format
5.3.1 General
For MP4 file format based content (system format MP4, as specified in IEC 62766-2-1 the
ISO base media file format live profile, as defined in 8.4 of ISO/IEC 23009-1:2012, is adopted,
with the additional restrictions and constraints as specified in the present clause. This
constitutes the definition of an interoperability point of the MPEG DASH ISOBMFF live profile.
This interoperability point is identified with the URI urn:oipf:dash:profile:isoff-live:2012 and is
called the “OIPF ISOBMFF live” interoperability point.
5.3.2 Protected content
5.3.2.1 General
The present document does not provide any adaptive bit-rate streaming method for use with
the DCF or PDCF protected format.
The MP4 common encryption format specified in ISO/IEC 23001-7 and the MIPMP protected
format are compatible with provision by adaptive bit-rate streaming as specified in this
subclause.
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5.3.2.2 DASH usage for protected MP4 format content in the TCA
For the TCA, content items provided in the protected MP4 file format shall include both the
DASH ContentProtection element in the MPD, and the MP4 extensions as specified in
clause 2 of Marlin adaptive streaming specification – simple profile or Marlin adaptive
streaming specification – full profile, whereby the ContentProtection element contains
mandatory Marlin related information (i.e. the @schemeIdUri attribute with specified URI
signalling that the segments are protected by Marlin). Note that Marlin adaptive streaming
specification – simple profile and Marlin adaptive streaming specification – full profile both in
turn refer to MPEG Common Encryption ISO/IEC 23001-7.
For content items provided in the MP4 common encryption format (Marlin adaptive streaming
specification – simple profile clause 2.3), if a segment is protected, the following restrictions
shall apply:
• when a protection system specific header (pssh) box for Marlin is delivered in content, the
box shall be delivered as part of the initialization segment and located in the movie (moov)
box.
5.4 Operational parameters
The DASH specification and the profiles defined therein do not set any limits to the number of
periods, adaptation sets, representations, etc. Hence the following operational constraints and
assertions apply to the usage of DASH for both systems layer formats, in the interest of
reasonable OITF implementation and predictable user experience.
• It is recommended to organise adaptive bit-rate content into the minimum number of
periods and adaptation sets needed for its presentation.
• The OITF shall support the processing of at least 16 representations per adaptation set.
• It is recommended that not more than 16 representations are provided in each adaptation
set.
5.5 Adaptation set audio/video source coding
Content segment source coding and corresponding settings of common Adaptation Set and
Representation video and audio coding parameters shall correspond to those of the video and
audio media formats defined in IEC 62766-2-1.
Content and service providers would like to have maximum flexibility with the application of
adaptive streaming, in order to cover as much as possible the likely variations in throughput
among all consumers of any content item. Maximum flexibility in terms of audio and video
coding means the ability to vary any respective coding parameter among the set of
representations provided. On the other hand, since it is a new concept that audio and video
coding parameters would be changed “on the fly” at the decoder, it is obvious that many
current implementation platforms will not be able to deal with certain kinds of changes
seamlessly, i.e. without noticeable artefacts. Some changes might not be desirable for the
user at all.
The following restrictions apply to all representations within the same adaptation set:
• all video component streams shall be coded using the same video codec;
• the inclusion both interlaced and progressive scan video components is not recommended;
• the inclusion of video components with different frame or field rates is not recommended;
• all audio component streams shall be coded using the same audio codec;
• the inclusion of audio components with different audio channel configurations is not
recommended;
• the inclusion of audio components with different audio sampling rates is not recommended.
In order to avoid artefacts when switching is called for between parameters critical for the
host platform, the OITF (as a DASH client) implementation may opt not to make one or more
representations available for rendering. Thus the DASH client needs to have all relevant
information in the MPD about the video and audio coding parameters of all provided
representations. The carriage of this information in DASH is documented in Table 10 of
ISO/IEC 23009-1:2014, “Common Adaptation Set, Representation and Sub-Representation
attributes and elements”.
• For video components it is recommended that accurate information about coding
parameters is provided for each Representation in the following attributes:
– Resolution: @width, @height and @sar.
– Frame/field rate and scan format: @frameRate and @scanType respectively.
• For audio components it is recommended that accurate information about the following
coding parameters is provided for each provided representation:
– Sampling rate: @audioSamplingRate.
– Channel configuration: AudioChannelConfiguration element.
5.6 MPD requirements, audio description
If the content item includes audio description components then the MPD shall identify these
using the Role and Accessibility descriptors as defined in Table 1. Furthermore for
receiver mix AD, the associated audio stream shall use depdendencyId to indicate the
dependency to the main representation, and imply that the associated audio stream shall not
be provided as a representation on its own.
Table 1 – Role and accessibility descriptor values for audio description
Role descriptor Accessibility descriptor
schemeIdUri urn:mpeg:dash:role:2011 urn:tva:metadata:AudioPurposeCS:2007
Value Broadcast mix AD alternate “1” – for the visually impaired, or
Receiver mix AD commentary
Clean Audio alternate “2” – for the hard of hearing
5.7 Key management of protected contents
For the TCA, the content keys required to access the protected media segments in the
representations available to the OITF in a period are delivered within a single Marlin license.
A Marlin license bundle can include multiple content ID/Content key pairs, which can be used
for different representations, adaptation sets and periods.
6 OIPF HTTP adaptive streaming
6.1 General
This clause specifies the OIPF HTTP adaptive streaming (HAS) format. HAS is based on, but
also defines extensions to the 3GPP release 9 specifications 3GPP TS 26.234 and 3GPP TS
26.244, to enable HTTP based adaptive streaming services to be delivered to the OITF.
The HAS MPD is described in 6.2.1.
A representation may be made up of multiple components, for example audio, video and
subtitle components. A partial representation may only contain some of these components
and a terminal may need to download (and play) multiple partial representations to build up a
− 16 − IEC 62766-2-2:2016 IEC 2016
complete representation, with the appropriate components according to the preferences and
wishes of the user. Annex B has a more detailed description on the use of partial
representations with OIPF HAS.
6.2 Media presentation
6.2.1 Media presentation description
The OIPF HAS media presentation description (MPD) shall be as specified in 12.2 of
3GPP TS 26.234:2010, with the following extensions and additional requirements:
• The MPD shall be an XML file that shall validate against the schema in Annex A. Note that
the XML schema in Annex A imports the schema specified of 3GPP TS 26.234. This
means that an MPD that does not use any of the OIPF specific extensions will validate
against both the schema defined in 3GPP TS 26.234 as well as in Annex A.
• A element may carry the @group-attribute set to a non-zero value. In
this case the attribute indicates that the element is not necessarily a
complete representation, but consists of one or more individual components (video, audio,
subtitle, etc.) which may be downloaded and provided to the terminal in addition to content
being downloaded from other elements. In this case the
element shall contain one or more elements, as specified
in 6.2.2, one for each component contained in the . Note that it is the
responsibility of the application on the terminal to select the desired components and to
initialize the terminal accordingly. Annex B contains an informative description of how this
can be done. The value of the @group-attribute shall be the same for representations that
contain at least one same component. Two representations with completely different
components (e.g. audio at two different languages) shall have different values for the
@group attribute.
An example instance of the OIPF compliant MPD with the constraints from 6.3 is depicted in
Figure 2.
6.2.2 Component element
Table 2 lists the contents of the component element.
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