Information technology -- Multimedia application format (MPEG-A)

This document specifies the CMAF multimedia format, which contains segmented media objects optimized for streaming delivery and decoding on end user devices in adaptive multimedia presentations. CMAF specifies a track format derived from the ISO base media file format, then derives addressable media objects from CMAF tracks that can be used for storage and delivery. CMAF specifies sets of tracks that share encoding and packaging constraints that enable the selection of multiple tracks to form a multimedia presentation and allow seamless switching of alternative encodings of the same content at different bit rates, frame rates, resolution, etc. CMAF specifies a hypothetical application model that determines how tracks in a CMAF presentation are intended to be combined and synchronized to form a multimedia presentation. The model abstracts delivery to allow any delivery method. The hypothetical application model assumes a manifest and player, but CMAF does not specify a manifest, player, or delivery protocol, with the intent that any that support the hypothetical application model can be used. CMAF specifies media profiles and brands that constrain media encoding and packaging of CMAF tracks to enable seamless adaptive switching of tracks and allow devices to identify compatible content by its brand. CMAF specifies presentation profiles that conditionally require sets of CMAF tracks conforming to specified media profiles and allow content creators and devices to identify compatible multimedia presentations. CMAF enables extensibility by specifying how new media profiles and presentation profiles can be specified and identified and includes guidelines for those specifications.

Technologies de l'information -- Format pour application multimédia (MPEG-A)

General Information

Status
Published
Publication Date
18-Mar-2020
Current Stage
6060 - International Standard published
Start Date
27-Feb-2020
Completion Date
19-Mar-2020
Ref Project

RELATIONS

Buy Standard

Standard
ISO/IEC 23000-19:2020 - Information technology -- Multimedia application format (MPEG-A)
English language
124 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

INTERNATIONAL ISO/IEC
STANDARD 23000-19
Second edition
2020-03
Information technology — Multimedia
application format (MPEG-A) —
Part 19:
Common media application format
(CMAF) for segmented media
Technologies de l'information — Format pour application multimédia
(MPEG-A) —
Partie 19: Format CMAF (Common Media Application Format) pour
médias segmentés
Reference number
ISO/IEC 23000-19:2020(E)
ISO/IEC 2020
---------------------- Page: 1 ----------------------
ISO/IEC 23000-19:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2020

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
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO/IEC 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/IEC 23000-19:2020(E)
Contents Page

Foreword ......................................................................................................................................................................................................................................vii

Introduction ............................................................................................................................................................................................................................viii

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

3.1 Media objects ............................................................................................................................................................................................ 3

3.2 Logical structure .................................................................................................................................................................................... 3

3.3 Application model ................................................................................................................................................................................ 4

4 Abbreviated terms .............................................................................................................................................................................................. 6

5 Document organization ................................................................................................................................................................................. 8

6 CMAF hypothetical application model, media object model and profiles .............................................10

6.1 Overview of the hypothetical application model and media object model .....................................10

6.2 CMAF content processing model ..........................................................................................................................................11

6.3 Late binding CMAF track synchronization ...................................................................................................................12

6.4 Adaptive switching of CMAF tracks in CMAF switching sets ........................................................................13

6.5 CMAF specified objects and profiles..................................................................................................................................14

6.5.1 Object derivation and interoperability code points .......................................................................14

6.5.2 Encoded media objects ........................................................................................................................................... .14

6.5.3 Logical media object sets .......................................................................................................................................14

6.5.4 Addressable media objects ..................................................................................................................................14

6.5.5 CMAF profiles, brand and identifiers ..........................................................................................................15

6.6 CMAF media object model .........................................................................................................................................................16

6.6.1 CMAF fragments ............................................................................................................................................................16

6.6.2 CMAF tracks ......................................................................................................................................................................17

6.6.3 CMAF track files .............................................................................................................................................................17

6.6.4 CMAF segments ...................................................................... ........................................................................................18

6.6.5 CMAF chunks ...................................................................... ..............................................................................................18

6.6.6 CMAF switching sets and adaptive switching ......................................................................................19

6.6.7 CMAF selection sets and late binding .........................................................................................................22

6.6.8 CMAF presentation timing model ..................................................................................................................23

6.6.9 Manifest information.................................................................................................................................................26

6.6.10 CMAF addressable media objects, resources, and resource identifiers ........................26

7 CMAF track format ...........................................................................................................................................................................................27

7.1 Overview ...................................................................................................................................................................................................27

7.2 CMAF brands..........................................................................................................................................................................................27

7.3 CMAF media objects ........................................................................................................................................................................28

7.3.1 CMAF boxes .......................................................................................................................................................................28

7.3.2 CMAF track media objects ....................................................................................................................................30

7.3.3 CMAF addressable media objects ...................................................................................................................34

7.3.4 CMAF switching sets ..................................................................................................................................................36

7.3.5 CMAF selection sets ........................................................................................................................................... .........39

7.3.6 CMAF presentations ...................................................................................................................................................39

7.4 Additional boxes, not defined in the ISO Base Media File Format ...........................................................40

7.4.1 Track Encryption Box ('tenc') ........................................................................................................................40

7.4.2 Sample Encryption Box ('senc') .................. ..................................................................................................40

7.4.3 Protection System Specific Header Box ('pssh') .............................................................................40

7.4.4 Media profile specific boxes ................................................................................................................................40

7.4.5 Event Message Box ('emsg') ..............................................................................................................................40

7.5 Constraints on ISO Base Media File Format boxes ................................................................................................41

7.5.1 Movie Header Box ('mvhd') ................................................................................................................................41

7.5.2 Metadata Boxes ..............................................................................................................................................................41

7.5.3 Kind Box ('kind') ........................................................................................................................................................41

© ISO/IEC 2020 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/IEC 23000-19:2020(E)

7.5.4 Track Header Box ('tkhd') ..................................................................................................................................42

7.5.5 Media Header Box ('mdhd') ................................................................................................................................42

7.5.6 Video Media Header Box ('vmhd') ................................................................................................................42

7.5.7 Sound Media Header Box ('smhd') ...............................................................................................................43

7.5.8 Subtitle Media Header Box ('sthd') ...........................................................................................................43

7.5.9 Data Reference Box ('dref') .............................................................................................................................43

7.5.10 Sample Description Box ('stsd') ..................................................................................................................43

7.5.11 Protection Scheme Information Box ('sinf') ....................................................................................43

7.5.12 Track contained media sample information boxes .........................................................................43

7.5.13 Edit List Box ('elst') ...............................................................................................................................................44

7.5.14 Track Extends Box ('trex') ................................................................................................................................44

7.5.15 Movie Fragment Header Box ('mfhd') .......................................................................................................44

7.5.16 Track Fragment Header Box ('tfhd') ........................................................................................................44

7.5.17 Track Run Box ('trun') ..........................................................................................................................................45

7.5.18 Sample Group Description Box ('sgpd') .................................................................................................45

7.5.19 Media Data Box ('mdat') .......................................................................................................................................45

7.5.20 Sub-sample Information Box ('subs') ......................................................................................................46

7.6 The Structural CMAF Brand 'cmfc' ..................................................................................................................................46

7.7 The structural CMAF Brand 'cmf2' ..................................................................................................................................46

7.7.1 General...................................................................................................................................................................................46

7.7.2 Edit List Box ('elst') ...............................................................................................................................................46

7.7.3 Track Run Box ('trun') ..........................................................................................................................................46

8 Common encryption of CMAF tracks ............................................................................................................................................46

8.1 Multiple DRM system support ................................................................................................................................................46

8.2 Track encryption ................................................................................................................................................................................47

8.2.1 General requirements ...............................................................................................................................................47

8.2.2 CMAF track constraints ...........................................................................................................................................48

8.2.3 Encryption constraints ............................................................................................................................................49

8.2.4 CMAF presentation encryption ........................................................................................................................50

9 Video CMAF tracks ...........................................................................................................................................................................................50

9.1 Overview ...................................................................................................................................................................................................50

9.2 General video CMAF track format .......................................................................................................................................51

9.2.1 General video CMAF track structure and constraints ...................................................................51

9.2.2 Video Media Header ('vmhd') ...........................................................................................................................51

9.2.3 Track Header Box ('tkhd') ..................................................................................................................................52

9.2.4 Sample Description Box ('stsd') ..................................................................................................................52

9.2.5 Video CMAF fragment presentation time ................................................................................................53

9.2.6 Video media sample dependencies ...............................................................................................................53

9.2.7 Video edit lists .................................................................................................................................................................53

9.2.8 General video CMAF fragment random access constraints......................................................53

9.2.9 Additional random access pictures within CMAF video fragments ..................................53

9.2.10 Image framing and encoding constraints ................................................................................................54

9.2.11 General video CMAF switching set constraints ..................................................................................54

9.3 NAL structured video CMAF tracks ....................................................................................................................................55

9.3.1 Overview ..............................................................................................................................................................................55

9.3.2 CMAF track format constraints for NAL structured video ........................................................56

9.3.3 NAL structured video access units contained in media samples ........................................57

9.3.4 NAL structured video coding sequences corresponding to CMAF fragments .........57

9.3.5 Elementary stream constraints ........................................................................................................................58

9.3.6 General CMAF switching set constraints for NAL structured video .................................58

9.3.7 Single initialization CMAF switching set constraints for NAL structured

video tracks and media profiles .......................................................................................................................58

9.4 AVC video CMAF tracks .................................................................................................................................................................59

9.4.1 Storage of AVC elementary streams .............................................................................................................59

9.4.2 Constraints on AVC elementary streams ..................................................................................................60

9.5 AVC video Internet Media Type parameters ...............................................................................................................61

9.5.1 AVC signalling of "codecs" parameters .....................................................................................................61

iv © ISO/IEC 2020 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/IEC 23000-19:2020(E)

10 Audio CMAF tracks ...........................................................................................................................................................................................62

10.1 Overview ...................................................................................................................................................................................................62

10.2 General audio CMAF track format .......................................................................................................................................62

10.2.1 Derivation ...........................................................................................................................................................................62

10.2.2 Track Header Box ('tkhd') ..................................................................................................................................62

10.2.3 Sound Media Header Box ('smhd') ...............................................................................................................63

10.2.4 Sample Description Box ('stsd') ..................................................................................................................63

10.2.5 AudioSampleEntry ......................................................................................................................................................63

10.2.6 Audio offset edit list ...................................................................................................................................................63

10.3 AAC audio CMAF tracks ................................................................................................................................................................63

10.3.1 Overview ..............................................................................................................................................................................63

10.3.2 "codecs" parameter signalling .........................................................................................................................63

10.3.3 Considerations for AAC audio encoding ...................................................................................................64

10.3.4 AAC track constraints ...............................................................................................................................................65

10.3.5 AAC elementary stream constraints ............................................................................................................66

10.4 AAC core audio CMAF media profile .................................................................................................................................67

10.5 AAC adaptive switching audio CMAF media profile .............................................................................................67

10.5.1 General constraints .....................................................................................................................................................67

10.5.2 CMAF fragment encoding constraints ........................................................................................................68

10.5.3 General considerations and requirements .............................................................................................68

10.5.4 Constraints for AAC-LC ............................................................................................................................................68

10.5.5 Constraints for HE-AAC ...........................................................................................................................................69

10.5.6 Constraints for HE-AACv2 .....................................................................................................................................70

11 Subtitles and captions ..................................................................................................................................................................................71

11.1 Overview ...................................................................................................................................................................................................71

11.2 WebVTT ......................................................................................................................................................................................................71

11.3 IMSC text and image tracks .......................................................................................................................................................72

11.3.1 General...................................................................................................................................................................................72

11.3.2 Common constraints .................................................................................................................................................72

11.3.3 IMSC1 text track constraints ...............................................................................................................................73

11.3.4 IMSC1 image track constraints .........................................................................................................................73

11.4 CTA-608 and CTA-708 ....................................................................................................................................................................73

11.5 Metadata for subtitles ....................................................................................................................................................................74

12 CMAF media profiles and CMAF presentation profiles ..............................................................................................74

12.1 CMAF media profiles .......................................................................................................................................................................74

12.1.1 General guidelines for specifying CMAF media profiles .............................................................74

12.1.2 Guidelines for audio CMAF media profiles .............................................................................................75

12.1.3 Guidelines for video CMAF media profiles .............................................................................................75

12.2 CMAF presentation profiles ......................................................................................................................................................76

12.2.1 General...................................................................................................................................................................................76

12.2.2 CMAF profile conformance ..................................................................................................................................76

Annex A (normative) CMAF presentation profiles, media profiles and supplemental data ....................79

Annex B (normative) HEVC video CMAF track format and CMAF media profiles ...............................................83

Annex C (informative) Subsampling of NAL structured video tracks in CMAF switching sets ...............88

Annex D (informative) Hypothetical player model .............................................................................................................................98

Annex E (informative) Event messages .......................................................................................................................................................101

Annex F (informative) Error handling for missing media .......................................................................................................102

Annex G (informative) Recommendations for AAC CMAF switching set encoding ........................................103

Annex H (normative) Scalable HEVC media profile and track format ........................................................................106

Annex I (normative) AAC multichannel CMAF media profiles and track format ............................................112

Annex J (normative) MPEG-H 3D audio track format and CMAF media profile ................................................115

Annex K (normative) MPEG-D USAC track format and CMAF media profile ........................................................120

© ISO/IEC 2020 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO/IEC 23000-19:2020(E)

Annex L (normative) IMSC 1.1 media profiles .....................................................................................................................................122

Bibliography .........................................................................................................................................................................................................................124

vi © ISO/IEC 2020 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/IEC 23000-19:2020(E)
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).

Attention is drawn to the possibility that some of the elements of this document may be the sub

...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.