1、BSI Standards Publication BS ISO/IEC 23001-12:2015 Information technology MPEG systems technologies Part 12: Sample Variants in the ISO base media file formatBS ISO/IEC 23001-12:2015 BRITISH STANDARD National foreword This British Standard is the UK implementation of ISO/IEC 23001-12:2015. The UK pa
2、rticipation in its preparation was entrusted to Technical Committee IST/37, Coding of picture, audio, multimedia and hypermedia information. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessa
3、ry provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2015. Published by BSI Standards Limited 2015 ISBN 978 0 580 87625 7 ICS 35.040 Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard wa
4、s published under the authority of the Standards Policy and Strategy Committee on 31 December 2015. Amendments/corrigenda issued since publication Date T e x t a f f e c t e dBS ISO/IEC 23001-12:2015 Information technology MPEG systems technologies Part 12: Sample Variants in the ISO base media file
5、 format Technologies de linformation Technologies des systmes MPEG Partie 12: Variantes dchantillon dans le format ISO de base pour les fichiers mdias INTERNATIONAL STANDARD ISO/IEC 23001-12 Reference number ISO/IEC 23001-12:2015(E) First edition 2015-12-15 ISO/IEC 2015 BS ISO/IEC 23001-12:2015ii IS
6、O/IEC 2015 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO/IEC 2015, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or po
7、sting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax
8、 +41 22 749 09 47 copyrightiso.org www.iso.org ISO/IEC 23001-12:2015(E)BS ISO/IEC 23001-12:2015ISO/IEC 23001-12:2015(E)Foreword iv 1 Scope . 1 2 Normative references 1 3 Terms, definitions and abbreviated terms 1 3.1 Terms and definitions . 1 3.2 Abbreviated terms . 2 4 Overview (informative) . 2 5
9、Variant Constructors 4 5.1 Overview 4 5.2 Access to Variant Constructors . 4 5.3 Encryption of Variant Constructors 5 6 Variant Byte Ranges 5 6.1 Overview 5 6.2 Access to Variant Byte Ranges . 5 6.3 Encryption of Variant Byte range information 6 7 Sample Variants . 6 7.1 Overview 6 7.2 Access to Sam
10、ple Variants . 6 7.3 Encryption of Sample Variants 6 8 ISO storage 6 8.1 Overview 6 8.2 Variant tracks . 7 8.2.1 Definition 7 8.2.2 Association 7 8.2.3 Variant Metadata Sample Entry 7 8.3 Sample data 8 8.3.1 Variant Data 8 8.3.2 Variant Constructor list 8 8.3.3 Variant Constructor . 9 8.3.4 Encrypti
11、on 11 8.3.5 Association .12 9 Variant Processor Model and Example (Informative) 12 9.1 Variant Processor Model .12 9.2 Example 13 ISO/IEC 2015 All rights reserved iii Contents PageBS ISO/IEC 23001-12:2015ISO/IEC 23001-12:2015(E) Foreword ISO (the International Organization for Standardization) and I
12、EC (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
13、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
14、established a joint technical committee, ISO/IEC JTC 1. 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 note
15、d. 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 subject of patent rights. ISO and IEC shall not be held responsible for iden
16、tifying 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). Any trade name used in this document is information given for the conven
17、ience of users and does not constitute an endorsement. For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword
18、- Supplementary information The committee responsible for this document is ISO/IEC JTC 1, Information technology, SC 29, Coding of audio, picture, multimedia and hypermedia information. ISO/IEC 23001 consists of the following parts, under the general title Information technology MPEG systems technol
19、ogies: Part 1: Binary MPEG format for XML Part 2: Fragment request units Part 3: XML IPMP messages Part 4: Codec configuration representation Part 5: Bitstream Syntax Description Language (BSDL) Part 7: Common encryption in ISO base media file format files Part 8: Coding-independent code points Part
20、 9: Common encryption of MPEG-2 transport streams Part 10: Carriage of timed metadata metrics of media in ISO base media file format Part 11: Energy-efficient media consumption (green metadata) Part 12: Sample Variants in the ISO base media file formativ ISO/IEC 2015 All rights reservedBS ISO/IEC 23
21、001-12:2015INTERNATIONAL ST ANDARD ISO/IEC 23001-12:2015(E) Information technology MPEG systems technologies Part 12: Sample Variants in the ISO base media file format 1 Scope This part of ISO/IEC 23001 defines the carriage of Sample Variants in the ISO base media file format (ISO/IEC 14496-12). 2 N
22、ormative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendmen
23、ts) applies. ISO/IEC 14496-12:2015 1) , 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 3 Terms, definitions and abbreviated
24、terms 3.1 Terms and definitions 3.1.1 Double Encrypted Sample Variant byte range data encrypted by first a Media Key (as part of the encryption of the complete Sample Variant) and then second a Variant Byte Range key Note 1 to entry: See 6.1. 3.1.2 Media Key encryption key associated with one or mor
25、e media samples 3.1.3 Media KID encryption KID associated with one or more media samples 3.1.4 Sample Variant assembled media sample replacing an original sample 3.1.5 Variant Byte Range location of a sequence of bytes that might constitute a portion of a Sample Variant 1) ISO/IEC 14496-12 is techni
26、cally identical to ISO/IEC 15444-12. ISO/IEC 2015 All rights reserved 1BS ISO/IEC 23001-12:2015ISO/IEC 23001-12:2015(E) 3.1.6 Variant Constructor Sample Variant metadata that defines how to assemble an individual Sample Variant 3.1.7 Variant Media Data media data used to construct a Sample Variant,
27、some of which may come from the original sample media data 3.1.8 Variant Processor logical module that performs the processing steps that implement the process of assembling Sample Variants 3.2 Abbreviated terms For the purposes of this document, the following abbreviated terms apply. CENC Common EN
28、Cryption (as specified by ISO/IEC 23001-7:2015) DRM Digital Rights Management ISOBMFF ISO Base Media File Format (as specified by ISO/IEC 14496-12:2015) IV Initialization Vector KID Key Identifier 4 Overview (informative) This part of ISO/IEC 23001 defines a framework for the carriage of Sample Vari
29、ants in the ISOBMFF. Sample Variants are typically used to provide forensic information in the rendered sample data that can, e.g. identify the DRM client. This variant framework is intended to be fully compatible with ISOBMFF and CENC, and agnostic to the particular forensic marking system used. Th
30、e Sample Variant framework uses three core constructs to define and carry Sample Variant data in ISOBMFF: Variant Constructors, Variant Byte Ranges and Variant Samples. NOTE The Variant Process Model described in Clause 9 can also assist in introducing the concepts. Figure 1 shows a scenario where a
31、 sample (Sample 2) has a number of Sample Variants. Figure 1 shows 3 samples in a series left to right, the middle of which has variants. The top row is a conceptual depiction of what is encoded using ISOBMFF and the bottom row shows what is output after Sample Variant processing. Access to samples
32、is under the control of KIDs as depicted in the top row of in Figure 1. For Sample Variants, a hierarchy of KIDs is used to provide access to data, with the higher level KIDs providing access to Sample Variant Metadata and the lower level KIDs providing access to media data.2 ISO/IEC 2015 All rights
33、 reservedBS ISO/IEC 23001-12:2015ISO/IEC 23001-12:2015(E) Figure 1 Sample Variant structure The control point for the use of the proposed framework is the content publisher: the content publisher will encode encrypted, compressed Sample Variant data into the ISOBMFF file and ensure that each set of
34、Sample Variant data for a given sample time is encrypted with a different key and signalled with a different KID. the content publisher will work with the DRM to manage the release of KIDs/keys such that the playback path (the actual sample data used during playback) is controlled and the player can
35、 only decrypt and render the data that it has been authorized to render. The decoder model for the processing of the file is shown in Figure 2. Critical to the Sample Variant decoding process is control over if and how the Sample Variants are processed. NOTE The decrypt and decode steps are standard
36、 operations as they would be for any CENC-enabled decoder. ISO/IEC 2015 All rights reserved 3BS ISO/IEC 23001-12:2015ISO/IEC 23001-12:2015(E) Figure 2 Variant Decoder Model By operating in the encrypted/compressed domain, secure baseband link operation (e.g. dedicated, secure video pathways) is pres
37、erved and is intended to be fully compatible with CENC. 5 Variant Constructors 5.1 Overview A Variant Constructor defines which bytes are used to assemble a Sample Variant. There may be one or more Variant Constructors defined for a given ISOBMFF sample. The Variant Processor may use a Variant Const
38、ructor if the Variant Processor has access to the Variant Constructor. In addition to the presence of the Variant Constructor, “access” includes cryptographic access. A Variant Constructor defines which data is used to assemble a Sample Variant and the associated Media KID and initialization vector
39、for decrypting the Sample Variant. 5.2 Access to Variant Constructors If the decoder is given access to the Media Key for the sample defined by the ISOBMFF media track, Sample Variant processing will not occur for this sample. If the decoder does not have access to the original Media Key for the sam
40、ple defined by the ISOBMFF media track, the Variant Processor shall be given access to one Variant Constructor associated with the sample. The KID/Key associated with the Variant Constructor controls access to a particular Variant Constructor and is therefore a function of the set of KID/Key value p
41、airs made available to the Variant Processor by the DRM. Only one Variant Constructor per sample should be made available to the Variant Processor. If the Variant Processor is given access to a Variant Constructor, the decoder shall also be given access to the Media Key associated with the Media KID
42、 defined in the Variant Constructor. If the Variant Processor has access to more than one KID/Key associated with Variant Constructor for a given sample, the Variant Processor utilizes the first Variant Constructor that it has access to in data encoding order. The Variant Processor uses exactly one
43、Variant Constructor to assemble a Sample Variant.4 ISO/IEC 2015 All rights reservedBS ISO/IEC 23001-12:2015ISO/IEC 23001-12:2015(E) 5.3 Encryption of Variant Constructors Each Variant Constructor shall be encrypted with a “Variant Constructor key”. As a Variant Processor is provided only with the Va
44、riant Constructor keys for the Variant Constructor that is to be used by that particular Variant Processor, any Variant Constructors not used by that Variant Processor are not exposed by a security compromise of that Variant Processor. 6 Variant Byte Ranges 6.1 Overview Each Variant Constructor defi
45、nes a sequence of one or more Variant Byte Ranges. Each Variant Byte Range defines the location of a sequence of bytes that might constitute bytes in a Sample Variant. Variant Byte Ranges can contain unused data. The sequence of Variant Byte Ranges defined in a Variant Constructor are grouped into o
46、ne or more Variant Byte Range groups. Each Variant Byte Range group shall define one or more Variant Byte Ranges. An individual Variant Byte Range within a Variant Byte Range group: May reference bytes of data that constitute bytes in a Sample Variant that is made available to certain Variant Proces
47、sors (“real Variant Byte Range”). May reference bytes of data that are not made available to any Variant Processor (“fake Variant Byte Range”). A “fake Variant Byte Range” can be used to hide the amount of actual “real Variant Byte Ranges” defined within a Variant Constructor. The Variant Processor
48、uses all Variant Byte Ranges that it has access to. In addition to the presence of the Variant Byte Range, “access” includes cryptographic access. Data for different Sample Variants can be stored non-contiguously as referenced by different Variant Constructors. Data for a particular Sample Variant c
49、an also be stored non-contiguously using a sequence of two or more Variant Byte Ranges. 6.2 Access to Variant Byte Ranges If a Variant Byte Range within a Variant Byte Range group signals that the data referenced by the Variant Byte Range is unencrypted (and the Variant Processor has access to the Variant Constructor), then the Variant Processor has access to the Variant Byte Range and the associated unencrypted bytes. If the Variant Byte Range defined wit
