1、Information technology Dynamic adaptive streaming over HTTP (DASH) Part 1: Media presentation description and segment formats AMENDMENT 1: High Profile and Availability Time Synchronization Technologies de linformation Diffusion en flux adaptatif dynamique sur HTTP (DASH) Partie 1: Description de la
2、 prsentation et formats de remise des mdias AMENDEMENT 1 INTERNATIONAL STANDARD ISO/IEC 23009-1 Second edition 2014-05-15 Reference number ISO/IEC 23009-1:2014/Amd.1:2015(E) AMENDMENT 1 2015-06-15 ISO/IEC 2015 ii ISO/IEC 2015 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO/IEC 2015, Published i
3、n 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 posting on the internet or an intranet, without prior written permission. Permission ca
4、n 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 +41 22 749 09 47 copyrightiso.org www.iso.org ISO/IEC 23009-1:2014/Amd.1:2015(E)ISO/
5、IEC 23009-1:2014/Amd.1:2015(E) ISO/IEC 2015 All rights reserved iiiContents Page Foreword iv 7.3.1 General . 9 8.7 ISO base Media File Format Extended Live profile 14 8.7.1 General . 14 8.7.2 Media Presentation Description constraints 14 8.7.3 Segment format constraints . 15 8.7.4 Inband Events 15 8
6、.8 ISO Base Media File Format Extended On Demand profile 15 8.8.1 General . 15 8.8.2 Media Presentation Description constraints 16 8.8.3 Segment format constraints . 17 8.9 ISO Base Media File Format Common profile 17 8.9.1 General . 17 8.9.2 Media Presentation Description constraints 17 8.9.3 Segme
7、nt format constraints . 17 ISO/IEC 23009-1:2014/Amd.1:2015(E) iv ISO/IEC 2015 All rights reservedForeword ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that a
8、re 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 internatio
9、nal organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1. The procedures used to develop this document and those intended for its furt
10、her 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).
11、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
12、 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 convenience of users and does not constitute an endorsement. For an explanation on the meaning of ISO specific terms and expressions relat
13、ed 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 - Supplementary information The committee responsible for this document is ISO/IEC JTC 1, Information technology, SC 29, Coding of a
14、udio, picture, multimedia and hypermedia information. Error! Reference source not found. ISO/IEC 23009-1:2014/Amd.1:2015(E) ISO/IEC 2015 All rights reserved 1Information technology Dynamic adaptive streaming over HTTP (DASH) Part 1: Media presentation description and segment formats, AMENDMENT 1: Hi
15、gh Profile and Availability Time Synchronization Replace 5.2.3.2 Elements and Attributes added in this Revision with 5.2.3.2 Elements and Attributes added in ISO/IEC 23009-1:2014 2 ndedition ISO/IEC 23009-1:2014/Amd.1:2015(E) 2 ISO/IEC 2015 All rights reservedAdd 5.2.3.3 Elements and Attributes adde
16、d in this Revision This revision adds the following elements and attributes to the schema defined in Annex B compared to the 2014 revision (ISO/IEC 23009-1:2014) of this part of the standard: MPD.UTCTiming ISO/IEC 23009-1:2014/Amd.1:2015(E) ISO/IEC 2015 All rights reserved 3In Table 3 add UTCTiming
17、row at the end after Metrics UTCTiming 0 . N specifies information on ways to obtain a synchronization to wall-clock time as used in this Media Presentation. The order of the elements expresses a preference of choice by the Media Presentation author. For more details refer to 5.8.4.10. ISO/IEC 23009
18、-1:2014/Amd.1:2015(E) 4 ISO/IEC 2015 All rights reservedIn 5.3.1.3 Replace with ISO/IEC 23009-1:2014/Amd.1:2015(E) ISO/IEC 2015 All rights reserved 5Add the following section 5.8.4.10 UTC Timing Descriptor Using the UTCTiming element, the Media Presentation author provides additional information for
19、 the client to optionally obtain wall-clock time to be used in Media Presentation. If multiple schemes are specified by the Media Presentation author, their order indicates their relative preference, first having the highest, and the last having the least priority. However, the client may choose any
20、 method, potentially having to deal with reduced accuracy. ISO/IEC 23009-1:2014/Amd.1:2015(E) 6 ISO/IEC 2015 All rights reservedAdd the following section 5.8.5.X DASH UTC Timing Schemes This part of the Standard defines several methods, specified in Table X, by which DASH clients can obtain wall-clo
21、ck times as used by the Media Presentation. Specifically this clock is synchronized to the one used to generate the MPD. ISO/IEC 23009-1:2014/Amd.1:2015(E) ISO/IEC 2015 All rights reserved 7Table X Different UTC timing Methods schemeIdURI Description urn:mpeg:dash:utc:ntp:2014 The identifier indicat
22、es that the value contains a white-space separated list of servers that are recommended to be used in combination with the NTP protocol as defined in IETF RFC 5905 for getting the appropriate time. urn:mpeg:dash:utc:sntp:2014 The identifier indicates that the value contains a white-space separated l
23、ist of servers that are recommended to be used in combination with the SNTP protocol as defined in IETF RFC 5905 for getting the appropriate time. urn:mpeg:dash:utc:http- head:2014 The identifier indicates that the value contains a white-space separated list of HTTP URLs that are recommended to be u
24、sed in combination with the HTTP protocol as defined in IETF RFC 2616 for getting the appropriate time. The value of the value attribute contains a white-space separated list of HTTP URLs to which HTTP HEAD requests can be made to obtain the Date information in the HTTP Header providing the wall-clo
25、ck time for this Media Presentation urn:mpeg:dash:utc:http- xsdate:2014 The identifier indicates that the value contains a white-space separated list of HTTP URLs that are recommended to be used in combination with the HTTP protocol as defined in IETF RFC 2616 for getting the appropriate time. The v
26、alue of the value attribute contains a white-space separated list of HTTP URLs to which HTTP GET requests can be made to obtain the timing information. The timing information is contained in the message body of the HTTP response to the above HTTP GET request and contains time value formatted accordi
27、ng to xs:dateTime as defined in W3C XML Schema Part 2: Datatypes specification. This value is based on a wall clock synchronized to the one used to generate the MPD. urn:mpeg:dash:utc:http- iso:2014 The identifier indicates that the value contains a white-space separated list of HTTP URLs that are r
28、ecommended to be used in combination with the HTTP protocol as defined in IETF RFC 2616 for getting the appropriate time. The value of the value attribute contains a white-space separated list of HTTP URLs to which HTTP GET requests can be made to obtain the timing information. The timing informatio
29、n is contained in the message body of the HTTP response to the above HTTP GET request and contains time value formatted according to ISO time code as defined in ISO/IEC 8601. This value is based on a wall clock synchronized to the one used to generate the MPD. urn:mpeg:dash:utc:http- ntp:2014 The id
30、entifier indicates that the value contains a white-space separated list of HTTP URLs that are recommended to be used in combination with the HTTP protocol as defined in IETF RFC 2616 ISO/IEC 23009-1:2014/Amd.1:2015(E) 8 ISO/IEC 2015 All rights reservedfor getting the appropriate time. The value of t
31、he value attribute contains a white-space separated list of HTTP URLs to which HTTP GET requests can be made to obtain the timing information. The timing information is contained in the message body of the HTTP response to the above HTTP GET request and contains time value formatted according to for
32、matted according to NTP timestamp format in IETF RFC 5905. This value is based on a wall clock synchronized to the one used to generate the MPD. urn:mpeg:dash:utc:direct:2014 The identifier indicates that the value field, contains a time formatted according to xs:dateTime as defined in W3C XML Schem
33、a Part 2: Datatypes specification. This value is based on a wall clock synchronized to the one used to generate the MPD ISO/IEC 23009-1:2014/Amd.1:2015(E) ISO/IEC 2015 All rights reserved 9Replace 7.3.1 with the following: 7.3.1 General The Media Presentation as introduced in 5 and 6 is instantiated
34、 in this subclause using the ISO base media file format as defined in ISO/IEC 14496-12 as Segment formats. An ISOBMFF-based DASH Media Presentation is described by an MPD as specified in 5.1. The MIME type of the MPD shall be as defined in Annex C. The general rules defined in 7.2 shall apply. The m
35、imeType attribute of each Representation shall be provided according to RFC 4337. Additional parameters may be added according to RFC 6381. If present, the SegmentProfiles shall provide a comma-separated list of the individual Segment profile identifiers. The following Segment types and formats may
36、be used Initialization Segments complying with formats as defined in 6.3.3. Media Segments complying with formats as defined in 6.3.4.2. Self-Initializing Media Segments complying with formats as defined in 6.3.5. For ISOBMFF-based Media Presentation the following applies: 1) In all cases for which
37、a Representation contains more than one Media Segment, the following applies: i) The Initialization Segment as defined in 6.3.3 shall be present. ii) Media Segments shall not be self-initializing. The Media Segment format is defined in 6.3.4. iii) If the Media Segment is the last Media Segment in th
38、e Representation, this Media Segment may carry the lmsg compatibility brand. If the Media Segment is not the last Media Segment in the Representation, the lmsg compatibility brand shall not be present. The lmsg type is defined in this subclause. 2) In case a Representation contains only a single Med
39、ia Segment, then one of the following two options are valid. One Initialization Segment as defined in 6.3.3 and one Media Segment as defined in 6.3.4 that is not self-initializing. One Self-Initializing Media Segment as defined in 6.3.5. Index Segments may be present. The content authoring rules for
40、 the Media Segments in combination with certain MPD attributes for ISOBMFF- based DASH are provided in 7.3.2. In case Sub-Representations are used, the rules in 7.3.4 shall apply. NOTE 1 Multiple servers may be used to improve accuracy NOTE 2 Use of NTP servers not specified in the value attribute i
41、s allowedISO/IEC 23009-1:2014/Amd.1:2015(E) 10 ISO/IEC 2015 All rights reservedAdd to 5.10 5.10.3.3.6 Inband Event Alignment If AdaptationSet.InbandEventStream element is present and AdaptationSetSegmentAlignment attribute is present and non-false, event message boxes in non-overlapping Segments sha
42、ll be aligned. Let S R1 (T) be the a segment of Representation R 1 with earliest presentation time T, and let the Adaptation Set contain N representations. If S R1 (T) contains one or more Event Message (emsg) boxes, identical emsg boxes shall be contained in each of the non-overlapping Segments S R
43、2 (T)S RN (T). NOTE 1 As a consequence, under the above constrains, all representations in the Adaptation Set will contain events. NOTE 2 If AdaptationSetSegmentAlignment is an integer larger than 1, the alignment described above applies only to non-overlapping Segments. NOTE 3 If Segments are non-o
44、verlapping, but their EPT differ, alignment described above still applies, and Event Message boxes will be in the beginning of both Segments. ISO/IEC 23009-1:2014/Amd.1:2015(E) ISO/IEC 2015 All rights reserved 11Add to 8.3.3 Index Segments shall not be present. However, a RepresentationIndex element
45、 or a indexRange attribute may be present to signal the byte range for Segment Index within a Media Segment. Add to 8.4.3 Index Segments shall not be present. ISO/IEC 23009-1:2014/Amd.1:2015(E) 12 ISO/IEC 2015 All rights reservedAdd 8.7 ISO base Media File Format Extended Live profile 8.7.1 General
46、This profile is largely an extension of ISO-BMFF Live profile as described in 8.4 of this part of the standard. The main extensions are non-exclusion of remote elements and features introduced in the second edition of this part of the standard, such as events. This profile also imposes additional re
47、strictions on MPD and Segment format in order to simplify implementations. The ISO-Base Media File Format Extended Live profile is identified by the following URN: “urn:mpeg:dash:profile:isoff-ext-live:2014“ . 8.7.2 Media Presentation Description constraints 8.7.2.1 General The Media Presentation De
48、scription shall conform to the following constraints: The rules for the MPD and the Segments as defined in ISO/IEC 23009-1 7.3, shall apply. Periods which do not conform to the constraints in 8.7.2.2 may not be presented Representations not inferred to have profiles equal to the profile identifier a
49、s defined in 8.7.1 may be ignored 8.7.2.2 Constraints on Period elements The Subset element may be ignored. The Period.SegmentList element shall not be present If a Period contains multiple Adaptation Sets with contentType=“video“ then at least one Adaptation Set shall contain a Role element with schemeIdUri=“urn:mpeg:dash:role:2011“ and value=“main“ and each Adaptation Set containing such a Role elemen
