MPEGDASH标准资源-CSDN下载

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ISO/IEC 23009-1:2012(E) MPEG DASH 标准：Information technology — Dynamic adaptive streaming over HTTP (DASH) — Part 1: Media presentation description and segment formats MPEG DASH（Dynamic Adaptive Streaming over HTTP）是ISO/IEC 23009-1:2012(E)标准的一部分，该标准由国际标准化组织（ISO）和国际电工委员会（IEC）联合技术委员会1/分技术委员会29（JTC 1/SC 29）下的工作小组11（WG 11）制定，其秘书处负责管理。该标准主要关注信息技术领域，特别是通过HTTP进行动态自适应流媒体传输。 MPEG DASH是一种先进的视频流媒体技术，它允许视频内容根据用户的网络条件和设备性能进行动态调整，确保流畅的播放体验。这一标准的引入，使得内容提供商能够以高效的方式将高质量的多媒体内容分发到各种不同的设备上，包括移动设备、智能电视和桌面电脑，无需为每种设备单独设计和优化流媒体解决方案。该标准的第一部分，即"Media presentation description and segment formats"（媒体呈现描述和片段格式），涵盖了以下几个关键方面： 1. **媒体呈现描述**（Media Presentation Description, MPD）：这是MPEG DASH中的核心元素，它定义了媒体内容的结构和可用性信息，包括不同质量的流、时间轴、编码参数等。MPD使得客户端（如播放器）能够了解如何根据当前网络状况选择合适的视频质量。 2. **段格式**：MPEG DASH将媒体内容分解成较小的、可独立下载的片段，这些片段可以是音频、视频或者其他类型的数据。这种分段允许客户端在播放过程中动态地选择和下载新的片段，以适应变化的网络环境。 3. **自适应流媒体**：MPEG DASH支持基于网络带宽变化的自适应比特率（Adaptive Bitrate，ABR）流媒体，这意味着如果用户的网络条件恶化，系统会自动降低视频质量以保持流畅播放；当网络状况改善时，视频质量也会自动提升。 4. **多平台和设备兼容性**：由于MPEG DASH是基于HTTP的，它可以利用现有的互联网基础设施，无需额外的专有协议。这使得它能够广泛应用于多种设备和操作系统，如iOS、Android、Windows等。 5. **版权保护**：MPEG DASH还考虑到了内容的版权保护，支持数字权限管理（Digital Rights Management, DRM）系统，以确保只有授权用户可以访问受保护的内容。 6. **错误恢复和容错机制**：标准包含了应对网络中断或数据丢失的策略，确保即使在网络不稳定的情况下，也能尽可能地减少播放中断。 MPEG DASH标准为现代互联网视频服务提供了标准化的框架，促进了跨平台的互操作性和用户体验的优化。它的应用不仅限于视频，还可以扩展到音频和其他形式的实时媒体流，对于在线教育、远程会议、游戏直播等应用场景具有重要意义。随着互联网速度的不断提升和多媒体内容需求的增长，MPEG DASH将在未来的流媒体市场中扮演更加重要的角色。

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ISO/IECJTC1/SC29

Date:2012-01-05

ISO/IEC23009-1:2012(E)

ISO/IECJTC1/SC29/WG11

Secretariat:

Information technology— Dynamic adaptive streaming over HTTP (DASH)—

Part1: Media presentation description and segment formats

Élément introductif— Élément central— Partie1: Titre de la partie

Document type:International Standard

Document subtype:

Document stage:(60) Publication

Document language:E

STD Version 2.1c2

ISO/IEC23009-1:2012(E)
Contents Page
 Foreword................................................................................................................................................. x
 Introduction............................................................................................................................................ xi
1  Scope 1
2  Normative references 1
3  Terms, definitions, symbols and abbreviated terms 2
3.1  Terms and definitions....................................................................................................................... 2
3.2  Symbols and abbreviated terms...................................................................................................... 5
3.3  Conventions...................................................................................................................................... 6
4  Introduction 7
4.1  System description........................................................................................................................... 7
4.2  DASH client model............................................................................................................................ 8
4.3  DASH data model overview..............................................................................................................8
4.4  Protocols......................................................................................................................................... 11
4.5  Media Stream and Representation properties..............................................................................11
1.1.1  Media stream access points....................................................................................................... 11
1.1.2  Non-overlapping Segments and Subsegments.........................................................................12
1.1.3  Bitstream concatenation............................................................................................................. 12
4.6  Brands.............................................................................................................................................. 13
4.7  Schemes.......................................................................................................................................... 13
5  Media Presentation 14
5.1  General............................................................................................................................................. 14
5.2  Media Presentation Description....................................................................................................14
1.1.4  General.......................................................................................................................................... 14
1.1.5  Schema......................................................................................................................................... 15
5.3  Hierarchical data model.................................................................................................................. 16
1.1.6  Introduction.................................................................................................................................. 16
1.1.6.1  Overview 16
1.1.6.2  Semantics 16
1.1.6.3  XML syntax 18
1.1.7  Period............................................................................................................................................ 19
1.1.7.1  Overview 19
1.1.7.2  Semantics 20
1.1.7.3  XML syntax 21
1.1.8  Adaptation Sets............................................................................................................................ 21
1.1.8.1  Overview 21
 Representations shall appear in the same Adaptation Set if and only if they have identical values
for all of these media content component properties for each media content 
component. 22
 The values for the elements Role, Accessibility, Viewpoint and Rating are generally not provided
within the scope of this Part of ISO/IEC 23009. However, a number of simple schemes
are defined in 1.1.30. 22
1.1.8.2  Semantics 23
 when not set to ‘false’, this specifies that for any two Representations, X and Y, within the same 
Adaptation Set, the m-th Segment of X and the n-th Segment of Y are non-
overlapping (as defined in 1.1.2) whenever m is not equal to n. 24
 For Adaptation Sets containing Representations with multiple media content components, this 
attribute value shall be either 'true' or 'false'. 25
 For Adaptation Sets containing Representations with a single media content component, when 
two AdaptationSet elements within a Period share the same integer value for this 
©ISO/IEC2012– All rights reserved III

ISO/IEC23009-1:2012(E)
attribute, then for any two Representations, X and Y, within the union of the two 
Adaptation Sets, the m-th Segment of X and the n-th Segment of Y are non-
overlapping (as defined in 1.1.2) whenever m is not equal to n. 25
 More detailed rules may be defined for specific media formats.25
 specifies information about accessibility scheme 26
 For more details refer to 1.1.26 and 1.1.29.3. 26
 For more details refer to 1.1.26 and 1.1.29.2. 26
 specifies information on rating scheme. 26
 For more details refer to 1.1.26 and 1.1.29.4. 26
 specifies information on viewpoint annotation scheme. 26
 For more details refer to 1.1.26 and 1.1.29.5. 26
1.1.8.3  XML syntax 27
1.1.9  Media Content Component.........................................................................................................28
1.1.9.1  Overview 28
1.1.9.2  Semantics 28
1.1.9.3  XML syntax 29
1.1.10  Representation........................................................................................................................... 29
1.1.10.1  Overview 29
1.1.10.2  Semantics 30
1.1.10.3  XML syntax 32
1.1.11  Sub-Representation................................................................................................................... 33
1.1.11.1  Overview 33
1.1.11.2  Semantics 33
1.1.11.3  XML syntax 34
1.1.12  Common attributes and elements............................................................................................35
1.1.12.1  Overview 35
1.1.12.2  Semantics 35
 specifies the audio channel configuration of the audio media component type. 37
1.1.12.3  XML syntax 38
1.1.13  Subsets....................................................................................................................................... 38
1.1.13.1  Overview 38
1.1.13.2  Semantics 39
 @contains 39
1.1.13.3  XML syntax 39
1.1.14  Segments and Segment information........................................................................................39
1.1.14.1  General39
 Representations are assigned Segment Information through the presence of the elements 
BaseURL, SegmentBase, SegmentTemplate and/or SegmentList. The Segment 
Information provides information on the location, availability and properties of all 
Segments contained in one Representation. Specifically, information on the 
presence and location of Initialization, Media, Index and Bitstream Switching 
Segments is provided. 40
 SegmentBase, SegmentTemplate and SegmentList shall inherit attributes and elements from the
same element on a higher level. If the same attribute or element is present on both 
levels, the one on the lower level shall take precedence over the one on the higher 
level. 40
 All three elements SegmentBase, SegmentTemplate and SegmentList share common elements 
based on the SegmentBase element. Furthermore, SegmentTemplate and 
SegmentList share common attributes and elements. The common information is 
defined in 1.1.14.2. 40
1.1.14.2  Segment base information 40
1.1.14.2.1  Overview............................................................................................................................... 40
 The SegmentBase is sufficient if only a single Media Segment is provided per Representation 
and the Media Segment URL is included in the BaseURL element. 40
 In case multiple Media Segments are present, either a SegmentList or a SegmentTemplate is 
used that share the multiple Segment base information as provided in 1.1.14.2.3, 
Table12.40
 If the Representation contains more than one Media Segment, then either the attribute 
@duration or the element SegmentTimeline shall be present. The attribute @duration
and the element SegmentTimeline shall not be present at the same time. Segments 
IV ©ISO/IEC2012– All rights reserved

ISO/IEC23009-1:2012(E)
described by the Segment base information are referenced by an HTTP-URL 
conforming to the type URLType as defined in Table13. 40
1.14.2.2  Semantics............................................................................................................................. 41
 SegmentBase 41
 Segment Base Information 41
 MultipleSegmentBaseInformation 42
1.14.2.3  XML-Syntax.......................................................................................................................... 43
1.14.3  Segment list 44
1.14.3.1  Overview............................................................................................................................... 44
 The Segment list is defined by one or more SegmentList elements. Each SegmentList element 
itself contains a list of SegmentURL elements for a consecutive list of Segment 
URLs. Each Segment URL may contain the Media Segment URL and possibly a byte 
range. The Segment URL element may also contain an Index Segment. 44
1.14.3.2  Semantics............................................................................................................................. 44
 MultipleSegmentBaseInformation 44
1.14.3.3  XML-Syntax.......................................................................................................................... 45
1.14.4  Segment template 46
1.14.4.1  Overview............................................................................................................................... 46
 The Segment template is defined by the SegmentTemplate element. In this case, specific 
identifiers that are substituted by dynamic values assigned to Segments, to create a 
list of Segments. The substitution rules are provided in 1.1.14.4.4. 46
1.14.4.2  Semantics............................................................................................................................. 46
1.14.4.3  XML syntax........................................................................................................................... 47
1.14.4.4  Template-based Segment URL construction.....................................................................47
1.14.5  Segment information 48
1.14.5.1  Overview............................................................................................................................... 48
1.14.5.2  Initialization Segment information......................................................................................48
1.14.5.3  Media Segment information................................................................................................49
1.14.5.4  Index Segment information.................................................................................................50
1.14.5.5  Bitstream Switching Segment information........................................................................50
1.14.6  Segment timeline 51
1.14.6.1  General.................................................................................................................................. 51
1.14.6.2  Semantics............................................................................................................................. 52
1.14.6.3  XML syntax........................................................................................................................... 53
4  Media Presentation Description updates......................................................................................53
5  MPD assembly................................................................................................................................. 54
1.15  Introduction................................................................................................................................ 54
1.16  Syntax and semantics............................................................................................................... 54
1.17  Processing.................................................................................................................................. 55
6  Base URL Processing..................................................................................................................... 56
1.18  Overview..................................................................................................................................... 56
1.19  Semantics................................................................................................................................... 56
1.20  XML syntax................................................................................................................................. 57
1.21  Reference resolution................................................................................................................. 57
1.22  Alternative base URLs............................................................................................................... 57
7  Program information...................................................................................................................... 58
1.23  Overview..................................................................................................................................... 58
1.24  Semantics................................................................................................................................... 58
1.25  XML syntax................................................................................................................................. 58
8  Descriptors...................................................................................................................................... 59
1.26  General........................................................................................................................................ 59
1.27  Semantics of generic descriptor..............................................................................................59
1.28  XML syntax of generic descriptor.............................................................................................60
1.29  Specific descriptors................................................................................................................... 60
1.29.1  Content protection 60
1.29.2  Role 60
1.29.3  Accessibility 61
 One Adaptation Set or one media content component may have assigned multiple accessibility 
purposes even within the same scheme. 61
1.29.4  Rating 61
©ISO/IEC2012– All rights reserved V