3GPP TS 26.234 V8.2.0: 透明端到端包交换流服务与协议编解码

需积分: 5 116 浏览量更新于2024-07-14 收藏 886KB PDF 举报

"3GPP TS 26.234 V8.2.0 (2009-03)" 是一份3GPP组织发布的技术规范文档，专注于透明端到端的分组交换流服务（PSS）以及协议和编码。这份文档属于3GPP Release 8的一部分，主要涉及网络通信领域，特别是第三代移动通信（3G）系统和长期演进（LTE）技术。该技术规范旨在深入探讨通信协议的细节，以便于开发者和研究者理解并实现3GPP系统的标准。尽管在发布时未经3GPP组织伙伴的正式批准，但这份文档被用于3GPP内部的未来发展工作。3GPP不承担任何因使用此规范而产生的责任。对于3GPP系统的实际实施，应通过3GPP组织伙伴的公共出版办公室获取相关的规格和报告。 3GPP TS 26.234涵盖了以下几个关键技术知识点： 1. **透明端到端分组交换流服务（PSS）**：PSS是一种在3G和4G网络中提供连续性音频、视频和其他实时数据流服务的技术。它确保了从源到目的地的数据传输过程中，数据包的完整性和顺序不受影响。 2. **协议**：文档详细描述了用于PSS的通信协议，包括控制面和用户面的协议栈，如会话发起协议（SIP）、实时传输协议（RTP）和实时控制协议（RTCP）等，这些协议在多媒体通信中扮演着至关重要的角色。 3. **编码**：3GPP TS 26.234也关注了不同类型的编码算法，例如音频编码（如AMR-WB, AAC-LD等）和视频编码（如H.264），这些编码技术旨在高效地传输数据，同时保证服务质量。 4. **UMTS（通用移动通信系统）**：UMTS是3G移动通信标准，文档中可能包含了关于如何在UMTS网络中实现PSS的相关规定。 5. **LTE（长期演进）**：作为3G的后续技术，LTE提高了数据传输速率和网络效率。3GPP TS 26.234可能详细阐述了在LTE环境下PSS的实现方式。 6. **关键词**：UMTS、包模式、协议、编码、LTE，这些都是3GPP技术规范的关键组成部分，表明文档内容涵盖了与这些技术相关的多个方面。总体来说，3GPP TS 26.234 V8.2.0是理解和开发3GPP系统，特别是在3G UMTS和4G LTE环境中实现高效、高质量的分组交换流服务的重要参考资料。这份文档不仅对通信行业的专业人员有价值，也对学术研究和标准制定者有深远的影响。

3GPP

3GPP TS 26.234 V8.2.0 (2009-03)16Release 8

Figure 1 shows the functional components of a PSS client. Figure 2 gives an overview of the protocol stack used in a

PSS client and also shows a more detailed view of the packet based network interface. The functional components can

be divided into control, scene description, media codecs and the transport of media and control data.

The control related elements are session establishment, capability exchange and session control (see clause 5).

- Session establishment refers to methods to invoke a PSS session from a browser or directly by entering an URL

in the terminal's user interface.

- Capability exchange enables choice or adaptation of media streams depending on different terminal capabilities.

- Session control deals with the set-up of the individual media streams between a PSS client and one or several

PSS servers. It also enables control of the individual media streams by the user. It may involve VCR-like

presentation control functions like start, pause, fast forward and stop of a media presentation.

The scene description consists of spatial layout and a description of the temporal relation between different media that

is included in the media presentation. The first gives the layout of different media components on the screen and the

latter controls the synchronisation of the different media (see clause 8).

The PSS includes media codecs for video, still images, vector graphics, bitmap graphics, text, timed text, natural and

synthetic audio, and speech (see clause 7).

Transport of media and control data consists of the encapsulation of the coded media and control data in a transport

protocol (see clause 6). This is shown in figure 1 as the "packet based network interface" and displayed in more detail in

the protocol stack of figure 2.

UDP

TCP

RTP

RTSP

Payload formats

Video

Audio

Speech

Capability exchange

Scene description

Presentation description

Still images

Bitmap graphics

Vector graphics

Text

Timed text

Synthetic audio

HTTP

Capability exchange

Presentation

description

UDP

Timed Text

Scene description

Figure 2: Overview of the protocol stack

5 Protocols

5.1 Session establishment

Session establishment refers to the method by which a PSS client obtains the initial session description. The initial

session description can e.g. be a presentation description, a scene description or just an URL to the content.

A PSS client shall support initial session descriptions specified in one of the following formats: SMIL, SDP, or plain

RTSP URL.

3GPP

3GPP TS 26.234 V8.2.0 (2009-03)17Release 8

In addition to rtsp:// the PSS client shall support URLs [60] to valid initial session descriptions starting with file:// (for

locally stored files) and http:// (for presentation descriptions or scene descriptions delivered via HTTP).

Examples for valid inputs to a PSS client are: file://temp/morning_news.smil, http://example.com/morning_news.sdp,

and rtsp://example.com/morning_news.

URLs can be made available to a PSS client in many different ways. It is out of the scope of this specification to

mandate any specific mechanism. However, an application using the 3GPP PSS shall at least support URLs of the

above type, specified or selected by the user.

The preferred way would be to embed URLs to initial session descriptions within HTML or WML pages. Browser

applications that support the HTTP protocol could then download the initial session description and pass the content to

the PSS client for further processing. How exactly this is done is an implementation specific issue and out of the scope

of this specification.

As an alternative to conventional streaming, a PSS client should also support progressive download of 3GP files [50]

delivered via HTTP. A progressive-download session is established with one or more HTTP GET requests. In order to

improve playback performance for 3GP files that are not authored for progressive download, a PSS client may issue

(multiple pipelined) HTTP GET requests with byte ranges [17]. Example of a valid URL is

http://example.com/morning_news.3gp.

5.2 Capability exchange

5.2.1 General

Capability exchange is an important functionality in the PSS. It enables PSS servers to provide a wide range of devices

with content suitable for the particular device in question. Another very important task is to provide a smooth transition

between different releases of PSS. Therefore, PSS clients and servers should support capability exchange.

The specification of capability exchange for PSS is divided into two parts. The normative part contained in clause 5.2

and an informative part in clause A.4 in Annex A of the present document. The normative part gives all the necessary

requirements that a client or server shall conform to when implementing capability exchange in the PSS. The

informative part provides additional important information for understanding the concept and usage of the functionality.

It is recommended to read clause A.4 in Annex A before continuing with clauses 5.2.2-5.2.7.

5.2.2 The device capability profile structure

A device capability profile is an RDF [41] document that follows the structure of the CC/PP framework [39] and the

CC/PP application UAProf [40]. Attributes are used to specify device capabilities and preferences. A set of attribute

names, permissible values and semantics constitute a CC/PP vocabulary, which is defined by an RDF schema. For PSS,

the UAProf vocabulary is reused and an additional PSS specific vocabulary is defined. The details can be found in

clause 5.2.3. The syntax of the attributes is defined in the vocabulary schema, but also, to some extent, the semantics. A

PSS device capability profile is an instance of the schema (UAProf and/or the PSS specific schema) and shall follow the

rules governing the formation of a profile given in the CC/PP specification [39]. The profile schema shall also be

governed by the rules defined in UAProf [40] chapter 7, 7.1, 7.3 and 7.4.

5.2.3 Vocabularies for PSS

5.2.3.1 General

Clause 5.2.3 specifies the attribute vocabularies to be used by the PSS capability exchange.

PSS servers supporting capability exchange shall support the attributes in the four PSS components of the PSS base

vocabulary. PSS servers should also support the recommended attributes from the UAProf vocabulary [40]. A server

may additionally support other UAProf attributes.

3GPP

3GPP TS 26.234 V8.2.0 (2009-03)18Release 8

5.2.3.2 PSS base vocabulary

The PSS base vocabulary contains four components called "PssCommon", "Streaming", "ThreeGPFileFormat" and

"PssSmil". The division of the vocabulary into these components is motivated by the fact that the PSS contains three

different base applications:

- pure RTSP/RTP-based streaming (described by the Streaming component);

- 3GP file download or progressive download (described by the ThreeGPFileFormat component);

- SMIL presentation (described by the PssSmil component).

The last application can consist of downloadable images, text, etc., as well as RTSP/RTP streaming and downloadable

3GP files. Capabilities that are common to all PSS applications are described by the PssCommon component. The three

base applications are distinguished from each other by the source of synchronization: for pure streaming it is RTP, for

3GP files it is inherit in the 3GP file format, and for SMIL presentations timing is provided by the SMIL file.

NOTE: DIMS presentations can be streamed (RTSP/RTP) or downloaded (as 3GP files). Capabilities for such

presentations are described by the Streaming component and the ThreeGPFileFormat component,

respectively. See in particular the StreamingAccept and ThreeGPAccept attributes below.

The PSS base vocabulary is an extension to UAProf and is defined as an RDF schema in Annex F. Together with the

description of the attributes in the present clause, it defines the vocabulary. The vocabulary is associated with an XML

namespace, which combines a base URI with a local XML element name to yield an URI. Annex F provides the details.

The PSS specific components contain a number of attributes expressing capabilities. The following subclauses list all

attributes for each component.

5.2.3.2.1 PssCommon component

Attribute name: AudioChannels

Attribute definition: This attribute describes the stereophonic capability of the natural audio device.

Component: PssCommon

Type: Literal

Legal values: “Mono”, “Stereo”

Resolution rule: Locked

EXAMPLE 1:

Attribute name: MaxPolyphony

Attribute definition: The MaxPolyphony attribute refers to the maximal polyphony that the synthetic audio device

supports as defined in [44].

NOTE: The MaxPolyphony attribute is used to signal the maximum polyphony capabilities supported by the PSS

client. This is a complementary mechanism for the delivery of compatible SP-MIDI content and thus by

setting the MaxPolyphony attribute the PSS client is required to support Scalable Polyphony MIDI i.e.

Channel Masking defined in [44].

Component: PssCommon

Type: Number

Legal values: Integer between 5 and 24

Resolution rule: Locked

EXAMPLE 2:

3GPP

3GPP TS 26.234 V8.2.0 (2009-03)20Release 8

EXAMPLE 6: <PssVersion>3GPP-R6</PssVersion>

Attribute name: RenderingScreenSize

Attribute definition: The rendering size of the device’s screen in unit of pixels available for PSS media presentation.

The horizontal size is given followed by the vertical size.

Component: PssCommon

Type: Dimension

Legal values: Two integer values equal or greater than zero. A value equal “0x0”means that there exists no

possibility to render visual PSS presentations.

Resolution rule: Locked

EXAMPLE 7:

5.2.3.2.2 Streaming component

Attribute name: StreamingAccept

Attribute definition: List of content types (MIME types) relevant for streaming over RTP supported by the PSS

application. Content types listed shall be possible to stream over RTP. For each content type a

set of MIME parameters can be specified to signal receiver capabilities. A content type that

supports multiple parameter sets may occur several times in the list.

Component: Streaming

Type: Literal (Bag)

Legal values: List of MIME types with related parameters.

Resolution rule: Append

EXAMPLE 1:

<rdf:Bag>

<rdf:li>audio/AMR-WB; octet-alignment=1</rdf:li>

<rdf:li>video/H263-2000; profile=0; level=45</rdf:li>

</rdf:Bag>

</StreamingAccept>

EXAMPLE 1b:

<rdf:Bag>

<rdf:li>audio/AMR-WB+</rdf:li>

<rdf:li>video/H264; profile-level-id=42e00a</rdf:li>

<rdf:li>video/richmedia+xml; Version-profile=10</rdf:li>

</rdf:Bag>

</StreamingAccept>

Attribute name: StreamingAccept-Subset

Attribute definition: List of content types for which the PSS application supports a subset. MIME types can in most

cases effectively be used to express variations in support for different media types. Many

MIME types, e.g. AMR-WB have several parameters that can be used for this purpose. There

may exist content types for which the PSS application only supports a subset and this subset

cannot be expressed with MIME-type parameters. In these cases the attribute

StreamingAccept-Subset is used to describe support for a subset of a specific content type. If a

subset of a specific content type is declared in StreamingAccept-Subset, this means that

StreamingAccept-Subset has precedence over StreamingAccept. StreamingAccept shall always

include the corresponding content types for which StreamingAccept-Subset specifies subsets

of.

剩余154页未读，继续阅读

pangyachun

粉丝: 1
资源: 10

3GPP TS 26.234 V8.2.0: 透明端到端包交换流服务与协议编解码

3GPP TS 36.413 V15.0.0协议-中英文翻译对照版本（超详细）.docx

3GPP TS 23.285 V14.2.0 (2017-03)

3GPP TS 36.201 V8.2.0 (2008-12)英文文档

3GPP TS 26.234 V5.6.0

3GPP TS 23.401 V15.4.0协议-全文解析（超详细）.zip

3GPP TS 29.510 V15.0.0协议-中英文翻译版本（超详细）.docx

3GPP TS 38.413 V15.0.0协议-中英文翻译对照版本（超详细）

3GPP TS 26.132 V10.4.0 (2012-03)

3GPP TS 26.132 V10.4.0 (2012-03) release10

3GPP TS 31.102 V8.6.0 (2009-03).pdf

最新资源