1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T J.123TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2002) SERIES J: CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Interactive systems for digital television distribution Multiplexing format for webcasting
2、 on the TCP/IP network ITU-T Recommendation J.123 ITU-T J-SERIES RECOMMENDATIONS CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS General Recommendations J.1J.9 General specifications for analogue sound-programme transmission J.10J.19 Performance characteri
3、stics of analogue sound-programme circuits J.20J.29 Equipment and lines used for analogue sound-programme circuits J.30J.39 Digital encoders for analogue sound-programme signals J.40J.49 Digital transmission of sound-programme signals J.50J.59 Circuits for analogue television transmission J.60J.69 A
4、nalogue television transmission over metallic lines and interconnection with radio-relay links J.70J.79 Digital transmission of television signals J.80J.89 Ancillary digital services for television transmission J.90J.99 Operational requirements and methods for television transmission J.100J.109 Inte
5、ractive systems for digital television distribution J.110J.129 Transport of MPEG-2 signals on packetised networks J.130J.139 Measurement of the quality of service J.140J.149 Digital television distribution through local subscriber networks J.150J.159 IPCablecom J.160J.179 Miscellaneous J.180J.199 Ap
6、plication for Interactive Digital Television J.200J.209 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. J.123 (07/2002) i ITU-T Recommendation J.123 Multiplexing format for webcasting on the TCP/IP network Summary This Recommendation provides a multiplexing format
7、appropriate for audio and video transmission by download-based protocol over TCP/IP without any session control protocols between server and client. However, when session control protocols are not used, some necessary information should be added to the media data. Therefore, this Recommendation defi
8、nes a multiplexing format particular to webcasting on the TCP/IP. This format carries metadata, digital rights management (DRM) information and formatted text as well as audio and video bitstreams. Source ITU-T Recommendation J.123 was prepared by ITU-T Study Group 9 (2001-2004) and approved under t
9、he WTSA Resolution 1 procedure on 29 July 2002. ii ITU-T Rec. J.123 (07/2002) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. IT
10、U-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for st
11、udy by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a
12、 collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or
13、implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development pr
14、ocess. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore stron
15、gly urged to consult the TSB patent database. ITU 2002 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. J.123 (07/2002) iii CONTENTS Page 1 Scope 1 2 References. 1 2.1 Normative reference . 1 2.2 Info
16、rmative references 1 3 Terms and definitions . 1 4 Abbreviations 2 5 Reference architecture 2 6 File format 3 6.1 Basic structure 3 6.2 Object Structure 3 7 Box definitions . 5 7.1 File Type box 5 7.1.1 Definition 5 7.1.2 Syntax. 5 7.1.3 Semantics 5 7.2 Other boxes. 5 8 Extension Data 6 8.1 Digital
17、Rights Management 6 8.1.1 Syntax. 6 8.1.2 Semantics 6 8.2 Formatted text. 7 8.2.1 Basic structure 7 8.2.2 Text describing and controlling element 7 8.2.3 element . 8 8.2.4 element 8 8.2.5 element 8 8.2.6 element 9 8.2.7 element in element. 9 8.2.8 element 9 8.2.9 element 10 8.2.10 element in element
18、 10 8.2.11 element. 11 8.2.12 element 11 8.2.13 element. 11 8.2.14 element 12 iv ITU-T Rec. J.123 (07/2002) Page 8.2.15 Limitations for nesting of elements 12 Appendix I Sample parameters. 12 ITU-T Rec. J.123 (07/2002) 1 ITU-T Recommendation J.123 Multiplexing format for webcasting on the TCP/IP net
19、work 1 Scope This Recommendation defines a multiplexing format appropriate for audio and video transmission by download-based protocol over TCP/IP. By this format, webcasting on TCP/IP network is realized without any session control protocols between server and client. 2 References The following ITU
20、-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendatio
21、n are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it,
22、 as a stand-alone document, the status of a Recommendation. 2.1 Normative reference 1 ISO/IEC 14496-1:2001, Information technology Coding of audio-visual objects Part 1: Systems. 2.2 Informative references 2 ITU-T Recommendation J.120 (2000), Distribution of sound and television programs over the IP
23、 network. 3 ISO/IEC 14496-2:2001, Information technology Coding of audio-visual objects Part 2: Visual. 4 ISO/IEC 13818-3:1998, Information technology Generic coding of moving pictures and associated audio information Part 3: Audio. 5 IETF RFC 2068 (1997), Hypertext Transfer Protocol HTTP/1.1. 3 Ter
24、ms and definitions This Recommendation defines the following terms: 3.1 box: An object-oriented building block defined by a unique type identifier and length (called atom in the reference 1). 3.2 chunk: A contiguous set of samples for one track. 3.3 container box: A box whose sole purpose is to cont
25、ain and group a set of related boxes. 3.4 movie box: A container box whose sub-boxes define the metadata for a presentation (moov). 3.5 media data box: A container box which can hold the actual media data for a presentation (mdat). 3.6 presentation: One or more motion sequences, possibly combined wi
26、th audio. 3.7 sample: An individual frame of video, or a time-contiguous compressed section of audio. 2 ITU-T Rec. J.123 (07/2002) 3.8 sample description: A structure which defines and describes the format of some number of samples in a track. 3.9 sample table: A packed directory for the timing and
27、physical layout of the samples in a track. 3.10 track: A collection of related samples, which corresponds to a sequence of images or sampled audio. 3.11 webcasting: Webcasting is defined in ITU-T Rec. J.120: Distribution of sound and television programs over the IP network. 4 Abbreviations This Reco
28、mmendation uses the following abbreviations: DRM Digital Rights Management HTTP Hypertext Transport Protocol IP Internet Protocol TCP Transmission Control Protocol UUID Universal Unique Identifier 5 Reference architecture This Recommendation assumes that download-based protocol (e.g. HTTP) should be
29、 used for webcasting because it does not require any complex server-client protocols. The reference architecture for webcasting on TCP/IP is shown in Figure 1. J.123_F01InternetSTBHome networkPDAPCMobile terminalMobile terminalContents flowHTTP/TCP/IPHTTP/TCP/IPHTTP/TCP/IPHTTP/TCP/IPWebcastingserver
30、 (HTTP server)Mobile IPnetworkIP network(ISP, CATV)Figure 1/J.123 Architecture of webcasting on TCP/IP ITU-T Rec. J.123 (07/2002) 3 6 File format 6.1 Basic structure The file format consists of extension data, contents header and media data. Basic structure of the file is shown in Figure 2. J.123_F0
31、2VAVAVAVAVAVAMedia dataInformationContents header (Media type, Duration, etc.)Extension data (DRM, Formatted text, etc.)Chunk: Consists of several framesFile or one fragmentHeaderExtFigure 2/J.123 Basic structure of a file format 6.2 Object Structure The file is structured as a sequence of objects c
32、alled “Box“; some of these objects may contain other objects. The sequence of objects in the file shall contain exactly one presentation metadata wrapper (the Movie Box). It shall be located in the beginning of the file. The other objects found at this level may be UUID Boxes, or Media Data Boxes. T
33、he fields in the objects are stored with the most significant byte first, commonly known as network byte order or big-endian format. All boxes defined in this Recommendation are listed in Table 1, which are marked by a grey shade. 4 ITU-T Rec. J.123 (07/2002) Table 1/J.123 Box types and structure ft
34、yp File type and compatibility uuid Extension data moov Container for all the information mvhd Movie header, overall declarations trak Container for an individual track or stream tkhd Track header, overall information about the track tref Track reference container edts Edit list container elst An ed
35、it list mdia Container for the media information in a track mdhd Media header, overall information about the media hdlr Handler, declares the media (handler) type minf Media information container vmhd Video media header, overall information smhd Sound media header, overall information hmhd Hint medi
36、a header, overall information dinf Data information box, container dref Data reference box, declares source(s) of media data in track stbl Sample table box, container for the time/space map stsd Sample descriptions (codec types, initialization etc.) stts (Decoding) time-to-sample ctts (Composition)
37、time to sample stsc Sample-to-chunk, partial data-offset information stsz Sample sizes (framing) stz2 Compact sample sizes (framing) stco Chunk offset, partial data-offset information stss Sync sample table (random access points) stsh Shadow sync sample table padb Sample padding bits stdp Sample deg
38、radation priority mvex Movie extends box trex Track extends defaults moof Movie fragment mfhd Movie fragment header traf Track fragment tfhd Track fragment header trun Track fragment run mdat Media data container free Free space skip Free space udta User-data ITU-T Rec. J.123 (07/2002) 5 7 Box defin
39、itions 7.1 File Type box 7.1.1 Definition Box Type: ftyp Container: File Mandatory: Yes Quantity: Exactly one A media-file structured to this part of this specification may be compatible with more than one detailed specification, and it is therefore not always possible to speak of a single type or b
40、rand for the file. This means that the utility of the file name extension and mime type are somewhat reduced. This box must be placed as early as possible in the file (e.g. after any obligatory signature, but before any significant variable-size boxes such as the UUID Box, Movie Box or Media Data Bo
41、x). It identifies which specification is the best use of the file, and a minor version of that specification; and also a set of other specifications to which the file complies. Readers implementing this format should attempt to read files which are marked as compatible with any of the specifications
42、 which the reader implements. Any incompatible change in a specification should therefore register a new brand identifier to identify files conformant to the new specification. The type isom is defined in this clause, as identifying files which conform to the format in this Recommendation. More spec
43、ific identifiers can be used to identify precise versions of specifications providing more detail. Files would normally be externally identified (e.g. with a file extension or mime type) that identifies the best use (major brand), or the brand that the author believes will provide the greatest compa
44、tibility. 7.1.2 Syntax aligned(8) class FileTypeBox extends Box(ftyp) unsigned int(32) major-brand; unsigned int(32) minor-version; unsigned int(32) compatible-brands; / to end of the box 7.1.3 Semantics This box identifies the specifications to which this file complies. Each brand is a printable fo
45、ur-character code that identifies a precise specification. Only one brand is defined here: isom, identifies files structurally conformant to this media-independent part of this specification. major-brand is a brand identifier minor-version is an informative integer for the minor version of the major
46、 brand compatible-brands is a list, to the end of the box, of brands 7.2 Other boxes Definitions of all other boxes are found in the reference 1. 6 ITU-T Rec. J.123 (07/2002) 8 Extension Data Extension Data is formatted in “uuid“ box. Two functions for Extension Data are described as follows: Digita
47、l Rights Management Copy prohibition Expiration date Validation period after downloading Number of times play Formatted Text (Closed Caption) Text decoration: Foreground/background colour, Bold, Italic, Fonts, etc. Effects: Scroll, Wipe, Blink, etc. Synchronization with the media data Hyper link to
48、the Internet 8.1 Digital Rights Management Rights management information controls play and/or re-transmission of the downloaded MP4 file. It is contained in uuid Box of the file format. 8.1.1 Syntax aligned(8) class CopyGuardBox extends FullAtom (uuid, version = 0, flags) bit(32) copy-guard; unsigne
49、d int(32) limit-date; unsigned int(32) limit-period; unsigned int(32) limit-count; 8.1.2 Semantics Field Type Description Parameters type uint32 Type of Box uuid is set usertype uint816 ID “cpgd“-A88C-11d4-8197-09027087703 version uint8 Version 0 is set flags bit24 Rights management flags 0: No limitation 1: Limitation by expiration date 2: Limitation by validated period 4: Limitation by playing number of times Unless the case of No limitation, the following “never copy“
