1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T J.181 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1 (09/2014) SERIES J: CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Digital transmission of television signals Pa
2、rt 1 Digital program insertion cueing message for cable television systems Amendment 1: New Appendix II: Recommended practices for the implementation of ITU-T J.181 Recommendation ITU-T J.181 (2014) Amendment 1 Rec. ITU-T J.181 (2014)/Amd.1 (09/2014) i Recommendation ITU-T J.181 Digital program inse
3、rtion cueing message for cable television systems Amendment 1 New Appendix II: Recommended practices for the implementation of ITU-T J.181 Summary The core text of Recommendation ITU-T J.181 has been kept brief in many areas in order to maintain conciseness and accuracy. Amendment 1 to Recommendatio
4、n ITU-T J.181 provides an informative appendix on recommended practices which enhance Recommendation ITU-T J.181. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T J.181 2001-03-09 9 11.1002/1000/5386 1.1 ITU-T J.181 (2001) Amd. 1 2003-04-04 9 11.1002/1000/6355 2.0 ITU-T J.181
5、 2004-06-29 9 11.1002/1000/7379 3.0 ITU-T J.181 2014-01-13 9 11.1002/1000/12102 3.1 ITU-T J.181 (2014) Amd. 1 2014-09-12 9 11.1002/1000/12351 _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For
6、example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T J.181 (2014)/Amd.1 (09/2014) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommuni
7、cation Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-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 Assembl
8、y (WTSA), which meets every four years, establishes the topics for study 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
9、fall within ITU-Ts purview, the necessary standards are prepared on a 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. Compliance with this
10、 Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory langua
11、ge such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or implementation of this Rec
12、ommendation 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 process. As of the date of a
13、pproval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the T
14、SB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2015 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T J.181 (2014)/Amd.1 (09/2014) iii Introduction ITU-T J.181 is necessarily brief in many are
15、as in order to maintain conciseness and accuracy. This amendment adds Appendix II to ITU-T J.181 and serves as an informative guideline on practices for the implementation of the Recommendation. Rec. ITU-T J.181 (2014)/Amd.1 (09/2014) 1 Recommendation ITU-T J.181 Digital program insertion cueing mes
16、sage for cable television systems Amendment 1 New Appendix II: Recommended practices for the implementation of ITU-T J.181 1) Modifications to ITU-T J.181 Add the following text after Appendix I as a new Appendix II, Recommended practices for the implementation of ITU-T J.181. Appendix II Recommende
17、d practices for the implementation of ITU-T J.181 (This appendix does not form an integral part of this Recommendation.) II.1 Scope This amendment adds Appendix II as an informational companion to Recommendation ITU-T J.181. The appendix itself is not a specification or a standard; the information w
18、ithin is intended as guideline practices for the implementation of the Recommendation. Where this appendix contradicts the main Recommendation, the main Recommendation takes precedence. II.2 Purpose The purpose of this appendix is to aid splicing and ad insertion equipment designers, as well as the
19、purchasers and users of such equipment, such as the networks that will originate cue messages from their uplink sites. This appendix is also expected to aid in the system integration of advertising related equipment, both at the message origination and at message reception end. The Recommendation in
20、cludes content segmentation messages; updated information provided in this appendix is intended to aid the users of these messages. The following new devices that will be interpreting the Recommendation commands include: transcoders, packagers, network personal video recorder (PVR) and other content
21、 manipulation, storage and streaming delivery systems. Crucial information is provided for manufacturers of equipment that pass the cue messages as part of the MPEG-2 transport stream. An example of such equipment is a rate altering remultiplexer, which performs complex processing of the stream. Whe
22、n the stream is demultiplexed and processed and then remultiplexed, it is very important to place the ITU-T J.181 cue message in the proper position relative to the video service and relative to nearby time base discontinuities. Such equipment may also be required to alter the message before retrans
23、mission. II.3 Definitions Throughout this appendix, the terms used have specific meanings. Because some of the terms that are defined in ISO/IEC ITU-T H.222.0 have very specific technical meanings, the reader is referred to the original source for their definition. For terms used in this appendix, t
24、he brief definitions are given 2 Rec. ITU-T J.181 (2014)/Amd.1 (09/2014) below, and only apply to their use within this appendix. Outside this appendix, the definitions listed in clause 3 of this Recommendation take precedence. II.3.1 access unit: The coded representation of a video picture or an au
25、dio frame ITU-T H.222.0. II.3.2 analogue cue tone: In an analogue system, a signal which is usually either a sequence of DTMF tones or a contact closure that denotes to ad insertion equipment that an advertisement avail is about to begin or end. II.3.3 avail: Time space provided to cable operators b
26、y cable programming services during a program for use by the CATV operator; the time is usually sold to local advertisers or used for channel self-promotion. II.3.4 AVC: Abbreviation for “Advanced Video Coding“ and refers specifically to video compression standardized in b-ITU-T H.264. II.3.5 break:
27、 Avail or an actual insertion in progress. II.3.6 C3: An audience measurement that is specified to include live viewing as well as DVR viewing up to 75 hours from the ad minute original broadcast time. II.3.7 cipher block chaining (CBC): This is a specific method of encryption. It is one of the meth
28、ods used in DES. II.3.8 component splice mode: A mode of the Cueing Message whereby the program_splice_flag is set to 0 and indicates that each PID/component that is intended to be spliced will be listed separately by the syntax that follows. Components not listed in the Message are not be spliced.
29、II.3.9 cyclic redundancy check (CRC): A method to verify the integrity of a transmitted Message. II.3.10 cueing message: See Message. II.3.11 data encryption standard (DES): A method for encrypting data with symmetric keys. II.3.12 digital video broadcasting (DVB): An international consortium for th
30、e development of digital television systems. II.3.13 ITU-T J.181 cue message: See Message. II.3.14 electronic code book (ECB): This is a specific method of encryption. It is one of the methods used in DES. II.3.15 entitlement control message (ECM): These are private conditional access information me
31、ssages which specify control words and possibly other, typically stream-specific, scrambling and/or control parameters. II.3.16 entitlement management message (EMM): These are private conditional access information messages which specify the authorization levels or the services of specific decoders.
32、 They may be addressed to single decoders or groups of decoders. II.3.17 event: A splice event or a Viewing Event as defined below. II.3.18 in point: A point in the stream, suitable for entry. II.3.19 message: In the context of this appendix, a message is the contents of any splice_info_section. II.
33、3.20 media presentation description (MPD): A formalized description for a DASH Media Presentation for the purpose of providing a streaming service, II.3.21 out point: A point in the stream, suitable for exit. II.3.22 payload_unit_start_indicator: A bit in the transport packet header that signals, am
34、ong other things, that a section begins in the payload that follows ITU-T H.222.0. Rec. ITU-T J.181 (2014)/Amd.1 (09/2014) 3 II.3.23 packet identifier (PID): A unique 13-bit value used to identify elementary streams of a program in a single or multi-program Transport Stream ITU-T H.222.0. II.3.24 PI
35、D stream: A stream of packets with the same PID within a transport stream. II.3.25 presentation time: The time that a presentation unit is presented in the system target decoder ITU-T H.222.0. II.3.26 program: A collection of video, audio, and data PID streams which share a common program number wit
36、hin an MPTS ITU-T H.222.0. II.3.27 program in point: A group of PID stream In Points that correspond in Presentation Time. II.3.28 program out point: A group of PID stream Out Points that correspond in Presentation Time. II.3.29 program splice mode: A mode of the Cueing Message whereby the program_s
37、plice_flag is set to 1 and indicates that the Message refers to a Program Splice Point and that all PIDs/components of the program are to be spliced. II.3.30 program splice point: A Program In Point or a Program Out Point. II.3.31 registration descriptor: Carried in the PMT of a program to indicate
38、that, when signalling Splice Events, splice_info_sections is carried in a PID stream within this program. The presence of the Registration Descriptor signifies a programs compliance with ITU-T J.181. II.3.32 reserved: The term “reserved“, when used in the clauses defining the coded bit stream, indic
39、ates that the value may be used in the future for extensions to the standard. Unless otherwise specified in the core part of ITU-T J.181, all reserved bits are set to 1. II.3.33 splice event: An opportunity to splice one or more PID streams. II.3.34 splice immediate mode: A mode of the Cueing Messag
40、e whereby the splicing device chooses the nearest opportunity in the stream, relative to the splice_info_table, to splice. When not in this mode, the Message gives a “pts_time“, which is a Presentation Time, for the intended splicing moment. II.3.35 splice point: A point in a PID stream that is eith
41、er an Out Point or an In Point. II.3.36 TVE: Acronym for “TV Everywhere“, after being authenticated as a subscriber to an operator, it is the ability to view TV content on the internet in addition to on ones television. II.3.37 uimsbf: Unsigned integer, most significant bit first. II.3.38 viewing ev
42、ent: A television program or a span of compressed material within a service; as opposed to a Splice Event, which is a point in time. II.4 Abbreviations and acronyms This appendix uses the following abbreviations and acronyms, in addition to those listed in clause 4 of this Recommendation: AMF Action
43、 Message Format AVC Advanced Video Coding CBR Constant Bit Rate CDN Content Delivery Network DASH Dynamic Adaptive Streaming over HTTP ECM Entitlement Control Message EMM Entitlement Management Message ETV Enhanced TV 4 Rec. ITU-T J.181 (2014)/Amd.1 (09/2014) GOP Group of Pictures HD High Definition
44、 HLS HTTP Live Streaming IDR Instantaneous Decoding Refresh MPD Media Presentation Description MVPD Multichannel Video Programming OATC Open Authentication Technology Committee OCAP OpenCable Application Platform PVR Personal Video Recorder RTMP Real Time Messaging Protocol SD Standard Definition SP
45、TS A Single Program Transport Stream TS Transport Stream T-STD Transport Stream System Target Decoder TVE TV Everywhere VBR Variable Bit Rate VBV Video Buffer Verifier VOD Video on Demand II.5 Overview The Recommendation supports the splicing of MPEG-2 transport streams for the purpose of digital pr
46、ogram insertion, which includes insertion of advertisement and other content types. An in-stream messaging mechanism is defined in the Recommendation to signal splicing and insertion opportunities. A splicing device is free to ignore splicing events signalled by the cue message because the message i
47、s not a command to splice, but is rather an indicator of the presence of an ad avail. Inserting content into the avail is optional. A cue message can also signal other events such as program start/end, content identification and other program or advertisement related events. These events can be used
48、 for applications such as network PVR, TV everywhere, regional blackouts, live video on demand (VOD) capture or other advanced services. As shown in Figure II.1, cue messages are received and acted upon in the cable system head-ends by splicer and server devices to initiate the insertion of local ad
49、vertisements by splicing the ad bit stream (typically containing the commercial content) into the bit stream of programming content. Similar to b-ITU-T J.280, this Recommendation does not differentiate between a splicing device and a server. When the terms “splicer“ or “splicing device“ are used, the meaning of the sentence may apply to a splicer/server combination as well. In actual practice it is common for ad servers (and not splicers) to parse, interpret and initiate action upon cue messages. Since splicer and server devices can be co
