1、 STDmITU-T RECMN J-88-ENGL 1979 M 48b2591 Ob74164 304 E INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU J.88 (09/99) SERIES J: TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Digital transmission of television signals Transmission
2、of enhanced definition television signals over digital links ITU-T Recommendation J.88 (Previously CCITT Recommendation) ITU-T J-SERIES RECOMMENDATIONS TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS General Recommendations General specifications for analogue sound-programme
3、 transmission Performance characteristics of analogue sound-programme circuits Equipment and lines used for analogue sound-programme circuits Digital encoders for analogue sound-programme signals Digital transmission of sound-programme signals Circuits for analogue television transmission Analogue t
4、elevision transmission over metallic lines and interconnection with radio-relay links Digital transmission of television signals Ancillary digital services for television transmission Operational requirements and methods for television transmission Interactive systems for digital television distribu
5、tion Transport of MPEG-2 signals on packetised networks Measurement of the quality of service Digital television distribution through local subscriber networks J.1-J.9 J. 10-J. 19 3.20-J.29 5.30-5.39 3.40-3.49 J.50-J.59 5.60-5.69 J.70-J.79 J.8W.89 J.90-J.99 J. 100-J. 109 5.110-5.129 5.130-5.139 J. 1
6、40-J. 149 5.150-5.1 59 For further detaik, please refer to ITU-T List of Recommendations. STD-ITU-T RECMN JaBB-ENGL 1999 48b259L Ob74Lbb I187 ITU-T RECOMMENDATION 5-88 TRANSMISSION OF ENHANCED DEFINITION TELEVISION SIGNALS OVER DIGITAL LINKS Summary This Recommendation considers a bit-rate reduction
7、 scheme to be applied for the digital transmission of EDTV-II composite signals compatible with NTSC television signals i. Digital transmission thereof involves direct coding of the composite signals. Source ITU-T Recommendation 5.88 was prepared by ITU-T Study Group 9 (1997-2000) and was approved u
8、nder the WTSC Resolution No. 1 procedure on 16 September 1999. Recommendation 5.88 (09/99) 1 - - - STDmITU-T RECMN J-88-ENGL L999 4Bb259L Ob74Lb7 013 U FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommuni- cations. The ITU Telecomm
9、unication Standardization Sector (ITU-T) is a permanent organ of the ITU. The 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 Standardizat
10、ion Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. I
11、n some areas of infomation technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recog
12、nized operating agency. INTELLECTUAL PROPERTY RIGHTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of cla
13、imed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recom
14、mendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. O ITU 2000 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or
15、mechanical, including photocopying and microfilm, without permission in writing from the ITU. 11 Recommendation 5.88 (09/99) - CONTENTS 1 Scope 2 References 3 Definitions 4 Abbreviations 5 Transmission of enhanced definition television signals over digital links 5.1 Introduction . 5.2 System descrip
16、tion Annex A - Specification of direct composite coding for EDTV-II and NTSC signals . A.l Structure of coding bit stream . A.2 Coding process A.3 Decoding process Appendix I - Examples for adaptive scanning patterns . Appendix II - Examples for VLC of motion vectors . Appendix III - Examples for qu
17、antizer and mix mode parameters design Appendix IV - Fast Hadamard transform Appendix V - VLC patterns for WHT coefficients . Recommendation 5.88 (09/99) Page 1 1 1 2 3 3 3 3 3 10 25 29 31 33 41 44 . 111 Recommendation 5.88 TRANSMISSION OF ENHANCED DEFINITION TELEVISION SIGNALS OVER DIGITAL LINKS (G
18、eneva, 1999) 1 Scope The introduction of an enhanced television system, namely EDTV-Il (compatible with the NTSC system), has led to the need to carry this signal over digital links. Due to the high cost expected for the enhanced television encoders, a specific coding system has been developed to al
19、low transmission of the EDTV-Il signals foreseen for primary distribution and also for contribution where no further post- processing is needed. 2 References The following IT-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of thi
20、s Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recomendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and ot
21、her references listed below. A list of the currently valid ITU-T Recommendations is regularly published. i Recommendation ITU-R BT.1298 (1997), Enhanced wide-screen NTSC TV transmission system. 2 IT-T Recommendation H.222.0 (1995) I ISOAEC 13818-1: 1996, Information Technologv - Generic coding of mo
22、ving pictures and associated audio informations: Systems. 3 Definitions This Recommendation defines the following terms: 3.1 visual system). 3.2 composite TV signals efficiently by a limited number of bits. 3.3 adaptive quantizer: Quantizer step size is controlled by a slice type, buffer occupancy a
23、nd HVS (human adaptive scanning: Transmission orders of WHT coefficients. Four types of scanning are used to transmit bit rate: The rate at which the compressed bit stream is delivered from the channel to the input of a decoder. 3.4 3.5 block: A unit for direct execution of WHT on the composite EDTV
24、-II signal under the 8 pixels x 8 lines size. coding mode: Mix A, Mix B and refresh (all intra) mode. 3.6 motion compensated reference block in the previous frame. colour sub-carrier phase shift: Phase shift of 3.58 MHz colour sub-carrier of the coding block from the 3.7 domain to solve colour sub-c
25、arrier phase shift. 3.8 3.9 composite motion compensation: Motion Compensation (MC) is conducted on WHT domain not on pixel criticality: The reference for the difficulty of the picture judged in macro block units. EDTV-II sampling: 14.3 MHz with %bit precision. 3.10 components located in the upper a
26、nd lower parts of the picture. 3.11 NTSC signals have less spectrum density. EDTV-II signals: NTSC-compatible components transmitted in the centre part of the picture and helper Fukinuki hole: Frequency regions around the colour sub-carrier of the compatible centre part where normal Recommendation J
27、.88 (09/99) 1 STD*ITU-T RECMN J*BB-ENGL 1999 48b2591 Ob743170 bO8 3.12 signal (HH), Vertical High Cequency helper signal (VH) and Vertical Temporal helper signal (VT). helper signals: Three types of spatio and temporal enhancement signals: Horizontal High frequency helper 3.13 macro block A size of
28、16 pixels x 16 lines and is composed of four 8 x 8 Walsh-Hadamard Transform. 3.14 mix mode: Mixing Inter and Intra mode in the same macro block to enhance coding efficiency. 3.15 PES packet: The data structure used to carry elementary stream data. A PES packet consists of a PES packet header followe
29、d by a number of continuous bytes from an elementary data stream. It is a layer in the system coding syntax described in 2.4.3.6 of ITU-T Rec. H.222.0 1 ISOAEC 13818-1 123. 3.16 picture layer: A repeated structure composed of a head I-picture and a plurality of subsequent p-pictures. 3.17 coordinate
30、d. sequence layer: Uppermost layer of a coding bit stream by which coding and decoding parameters are 3.18 slice layer: Composed of 768 pixels x 16 lines active pixels, and comprises a horizontal arrangement of macro blocks. The slice is categorized into four types of ID and control signal area, bou
31、ndary area, block area and active image area. 3.19 level as a symbol. two-imensional VLC: Hufhan code having the combination of zero-run length and quantization output 4 Abbreviations This Recommendation uses the following abbreviations: BP BUFP CF EDTV FSW GOP HH NTSC PC ssw VH VITS VLC VLD VT WHT
32、i 2 Maximum Buffer Capacity Buffi Pointer Colour Frame Enhanced Definition Television Video Frame Synchronizing Word Group of Pictures Horizontal High frequency component National Television System Committee Phase Compensation Sequence Synchronizing Word Vertical High frequency component Vertical In
33、terval Test Signal Variable Length Coding Variable Length Decoding Vertical Temporal frequency component Walsh-Hadamard Transform Recommendation J.88 (09/99) STD-ITU-T RECMN J-88-ENGL 3999 48b2593 Ob74373 544 5 Transmission of enhanced definition television signals over digital links 5.1 Introductio
34、n This Recommendation considers a bit-reduction coding scheme for application to digital transmission of EDTV-II composite signals defined for NTSC-compatible enhanced television. The bit-reduction coding system described below is a composite coding system that does not require any decodinghe-encodi
35、ng process for enhanced signals and colour component signals. Consequently the system is free from picture quality loss brought about by composite-component conversion required in component coding schemes. The bit rate required for contribution and distribution purposes is approximately 20 Mbits. 5.
36、2 System description The EDTV-II signals consist of NTSC-compatible components transmitted in the centre part of the picture and the helper components located in the upper and lower parts of the picture. Three kinds of helper signals are employed: a horizontal high frequency component (HH) multiplex
37、ed in frequency regions around the colour sub-canier (so-called Fukinuki hole) of the compatible centre part where normal NTSC signals have less spectrum densiy, the vertical high frequency component (VH), and the vertical temporal helper signal (VT) compressed in the spatial domain and multiplexed
38、in the upper and lower parts of the picture. Thus, EDTV-II composite signals have a complex structure. Although component bit-reduction coding can be applied to EDTV-II signals, it requires a decodingre-encoding process for the colour and HH components as well as the VWVT components at every stage o
39、f transmission chain. This decodingre-encoding process inevitably causes severe damage to picture quality, especially in the case of tandem connections. This degradation is caused by the irreversible nature of the decodingre-encoding process. Hardware for the composite coding scheme was implemented
40、based on an interframe motion-compensated Walsh- Hadamard Transform coding scheme. A preliminary picture quality evaluation test was conducted with the hardware and it showed that the system provides picture quality adequate for the contribution and primary distribution of the EDTV-II programmes at
41、a transmission bit rate of approximately 20 Mbits. This evaluation test also showed that the system provides coding performance equivalent or superior to the MPEG-2 codec for NTSC composite signals at a transmission bit rate above 15 Mbit/s. The above considerations and the test results mentioned sh
42、ow that the composite coding system is well suited for transmission of signals such as EDTV-II and NTSC when relatively high quality is required. Detailed specification for a composite coding system suitable for digital transmission of EDTV-II as well as NTSC signals is given in Annex A. Annex A Spe
43、cification of direct composite coding for EDTV-II and NTSC signals A.l Structure of coding bit stream The coding bit stream is converted to the PES packet in order to be operable on ITU-T Rec. H.222.0 1 ISO/IEC 13818-1 (MPEG systems) 2. Therefore, the bit stream is arranged in a three-layer structur
44、e composed of a sequence layer, a picture layer, and a slice layer. The unit of the PES packet is basically a slice in view of the maximum code generation. The outline of the bit coding stream structure is shown in Figure A. 1-1. Recommendation 5.88 (09/99) 3 bit stream coding PES picture PES header
45、 1 header 1 header I lice 1 PES packet L -_ MPEG systems: sequence/picture/siice I I I I I PES picture PES header header header I l I TO90695OS9/dO1 _ header Figure A.l-UJ.88 - Outline of coding bit stream structure SSW A.l.l Sequence layer Br-S The sequence layer is the uppermost layer of a coding
46、bit stream. The sequence layer has the purpose of coordinating coding and decoding parameters. In detail, the sequence header transmits required parameters fiom the coding side to the decoding side with the desired timing in order to coordinate automatically coding and decoding for channel hopping,
47、switching of systems, and problems of systems. A sequence header may be interpolated as desired at any position as long as the position is a blank between pictures shown by the picture header in a picture layer as described later. There are three types of sequence headers fiom 1 to 3 as described be
48、low. A.l.l.l Sequence header 1 Load-Adaptive-Scan-Matrix Qsivlu x 1 byte Load-Motion-Vector-Code +255.5) x 3 bytes (MVX, MVy = -256 to I l I I 4a I 16 j I I I I T09069M)-99/d02 1 228x3 I i) SSW: Sequence head word SSW is a sequence synchronizing word. The pattern is composed of one bit “1“ and 47 bi
49、ts “O“. SSW is transmitted once, at the timing when the receiving side becomes receivable, establishes the sequence synchronization and transmits parameters. 2) Br-S: Bit rate (sequence) Under a premise of the change of parameters, bit rate change is executed. The multiple number of 90 kbitis is represented by 90 x Br-S kbit/s (O to 5898.15 Mbitis). 3) LoadyAdaptive-Scan-Matrix Four types of Adaptive-Scan parameters (represented by Qs 2 bit which will be described in A.2.6 and A.3.2 later) are transmitted. The scanning pa
