1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU J.80 (ex CMTT.721) (09/93) TELEVISION AND SOUND TRANSMISSION TRANSMISSION OF COMPONENT-CODED CONTRIBUTION-QUALITY APPLICATIONS DIGITAL TELEVISION SIGNALS FOR AT BIT RATES NEAR 140 Mbis ITU-T Recommendation J.
2、80 (Formerly Recommendation ITU-R CMlT.721) ITU-T RECMN*J-BO 93 48b259L 0576038 Ob3 FOREWORD The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the Intemational Telecom- munication Union. The IT-T is *responsible for studying technical, operating and tariff questions an
3、d issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, established the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendation
4、s on these topics. ITU-T Recommendation J.80 (formerly Recommendation ITU-R CMTT.721) was revised by the former ITU-R Study Group CMTT and was approved under the CCIR Resolution 97 procedurmn 8-September 1993. See Note 1 below. NOTES 1 As a consequence of a reform process within the International Te
5、lecommunication Union (ITU), the CCITT ceased to exist as of 28 February 1993. In its place, the IT Telecommunication Standardization Sector (ITU-T) was created as of 1 March 1993. Similarly, in this reform process. the CCIR and the IFRB have been replaced by the Radiocommunication Sector (ITU-R). C
6、onformorming to a joint decision by the World Telecommunication Standardization Conference (Hensinki, March 1993) and the Radiocommunication Assembly (Geneva, November 1993), the IT-R Study Group CMT was transferred to ITU-T as Study Group 9, except for the satellite news gathering (SNG) study area
7、which was transferred to ITU-R Study Group 4. 2 telecommunication administration and a recognized operating agency. In this Recommendation, the expression “Administration” is used for conciseness to indicate both a O ITU 1994 All rights reserved. No part of this publication may be reproduced or util
8、ized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. ITU-T RECMNtJ-BO 93 = 48b259L 059b039 TTT CONTENTS Video inpuiloutput . Signal pre-processing . Coding scheme . Multiplexing scheme Video bit rate 5.1 Main ch
9、aracteristics 5.2 Multiplexing scheme . Annex A . Main parameters for transmitting 525-line YV contribution signals by use of the TV container Annex B . Multiplexing scheme for MAC/packet signals Annex C . Channel framing : Insertion of the TV container into a G.751-compatible frame Mapping of the T
10、V container into Virtual Container VC-4 according to Recommendation G.709. . C.l C.2 Page 1 2 2 3 4 4 5 10 12 13 13 13 Recommendation J.80 (09/93) 1 - ITU-T RECMN*J*BO 93 48b259L 0576040 711 Recommendation J.801) TRANSMISSION OF COMPONENT-CODED DIGITAL TELEVISION SIGNALS FOR CONTRIBUTION-QUALITY APP
11、LICATIONS AT BIT RATES NEAR 140 Mbiils (1990; revised 1992, 1993) The ITU-R, considering (a) that for contribution-quality applications, transmission should be based on component-coded digital video signals conforming to Recommendation ITU-R BT.601; (b) that such transmission should satisfy the user
12、 requirements for contribution-quality codecs at 60/70 to 140 Mbit/s as specified by IT-R Study Group 11, in Recommendation ITU-R BT.800; (cl that according to these user requirements such transmission shauld preserve the picture quality inherent in the 4:2:2 encoding process based on Recommendation
13、 IT-R BT.601 to the maxifium extent possible; (d) that such transmission should similarly preserve the downstream processing capabilities by maintaining the spatial and temporal resolution of the 4:2:2 signals as given by Recommendation ITU-R BT.601; (e) that in addition to component-coded digital v
14、ideo signals conforming to Recommendation IT-R BT.601, some features should be applicable for the transmission of TV signals resulting from other source coding methods, in particular, component-coded TV signals for distribution, multiplexed analogue component (MAC) signals in digital form, or compos
15、ite signals encoded according to Recommendation CMTT.658; (f) that additional transmission capacity should be provided for two pairs of stereo-sound channels, ancillary signals (e.g. Teletext, test signals) and error-protection data; (8) that for transmission the complete TV signal could be fitted i
16、nto the fourth hierarchical level given by Recommendation G.702 as well as into the STM-1 level given by Recommendation G.707; (h) that such transmission could be realized by hardware implementation at a moderate level of complexity and cost, recommends that for transmission at data rates near 140Mb
17、it/s of component-coded digital video signals for 625-line systems according to Recommendation IT-R BT.601, the bit rate reduction codec should be characterized as follows2): 1 Video inpuiloutput A standard 4:2:2 video signal conforming with Recommendation ITU-R BT.601 is used. Bit-parallel or bit-s
18、erial interfacing in accordance with Recommendation ITU-R BT.656 can be applied. Formerly Recommendation ITU-R CMlT.721. Annex A. 2, The main parameters of a proposal for transmitting YUV contribution signals in countries using the 525-line TV system is given in Recommendation 5.80 (03/93) 1 ITU-T R
19、ECMN+J.BO 93 m 4862571 059b041 658 m 2 Signal pre-processing The horizontal and vertical blanking intervals are removed. Ancillary data such as Teletext or test signals which are normally transmitted in the vertical blanking interval of the video signal are assigned to separate slots in the video mu
20、ltiplex. No sub-sampling is used in order to satisfy the down-stream processing requirements of inter-studio links. 3 Coding scheme Fixed two-dimensional predictors are applied both for the luminance and colour-difference components. Non-adaptive hybrid DPCM in combination with folded quantizers for
21、m the main elements of the coding scheme which reduces significantly the picture quality degradations due to overload effects as shown by simple DPCM systems. In addition, sensitivity to transmission errors comparable to systems with PCM representation is obtained. The same folded quantizer characte
22、ristic is used for the DPCM and PCM quantization of the Iuminance and colour-difference components. Details of the quantizer characteristics used for the DPCM and PCM quantization of the luminance and colou-difference components are given in Table 1. The necessary limitation is performed for the rec
23、onstructed values in the DPCM-loop. No variable-length coding will be used and no post-processing is provided for the output signal. TABLE UJ.80 Quantizer characteristics Level No. O 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 From O 1 2 3 4 5 6 7 8 9 10 13 16
24、 19 22 25 28 33 38 43 48 53 58 65 72 79 86 93 1 O0 107 114 121 Value O 1 2 3 4 5 6 7 8 9 11 14 17 20 23 26 30 35 40 45 50 55 61 68 75 82 89 96 103 110 117 124 To 0 1 2 3 4 5 6 7 8 9 12 15 18 21 24 27 32 37 42 47 52 57 64 71 78 85 92 99 106 113 1 20 127 2 Recommendation 5.80 (03/93) _ ITU-T RECMN*J.B
25、O 93 = 48b259L O596042 594 4 Video bit rate A 6 bithampie for each of the luminance and colour-difference components results in a video bit rate of 124 416 kbitls. The main characteristics of the video coding are summarized in Table 2. TABLE ZJ.80 Summary of the niain characteristics recommended for
26、 the coding of component-coded digitai television signais for contribution-quality applications at bit rates near 140 Mbiffs Standard Coding Interface Blanking Sub-sampling Pre-filtering Predictor Calculation of the prediction value X Predictor preset Adaptive control of predictors Motion compensati
27、on Quantizer characteristics Bi tshample Variable length code j25-line digital video in component form k2:2 signals according to Recommendation lT-R BT.601 Bit parallel or bihserial in accordance with Recommendation ITU-R BT.656 Removal of horizontal and vertical blanking intervals None None Two-dim
28、ensional intra-field for luminance and colour-difference components c A X - n A+C X=- 2 The prediction value Xis calculated with %bit accuracy (rounded) Video levels outside the active picture are set to 16 for Y and 128 for C, C, to preset the initial value of the predictor in both the coder and de
29、coder None None FoIded quantizer combined with non-adaptive hybrid DPCM (Table 1) 6, for each of the luminance Y, and colour-difference components CR, CB None None 124 416 kbitls TO90 1EO094/c Recommendation 5.80 (03/93) 3 ITU-T RECHN*J=BO 73 4862571 0576043 420 Sounddata 1,2 Ancillary data 5 Multip
30、lexing scheme 2 x 2048 kbit/s (e.g. 2 stereo audio signal) 576 kbitis for teletext channel and test-line channel a) 5.1 Main characteristics Video framing Video frame data rate This scheme makes use of a so-called TV container with a data rate of 138240 kbit/s that is able to convey different video
31、source signais with data rates of 135 O00 kbit/s and sounddata signals with data rates of 2048 kbit/s. Within the video frame data rate of 129 600 kbit/s, two 2048 kbit/s channels are available for sounddata transmission which can be used for the transmission of two stereo sound signais, e.g. accord
32、ing to Recommendation CM”T.724. 2-byte synchronization word per video line (1 125 bytes) 129 600 kbitis Although the main purpose of this TV container is directed to Y, CR, CB contribution signals and MAC/packet family signals, it can be applied to other component or composite signals. By means of s
33、tuffing or mapping techniques the TV container could be adapted to the channel framing of different transport media; in particular, the TV container will fit into a channel framing according to Recommendation G.751 as well as those of Recommendations G.707 to G.709. Video and sounddata error protect
34、ion FEC redundancy Table 3 summarizes the main characteristics of the transmission scheme. Forward error correction using a two-dimensional product code: 110,108,3 RS code for rows, 102,100,3 RS code for columns (symbol length 1 byte each) 3.89% The multiplexing scheme is also applicable to the tran
35、smission of MAC-type signals. The corresponding multiplexing scheme is given in Annex B. - FEC frame data rate (“TV container” input data rate) Sound/data 3 TABLE 3/J.80 135 o00 kbit/s 2048 kbitis (e.g. 2 stereo DS-1 audio signals) Main characteristics of transmission scheme (625-line systems) I 124
36、 416 kbit/s Video data rate Service channels (S1 . S8) b, “TV container” framing 8 x 64 kbit/s 256 kbit/s “TV container” output data rate 1) Channel framing according to Recommendation G.75 1 Channel rate 138 240 kbitis Recommendation G.75 1 compatible framing using a frame length of 2928 bits (6 gr
37、oups of 488 bits) and a 12-bit synchronization wordC) 139 264 kbitis 2) Channel framing according to Recommendation G.709 Channel rate Recommendation G.709 compatible framing for direct synchronous or asynchronous mapping into virtual container VC-4 1 149 760 kbitis a) The protocols for both channel
38、s and their multiplexing into the ancillary data stream are for further study. b) The channel S1 is assigned as a supervisory channel. C) A proposal for the G.751 compatible framing of the TV container and the mapping into VC-4 is given in Annex C. 4 Recommendation J.80 (03193) ITU-T RECMN*J-BO 93 W
39、 4862591 0596044 367 W 5.2 Multiplexing scheme 5.2.1 Sample arrangement of Y, CR, CE within the multiplex scheme For multiplexing, the 6-bit structure of the video data words is changed to an 8-bit structure whereby the transmission order according to Recommendation ITU-R BT.656 CE, Y, CR, Y. CB, Y,
40、 CR, etc. will remain unchanged. Thus, the WV encoder provides a data output according to the format given in Figure 1. 3 octets 4 4 Frame length: (1 N line) Repetition rata 14400Hz (576 actiie lines) Bit rate: LA r,- - 3 octets 3 octets b b 360 x 3 Octets = 1080 Octets TOD31 81 094ldM 1080 octets (
41、1 octet = 8 bits) 1 24 41 6 kbit/S FIGURE VJ.80 Structure of a TV lie 5.2.2 Sounddata For sound/data, two 2 048 kbit/s channels associated with positive justification are included in the video multiplex. Each of these channels can carry a stereo sound signal, e.g. according to Recommendation CMT.724
42、. 5.2.3 Ancillary data A data rate of 576 kbit/s is available inside the video multiplex for ancillary data (e.g. Teletext, test signals) which are normally transmitted in the vertical blanking interval of the video signal. 5.2.4 Video multiplex The sound/data and ancillary data are interleaved with
43、in the video data stream as shown in Figure 2. In addition, the video multiplex includes a 2 byte synchronization - word consisting of F1, F2 (which indicate the beginning of the first line of the video fiame) and of F1, F2 for the following lines of the video frame. The bit structure of the two syn
44、chronization bytes is given by the following sequences: F1: O011 O001 F2: 10000011 The video multiplex including video, sound/data, ancillary data and sync words results in a data rate of 129 600 kbit/s. Recommendation 5.80 (03/93) 5 ITU-T RECMN*J=BO 93 4862591 0596045 2T3 m V JS1 .V D1 V D2 V D1 V
45、D2 V D1 V D2 V D1 V A V D2 V D1 V D2 V D1 V D2 V D1 V D2 V JS2 V D1 V D2 V D1 V 02 V D1 V 02 V D1 V A V JS4 V Jc3 V D2 V D1 V D2 V D1 V D2 1 V 02 V O1 A V D1 V D2 A V D2 V D1 A V JD1 V JD2 Slots: v D1 D2 A JS1 . JS4 JD1, JD2 Bytes: JS1 JS2 JS3 Js4 JDl J D2 Video infomiation Data chamei 1 Data charne
46、l 2 Ancillary data Justification service Justification data channel J1 J1 J1 J1 J2 J2 J2 J2 J1 J1 J1 J1 J2 J2 52 J2 D1 D1 D1 D1 D1 D1 D1 J1 D2 D2 D2D2D2 D2 D2 J2 DlDlDlDlDlDlD2Sl D2 D2 D2D2D2 D2 D2 S2 40 x27= 1080 16x 1= 16 16x 1= 16 5x 1= 5 4x 1= 4 2x 1= 2 Total: 1123 binary binary binary binary bi
47、nary binary I 1123 l9012(94/a)3 Bits: J1 J2 D1, D2 S1, S2 1 = justiing data channel 1, O = not justing 1 = justifying data channel 2, O =not justiing Bits from the repetition rate of the FEC frame is 1500 Hz. FIGURE 3/J.80 FEC matrix The structure of the FEC framing will provide access to the video
48、channel of the TV container which offers a total bit rate of 135 O00 kbit/s for the complete TV input signai. Each output frame contains 9.6 complete TV lines whereby each row of the frame starts with a 2-octet synchronization word (see Figure 4). The bit structure of the four synchronization octets
49、 is given by the following sequences: c1: O011 1100 c2: 1101 O101 ci: 11000011 E: 00101010 This framing arrangement leads exactly to the bit rate offered by the video channel of the TV container 5.2.7 TV container framing The structure of the TV container and details on the frame alignment, additional service and data channels as well as on the justification method are given in Figure 5. Recommendation J.80 (03/93) 7 - ITU-T RECflN*J-BO 93 48b259L 059bO47 07b 748 1-bitstuffing 3-bitsbffing 2 I A I A 1 A.( A 1 A I A I A (JDPA TOW i8
