1、 Rec. ITU-R BT.1119-2 1 RECOMMENDATION ITU-R BT.1119-2*WIDE-SCREEN SIGNALLING FOR BROADCASTING (Signalling for wide-screen and other enhanced television parameters) (Question ITU-R 42/11) (1994-1995-1998) Rec. ITU-R BT.1119-2 The ITU Radiocommunication Assembly, considering a) that 16:9 wide-screen
2、television receivers are increasingly being made available to the public in 525-lineand 625-line countries. The advent of a wide-screen receiver market is leading programme producers to consider the production aspects of wide-screen programmes that will be shown on 4:3 displays as well as 16:9 displ
3、ays; b) that provision for a common system for optimizing the display of the original programme material on a suitably equipped 16:9 display device would be a valuable enhancement to the service provided, together with the means to make appropriate automatic arrangements for any subtitling; c) that
4、there would be benefits for multi-standard receivers and, recorders, and costs, if a unique signalling system were used for all television standards, recommends 1 that for broadcasters wishing to broadcast a wide-screen signalling system, the system given in Annex 1 should be used for 625-line analo
5、gue broadcasts and the system in Annex 2 should be used for 525-line analogue broadcasts. ANNEX 1 1 Scope This specification is applicable to 625-line PAL and SECAM systems in use in cases where wide-screen signalling is to be provided by the broadcasters for use by new 16:9 television receivers. It
6、 specifies the wide-screen signalling information, the coding and the way of incorporating the coded information into a 625-line system. The wide-screen signalling information contains information on the aspect ratio range of the transmitted signal and its position as it would appear on a convention
7、al 4:3 display and on the position of the subtitles and on the camera/film mode. Furthermore some bits are reserved for future EDTV signalling (e.g. PALplus, see Recommendation ITU-R BT.1197) as well as for future use. This Annex specifies the transmitted signal. Appendix 1 gives the rules of operat
8、ion for the minimum requirements for receiver display formats as well as for subtitling. Appendix 2 gives some recommended practices. _ *This Recommendation should be brought to the attention of the European Broadcasting Union (EBU) and the European Telecommunications Standards Institute (ETSI). 2 R
9、ec. ITU-R BT.1119-2 2 Normative references This Recommendation does not incorporate any normative reference. 3 Definitions For the purpose of this Recommendation, the following definition applies: Letterbox operation: the transmission of a picture format with an aspect ratio greater than 1.33, in su
10、ch a way that empty (black) lines are added to conform to a 4:3 transmission format. 3.1 Symbols and abbreviations a : aspect ratio Fs : clock frequency Td : data bit period Ts : sampling period TXT : teletext. 4 Requirements 4.1 Line code The following sections specify the line code of the wide-scr
11、een signalling. 4.1.1 Position The signalling bits shall be transmitted as a data burst in the first part of line 23. The position of the beginning of the wide-screen signalling bits shall be 11.0 0.25 s from OHof the horizontal sync, as indicated in Fig. 1. In each frame the first part of line 23 s
12、hall be occupied with the wide-screen signalling. 4.1.2 Clock frequency The clock frequency shall be: Fs= 5 MHz ( 1 104). The period shall be: Ts= 200 ns. 4.1.3 Signal waveform The signal waveform shall be approximately a sine squared pulse. The half amplitude pulse duration shall be: 200 10 ns. 4.1
13、.4 Signal amplitude The signal amplitude with respect to a maximum video signal amplitude of 700 mV shall be: 500 mV 5%. 4.1.5 Modulation coding Bi-phase coding shall be used in accordance with Fig. 2. Duration of one data bit: Td. Rec. ITU-R BT.1119-2 3 1119-01OH500 mV 5%FIGURE 1Position of status
14、bit signalling in line 231.5 s10.5 s11.0 0.25 s38.4 s44.5 s27.4 s4 Rec. ITU-R BT.1119-2 1119-02 1 1 1 111100 0 1 1 1 110TdTsTdFIGURE 2Example of bi-phase-L codingNRZ-LBi-phase-LThe data bits shall be inserted in NRZ-L at the input of the (bi-phase-L) code modulator. The code modulator will produce o
15、n line 23, the data in bi-phase-L code, in which one data bit period equals 2 3 clock periods, whereby: Td= 6 Ts4.1.6 Preamble The preamble contains a run-in and a start code. The preamble shall be in accordance with Table 1. 4.1.7 Data bits There shall be 14 bits in total. One of these 14 bits shal
16、l be allocated to the error detection code. There shall be 13 data bits available for transmission of information. The data bits shall be grouped in four data groups (see Table 1). 4.1.8 Odd parity bit For error detection, an odd parity bit has been introduced. The odd parity bit shall belong to the
17、 first three data bits only (see Table 1). Rec. ITU-RBT.1119-25TABLE 1 Status bits transmission scheme Status bits transmission Insertion: first half of line 23 Coding: bi-phase modulation coding Clock: 5 MHz (Ts= 200 ns) Run-in Start code Group 1 Aspect ratio Group 2 Enhanced services Group 3 Subti
18、tles Group 4 Reserved 29 elements based on 5 MHz 24 elements based on 5 MHz 24 elements based on 5 MHz 24 elements based on 5 MHz 18 elements based on 5 MHz 18 elements based on 5 MHz Bit numbering 0 1 2 3 LSB MSB per info bit(1)“0“ = 000 111 “1“ = 111 000 Bit numbering 4 5 6 7 LSB MSB per info bit(
19、1)“0“ = 000 111 “1“ = 111 000 Bit numbering 8 9 10 LSB MSB per info bit(1)“0“ = 000 111 “1“ = 111 000 Bit numbering 11 12 13 LSB MSB per info bit(1)“0“ = 000 111 “1“ = 111 000 0 1F1C 71C7 1 1111 0001 1100 0111 0001 1100 0111 0 1E 3C1F 0001 1110 0011 1100 0001 1111 3 2 1 0 bit number 1000 full format
20、 4:3 0001 box 14:9 centre 0010 box 14:9 top 1011 box 16:9 centre 0100 box 16:9 top 1101 box 16:9 centre 1110 full format 14:9 centre shoot and protect 14:9 0111 full format 16:9 anamorphic b3= odd parity bit b4film bit 0 camera mode 1 film mode b5= colour coding bit 0 conventional coding 1 Motion Ad
21、aptative Colour Plus b6= helper bit 0 no helper 1 modulated helper b7= Reserved. Should be set to “0“ until otherwise defined 8 bit number 0 no subtitles within teletext 1 subtitles within teletext 10 9 bit number 00 no open subtitles 01 subtitles in active image area 10 subtitles out of active imag
22、e area 11 reserved Reserved. Should all be set to “0“ until otherwise defined (1)1 info bit consists of 6 elements based on 5 MHz clock. 6 Rec. ITU-R BT.1119-2 4.2 Information content of data bits The 13 data bits shall be grouped in four groups. Group 1 shall contain 4 bits in which the first 3 bit
23、s carry data and the last bit shall denote the odd parity bit of the first three data bits. Group 2 shall contain 4 data bits, Group 3 shall contain 3 data bits and Group 4 shall contain 3 data bits. The data bits shall be labelled b0up to and including b2combined with b4up to and including b13,b3sh
24、all be the odd parity bit as is shown in Tables 1 and 2. The index also indicates the order of transmission: b0shall be the first transmitted bit. 4.2.1 Data group 1 4.2.1.1 Aspect ratio b0, b1, b2: shall denote the aspect ratio label, the letterbox format and position according to Table 2. Diagrams
25、 illustrating the way that pictures will be displayed on: 16:9 displays equipped to make use of wide-screen signalling information; and on conventional 4:3 displays (not equipped to decode wide-screen signalling information) are given in Figure 3. b3: shall denote the odd parity of b0, b1, b2,b3acco
26、rding to Table 2. TABLE 2 Aspect ratio label, letterbox and position code b3b2b1b0Aspect ratio label Full format or letterbox Position (when shown on a con-ventional 4:3 display) No. of active lines(1)1 000 4:3 Full format Not applicable 576 0 001 14:9 Letterbox Centre 504 0 010 14:9 Letterbox Top 5
27、04 1 011 16:9 Letterbox Centre 430 0 100 16:9 Letterbox Top 430 1 101 16:9 Letterbox Centre Not defined 1 110 14:9 Full format(2)Centre 576 0 111 16:9 Full format (anamorphic) Not applicable 576 (1) The number of active lines is only an indication for the exact aspect ratio a = 1.33, a = 1.57 and a
28、= 1.78. (2) The actual transmitted aspect ratio is 4:3, but within this 4:3 area a 14:9 window is protected so that it contains all the relevant picture content to encourage a wide-screen display on a 16:9 television set.Rec. ITU-R BT.1119-2 7 1119-03a41414991414991693FIGURE 3Diagrams showing the ap
29、pearance of various display modes when displayed on 16:9 and 4:3 displaysAs displayed on a 16:9 display(equipped to decode wide-screensignalling information)As displayed on a 4:3 display(not equipped to decode wide-screensignalling information)Case 000Case 001Case 010Case 011430activelines504activel
30、ines504activelines576activelines8 Rec. ITU-R BT.1119-2 1119-03b 16914149934169Case 100Case 101Case 110Case 111576activelines504activelines16:9 a 1.90 b4Film bit 0 Camera mode1 Film mode(1)(1) The field dominance shall conform to Recommendation ITU-R BR.469 and EBU Recommendation R62-1990. b5Colour c
31、oding bit 0 Conventional coding 1 Motion adaptive colour plus coding 10 Rec. ITU-R BT.1119-2 TABLE 6 Helper bit 4.2.3 Data group 3, subtitles 4.2.3.1 Subtitles within teletext bit b8: shall denote the subtitles within teletext in accordance with Table 7. TABLE 7 Subtitles within teletext bit 4.2.3.2
32、 Subtitling mode b9, b10: shall denote the mode of subtitling in accordance with Table 8. TABLE 8 Subtitling mode Figure 4 indicates the meaning of the terms “in active image area” and “out of active image area”. NOTE In the case of “out of active image area”, subtitling the helper bit, b6, must be
33、set to “0”. 4.2.4 Data group 4, reserved b11, b12, b13: reserved these should be set to “0” until otherwise defined. b6Helper bit 0 No helper1 Modulated helperb8Subtitles within teletext bit 0 No subtitles within teletext 1 Subtitles within teletext b10, b9Subtitles in/out of active image area 00 No
34、 open subtitles 01 Subtitles in active image area 10 Subtitles out of active image area 11 Reserved NOTE 1 The “out of active image area” subtitling, which extends into the active image area shall be treated as “out of active image area”. Rec. ITU-R BT.1119-2 11 1119-04FIGURE 4Examples of letterbox
35、signals with logos and subtitlingLogoSubtitles in activeimage areaSubtitles out ofactive image areaPossible subtitlePossible subtitlePossible subtitlePossible subtitleLetterbox centreAPPENDIX 1 TO ANNEX 1 Rules of operation 1 Receiver display formats To ensure automatic selection of the most appropr
36、iate display mode, the receiver with a 16:9 display should comply with the following minimum requirements. TABLE 9 Aspect ratio minimum requirements Case 1: 4:3 full format: The 4:3 aspect ratio picture should be displayed centred with black bars at the left and right hand side of the display. Case
37、2: letterbox signalled as 14:9. The 14:9 aspect ratio picture should be displayed using one of the following two methods: the 14:9 aspect ratio picture should be displayed centred with small bars at the left and right hand sides of the display. the 14:9 picture may be displayed filling the full widt
38、h of the visible screen by incorporating a small horizontal geometrical error typically 8%. Case 3: letterbox signalled as 16:9. The 16:9 aspect ratio picture should be displayed using the full width of the screen. b2b1b0Aspect ratio label Minimum requirements 000 4:3 Case 1 001 14:9 Case 2 010 14:9
39、 Case 2 b2b1b0Aspect ratio label Minimum requirements 011 16:9 Case 3 100 16:9 Case 3 101 16:9 Case 4 12 Rec. ITU-R BT.1119-2 Case 4: letterbox signalled as 16:9. The 16:9 aspect ratio picture should be displayed using one of the following two methods: as under Case 3; It should be noted that the vi
40、ewer should be free to override the automatically selected display condition. The speed of the automatic change of aspect ratio is limited mainly by the response time of the deflection circuits. 2 Subtitling When the subtitling of letterboxed pictures is in, or partly in, the “out of active image ar
41、ea”, the new 16:9 receivers will lose this information, unless they display the picture in the 4:3 mode. This would mean that on the 16:9 receiver black bars would be present all around the active image content, and this should be avoided. To serve both the interests of the existing 4:3 and the new
42、16:9 viewers, it is of great importance that: wide-screen programmes should always have the subtitling (whether “in active image area” or “out of active image area”) conveyed as well by means of the teletext service; new 16:9 receivers, complying with this standard, should be equipped with a teletex
43、t decoder and always have the possibility of detecting the teletext presence bit b8. 3 Procedure in absence of signalling In the absence of signalling bits, the receiver should go to a default mode. APPENDIX 2 TO ANNEX 1 Recommended practices 1 Low pass pre-filtering It is recommended that the recei
44、ved status bit is low pass filtered before decoding. This low pass filter should preserve the main spectral energy of the status bits signal, which resides in the spectral domain of 0 up to 1.67 MHz. 2 Response time on a change in the received signalling information The maximum response time on a ch
45、ange in the received status bits signalling information is recommended to be 120 ms. ANNEX 2 1 Scope The specification is applicable to the 525-line NTSC system in cases where wide-screen signalling is to be provided by the broadcasters for use by new television receivers. It specifies wide-screen s
46、ignalling information, the coding and the method of incorporating the coded information into a 525-line system. Rec. ITU-R BT.1119-2 13 The wide-screen signalling information contains information on the aspect ratio of the transmitted signals and various information required for the EDTV-II enhanced
47、 television system, such as the incorporation of various picture quality helper signals and on the designation field/frame types. Furthermore, some bits are reserved for future use. This Annex specifies the transmitted signal. 2 Definitions, symbols and abbreviations 2.1 Definitions Letterbox operat
48、ion: the use of a picture format to transmit 16:9 aspect ratio pictures, in such a way that upper and lower black areas are added to conform to a 4:3 transmission format. Full format operation: the use of all active picture lines to carry a 4:3 transmission format. 2.2 Symbols and abbreviations SC:
49、duration of one cycle of chrominance signal subcarrier (SC = 1/3.579545 s) D: delay element of one data bit period IRE: unit picture signal level when pedestal level is zero and the picture signal white level is 100 Fs: clock frequency Ts: sampling period 1119-05B27B140 IRE20 IRE15 IRE0 IRE 40 IRE00 20 IRE 15 IREFIGURE 5Information bit location of wide-screen signalling in line 22 and 285227.5 SC63.56 s14 Rec. ITU-R BT.1119-2 3 Requirements The following subclauses specify the line code for wide-screen signalling. 3.1.1 P
