1、SMPTE STANDARD SMPTE 294M-2001 Revision of ANSI/SMPTE 294M-1997 for Television - 720 x 483 Active Line at 59.94-Hz Progressive Scan Production - Bit-Serial Interfaces Contents 1 Scope 2 Normative references 3 General 4 Dual-link interface 5 Single-link interface 6 Digital timing reference sequences
2、7 Ancillaiy data signal format 8 Digital vertical interval time code and video index 9 Signal levels and specifications 1 O Connector and cable types 11 Channel coding 12 Transmission order Annex A Vertical colordiff erence filter Annex B Bibliography O 1 Scope This standard defines two alternatives
3、 for bit-serial interfaces for the 720 x 483 active line at 59.94-Hz progressive scan digital signal for production, defined in ANSVSMPTE 293M. Interfaces for coaxial cable are defined, each having a high degree of common- ality with interfaces operating in accordance with ANSVSMPTE 259M (BTA Report
4、 T-1004 contains additional information regding the application of these interfaces in practical systems): a) Dual-link interface (4:2:2P): Each link operating at 270 Mb/s, in which the active data in the Y, CB, CR format (equivalent to 8:4:4) are transparently divided, line sequentially, into two d
5、ata streams, each equivalent to the 4:2:2 component signal of ANSVSMPTE 259M. b) Single-link interface (4:2:0P): Operating at 360 Mb/s, in which the active data representing the color- difference components in the Y, CB, CFI format (equivalent to 8:4:4) are field quincunx down-con- verted by a facto
6、r of two, prior to reformatting with the Page 1 of 13 pages full luminance data, into a single data stream equiva- lent to the component signal of ANSVSMPTE 259M (but at a higher data rate, conceptually 8:4:0). NOTES 1 The data rate of 360 Mb/s is related by a factor of 4/3 to the basic data rate of
7、 270 Mb/s specified for - Q: Horizontal parallel data sampling rate, 27 MHz; - Y$: Main channel luminance, colordiff erence data; - Y“,C Subchannel luminance, cobrdfierence data; - Link A: 4:2:2P main channel; - Link 6: 4:2:2P subchannel; - CBV CRV: VertiCallY filtered and quincunx sub- sampled colo
8、r-difference data. 4 Dual-link interface (4:2:2P) 4.1 The main parameters of the dual-link (4:2:2P, 2 x 270 Mb/s) interface are shown in table 1. 4.2 The processing of the data from the 8:4:4 level of the 720 x 483 active line at 59.94-Hz progressive scan production (see ANSI/SMPTE 293M) is illustra
9、ted in figures 1, 2, and 3. Essen- tially, the odd lines of one field and the even lines of the next field are selected line by line and formed into the data for one interface link, while the even lines of the field and the odd lines of the next field are selected to form the data for the other inte
10、rface link. In the output field where the odd-numbered lines of the active input field are interface link A, the F bit of the TRS is set to O in both links; where the even- numbered lines of the active input field are in link A, the F bit of the TRS is set to 1. NOTES 1 Buffering having a minimum du
11、ration of one horizontal line is required by this process at each interface, making a minimum transmission delay of two horizontal lines. Table 1 - Parameters of interface data Page 2 of 13 pages COPYRIGHT Society of Motion Picture the data rate is 360 Mb/s. 6 Digital timing reference sequences (SAV
12、, EAV) 6.1 SAV and EAV timing reference signals shall define the start and end of active data and may be used to maintain synchronization across the digital interface. 5 Singlelink interface (4:2:0P) * The main parameters Of this 360-Mb/s system are shown in table 1. 5.2 The processing of the data f
13、rom the 8:4:4 level of the 720 x 483 active line at 59.94-Hz progressive scan production (see ANSI/SMPTE 293M) is illustrated in figures 1 and 4. 5.3 The active color-diff erence components CB, CR are vertically filtered and subsarnpled to a field quincunx pattern as shown in figures 4 and 5. This r
14、esults in a sample grid for the color-difference components that is twice the spacing in both the horizontal and vertical di- mensions, respectively. The quincunx arrange- ment of sampling sites is field alternating vertically. The number of samples in two active lines is now 720 for Y, 720 for Y”,
15、and 720 for CBICR combined, for a total of 2160. NOTE - Examples of a basic minimal vertical color-differ- ence filter and an adaptive color-difference filter are shown in figures A.l and A.2, respectiveiy. In either case, an appropriate matching delay is required in the luminance data. 5.4 The Y, Y
16、”, and CB/CR data are interleaved at sample level as illustrated in figure 1, in the order CB, Y, Y”, CR, Y”, CB, etc. 5.5 TRS data, SAV, and EAV are added with a digital blanking interval of 120 samples, as shown in figure 1. NOTE -The resulting data stream has a data rate in serial form (10 bits)
17、of 360 Mb/s in the format of ANWSMPTE 6.2 An SAV or EAV sequence shall comprise four consecutive codewords: a codeword of all ones, a codeword of all zeros, another code- word of all zeros, and a codeword including F, V, H (field, vertical, and horizontal), P3, P2, P1, and PO (parity) bits. An SAV s
18、equence shall be identified by having H = O; EAV shall have H = 1. V is set as shown in figures 2 and 4. The definition is based on the ANSVSMPTE 125M convention. F is set as defined in 5.6. Tables 2 and 3 show the details of the coding. 6.3 Every transmission package shall include a four-sample EAV
19、 sequence and a four-sample SAV sequence. 7 Ancillary data signal format Ancillary data are transmitted through interfaces specified in clauses 4 and 5 as ancillary data packets conforming to SMPTE 291M. Ancillary data may be inserted in any portion of the data stream not occupied by timing referenc
20、e signals or video data. Two categories of ancillary data, HANC and VANC, are defined for different portions of the data stream. Note that the three-word header used to identify an- cillary data is the same for HANC and VANC, although %bit representation of the header is permitted for VANC only. Pag
21、e 6 of 13 pages COPYRIGHT Society of Motion Picture -Those corresponding to CIB/CR and C“B/C“R samples must have the value 2001,. 7.1 HANCdata HANC data are permitted in all horizontal intervals, but not in the active portion of lines. HANC data are All permitted data identification words and data f
22、or- mats shall exclude the protectedvalues (OOOh to003h) and (3Fch to 3FFh). 8 Digital vertical interval time code and video index Digital vertical interval time code (DVITC) and video index, if present, are carried by the data in the active portion of reference 525 interlaced system lines 14 and 27
23、7. Of format, and each block Of data is Note - In the case of a dual-link interface (4:2:2p), preceded by the three-word ancillary data header DVITC and video index data are transmitted through link A. 8.1 DVITC This signal, if present, is carried by the luminance data in the active portion of refer
24、ence 525 interlaced system lines 14 and 277. OOOh 3FFh 3FFh. Because of the existence of both 8- and 1 O-bit equip- ment, for detection purposes, all values in the ranges OOOh-OO3h and 3 FCh-3FFh shall be considered equivalent to OOOh and 3FFh, respectively. The ancillary data header may occur multi
25、ple times during each horizontal blanking period if different blocks of data are transmitted. All permitted data identification words and data for- mats shall exclude the protected values (OOOh to 003h) and (3FCh to 3FFh). 7.2 VANCdata NOTE - In the case of a single-link interface (4:2:0P), DVITC is
26、 carried by the luminance data (Y) samples. 8.2 Video index This signal, if present, is canied by the color-diffeence data in the active portion of reference 525 interlaced system lines 14 and 277. Atotal of 90 8-bit data words is represented serially by DATA(2) of the 720 color- difference samples
27、of the active portion of the line. VANC data are permitted only in the active portion of reference 525 interlaced system lines 1-13, 15-1 9, 264-276, and 278-282. The relationship between the 525 progressive line number and the reference 525 interlaced system line number is described in figures 2 an
28、d 4. Lines 14 and 277 are reserved for digital vertical interval time code (DVITC) and video index. VANC data are of 8-bit format, and each block of VANC data shall be preceded by the three-word ancillary data header OOOh 3FFh 3FFh Because of the existence of both 8- and 1 O-bit equip- ment, for det
29、ection purposes all values in the ranges OoOh-003h and 3FCh-3FFh must be considered equivalent to OoOh and 3FFh, respectively. The first color-difference word of the active portion of line (CB O sample in figure 1) represents the least significant bd (bit O) of video index word O. The second color-d
30、ifference word represents bit 1 of the same word, etc. The last color-difference word of the active portion of the line (CR 359 sample in figure 1) represents the most significant bit (bit 7) of video index word 89. For all samples, a value of 20411 represents a binary one for the appropriate video
31、index bd, and a value of 20011 represents a binary zero for the appropriate video index bit. NOTE - These data may be corrupted by compression systems. Page 9 of 13 pages COPYRIGHT Society of Motion Picture b) Single-link interface (4:2:0P): 360-MHz serial clock locked to the 27-MHz system reference
32、. 9.1 The output of the generator shall be meas- ured across a 75-0hm resistive load connected through a short coaxial cable. 9.1.1 The generator shall have an unbalanced output circuit with a source impedance of 75 ohms and a return loss of at least 15 dB over a frequency range of 5 MHz to the cloc
33、k frequency of the signal being transmitted (see ANSI/SMPTE 259M for measurement dimen- sions and methods). 9.1.2 The peak-to-peak signal amplitude shall be 800 mV f 10%. 9.2 The dc offset, as defined by the midamplitude points of the signal, shall be nominally 0.0 Vf 0.5 V. 9.3 The rise and fall ti
34、mes, determined between the 20% and 80% amplitude points, shall be no less than 0.5 ns and no greater than 1.50 ns. 9.4 Overshoot of the rising and falling edges of the waveform shall not exceed 10% of the amplitude. 9.5 The jitter in the timing of the rising edges of the data signal shall be measur
35、ed in accordance with SMPTE RP 184. Measurement and parameters are defined in SMPTE RP 184 and shall have the following values for compliance with this standard: Timing jitter lower band edge 10 Hz fl Alignment jitter lower band edge 1 kHz f3 Upper band edge 1/10 clock rate f4 NOTES 1 Al, A2, fl. f3
36、, and f4 are measurement parameters defined in SMPTE RP 184. 2 Color bars are chosen as a nonstressing test signal for jitter measurements. Use of a signal with long runs of zeros may give misleading results. 3 Use of a serial clock divider value of 10 is acceptable under conditions described in SMP
37、TE RP 184 (annex B). However, it may mask word-correlated jitter components. The divider value should be stated in conjunction with equipment jitter specifications. 9.6 The input to the serial receiver signal shall present an impedance of 75 ohms with a return loss of at least 15 dB over a frequency
38、 range of 5 MHz to the clock frequency of the signal being transmitted. 10 Connector and cable types 10.1 The connector shall have the mechanical characteristics conforming to the 50-ohm BNC type. Mechanical dimensions of the connector may produce either a 50- or 75-ohm impedance. However, the elect
39、rical characteristics of the connector and its associated interface circuitry shall provide a resistive impedance of 75 ohms and shall permit it to be used at frequen- cies up to 850 MHz. Where a 75-ohm connector is used, its mechanical characteristics shall inter- face reliably with the nominal 50-
40、ohm BNC type defined by I EC 601 69-8. 10.2 Application of this standard does not re- quire a particular type of coaxial cable. It is necessary for the frequency response of the cable loss, in decibels, to be approximately proportional to $from 1 MHz to the clock frequency of the signal being transm
41、itted to ensure correct opera- tion of automatic cable equalizers over moderate to maximum lengths. Page 10 of 13 pages COPYRIGHT Society of Motion Picture otherwise, the switch shall be in position 1. Figure A.2 - Example demonstrating an adaptive filter used for the color-difference components Bef
42、ore subsampling the 8:4:4 data into a 4:2:0P quincunx signal Annex B (informative) Bibliography ANSIISMPTE 125M-1995, Television - Component Video Signal 4:2:2 - Bit-Parallel Digital Interface BTA Report T-1004, Video Signal Interfaces for EDTV-II Studio Equipment Page 13 of 13 pages COPYRIGHT Society of Motion Picture & Television EngineersLicensed by Information Handling Services
