SMPTE ST 240M-1999 Television - 1125-Line High-Definition Production Systems - Signal Parameters.pdf

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1、STD*SflPTE 240M-ENGL 1999 = 8357403 0003967 203 SMPTE STANDARD for Television - SMPTE 240M-I 999 Revision of ANWSMPTE 240M-1995 11 25-Line High-Definition Production Systems - Signal Parameters 1 Scope This standard defines the basic characteristics of the analog video signals associated with origin

2、ation equipment operating in 11 25-line highdefinition tele- vision production systems. This standard defines systems operating at 60.00 Hz and 59.94 Hz field rates. The digital representation of the signals described in this standard may be found in SMPTE 260M. These two documents define between th

3、em both digital and analog implementations of 1125-line HDTV production systems. 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the edition indicated was valid. All standards

4、are sub- ject to revision, and parties to agreements based on this standard are encouraged to investigate the Page 1 of 7 pages pocsibi1.Q of applying the most recent edition of the standard indicated below. SMPTE 260M-1999, Television - 1125/60 High- Definition Production System - Digital Repre- se

5、ntation and Bit-Parallel Interface 3 Scanning parameters The video signals represent a scanned raster with the characteristics shown in table 1. 4 System colorimetry and transfer function The system is intended to create a metameric repro- duction (visual color match) of the original scene as if lit

6、 by CIE illuminant D65. To this end, the combination of a cameras optical spectral analysis and linear signal rnatrixing shall match the CIE color-matching functions (1931) of the reference primaries. Further, the combination of a reproducers linear matrixing and reproducing primaries shall be equiv

7、alent to the reference primaries (see annex A.l). Table 1 - Scanned raster characteristics 1 125160 system 1125159.94 system Total scan lines per frame 1125 Active lines per frame 1035 Scanning format Interlaced 2:l Aspect ratio 16:9 Field repetition rate Line repetition rate (derived) 33750.00 Hz 3

8、371 6.28 . Hz2 60.00 Hz f 10 ppm 59.94 . HZ * io ppm The 59.94 . Hz notation denotes an approximate value. The exact value is a. l.ool 60 x 1125 , , 1 2The 33716.28 . Hz notation denotes an approximate value. The exact value is I Copyright Q 1999 by THE SOCIEPI OF MOTION PICTURE AND TELEVISION ENGIN

9、EERS 595 W. Hartsdaie Ave., white Plains, NY 10607 (914) 761-1100 APPrnVd November 1 1,1999 STD.SMPTE 240M-ENGL 1993 8357403 0003968 148 D SMPTE 24W-1999 4.1 Chromaticity of reference primaries The reference red, green, and blue primaries shall have CIE 1931 (x,yj chromaticities as follows: and Lr i

10、s the light output from the reference reproducer normalized to the system reference white. 5 Video signal definitions The image is represented by three parallel, time-co- red 0.630 0.340 incident video signals. Each incorporates a svnchro- CIE x CIE y green blue 0.31 O 0.155 0.595 0.070 4.2 Referenc

11、e white The system reference white is an illuminant which causes equal primary signals to be produced by the reference camera, and which is produced by the reference reproducer when driven by equal primary signals. For this system, the reference white is speci- fied in terms of its 1931 CIE chromati

12、city coordinates, which have been chosen to match those of CIE illu- minant D65: CIE x CIE y nizing waveform: The signals shall be eithe; of the following sets: Color Color primary set difference set EG - green Ey - luma EB - blue ER - red EPB - blue color difference EPR - red color difference where

13、 EG EB ER are the signals appropriate to directly drive the primaries of the reference repro- ducer (being nonlinearly related to light levels as specified in 4.3 and 4.4) and E EPB EPR can be derived from EG EB ER as follows: white 0.31 27 0.3290 The luma function is specified to be: 4.3 Opto-elect

14、ronic transfer characteristic of EI/ = (0.701 X EG? + (0.087 X EB? + (0.212 X ER) reference camera base equation The opto-electronic transfer function of the reference camera is defined to be: 4Lc 1.1115045-0.1115, 0.02285 Li1 EPB is amplitude-scaled (EB - EY), according to: derived equation (EB - E

15、Y) 1.826 01 Lc 0.0228 EPB = vc= and EPR is amplitude-scaled (ER- EO, according to: where VC is the video signal output of the reference and Lc is the light input to the reference camera normalized to the system reference white. 4.4 Electro-optical transfer characteristic of levels in 7.3. reference

16、reproducer The electro-optical transfer function of the reference reproducer is defined to be: derived equation camera normalized to the system reference white, (ER - E./) EPR = 1.576 where the scaling factors are derived from the signal (See annex A.3 for the derivation of the coefficients in the l

17、uma and annex A.4 for a summa, of the formulas for converting between the two sets). 1.3 4 O I Vr 0.0913 6 Reference clock Signal durations and timings in this standard are specified both in reference clock periods and in micro- seco11CIc. The referenceclockas defined in the following table is the f

18、undamental timing reference in the system. Lr= h 1.1115 + 0.1115 )(A) , 0.0913 S VrS 1 where Vr is the video signal level driving the reference reproducer normalized to the system reference white, Page 2 of 7 pagee STD.SMPTE 240M-ENGL 3,999 8357403, 0003b 084 SMPTE 240M-1999 1 125160 1 125159.94 sys

19、tem system Reference clock periods in total line 2200 2200 Reference clock period - T (derived) 13.481 . ns Reference clock frequency (derived) 74.25 MHz 74.17 . MHz 13.468 . ns NOTE - The 74.17 . MHz notation denotes an approximate value. The exact value is 60x 1 125x 2200 2x1.001 * The combined vi

20、deo and synchronizing signal shall be as shown in figure 1, For illustrative purposes, a video signal of the form EY, EG, EB, or ER is shown. The details of the synchronizing signal are identical for the EPB and EPR color-difference signals. 7.1 Timing 7.1.1 The timing of events within a horizontal

21、line of video is illustrated in figure l(a) and summarized in table 2. All event times are speci- fied in terms of the reference clock period at the midpoint of the indicated transition. The analog production aperture extends from the start of active video to the end of active video (see figure 1 (a

22、) and annex AS). 7.1.2 The duration of the various portions of the video and sync waveforms are illustrated in figures 1 (b), 1 (c), and 1 (d), and summarized in table 3. 7.2 Bandwidth 7.2.1 The color primary set EG EB ER com- prises three equal-bandwidth signals whose nominal bandwidth is 30 MHz. 7

23、.29 The color-difference set EY EPB EPR comprises a luma signal EY whose nominal bandwidth is 30 MHz, and color-difference signals EPB and EPR whose nominal bandwidth is 30 MHz for analog originating equipment, and 15 MHz for digital originating equipment. 7.3 Levels The video signals are represente

24、d in analog form as follows: EY, EG, EB, ER signals: Reference black level 0 (mv) Reference white level 700 (mV) Synchronizing level I300 (mv) EPB, EPR signals: Reference zero signal level 0 (mV) Reference peak levels f 350 (mV) Synchronizing levei k300 (mV) All signals: Sync pulse amplitude 300k 6

25、(mV) Amplitude difference between positive- and negative going sync pulses Table 2 - Timing of events of a video line I Reference clock periods Rising edge of sync (timing reference) Trailing edge of sync 44 O Start of active video 192 End of active video 2112 Leading edge of sync 21 56 Page 3 of 7

26、pages SMPTE 24W-1999 STD.SMPTE 240M-ENGL 1999 W 8357401 0003970 8Tb D Table 3 - Duration of video and sync waveforms Reference Time (ps) Time (p) Tolerance clock periods 11 25/60 1 125159.94 (w) a 44 0.593 0.593 f 0.040 - 0.000 + 0.081 b 88 1.185 1.186 C 44 0.593 0.593 f 0.040 d 132 1.778 1.780 f 0.

27、040 - 0.000 + 0.081 e 192 2.586 2.588 f (Sync rise time) 4 0.054 0.054 f 0.020 Total line 2200 29.630 29.659 I 25.884 + o - 0.162 Active line 1920 25.859 III III e- lWW - lo41 4 CiunApIum II I II kcr I I I II II IlII III I II I wdock: ou 192 2112 2156 2200 28.444 29.037 29.830 28.473 anea 23.659 Fig

28、ure i(a) - Timing of events within a video line Page 4 of 7 pages STD-SMPTE 240M-ENGL L999 W 8357403 0003973 732 SMPTE 2401111-1999 r O I Page 5 of 7 pages SMPTE 24OM-1999 STD*SMPTE i40M-ENGL 1999 M 8353YOL 0003972 b79 9 Annex A (informative) Additional data 111 System colorimetry The parameter valu

29、es in clause 4 are based on current practice and technical constraints. It is recognized that the availability of a wider color gamut is highly desirable in an originating system. Furthermore, it is useful, for purposes of picture processing, to have available video signals proportional to light lev

30、els. In order to obtain signals proportional to light levels, nonlinear processing is needed to remove the nonlinear characteristic given in 4.3. The equations given in 4.4 should be applied. An approach to achieving the wider color gamut is under study which will involve retaining the reference pri

31、maries of 4.1 for the basic color coding and enlarging the color gamut by allowing negative RGB primary signals. (Consideration is also being given to the possibility of adopting the refer- ence primaries specified in ITU-R BT.709, which are very close to the primaries specified in this standard.) T

32、he YPbP, signals derived from these extended-range RGB signals using the equations of clause 5 will fall within normal signal ranges. A2 Rdationshlp between bask and derived parameters Certain parameters have been determined as basic and fundamental system parameters. The values of all other system

33、parameters can be derived from those chosen as basic, as shown in this annex. Basic parameters: - Field repetition rate (F) specified in clause 3. - Total scan lines per frame (S) specified in clause 3. - Reference clock periods in total line (R) specified in clause 6. Computation of derived paramet

34、ers: - Line repetition rate (L): L = S x F/2 - Reference clock frequency (C): C = S x R x F/2 - Reference clock period (T): T = (S x R x F/2)-1 A3 Derivation of the luma equation A3.1 Discussion of the luma function It is common practice to encode the R,G,B component signals into a signal which conv

35、eys luminance information, and two signals which convey chrominance information. This was essential in the case of NTSC, PAL, and SECAM, where backwards compatibility with an existing mono- chrome system was required; and it is advantageous in modern systems, where the lower sensitivity of the eye t

36、o high-frequency chroma information can be exploited to reduce the bandwidth of the chroma signals. The luminance function Y is defined by the CIE, and repre- sents the brightness response of a standard obsewer. It is possible to determine the contributions of red, green, and blue light from a given

37、 phosphor set operating at a specified white point which are required to synthesize a true CIE luminance value for each scene element. The computation is summarized in A.3.2. Because CRT phosphors do not respond linearly to electrical stimulation, the signals driving the phosphors must be pre- condi

38、tioned with an inverse nonlinearity. The preconditioning, usually called gamma correction, is normally done in the camera for several reasons. As a consequence, the RGB signals which are available for encoding are not linear with respect to light and cannot be linearly combined into a signal which r

39、epresents true CIE luminance. The encoded signal which is produced will be called luma in order to permit clarity in terminology. Although the luma function does not represent the exact luminance of the scene element, it is common practice to encode it using the coefficient values derived for the lu

40、minance function. For the purpose of this standard, the precise coefficient values are computed according to the method of A.3.2. The values are then rounded to three decimal places of accuracy, and those rounded values are defined as exact coefficient values in the specification of the luma equatio

41、n in clause 5. 1139 Lumlnance function coetflcents for a phosphor set The luminance function Y for a given phosphor set and white reference point is the mixture of the red, green, and blue lights (R,G,B) which represents the perceived brightness of scene elements. The proportions of R,G,B which must

42、 be mixed to yield the correct value of Y can be calculated from the chromaticity coordinates of the reproducer primaries, and the chromatic- ity of reference white (i.e., the color reproduced when the reference reproducer is driven by equal primary signals), according to well-known methods. Stated

43、briefly, the equation for Y can be found as follows: y = J#r JgYg JbYb i where Jg, Jb, and Jr are derived according to: !i = x ;y* (i?) (z) 4298 and Xr,yr,Zr are the chromaticity coordinates of the red primary; xg,yg,zQ are the chromaticity coordinates of the green primary; Xb, yb, zb are the chroma

44、ticity coordinates of the blue primary; and XW, yw, zw are the chromaticity coordi- nates of reference white. Page 6 of 7 pages STD.SMPTE 240M-ENGL lqqq 8357403 0003973 505 SMPTE 240M-1999 A4 Transformation between ER Ed EBI and W EPB EPRI The transformations between the two sets are: I 000 -0.227 -

45、0.477 EY E: = ,:o00 1.826 0.000 EPB ER 1.000 0.000 1.576 EPR 0.701 0.087 -0.384 0.500 -0.445 -0.055 E., = EPR A5 Plchire boundaries The production aperture defined by this standard comprises a picture made up of 1920 reference clock periods (T) horizontally by 1035 lines vertically. The 1920T width

46、of this analog production aperture is specified at 50% video level, and represents the maximum active video permissible under this standard. It is good practice to adjust and operate all studio equipment with this minimal amount of blanking. This analog production aperture has identical dimensions t

47、o the digital production aperture of SMPTE 260M. Annex B (informative) Bibliography In practical system implementations, blanking may be wider, up to the amount (6T at each end) specified by the tolerance in table 3. If the full amount of the tolerance is exercised at start and end of active picture

48、, the minimum active video is obtained. A.6 Reference reproducer and actual monltors In 4.4, the electro-optical transfer characteristics of the reference reproducer are defined. This reference repro- ducer does not represent the transfer characteristics of a real monitor; rather, it is a mathematic

49、al description of a transfer function that is the exact inverse of the reference camera opto-electronic transfer function leading to a linear system that is convenient for many analyses. Experience has shown that, for the most pleasing subjective picture qualily, television systems are often adjusted to have an overall light transfer characteristic represented by a power function whose exponent is slightly greater than unity. Therefore, real reproducers will often implement a t