1、 Recommendation ITU-R BT.601-7(03/2011)Studio encoding parameters of digital television for standard 4:3 and wide-screen 16:9 aspect ratiosBT SeriesBroadcasting service(television)ii Rec. ITU-R BT.601-7 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficien
2、t and economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are pe
3、rformed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Form
4、s to be used for the submission of patent statements and licensing declarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be
5、 found. Series of ITU-R Recommendations (Also available online at http:/www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile,
6、 radiodetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum managem
7、ent SNG Satellite news gathering TF Time signals and frequency standards emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2011 ITU 2011 All rights reserved. No part o
8、f this publication may be reproduced, by any means whatsoever, without written permission of ITU. Rec. ITU-R BT.601-7 1 RECOMMENDATION ITU-R BT.601-7 Studio encoding parameters of digital television for standard 4:3 and wide-screen 16:9 aspect ratios (Question ITU-R 1/6) (1982-1986-1990-1992-1994-19
9、95-2007-2011) Scope This Recommendation also covers the pixel characteristics that represent a 525- or 625-line interlace digital television image. This Recommendation specifies methods for digitally coding video signals. It includes a 13.5 MHz sampling rate for both 4:3 and 16:9 aspect ratio images
10、 with performance adequate for present transmission systems. The ITU Radiocommunication Assembly, considering a) that there are clear advantages for television broadcasters and programme producers in digital studio standards which have the greatest number of significant parameter values common to 52
11、5-line and 625-line systems; b) that a worldwide compatible digital approach will permit the development of equipment with many common features, permit operating economies and facilitate the international exchange of programmes; c) that an extensible family of compatible digital coding standards is
12、desirable. Members of such a family could correspond to different quality levels, different aspect ratios, facilitate additional processing required by present production techniques, and cater for future needs; d) that a system based on the coding of components is able to meet these desirable object
13、ives; e) that the co-siting of samples representing luminance and colour-difference signals (or, if used, the red, green and blue signals) facilitates the processing of digital component signals, required by present production techniques, recommends that the following be used as a basis for digital
14、coding standards for television studios in countries using the 525-line system as well as in those using the 625-line system. 1 Extensible family of compatible digital coding standards 1.1 The digital coding should allow the establishment and evolution of an extensible family of compatible digital c
15、oding standards. It should be possible to interface simply between any members of the family. 1.2 The digital coding should be based on the use of one luminance and two colour-difference signals (or, if used, the red, green and blue signals). 2 Rec. ITU-R BT.601-7 1.3 The spectral characteristics of
16、 the signals must be controlled to avoid aliasing whilst preserving the passband response. Filter specifications are shown in Appendix 2. 2 Specifications applicable to any member of the family 2.1 Sampling structures should be spatially static. This is the case, for example, for the orthogonal samp
17、ling structures specified in this Recommendation. 2.2 If the samples represent luminance and two simultaneous colour-difference signals, each pair of colour-difference samples should be spatially co-sited. If samples representing red, green and blue signals are used they should be co-sited. 2.3 The
18、digital standard adopted for each member of the family should permit worldwide acceptance and application in operation; one condition to achieve this goal is that, for each member of the family, the number of samples per line specified for 525-line and 625-line systems shall be compatible (preferabl
19、y the same number of samples per line). 2.4 In applications of these specifications, the contents of digital words are expressed in both decimal and hexadecimal forms, denoted by the suffixes “d” and “h” respectively. To avoid confusion between 8-bit and 10-bit representations, the eight most-signif
20、icant bits are considered to be an integer part while the two additional bits, if present, are considered to be fractional parts. For example, the bit pattern 10010001 would be expressed as 145dor 91h, whereas the pattern 1001000101 would be expressed as 145.25dor 91.4h. Where no fractional part is
21、shown, it should be assumed to have the binary value 00. 2.5 Definition of the digital signals Y, CR, CB, from the primary (analogue) signals ER , EG and EB This paragraph describes, with a view to defining the signals Y, CR, CB, the rules for construction of these signals from the gamma pre-correct
22、ed primary analogue signals ER , EG and EB . The signals are constructed by following the three stages described in 2.5.1,2.5.2 and2.5.3. The method is given as an example, and in practice other methods of construction from these primary signals or other analogue or digital signals may produce ident
23、ical results. An example is given in 2.5.4. 2.5.1 Construction of luminance (EY ) and colour-difference (ER EY ) and (EB EY ) signals The construction of luminance and colour-difference signals is as follows: EY = 0.299 ER + 0.587 EG + 0.114 EB then: BGRBGRBYBEEEEEEEEE += 886.0587.0299.0114.0587.029
24、9.0)( and BGRBGRBYBEEEEEEEEE = 114.0587.0299.0114.0587.0299.0)( Taking the signal values as normalized to unity (e.g. 1.0 V maximum levels), the values obtained for white, black and the saturated primary and complementary colours are shown in Table 1. Rec. ITU-R BT.601-7 3 TABLE 1 Normalized signal
25、values Condition EREG EB EY ER EY EB EY White Black 1.0 0 1.0 0 1.0 0 1.0 0 0 0 0 0 Red Green Blue 1.0 0 0 0 1.0 0 0 0 1.0 0.299 0.587 0.114 0.701 0.587 0.114 0.299 0.587 0.886 Yellow Cyan Magenta 1.0 0 1.0 1.0 1.0 0 0 1.0 1.0 0.886 0.701 0.413 0.114 0.701 0.587 0.886 0.299 0.587 2.5.2 Construction
26、of re-normalized colour-difference signals (ECR and ECB ) Whilst the values for EY have a range of 1.0 to 0, those for (ER EY ) have a range of + 0.701 to 0.701 and for (EB EY ) a range of + 0.886 to 0.886. To restore the signal excursion of the colour-difference signals to unity (i.e. + 0.5 to 0.5)
27、, re-normalized red and blue colour-difference signals ECRand ECBrespectively can be calculated as follows: 402.1114.0587.0701.0402.1BGRYRCEEEEEER=and 772.1886.0587.0299.0772.1BGRYBCEEEEEEB+=The symbols ECRand ECBwill be used only to designate re-normalized colour-difference signals, i.e. having the
28、 same nominal peak-to-peak amplitude as the luminance signal EY thus selected as the reference amplitude. 2.5.3 Quantization In the case of a uniformly-quantized 8-bit or 10-bit binary encoding, 28or 210, i.e. 256 or 1 024, equally spaced quantization levels are specified, so that the range of the b
29、inary numbers available is from 0000 0000 to 1111 1111 (00 to FF in hexadecimal notation) or 0000 0000 00 to 1111 1111 11 (00.0hto FF.Chin hexadecimal notation), the equivalent decimal numbers being 0.00dto 255.75d, inclusive. In this Recommendation, levels 0.00dand 255.75dare reserved for synchroni
30、zation data, while levels 1.00dto 254.75dare available for video. 4 Rec. ITU-R BT.601-7 Given that the luminance signal is to occupy only 220 (8-bit) or 877 (10-bit) levels, to provide working margins, and that black is to be at level 16.00d, the decimal value of the quantized luminance signal, Y, i
31、s: ()DDEYY/16219int += where D takes either the value 1 or 4, corresponding to 8-bit and 10-bit quantization respectively. The operator int( ) returns the value of 0 for fractional parts in the range of 0 to 0.4999 and +1 for fractional parts in the range 0.5 to 0.999 ., i.e. it rounds up fractions
32、above 0.5. Similarly, given that the colour-difference signals are to occupy 225 (8-bit) or 897 (10-bit) levels and that the zero level is to be level 128.00d, the decimal values of the quantized colour-difference signals, CRand CB, are: ()DDECRCR/128224int += and ()DDECBCB/128224int += The digital
33、equivalents are termed Y, CRand CB. 2.5.4 Construction of Y, CR , CBvia quantization of ER , EG , EB In the case where the components are derived directly from the gamma pre-corrected component signals ER , EG , EB , or directly generated in digital form, then the quantization and encoding shall be
34、equivalent to: ()DDEERRD/16219int)formdigitalin( += ()DDEEGGD/16219int)formdigitalin( += ()DDEEBBD/16219int)formdigitalin( += Then: ()DDEEEYDDDBGR/114.0587.0299.0int += DDEkEkEkDDDBmYGmYRmY/222int321+ DDEEECDDDBGRR/128219224402.1114.0587.0701.0int+= DDEkEkEkDDDBmCRGmCRRmCR/128222int321+ Rec. ITU-R B
35、T.601-7 5 DDEEECDDDBGRB/128219224772.1886.0587.0299.0int+= DDEkEkEkDDDBmCBGmCBRmCB/128222int321+ where k and m denote the integer coefficients and the bit-lengths of the integer coefficients, respectively. The integer coefficients of luminance and colour-difference equations should be derived as per
36、 Annex 2. TABLE 2 Integer coefficients of luminance and colour-difference equations Coeffi-cient bits Denominator Luminance Y Colour-difference CRColour-difference CBm 2mkY1kY2kY3 kCR1kCR2kCR3kCB1kCB2kCB38 256 77 150 29 131 110 21 44 87 131 9 512 153 301 58 262 219 43 88 174 262 10 1 024 306 601 117
37、 524 439 85 177 347 524 11 2 048 612 1 202 234 1 047 877 170 353 694 1 047 12 4 096 1 225 2 404 467 2 095 1 754 341 707 1 388 2 095 13 8 192 2 449 4 809 934 4 189 3 508 681 1 414 2 776 4 190 14 16 384 4 899 9 617 1 868 8 379 7 016 1 363 2 828 5 551 8 379 15 32 768 9 798 19 235 3 735 16 758 14 033 2
38、725 5 655 11 103 16 758 16 65 536 19 595 38 470 7 471 33 516 28 066 5 450 11 311 22 205 33 516 NOTE 1 The bold values indicate that the values are modified from the nearest integer values by the optimization. To obtain the 4:2:2 components Y, CR, CB, low-pass filtering and sub-sampling must be perfo
39、rmed on the 4:4:4 CR, CBsignals described above. Note should be taken that slight differences could exist between CR, CBcomponents derived in this way and those derived by analogue filtering prior to sampling. 2.5.5 Limiting of Y, CR , CBsignals Digital coding in the form of Y, CR, CBsignals can rep
40、resent a substantially greater gamut of signal values than can be supported by the corresponding ranges of R, G, B signals. Because of this it is possible, as a result of electronic picture generation or signal processing, to produce Y, CR, CBsignals which, although valid individually, would result
41、in out-of-range values when converted to R, G, B. It is both more convenient and more effective to prevent this by applying limiting to the Y, CR, CBsignals than to wait until the signals are in R, G, B form. Also, limiting can be applied in a way that maintains the luminance and hue values, minimiz
42、ing the subjective impairment by sacrificing only saturation. 6 Rec. ITU-R BT.601-7 2.6 Colour and opto-electronic transfer characteristic1Item Characteristics Parameter 625 525 2.6.1 Chromaticity coordinates, CIE 1931(1)x y x y Primaries Red 0.640 0.330 0.630 0.340 Green 0.290 0.600 0.310 0.595 Blu
43、e 0.150 0.060 0.155 0.070 2.6.2 Assumed chromaticity for equal primary signals Reference white D65x y ER= EG= EB0.3127 0.3290 2.6.3 Opto-electronic transfer characteristics before non-linear precorrection Assumed linear 2.6.4 Overall opto-electronic transfer characteristic at source E = (1.099 L0.45
44、 0.099) for 1.00 L 0.018 E = 4.500 L for 0.018 L 0 where: L: luminance of the image 0 L 1 for conventional colorimetry E: corresponding electrical signal. (1)Chromaticity coordinates specified are those currently used by 625-line and 525-line conventional systems. 3 Family members The following fami
45、ly members are defined: 4:2:2 for 4:3 aspect ratio, and for wide-screen 16:9 aspect ratio systems when it is necessary to keep the same analogue signal bandwidth and digital rates for both aspect ratios. 4:4:42for 4:3 and 16:9 aspect ratio systems with higher colour resolution. Annex 1 Encoding para
46、meters for members of the family 1 Encoding parameter values for the 4:2:2 member of the family The specification (see Table 3) applies to the 4:2:2 member of the family, to be used for the standard digital interface between main digital studio equipment and for international programme exchange of 4
47、:3 aspect ratio digital television or wide-screen 16:9 aspect ratio digital television when it is necessary to keep the same analogue signal bandwidth and digital rates. 1It is recognized that a practice is now sometimes used by which, when programs produced in HDTV are release in SDTV, their HDTV p
48、ixel map is re-mapped onto the SDTV pixel map without changing the colorimetry of the original program. 2In the 4:4:4 members of the family the sampled signals may be luminance and colour difference signals (or, if used, red, green and blue signals). Rec. ITU-R BT.601-7 7 TABLE 3 2 Encoding parameter values for the 4:4:4 member of the family The specifications given in Table 4 apply to the 4:4:4 member of the family suitable for television source equipment and high-quality video signal processing applications. Parameters 525-
