ITU-R BR 1441-2000 Compromise Scanned Area Dimensions for Television from 35 mm Wide-Screen Films《来自35毫米宽屏幕胶片的电视的折中扫描区域尺寸》.pdf

1、 Rec. ITU-R BR.1441 1 RECOMMENDATION ITU-R BR.1441*COMPROMISE SCANNED AREA DIMENSIONS FOR TELEVISION FROM 35 mm WIDE- SCREEN FILMS (Question ITU-R 240/11) (2000) Rec. ITU-R BR.1441 The ITU Radiocommunication Assembly, considering a) that the scanned area dimensions listed in Recommendation ITU-R BR.

2、1374 are: a.1) maximum projectable image area dimensions corresponding to ISO standards for cinematographic film intended for optical projection; a.2) maximum safe areas to be scanned from film specially shot and framed for television; b) that the scanned areas for wide-screen films given in Recomme

3、ndation ITU-R BR.1374 are based on one of the principles: b.1) to fill the television display with a full height central area of the film image (full screen); b.2) to show the full width of the film with black areas top and bottom of the television display (letterbox); c) that for some wide-screen f

4、ilms, a compromise, between the full-screen and letterbox scanning areas, may be preferred for artistic or heritage reasons; d) that there should be some recognized image aspect ratios and related image area dimensions that can be used as compromise alternatives for telecine scanning, recommends 1 t

5、hat, if required for artistic or other reasons, the following compromise presentation formats for wide-screen film on television should be used: For 4:3 television: 14:9, 16:9, 18:9 For 16:9 television: 18:9; 2 that those who prefer to use a compromise scanning area for wide-screen films should use

6、one of the scanning areas listed in Annex 1: Table 1 for 4:3 television systems; Table 2 for 16:9 television systems; 3 that a suitable test film should be used to align telecine equipment according to the recommended scanned areas (a suitable 35 mm test film is being prepared at the British Kinemat

7、ograph Sound and Television Society (BKSTS), London, United Kingdom (http:/); 4 that it should be taken into account that the dimensions and diagrams in this Recommendation relate to the image content of the transmitted signal. The possible cropping of the image due to over-scanning in the receiver

8、is discussed in Annex 1, 1. _ *This Recommendation should be brought to the attention of the International Standardization Organization (ISO). 2 Rec. ITU-R BR.1441 ANNEX 1 Compromise scanned aspect ratios for 4:3 and 16:9 television 1 Background Many of the wide-screen films produced in the past and

9、 at present for cinema presentation exist in formats with aspect ratios that are different to those used on television. These film aspect ratios include: 1.66:1 non anamorphic, wide-screen; 1.85:1 non anamorphic, wide-screen; 2.39:1 anamorphic, wide-screen. When these wide-screen film formats are sc

10、anned for 4:3 and 16:9 television, two basic principles are applied: The full screen method fills the TV screen. The full height of the film image is shown but image area at each side will be cropped. The letterbox method reproduces the film in its intended presentation format but leaves black areas

11、 at top and/or bottom of the television screen. In different countries, one or the other method is established and preferred by the audience. Some broadcasters have adopted a third, compromise, method to present some wide-screen films on television. This method is based on scanning between the full-

12、screen and the letterbox presentations. There will be smaller black areas top and bottom of the TV screen than in full letterbox presentation and less of the film image area each side will be cropped than in the full screen presentation. This Recommendation specifies a set of compromise aspect ratio

13、s and the corresponding image area dimensions to be scanned from 35 mm wide-screen motion picture films. It is intended to be a reference document for compromise transfer from telecine of programmes intended for transmission, exchange or distribution. 2 Television presentation The recommended compro

14、mise aspect ratios for reproduction on television are: Wide-screen films reproduced with one of these compromise aspect ratios will show the full height of the film image but some of the film image area will be cropped each side. In addition, there will be black areas at the top and/or bottom of the

15、 television display. Over-scanning in traditional cathode ray tube display results in some cropping of the transmitted image. The actual image content and the size of the black bars on the screen will depend on the amount of over-scanning. Receivers typically crop 5-10% of the overall image. In an i

16、mage displayed full-screen, both the image height and width will be cropped. In a letterbox display, the width will be cropped but only part of the black bars will be cropped from the height. This will result in a change in the aspect ratio of the displayed image. However, future flat screen display

17、s are not expected to suffer from the over-scanning effect and therefore will display the transmitted image without cropping. Television system Recommended compromise aspect ratios 4:3 television 14:9 16:9 18:9 (2:1) (See Fig. 1) 16:9 television 18:9 (2:1) (See Fig. 2) Rec. ITU-R BR.1441 3 1441-0118

18、:916:914:94:3FIGURE 1Compromise aspect ratios for 4:3 television systemsFIGURE 1/BR.1441.D01 = 3 CM 1441-0218:916:9FIGURE 2Compromise aspect ratios for 16:9 television systemsFIGURE 2/BR.1441.D01 = 3 CM 3 The scanning principle Following Recommendation ITU-R BR.1374 Scanned area dimensions from 16 m

19、m and 35 mm cinematographic film used in television, the wide-screen images on films should be scanned according to the international standards for projected image height. The related scanned width shall be according to the preferred compromise aspect ratio. 4 Reference values for calculating scanne

20、d area dimensions The reference dimensions adopted for calculating the scanned areas for 4:3 and 16:9 television are based on the current ISO Standard for projection of 35 mm cinematographic films (ISO 2907 Cinematography Maximum projectable image area on 35 mm motion-picture film Position and dimen

21、sions). The anchor dimensions are: Format Standard Reference dimension(mm) Derived dimension (mm) Image centre (mm) 35 mm Academy aperture aspect ratio: 1.37:1 ISO 2907 Image height: 15.29 Image width: 20.95 18.75 4 Rec. ITU-R BR.1441 Based on the derived width, the calculated image heights for the

22、projection apertures from film are: 5 Scanned area dimensions for television 5.1 4:3 television systems Scanned dimensions for 4:3 television systems are given in Table 1. The relationship between the scanning and film formats is shown in Figs. 3, 4 and 5. TABLE 1 Film shot and framed for projection

23、: compromise scanned areas for 4:3 television (Scanned area dimensions from images on film intended for contact printing and projection. The film material can be a print, an intermediate or camera original.) Aspect ratio Height (mm) 1.66:1 12.62 16:9 11.78 1.85:1 11.32 2.39:1 17.53 Item Image aspect

24、 ratio Scanned area dimensions (mm) Appearance Notes Framed for Displayed on 4:3 television Width Height Centre 1 35 mm: Academy aperture width 1.1 1.66:1 14:9 letterbox 19.63 12.62 18.75 1 1.2 16:9 14:9 letterbox 18.33 11.78 18.75 1 1.3 1.85:1 14:9 letterbox 17.61 11.32 18.75 1 1.4 2.39:1 14:9 lett

25、erbox 13.63 17.53 18.75 1 1.5 2.39:1 16:9 letterbox 15.58 17.53 18.75 1 1.6 2.39:1 18:9 letterbox 17.53 17.53 18.75 1 NOTE 1 These dimensions will crop film image area on each side and there will be black areas top and bottom of the screen.Cropped area on the film image Black area on the television

26、display Rec. ITU-R BR.1441 5 1441-034:314:9FIGURE 3Compromise scanned areas, 14:9 for 4:3 television(1.1) 1.66:1 3.1% of film area on each side cropped(1.2) 16:9 6.3% of film area on each side cropped(1.3) 1.85:1 8.0% of film area on each side cropped(1.4) 2.39:1 17.6% of film area on each side crop

27、pedFIGURE 3/BR.1441.D01 = 3 CM 1441-044:316:9FIGURE 4Compromise scanned areas, 16:9 for 4:3 television(1.5) 2.39:1 12.8% of film area on each side croppedFIGURE 4/BR.1441.D01 = 3 CM 1441-054:318:9FIGURE 5Compromise scanned areas, 18:9 for 4:3 television(1.6) 2.39:1 8.2% of film area on each side cro

28、ppedFIGURE 5/BR.1441.D01 = 3 CM 6 Rec. ITU-R BR.1441 5.2 16:9 television systems Scanned dimensions for 16:9 television systems are given in Table 2. The relationship between the scanning and film formats are shown in Fig. 6. TABLE 2 Film shot and framed for projection: scanned for 16:9 television (

29、Scanned area dimensions from images on film intended for contact printing and projection. The film material can be a print, an intermediate or camera original.) 1441-0616:918:9FIGURE 6Compromise scanned areas, 18:9 for 16:9 television(2.1) 2.39:1 8.2% of film area on each side croppedFIGURE 6/M.3020

30、.D01 = 3 CM Item Image aspect ratio Scanned area dimensions (mm) Appearance Notes Framed for Displayed on 16:9 television Width Height Centre 35 mm: Academy aperture width 2.39:1 18:9 17.53 17.53 18.5 1 NOTE 1 These dimensions will crop film image area on each side and there will be black areas top

31、and bottom of the screen. Cropped area on the film image Black area on the television display Rec. ITU-R BR.1441 7 6 Image area and television scanning The scanned areas from film should relate to the nominal active picture area of analogue television systems as determined by the blanking given in R

32、ecommendation ITU-R BT.470 Conventional television systems. For the digital representation of television systems, based on Recommendation ITU-R BT.601 Studio encoding parameters of digital television for standard 4:3 and wide-screen 16:9 aspect ratios, it is important to note that the horizontal sca

33、nned dimension on film should coincide with the central 702 samples of the digital active line (samples 9 to 710). BIBLIOGRAPHY EBU 1997 Recommendation R86. Scanned image area dimensions from films for television. EBU 1998 Recommendation R92. Active line length in analogue and digital 625/50 television systems. EBU 1998 Recommendation R93. Compromise scanned area dimensions for television from 35 mm wide-screen films.