SMPTE RP 218-2009 Specifications for Safe Action and Safe Title Areas for Television Systems《电视系统动作安全区和字幕安全区规范》.pdf

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1、 Table of Contents Page Foreword . 2 Intellectual Property 2 Introduction 2 1 Scope . 3 2 Conformance Notation . 3 3 Definitions 3 3.1 Aspect Ratio . 3 3.2 Image Lattice 3 3.3 Producition . 4 4 Safe Action and Safe Title Areas . 4 4.1 Safe Action Area 4 4.2 Safe Title Area . 4 4.3 Production Area .

2、4 5 Electronic Graticules 4 5.1 Width of Graticule . 4 5.2 Safe Action Area Graticule . 4 5.3 Safe Title Area Graticule 4 Annex A Example Calculation of Safe Area and Safe Title Positions (Normative) 5 Annex B System Examples (Normative) 7 Annex C Bibliography (Informative) . 15 Revision Notes 16 Pa

3、ge 1 of 16 pages SMPTE RP 218:2009 Revision of RP 218-2002 Copyright 2009 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 3 Barker Avenue., White Plains, NY 10601 (914) 761-1100 Approved December 18, 2009 SMPTE RECOMMENDED PRACTICE Specifications for Safe Action and Safe Title Areas for Te

4、levision Systems SMPTE RP 218:2009 Page 2 of 16 pages Foreword SMPTE (the Society of Motion Picture and Television Engineers) is an internationally-recognized standards developing organization. Headquartered and incorporated in the United States of America, SMPTE has members in over 80 countries on

5、six continents. SMPTEs Engineering Documents, including Standards, Recommended Practices, and Engineering Guidelines, are prepared by SMPTEs Technology Committees. Participation in these Committees is open to all with a bona fide interest in their work. SMPTE cooperates closely with other standards-

6、developing organizations, including ISO, IEC and ITU. SMPTE Engineering Documents are drafted in accordance with the rules given in Part XIII of its Administrative Practices. SMPTE RP 218 was prepared by Technology Committee 10E. Intellectual Property At the time of publication no notice had been re

7、ceived by SMPTE claiming patent rights essential to the implementation of this Recommended Practice. However, attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. SMPTE shall not be held responsible for identifying any or all such pate

8、nt rights. Introduction This section is entirely informative and does not form an integral part of this Engineering Document. This Recommended Practice provides the tools for calculating Safe Action and Safe Title Areas of any size. It also defines a set of Safe Areas, which are given in Annex B. Th

9、ese are legacy safe areas and are not reflective of current practice; for current practice, users should consult SMPTE ST 2046-1 and SMPTE RP 2046-2. Users are advised that at the time of issue of this revision, the closed captioning system defined in CEA 708 specified the Safe Title Area defined in

10、 this Recommended Practice as the area of the image within which captions must be displayed. As this area is significantly smaller than the SMPTE ST 2046-1 Safe Action and Safe Title Areas, users are cautioned that it may not be possible to directly overlay captions on elements around the outer marg

11、ins of the SMPTE ST 2046-1 Safe Areas. SMPTE RP 218:2009 Page 3 of 16 pages 1 Scope This practice describes a method for locating the safe action and safe title areas for television systems. This document is intended for application in program production where the image aspect ratio of the acquired

12、essence is the same as that of the display. The safe areas defined in Annex B of this Recommended Practice are a legacy of past practice. They are based on the limitations of CRT-based displays. Users are advised to consult SMPTE ST 2046-1 for the current safe areas, which are based on fixed pixel m

13、atrix displays and are significantly larger. Moreover, the safe areas defined herein do not offer guidance in situations where material generated in one aspect ratio may need to be displayed in a different aspect ratio. Users are advised to consult SMPTE RP 2046-2 for this information. Safe action a

14、nd safe title areas are located within the television system image production aperture lattice. Safe action area specifies an image area within which all significant action must take place. Safe title area specifies an image area within which important title information must be confined. These areas

15、 ensure visibility of action and title information on the majority of home television receivers. 2 Conformance Notation Normative text is text that describes elements of the design that are indispensable or contains the conformance language keywords: “shall“, “should“, or “may“. Informative text is

16、text that is potentially helpful to the user, but not indispensable, and can be removed, changed, or added editorially without affecting interoperability. Informative text does not contain any conformance keywords. All text in this document is, by default, normative, except: the Introduction, any se

17、ction explicitly labeled as “Informative“ or individual paragraphs that start with “Note:” The keywords “shall“ and “shall not“ indicate requirements strictly to be followed in order to conform to the document and from which no deviation is permitted. The keywords, “should“ and “should not“ indicate

18、 that, among several possibilities, one is recommended as particularly suitable, without mentioning or excluding others; or that a certain course of action is preferred but not necessarily required; or that (in the negative form) a certain possibility or course of action is deprecated but not prohib

19、ited. The keywords “may“ and “need not“ indicate courses of action permissible within the limits of the document. The keyword “reserved” indicates a provision that is not defined at this time, shall not be used, and may be defined in the future. The keyword “forbidden” indicates “reserved” and in ad

20、dition indicates that the provision will never be defined in the future. Unless otherwise specified, the order of precedence of the types of normative information in this document shall be as follows: Normative prose shall be the authoritative definition; Tables shall be next; followed by formal lan

21、guages; then figures; and then any other language forms. 3 Definitions 3.1 Aspect Ratio Aspect ratio is the ratio of the horizontal dimension to the vertical dimension of a rectangular active image area. 3.2 Image Lattice An image lattice is a two-dimensional, rectangular array of pixels. SMPTE RP 2

22、18:2009 Page 4 of 16 pages 3.3 Production Aperture Production aperture is the image lattice that represents the maximum possible active image extent in a given standard. In this practice, production aperture is defined in pixel units, the number active image pixels per horizontal row by the number o

23、f active image pixels per vertical column in a rectangular image area of any aspect ratio. 4 Safe Action and Safe Title Areas 4.1 Safe Action Area The safe action area is the maximum image area within which all significant action shall be contained. The image area defined by the safe action area is

24、smaller than, and concentric with the production aperture image area. The horizontal safe action area shall be 90% of the production aperture picture width. The vertical safe action area shall be 90% of the production aperture picture height. 4.2 Safe Title Area The safe title area is the maximum im

25、age area within which all significant titles shall be contained. The image area defined by the safe title area is contained within the production aperture image area and is smaller than, and cocentric with the image area defined by the safe action area. The horizontal safe title area shall be 80% of

26、 the picture width. The vertical safe title area shall be 80% of the picture height. 4.3 Production Area It shall be noted that it is not the intent of this practice that information outside the safe action and safe title areas be discarded. Production aperture image area shall be retained and, to t

27、he extent permitted by transmission standards, shall be transmitted. 5 Electronic Graticules An electronic graticule that displays the border of the safe action area and/or safe title area can be generated and superimposed on a source production area image, thus indicating image areas within which a

28、ction and/or title essence shall be contained. The graticule display shall take the form of thin but visible lines. 5.1 Width of Graticule The graticule shall be of sufficient width to be displayed clearly. Each vertical line contained in the graticule shall be 0.5% of the number of active pixels pe

29、r horizontal (scanning) line, rounded down to the nearest whole number of pixels. Each horizontal line contained in the graticule shall be 0.5% of the number of active (scanning) lines, rounded up to the nearest whole number of (scanning) lines. 5.2 Safe Action Area Graticule The safe action area gr

30、aticule shall be a solid, visible line superimposed on the source production area image. 5.3 Safe Title Area Graticule The safe title area graticule shall be a dashed, visible line superimposed on the source production area image. SMPTE RP 218:2009 Page 5 of 16 pages Annex A (Normative) Example Calc

31、ulation of Safe Area and Safe Title Positions A.1 Safe Action Area and Safe Title Area Calculation The following formulae may be used to calculate the safe action area and safe title area for a production area of any size and aspect ratio. Calculations for safe area width (horizontal) and safe area

32、height (vertical) are independent. Zero based numbering is used to remain consistent with previous standards and practices such as ITU-R BT.601-5 and SMPTE RP 187. A.1.1 Legend H = Production area pixels per row (horizontal) V = Production area pixels per column (vertical) %H = Picture width of safe

33、 area in percent %V= Picture height of safe area in percent PH= Pixels from production area edges to side safe action boundaries (horizontal) PV= Pixels from production area edges to top and bottom safe action boundaries (vertical) HSW = Safe area width pixels per row (horizontal) VSH = Safe area he

34、ight pixels per column (vertical) CL= Left side safe area boundary pixel column number CR= Right side safe area boundary pixel column number RT= Top edge safe area boundary pixel row number RB= Bottom edge safe area boundary pixel row number A.1.2 Number of pixels from left and right aperture edges

35、to safe area boundaries: PH= (H (%H H) 2 A.1.3 Number of pixels from top and bottom aperture edges to safe area boundaries: PV= (V (%V V) 2 A.1.4 Rounding Rounding is applied to locate boundaries in their most safe positions, toward the center of the image and away from the edges of the image. The v

36、alues PHand PVshall be rounded up to the nearest whole number. A.1.5 Pixels contained in the safe area Safe area pixels per row HSW= H (2 PH) Safe area pixels per column VSH= V (2 PV) SMPTE RP 218:2009 Page 6 of 16 pages A.1.6 Safe area boundary locations A.1.6.1 Safe area boundary column numbers fo

37、r picture sides: Left side boundary pixel column number CL= PH 1 Right side boundary pixel column number CR= H PH A.1.6.2 Safe area boundary row numbers for top and bottom edges of the picture: Top edge boundary pixel row number RT= PV 1 Bottom edge boundary pixel row number RB= V PVSMPTE RP 218:200

38、9 Page 7 of 16 pages Annex B (Normative) System Examples The safe areas defined in Annex B of this Recommended Practice are a legacy of past practice. They are based on the limitations of CRT-based displays. Users are advised to consult SMPTE ST 2046-1 for the current safe areas, which are based on

39、fixed pixel matrix displays and are significantly larger Tables B.1 through B.6 illustrate examples of Safe Action Area and Safe Title area calculations for a number of television standards. Table B.1a Safe action area 1920 x 1080 Horizontal pixels Vertical pixels Total pixels Production area pixel

40、matrix 1920 1080 2,073,600 Safe action percent of width and height 90% 90% Safe action pixel matrix 1728 972 1,679,616 Number of pixels from production area edge to safe action boundary 96 54 Pixel column number Pixel row number Safe action boundary left side pixel column 95 Safe action boundary top

41、 edge pixel row 53 Safe action boundary right side pixel column 1824 Safe title boundary bottom edge pixel row 1026 Table B.1b Safe title area 1920 x 1080 Horizontal pixels Vertical pixels Total pixels Production area pixel matrix 1920 1080 2,073,600 Safe title percent of width and height 80% 80% Sa

42、fe title pixel matrix 1536 864 1,327,104 Number of pixels from production area edge to safe title boundary 192 108 Pixel column number Pixel row number Safe title boundary left side pixel column 191 Safe title boundary top edge pixel row 107 Safe title boundary right side pixel column 1728 Safe titl

43、e boundary bottom edge pixel row 972 SMPTE RP 218:2009 Page 8 of 16 pages Table B.2a Safe action area 1920 x 1035 Horizontal pixels Vertical pixels Total pixels Production area pixel matrix 1920 1035 1,987,200 Safe action percent of width and height 90% 90% Safe action pixel matrix 1728 931 1,608,76

44、8 Number of pixels from production area edge to safe action boundary 96 52 Safe action boundary left side pixel column 95 51 Safe action boundary top edge pixel row Safe action boundary right side pixel column 1824 983 Safe sction boundary bottom edge pixel row Table B.2b Safe title area 1920 x 1035

45、 Horizontal pixels Vertical pixels Total pixels Production area pixel matrix 1920 1035 1,987,200 Safe title percent of width and height 80% 80% Safe title pixel matrix 1536 827 1,270,272 Number of pixels from production area edge to safe title boundary 192 103 Safe title boundary left side pixel col

46、umn 191 103 Safe title boundary top edge pixel row Safe title boundary right side pixel column 1728 931 Safe title boundary bottom edge pixel row SMPTE RP 218:2009 Page 9 of 16 pages Table B.3a Safe action area 1280 x 720 Horizontal pixels Vertical pixels Total pixels Production area pixel matrix 12

47、80 720 921,600 Safe action percent of width and height 90% 90% Safe action pixel matrix 1152 648 746,496 Number of pixels from production area edge to safe action boundary 64 36 Safe action boundary left side pixel column 63 35 Safe action boundary top edge pixel row Safe action boundary right side

48、pixel column 1216 684 Safe action boundary bottom edge pixel row Table B.3b Safe title area 1280 x 720 Horizontal pixels Vertical pixels Total pixels Production area pixel matrix 1280 720 921,600 Safe title percent of width and height 80% 80% Safe title pixel matrix 1024 576 589,824 Number of pixels

49、 from production area edge to safe title boundary 128 72 Safe title boundary left side pixel column 127 71 Safe title boundary top edge pixel row Safe title boundary right side pixel column 1152 648 Safe title boundary bottom edge pixel row SMPTE RP 218:2009 Page 10 of 16 pages Table B.4a Safe action area 720 x 480 Horizontal pixels Vertical pixels Total pixels Production area pixel matrix 720 480 345,600 Safe action percent of width and hei