SMPTE ST 2016-2-2014 Format for Pan-Scan Information.pdf

1、 Copyright 2014 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 3 Barker Avenue, White Plains, NY 10601 (914) 761-1100 Approved August 16, 2014 Table of Contents Page Foreword . 3 Intellectual Property 3 Introduction 3 1 Scope 4 2 Conformance Notation 4 3 Normative References 4 4 Definitio

2、ns . 4 5 Pan-Scan Information . 5 5.1 Overview . 5 5.2 Pan-Scan Data Sets. 6 5.3 Pan-Scan Data Flags and Aspect Ratio 6 5.4 Horizontal Viewport Offset Pan . 7 5.5 Vertical Viewport Offset Tilt . 7 5.6 Vertical Size Coefficient Zoom Vertical . 7 5.7 Horizontal Size Coefficient Zoom Horizontal 7 5.8 O

3、utput Image Aspect Ratio Coding . 7 6 Relationship Among AFD, Bar Data and Pan-Scan Information 8 7 Coding of Pan-Scan Information . 8 7.1 Pan-Scan Information Coding 8 7.1.1 Data Set ID Byte 8 7.1.2 Pan-Scan Flags Byte . 9 7.1.3 Pan-Scan Information Fields 9 7.2 Data Repetition Rate 9 Annex A Bibli

4、ography (Informative) 10 Annex B Example Pan-Scan Information (Informative) 11 B.1 Example of Pan-Scan to Extract a 4:3 Image from a 16:9 Image . 11 Page 1 of 13 pages SMPTE ST 2016-2:2014 Revision of SMPTE 2016-2-2007 SMPTE STANDARD Format for Pan-Scan Information SMPTE ST 2016-2:2014 Page 2 of 13

5、pages Figures Figure 1 Pan-Scan Parameters 6 Figure B.1 Extraction of a 4:3 viewport from a 1920 x 1080 16:9 source image . 11 Tables Table 1 Pan-Scan informational payload . 5 Table 2 Pan-Scan presence flags and aspect ratio code . 7 Table 3 Output image aspect ratio codes . 8 Table B.1 Pan-Scan pa

6、rameters for a 4:3 viewport from a 1920 x 1080 16:9 source image Right pan 13 Table B.2 Pan-Scan parameters for a 4:3 viewport from a 1920 x 1080 16:9 source image Left pan 13 Table B.3 Pan-Scan parameters for a 4:3 viewport from a 1920 x 1080 16:9 source image Centered 13 SMPTE ST 2016-2:2014 Page

7、3 of 13 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 six continents. SMPTEs Engineering Docum

8、ents, 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-developing organizations, including ISO,

9、IEC and ITU. SMPTE Engineering Documents are drafted in accordance with the rules given in its Standards Operations Manual. SMPTE ST 2016-2 was prepared by Technology Committee 24TB. Intellectual Property At the time of publication no notice had been received by SMPTE claiming patent rights essentia

10、l to the implementation of this Engineering Document. 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 patent rights. Introduction Image formatting inform

11、ation describes certain spatial characteristics of a high definition or standard definition video image. It is generated and carried through all or some of the video production, distribution and emission chain. The image formatting metadata types are Active Format Description (AFD), Bar Data, and Pa

12、n Scan information. AFD and Bar Data are intended to be broadcast with the video signal that they describe. AFD information is intended to guide DTV receivers and/or intermediate professional video equipment regarding the display of video of one aspect ratio on a display of another aspect ratio. Bar

13、 Data information is used to signal the precise unused areas of an image raster when the active video does not completely fill that raster, in particular widescreen cinema material carried letterboxed in a frame with bars top and bottom. Pan-Scan information is a set of data that is intended to guid

14、e professional video equipment in extracting an image to be presented in an aspect ratio that is different from that in which the material was produced or distributed. Independent parameters are provided for pan (horizontal offset), tilt (vertical offset), vertical size, horizontal size and output a

15、spect ratio. Pan-Scan information is not intended for use beyond the production and distribution environments. The following suite of SMPTE standards defines the origination and carriage of AFD, Bar Data, and Pan-Scan information: SMPTE ST 2016-1 Format for Active Format Description and Bar Data SMP

16、TE ST 2016-2 Format for Pan-Scan Information SMPTE ST 2016-3 Vertical Ancillary Data Mapping of Active Format Description and Bar Data SMPTE ST 2016-4 Vertical Ancillary Data Mapping of Pan-Scan Information Other SMPTE standards can be used for alternative transport methods for this data. SMPTE ST 2

17、016-2:2014 Page 4 of 13 pages 1 Scope This Standard defines Pan-Scan information for origination and conveyance through the production and distribution processes for standard definition or high definition television signals. Associated standards define how this information is placed into ancillary d

18、ata packets and is KLV coded as SMPTE metadata (see Annex C). 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 text that is potentially helpful to

19、 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 section explicitly labeled as “Inform

20、ative“ 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 that, among several possibilities,

21、 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 prohibited. The keywords “may“ and “need

22、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 addition indicates that the provision

23、 will never be defined in the future. 3 Normative References The following document contains provisions which, through reference in this text, constitute provisions of this recommended practice. At the time of publication, the editions indicated were valid. All standards are subject to revision, and

24、 parties to agreements based on this recommended practice are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below. SMPTE RP 187:1995, Center, Aspect Ratio and Blanking of Video Images 4 Definitions 4.1 output image The rectangular area that

25、represents the result of an image conversion process. 4.2 source image The rectangular area represented by the production aperture of the source signal. 4.3 viewport A selected rectangular area of a source image that will be used to create an output image. SMPTE ST 2016-2:2014 Page 5 of 13 pages 5 P

26、an-Scan Information 5.1 Overview Pan-Scan information describes a variable image viewport and output image aspect ratio that may be employed in professional applications to create a new output image from the source image. Pan-Scan information shall consist of six elements, comprising a Pan-Scan data

27、 set ID, Pan-Scan data flags and aspect ratio code, horizontal viewport offset, vertical viewport offset, vertical size coefficient, and horizontal size coefficient. These elements shall be coded as shown in table 1. One byte shall be used to label the data set with an ID code. One byte shall be use

28、d to represent the Pan-Scan flags and aspect ratio code. Eight bytes shall be used to represent two 16-bit numbers and two 14-bit numbers defining a viewport (target) aperture relative to the source image. Bits p0, t0, v0, and h0 shall be the least significant bits. Center of picture shall be based

29、on the source input format, and shall be as defined in SMPTE RP 187. For SMPTE ST 125 (525i) and SMPTE ST 293 (525P) formats, the center of picture should be based on 483 active lines. Although an 8-bit data structure is shown here, different transport mechanisms may specify a different structure an

30、d bit/byte order for transport. Table 1 Pan-Scan informational payload Data Set Words Data Set Word bits Word Function b7 b6 b5 b4 b3 b2 b1 b0 1 Data Set ID id7 id6 id5 id4 id3 id2 id1 id0 2 P-S Flags id7 id0 is the Pan-Scan Data Set ID code; ar2 ar0 is the Output image aspect ratio code; p15 p0 is

31、the Horizontal viewport offset (Pan); t15 t0 is the Vertical viewport offset (Tilt); v13 v0 is the Vertical size coefficient (Zoom vertical); h13 h0 is the Horizontal size coefficient (Zoom horizontal). rsv is a reserved bit and shall be set to 0 SMPTE ST 2016-2:2014 Page 6 of 13 pages 5.2 Pan-Scan

32、Data Sets Applications may define more than one set of Pan-Scan Data Set parameters for an image sequence. Each data set shall be labeled by an 8-bit Data Set identification code. The intended use of the ID is to signal a unique pan-scan version. There may be multiple data sets per frame. Each data

33、set shall have unique ID value. See Section 7.1.1 for assignments of the Data Set ID values. The use of these elements shall be as illustrated in Figure 1. Horizontal offset (Pan) and vertical offset (Tilt) shall be 16-bit signed binary numbers, representing source image pixels or lines, with 4 bits

34、 subpixel resolution (i.e., “n“-bit fixed point binary number with “n-4“ significant bits and four fractional bits). Vertical size (Zoom Vertical) shall be an unsigned binary number representing source image lines. Horizontal size (Zoom Horizontal) shall be an unsigned binary number representing sou

35、rce image pixels. If the bounds of the viewport exceed the bounds of the source image these portions should be filled with a null signal (e.g. black or grey). If the bounds of the viewport are inside the source image, the pixels outside of the viewport should be discarded. Pan-Scan parameters shall

36、be interpreted based on the source image parameters (horizontal pixels and vertical lines). Image format up or down conversion (output image format resolution not the same as the input image format resolution) is outside the scope of this standard. S O U R C EV I E W P O R TZ o omP a nT i ltS o u r

37、c e Im ag e C e n t erV i ew p or t C en t erFigure 1 Pan-Scan Parameters 5.3 Pan-Scan Data Flags and Aspect Ratio The presence of Pan-Scan data shall be signaled with a 4-bit field for viewport data flags, carried in a one-byte field, as shown in Table 2. Setting all bits in the Pan, Tilt, V-Size a

38、nd H-Size flags to logical zero shall turn Pan-Scan off. Individual flags shall be set on or off (1 or 0) to indicate to a receive device which Pan-Scan data is present as well as to activate the appropriate image processing (such as cropping and filtering). This field shall also code the aspect rat

39、io of the output image using the codes shown in Table 3. The reserved bit shall be set to 0. SMPTE ST 2016-2:2014 Page 7 of 13 pages Table 2 Pan-Scan presence flags and aspect ratio code Bit Description Comments b7 Pan data present 1 = present b6 Tilt data present 1 = present b5 Vertical Size data p

40、resent 1 = present b4 Horizontal Size data present 1 = present b3 Reserved set to 0 b2 Output image aspect ratio ar-2 b1 ar-1 b0 ar-0 5.4 Horizontal Viewport Offset Pan The Pan value shall be a 16-bit signed binary number, using twos complement, with 4 bits of sub-pixel resolution. It shall specify

41、the location of the center of the viewport with respect to the center of the source image, in source pixels. Positive numbers shall represent a pan to the right. The illustration in figure 1 shows a viewport with a positive pan. A zero value shall represent “no pan“. The range of values of horizonta

42、l viewport offset (pan) shall be from 7FF.Fh (204715/16) to 800.0h (-2048).). If the Pan flag is set to 0, then the Horizontal viewport offset shall be equal to zero and the Horizontal viewport offset data shall be disregarded. 5.5 Vertical Viewport Offset Tilt The Tilt value shall be a 16-bit signe

43、d binary number, using twos complement, with 4 bits of sub-pixel resolution. It shall specify the location of the center of the viewport with respect to center of the source image, in source lines. Positive numbers shall represent a tilt down. The illustration in figure 1 shows a viewport with a pos

44、itive tilt. A zero value shall represent “no tilt“. The range of values of vertical viewport offset (tilt) shall be from 7FF.Fh (204715/16) to 800.0h (-2048). If the Tilt flag is set to 0, then the Vertical viewport offset shall be equal to zero and the Vertical viewport data shall be disregarded. 5

45、.6 Vertical Size Coefficient Zoom Vertical The vertical size coefficient value shall be a 14-bit unsigned binary number. It shall specify the height of the viewport, in lines of the source image. Values greater than the number of lines in the source image shall represent a zoom-out or shrinkage of t

46、he image. Values less than the number of lines in the source image shall represent a zoom-in or expansion of the image. The maximum value of the vertical size coefficient shall be 1FFFh (8191). If the Vertical Size flag is set to 0, then the Vertical Size shall be equal to the source image formats v

47、ertical line count and the Vertical Size coefficient data shall be disregarded. 5.7 Horizontal Size Coefficient Zoom Horizontal The horizontal size coefficient value shall be a 14-bit unsigned binary number. It shall specify the width of the viewport, in pixels of the source image. Values greater th

48、an the number of pixels in the source image line shall represent a zoom-out or shrinkage of the image. Values less than the number of pixels in the source image line shall represent a zoom-in or expansion of the image. The maximum value of the horizontal size coefficient shall be 1FFFh (8191). If th

49、e Horiz Size flag is set to 0, then the Horizontal Size coefficient shall be equal to the source image formats horizontal pixel count and the Horizontal Size coefficient shall be disregarded. 5.8 Output Image Aspect Ratio Coding Code values defining the output image aspect ratio shall be as shown in Table 3. SMPTE ST 2016-2:2014 Page 8 of 13 pages Table 3 Output image aspect ratio codes Code ar-2, ar-1, ar-0 Aspect ratio Description and application 000 Undefined 00