1、 Approved August 24, 2016 Copyright 2016 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 3 Barker Avenue, White Plains, NY 10601 (914) 761-1100 SMPTE ST 2094-40:2016 SMPTE STANDARD Dynamic Metadata for Color Volume Transform Application #4 Page 1 of 26 pages Table of Contents Page Foreword
2、 3 Intellectual Property . 3 Introduction 3 1 Scope . 4 2 Conformance Notation . 4 3 Normative References . 4 4 Terms and Definitions . 5 4.1 actual display peak luminance. 5 4.2 brightest pixel 5 4.3 input image essence 5 4.4 linearized maxRGB 5 4.5 linearized RGB 5 4.6 scene . 5 4.7 selected pixel
3、s . 5 5 Application Identification . 6 6 Extension to the Processing Window 6 6.1 Selection of Pixels for Processing . 6 6.2 Center of Ellipse 7 6.3 Rotation Angle . 7 6.4 Semi-Major Axis of the Internal Ellipse 7 6.5 Semi-Major Axis of the External Ellipse 7 6.6 Semi-Minor Axis of the External Elli
4、pse 7 6.7 Overlap Process Option 7 7 Targeted System Display 7 7.1 Introduction 7 7.2 Targeted System Display Actual Peak Luminance (2D LUT) . 7 SMPTE ST 2094-40:2016 Page 2 of 26 pages 8 Color Volume Mapping 8 8.1 Introduction 8 8.2 Mastering Display Actual Peak Luminance (2D LUT) . 8 8.3 Maximum S
5、cene Color Component Levels . 8 8.4 Average MaxRGB 8 8.5 Distribution MaxRGB . 8 8.6 Fraction of the Bright Pixels. 8 8.7 Scene Based Tone Mapping . 9 8.8 Color Saturation Weight 10 9 Application Constraints . 11 9.1 Metadata Set . 11 9.2 Processing Window Constraints 12 10 Computation of the Fracti
6、onBrightPixels 12 Annex A Mapping of Application #4 to the Generalized Color Transform Model (Informative) 14 Annex B Scene-based Color Volume Mapping Method Description (Informative) 15 B.1 Introduction 15 B.2 Source Normalized Actual Peak Luminance and Target Normalized Actual Peak Luminance 15 B.
7、2.1 Source Normalized Actual Peak Luminance . 15 B.2.2 Target Normalized Actual Peak Luminance 15 B.3 Color Components Normalization . 16 B.4 Scene Adaptive Tone Mapping . 16 B.4.1 Tone Mapping with the N-th Order Curve 16 B.4.2 Example: Tone Mapping with the 4th Order Bezier Curve . 17 B.5 Scene-ba
8、sed Color Saturation Mapping . 18 B.5.1 Color Saturation Mapping 18 B.5.2 Color Saturation Mapping Process 18 B.5.3 Color Saturation Mapping Weight 19 B.5.4 Color Saturation Mapping Maximum Gain . 20 B.6 Local Pixel Processing in Elliptical Pixel Selector . 21 B.6.1 Introduction 21 B.6.2 Transition
9、Weighting Function . 21 B.6.3 Output Pixel Values for up to Two Elliptical Pixel Selectors 22 Annex C Measurement of Actual Peak Luminance (Informative) . 24 Bibliography (Informative) . 26 SMPTE ST 2094-40:2016 Page 3 of 26 pages Foreword SMPTE (the Society of Motion Picture and Television Engineer
10、s) 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 Documents, including Standards, Recommended Practices, and Engineering Guidelines, are p
11、repared 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, IEC and ITU. SMPTE Engineering Documents are drafted in accordance with the rules
12、given in its Standards Operations Manual. SMPTE ST 2094-40 was prepared by Technology Committee 10E. Intellectual Property SMPTE draws attention to the fact that it is claimed that compliance with this Standard may involve the use of one or more patents or other intellectual property rights (collect
13、ively, “IPR“). The Society takes no position concerning the evidence, validity, or scope of this IPR. Each holder of claimed IPR has assured the Society that it is willing to License all IPR it owns, and any third party IPR it has the right to sublicense, that is essential to the implementation of t
14、his Standard to those (Members and non-Members alike) desiring to implement this Standard under reasonable terms and conditions, demonstrably free of discrimination. Each holder of claimed IPR has filed a statement to such effect with SMPTE. Information may be obtained from the Director, Standards o
15、r 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 not“ indicate courses of action permissible within the limits of the document. The keyw
16、ord “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 will never be defined in the future. A conformant implementation according to this doc
17、ument is one that includes all mandatory provisions (“shall“) and, if implemented, all recommended provisions (“should“) as described. A conformant implementation need not implement optional provisions (“may“) and need not implement them as described. Unless otherwise specified, the order of precede
18、nce of the types of normative information in this document shall be as follows: Normative prose shall be the authoritative definition; Tables shall be next; then formal languages; then figures; and then any other language forms. 3 Normative References The following standards contain provisions which
19、, through reference in this text, constitute provisions of this engineering document. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this engineering document are encouraged to investigate the possibility of ap
20、plying the most recent edition of the standards indicated below. SMPTE ST 2094-40:2016 Page 5 of 26 pages SMPTE ST 2086:2014, Mastering Display Color Volume Metadata Supporting High Luminance and Wide Color Gamut Images SMPTE ST 2094-1:2016, Dynamic Metadata for Color Volume Transform Core Component
21、s 4 Terms and Definitions SMPTE ST 2094-1, Section 4, Terms and Definitions applies to this document. This section defines additional terms and definitions used in this document. 4.1 actual display peak luminance peak luminance (in units of cd/m2) that a display is capable of delivering while render
22、ing the scene Note: This depends on the spatial distribution of the luminance levels of the pixels in the scene and the power consumption limits of the display 4.2 brightest pixel pixel with the maximum approximate luminance among the smoothed selected pixels in the scene, with the smoothing carried
23、 out by a box filter as defined in Section 10 4.3 input image essence image essence to which the color volume transform is applied and having three color components labeled R, G and B where the R component corresponds to the Mastering Display Color Volume Display Primary with the largest x chromatic
24、ity coordinate, the G component corresponds to the Mastering Display Color Volume Display Primary with the largest y chromaticity coordinate, and the B component corresponds to the remaining Mastering Display Color Volume Display Primary 4.4 linearized maxRGB maxRGB values as defined in SMPTE ST 209
25、4-1, normalized to the range 0, 1, representing linear light level with 0 representing 0 cd/m2 and 1 representing 10000 cd/m2 when the three normalized color components have the same value 4.5 linearized RGB linearized color component values, normalized to the range 0, 1, with 0 representing 0 cd/m2
26、 and 1 representing 10000 cd/m2 when the three normalized color components have the same value 4.6 scene selected pixels throughout all images in the time interval as defined in SMPTE ST 2094-1 4.7 selected pixels pixels within a processing window as defined in SMPTE ST 2094-1 or within the intersec
27、tion of a processing window and the external ellipse (as described in “Calculus and Analytic Geometry”, G.B. Thomas and R. L. Finney) of the elliptical pixel selector if the processing window is extended using the elliptical pixel selector as defined in Section 6 SMPTE ST 2094-40:2016 Page 6 of 26 p
28、ages 5 Application Identification The ApplicationIdentifier value shall be 4 and the ApplicationVersion value shall be 0 to identify this version of Application #4. These two values identify this document as the defining document for the application-specific metadata specified in Section 9.1. 6 Exte
29、nsion to the Processing Window 6.1 Selection of Pixels for Processing The Processing Window as defined in SMPTE ST 2094-1 may be extended with an elliptical pixel selector. The elliptical pixel selector shall consist of two aligned, concentric, similar ellipses (internal and external). The ellipse c
30、oordinate system shall be the same as the pixel coordinate system. An example of the elliptical pixel selector is shown in Figure 1, where , 1, 2, 2 indicate the rotation angle, the semi-major axis of the internal ellipse, the semi-major axis of the external ellipse and the semi-minor axis of the of
31、 the external ellipse respectively. (0,0) denotes the pixel coordinates of the center of the ellipse. The semi-major axes are along the direction of the rotation angle . Rotation angle = 0 is parallel to the x-axis and it increases in a clockwise fashion. The pixels between the internal and external
32、 ellipses form a transition region to aid in preventing visible boundary artifacts between the local processing region and the background. The selected pixels shall be the intersection of the external ellipse and the ProcessingWindow. Figure 1 An elliptical pixel selector consisting of two concentri
33、c ellipses: internal and external ellipses SMPTE ST 2094-40:2016 Page 7 of 26 pages 6.2 Center of Ellipse The CenterOfEllipse shall be a vector with two integers. This shall represent the center position (pixel coordinates) of the concentric internal and external ellipses of the elliptical pixel sel
34、ector. The order of the vector elements shall be x coordinate, y coordinate. The x coordinate shall be in the range of 0, image width - 1 and the y coordinate shall be in the range of 0, image height - 1. The x and y coordinates shall be in multiples of 1 pixel. The CenterOfEllipse is denoted by (0,
35、0) in Figure 1. 6.3 Rotation Angle The RotationAngle shall represent the clockwise rotation angle in degree of arc with respect to the positive direction of the x-axis of the concentric internal and external ellipses of the elliptical pixel selector centered at the CenterOfEllipse. RotationAngle sha
36、ll be in the range 0,180 and in multiples of 1. The RotationAngle is denoted by in Figure 1. 6.4 Semi-Major Axis of the Internal Ellipse The SemiMajorAxisInternalEllipse shall represent the semi-major axis value of the internal ellipse of the elliptical pixel selector in amount of pixels. The SemiMa
37、jorAxisInternalEllipse shall be in the range of 1, 65535 and in multiples of 1 pixel. The SemiMajorAxisInternalEllipse is denoted by 1 in Figure 1. 6.5 Semi-Major Axis of the External Ellipse The SemiMajorAxisExternalEllipse shall represent the semi-major axis value of the external ellipse of the el
38、liptical pixel selector in amount of pixels. The SemiMajorAxisExternalEllipse shall not be less than the SemiMajorAxisInternalEllipse. The SemiMajorAxisExternalEllipse shall be in the range of 1, 65535 and in multiples of 1 pixel. The SemiMajorAxisExternalEllipse is denoted by 2 in Figure 1. 6.6 Sem
39、i-Minor Axis of the External Ellipse The SemiMinorAxisExternalEllipse shall represent the semi-minor axis value of the external ellipse of the elliptical pixel selector in amount of pixels. The SemiMinorAxisExternalEllipse shall be in the range of 1, 65535 and in multiples of 1 pixel. The SemiMinorA
40、xisInternalEllipse is denoted by 2 in Figure 1. 6.7 Overlap Process Option The OverlapProcessOption shall be an enumerator that indicates one of the two methods of combining rendered pixels in an image with at least one elliptical pixel selector. The value of OverlapProcessOption shall be either 0 o
41、r 1, where 0 shall mean method 1 and 1 shall mean method 2. Example methods are described in Annex B. For overlapping elliptical pixel selectors in an image, the OverlapProcessOption shall have the same value. 7 Targeted System Display 7.1 Introduction The TargetedSystemDisplay metadata group associ
42、ated with Application #4 Scene-based Color Volume Mapping contains the metadata item defined in Section 7.2. 7.2 Targeted System Display Actual Peak Luminance (2D LUT) The TargetedSystemDisplayActualPeakLuminance shall be a two-input sampled function as defined in SMPTE ST 2094-1. It takes as x (i.e
43、. first input) FractionBrightPixels (as defined in Section 8.6) and y (i.e. second input) AverageMaxRGB (as defined in Section 8.4) and outputs the normalized actual peak SMPTE ST 2094-40:2016 Page 8 of 26 pages luminance of the targeted system display. Output values shall be in the range of 0,1 and
44、 in multiples of 1/15, with 0 corresponding to 0 cd/m2 and 1 corresponding to TargetedSystemDisplayMaximumLuminance. The default output value shall be 1. The array of the TargetedSystemDisplayActualPeakLuminance two-input sampled function shall be limited to a maximum of 25 rows and a maximum of 25
45、columns. 8 Color Volume Mapping 8.1 Introduction The color volume transform for Application #4 is based on scene-based color volume mapping, as described in Annex B. The ColorVolumeTransform metadata items associated with Application #4 are defined in Sections 8.2 to 8.8. 8.2 Mastering Display Actua
46、l Peak Luminance (2D LUT) The MasteringDisplayActualPeakLuminance shall be a two-input sampled function as defined in SMPTE ST 2094-1. It takes as x (i.e. first input) FractionBrightPixels (as defined in Section 8.6) and y (i.e. second input) AverageMaxRGB (as defined in Section 8.4) and outputs the
47、 normalized actual peak luminance of the mastering display used for mastering the image essence. An output value shall be in the range of 0,1 and in multiples of 1/15, with 0 corresponding to 0 cd/m2 and 1 corresponding to Maximum Display Mastering Luminance (as defined in SMPTE ST 2086). The defaul
48、t output value shall be 1. The array of the MasteringDisplayActualPeakLuminance two-input sampled function shall be limited to a maximum of 25 rows and a maximum of 25 columns. 8.3 Maximum Scene Color Component Levels The MaxSCL shall be a vector with three elements. They shall be the maximum of eac
49、h component of linearized RGB values in the scene. The elements shall each be in the range 0,1 and in multiples of 0.00001. The order of the elements shall be R,G,B. 8.4 Average MaxRGB The AverageMaxRGB shall be the average of linearized maxRGB values in the scene. The value shall be a number in the range 0,1 and in multiples of 0.00001. 8.5 Distribution MaxRGB The DistributionMaxRGB shall be a set of two equal-length vectors. Each element i in the first ve
