SMPTE ST 2073-3-2015 VC-5 Video Essence - Part 3 Image Formats.pdf

1、 Copyright 2015 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 3 Barker Avenue, White Plains, NY 10601 (914) 761-1100 Approved January 2, 2015 TT Table of Contents Page Page Foreword . 4 Intellectual Property 4 Introduction 4 1 Scope 5 2 Conformance Notation 5 3 Normative References 6 4 T

2、erms and Definitions . 6 5 Notation . 7 6 Overview (Informative) 7 7 Image Structure . 8 7.1 Sample Arrays (Informative) 8 7.2 Pattern Elements (Informative) 8 7.3 Pattern Element Dimensions . 9 7.4 Image Dimensions . 9 8 Bitstream Structure . 10 8.1 Component Array Count 10 8.2 Component Array Dime

3、nsions . 10 8.3 Component Vector . 10 8.4 Inverse Component Transform and Inverse Component Permutation 10 8.5 Inverse Component Transform 10 8.6 Inverse Component Permutation . 11 8.7 Mapping Between Pattern Element and Component Vector . 11 9 Image Formats 12 9.1 RGB(A) Image Format . 12 9.2 YC1C2

4、A) Image Format . 13 9.3 CFA Image Format . 14 9.4 Bayer Image Format 14 9.4.1 Bayer Image Parameters 14 9.4.2 Inverse Bayer Component Transform . 15 9.4.3 Forward Bayer Component Transform (Informative) 16 10 Bitstream Syntax 16 10.1 Bitstream Header . 16 10.2 Vendor-Specific Data . 16 Page 1 of 2

5、7 pages SMPTE ST 2073-3:2015 SMPTE STANDARD VC-5 Video Essence Part 3: Image Formats SMPTE ST 2073-3:2015 Page 2 of 27 pages 10.3 Inverse Component Transform 16 10.4 Inverse Component Permutation . 16 10.5 Unique Image Identifier 16 11 Syntax Elements 17 11.1 Chunk Elements . 17 11.1.1 Chunk Payload

6、 Padding . 17 11.1.2 Vendor-Specific Data 17 11.1.3 Inverse Component Transform . 17 11.1.4 Inverse Component Permutation 18 11.1.5 Unique Image Identifier . 18 Annex A Codec State Parameters (Normative) 19 A.1 Bitstream Extensions 19 A.2 Parameter Descriptions . 19 A.2.1 PatternWidth 19 A.2.2 Patte

7、rnHeight . 19 A.2.3 ComponentsPerSample . 19 A.2.4 Image Format . 19 A.2.5 Maximum Bits Per Component 19 A.3 Tag-Value Pairs. 20 Annex B Chunk Elements (Normative) . 21 B.1 Small Chunk Elements 21 B.2 Large Chunk Elements 21 Annex C Colorimetry (Normative) . 22 C.1 Colorimetry Specification 22 C.2 D

8、igital Representation . 22 C.3 Color Differences. 22 C.4 Color Primaries 22 C.5 Gamma Correction 22 C.6 YC1C2 Color Matrix 22 C.7 RGB Color Components . 23 Annex D Decoding Process (Informative) 24 Annex E Encoding Process (Informative) 25 E.1 Unique Image Identifier . 25 E.2 Component Vector Order

9、25 E.3 Forward Component Permutation . 25 E.4 Forward Component Transform 25 Annex F Profiles and Levels 26 F.1 Profiles (Informative) . 26 F.2 Levels (Normative) . 26 Annex G Bibliography (Informative) . 27 SMPTE ST 2073-3:2015 Page 3 of 27 pages Figures Figure 1 A sample array consists of a repeat

10、ing pattern of samples (pattern elements). .9 Figure 2 The sample array for an RGB image with 4:4:4 sub-sampling. . 13 Figure D.1 Inverse component transform, inverse component permutation, and repacking process . 24 Figure E.1 Unpacking process, component permutation, and component transform. 25 Ta

11、bles Table 1 Parameters for the RGB(A) image format. . 12 Table 2 Channel number assignment for RGB(A) images. . 12 Table 3 Parameters for the YC1C2(A) image format. . 13 Table 4 Channel number assignment for YC1C2(A) images. . 14 Table 5 Parameters for the Bayer image format. 14 Table 6 Channel num

12、ber assignment for Bayer images. . 15 Table A.1 Codec state parameters defined by this standard. 20 Table B.1 Small chunk elements that are defined by this standard. 21 Table C.1 Conventional reference primaries and reference white. 22 Table F.1 Definition of codec levels. 26 SMPTE ST 2073-3:2015 Pa

13、ge 4 of 27 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 Do

14、cuments, 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 I

15、SO, IEC and ITU. SMPTE Engineering Documents are drafted in accordance with the rules given in its Standards Operations Manual. SMPTE ST 2073-3 was prepared by Technology Committee 10E. Intellectual Property SMPTE draws attention to the fact that it is claimed that compliance with this Standard may

16、involve the use of one or more patents or other intellectual property rights (collectively, “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 p

17、arty IPR it has the right to sublicense, that is essential to the implementation of this 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

18、to such effect with SMPTE. Information may be obtained from the Director, Standards The PatternWidth, PatternHeight, and ComponentsPerSample parameters specify the structure of CFA images, including Bayer images; The MaxBitsPerComponent parameter specifies an upper bound on the number of bits needed

19、 to represent all values in the component arrays present in the bitstream; The VendorSpecificData chunk element allows private data to be embedded in a VC-5 bitstream; The InverseTransform, InverseTransform16, and InversePermutation chunk elements specify how to transform and reorder decoded compone

20、nt arrays into the same color space and order as originally presented to the encoder; The UniqueImageIdentifier chunk element specifies the image sequence and position within the sequence of an image represented by a VC-5 bitstream. This standard extends SMPTE ST 2073-1 by defining three stages for

21、transforming decoded component arrays into images: inverse component transform, inverse component permutation, and image repacking process. This standard extends SMPTE ST 2073-1 to specify levels of performance for decoder implementations. 2 Conformance Notation Normative text is text that describes

22、 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 the user, but not indispensable, and can be removed, changed, or added editorially without affecting interoperability. In

23、formative text does not contain any conformance keywords. All text in this document is, by default, normative, except: the Introduction, any section explicitly labeled as “Informative“ or individual paragraphs that start with “Note:” The keywords “shall“ and “shall not“ indicate requirements strictl

24、y 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, one is recommended as particularly suitable, without mentioning or excluding others; or that a certain course of action i

25、s 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 keyword “reserved” indicates a provisio

26、n 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. SMPTE ST 2073-3:2015 Page 6 of 27 pages A conformant implementation according to thi

27、s document 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 pr

28、ecedence 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 languages; then figures; and then any other language forms. 3 Normative References The following standards contain prov

29、isions that, through reference in this text, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the mo

30、st recent edition of the standards indicated below. SMPTE ST 330:2011, Unique Material Identifier (UMID) SMPTE ST 2073-1:2014, VC-5 Video Essence Part 1: Elementary Bitstream IEEE 802-2001, Standard for Local and Metropolitan Area Networks: Overview and Architecture. 4 Terms and Definitions For the

31、purposes of this standard, the following definitions shall apply: 4.1 color difference component Color component that represents the difference between two colors. 4.2 color difference component sub-sampling Color difference components with less spatial resolution than the Y components. 4.3 componen

32、t vector One-dimensional vector of scalar values. 4.4 Y component Weighted sum of RGB color components that are optionally gamma-corrected. 4.5 pattern element Two-dimensional array of samples used to tessellate the sample array. Note: The pattern element normally contains just a few samples. 4.6 Sa

33、mple Element in an array of samples, each element comprising one or more component values. 4.7 sample array Two-dimensional array of samples. 4.8 sample array dimensions Width and height of the sample array in units of samples. SMPTE ST 2073-3:2015 Page 7 of 27 pages 4.9 sample array height Number o

34、f lines (rows) in a sample array. 4.10 sample array width Number of samples per line (row) in a sample array. 4.11 signed integer Twos complement integer that may be positive, negative, or zero. 4.12 unsigned integer Integer that may be positive or zero. 4.13 VC-5 bitstream Bitstream that is complia

35、nt with one or more parts of SMPTE ST 2073. 5 Notation This document uses the notation defined in SMPTE ST 2073-1 VC-5 Elementary Bitstream. The value of the operation clamp(x, l, u) is l if x is less than l, u if x is greater than u, and otherwise equal to x. 6 Overview (Informative) This standard

36、extends the elementary bitstream with syntax elements that describe how common image formats are represented in VC-5 bitstreams. Each of the image formats covered in this document is modeled as a single sample array with one or more components per sample. Sample arrays are described in Section 7. An

37、y image that can be modeled as a single sample array can be unpacked into component arrays with one component from each sample in each array (Section 8). This standard defines the inverse component transform for reversing the effect of color space transformation applied by the encoder to improve com

38、pression (Section 8.5) and defines the inverse component permutation for reordering the component values into the same order as originally presented to the encoder (Section 8.6). Section 9 describes the image formats defined in this standard: RGB images with an optional alpha channel (Section 9.1),

39、YC1C2 images with an optional alpha channel, but no sub-sampling (Section 9.2), Color Filter Array (CFA) images (Section 9.3), and Bayer images (Section 9.4). Extensions to the bitstream syntax that are defined by this standard are described in Sections 10 and 11. The default colorimetry for images

40、with RGB or YC1C2 color components is defined in Annex C. Two new stages in the decoding process for applying the inverse component transform and reordering the components using the inverse component permutation are described in Annex D. The inverse transform and permutation followed by the image re

41、packing process (also described in Annex D) allows the component arrays output by the decoding process as defined in SMPTE ST 2073-1 (VC-5 Elementary Bitstream) to be repacked into an image. SMPTE ST 2073-3:2015 Page 8 of 27 pages 7 Image Structure 7.1 Sample Arrays (Informative) Images that do not

42、have color difference component sub-sampling can be modeled as a single sample array. A sample consists of one or more components at the same location in the sample array. All samples contain the same number and type of components in the same order. Components may be color components or other data s

43、uch as alpha values for compositing or disparity values. Sometimes, in other documents, the use of the term pixel corresponds to the use of the term sample in this document. The dimensions of a sample array are in units of samples. Sample arrays have W samples per row and H rows of samples for a tot

44、al of M samples: = Each sample has C components per sample for a total of N components per sample array: = Multiple image formats can map to the same set of component arrays input to the encoder. The image repacking process cannot output the original image format input to the image unpacking process

45、 without additional information provided to the decoder by the application. 7.2 Pattern Elements (Informative) The sample array can be partitioned into a repeating pattern of samples as shown in Figure 1. The repeating pattern of samples is called a pattern element. The sample order is the same in e

46、very pattern element. Each pattern element has w samples per row and h samples per column for a total of m samples per pattern element: = Each sample has C components per sample for a total of n components per pattern element: = SMPTE ST 2073-3:2015 Page 9 of 27 pages Figure 1 A sample array consist

47、s of a repeating pattern of samples (pattern elements) 7.3 Pattern Element Dimensions A sample array shall be partitioned into a repeating pattern of rectangular regions called pattern elements. (See the example in Figure 1.) Each pattern element in the sample array shall be the same width and heigh

48、t and shall consist of the same component types in the same order. The number of samples in each row of a pattern element shall be PatternWidth. The number of sample rows in each pattern element shall be PatternHeight. The number of components per sample shall be ComponentsPerSample. The order of th

49、e components in each sample shall be the same. Note: A pattern element is a three-dimensional array of component values (sample row, column within each row, and index to each component value in a sample). 7.4 Image Dimensions The ImageWidth shall equal the number of samples in each row and ImageHeight shall equal the number of samples in each column of the sample arra