SMPTE ST 2065-4-2013 ACES Image Container File Layout.pdf

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1、 Copyright 2013 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 3 Barker Avenue, White Plains, NY 10601 (914) 761-1100 Approved May 10, 2013 Table of Contents Page Foreword . 5 Intellectual Property 5 Introduction 5 1 Scope . 6 2 Conformance Notation . 6 3 Normative References . 6 4 Terms

2、and Definitions 7 5 General. 9 5.1 Image . 9 5.2 Image Channels . 9 5.3 Alpha Channel 9 5.4 Display Window, Data Window 10 5.5 Scan Lines . 11 5.6 Screen Window 11 6 Basic Data Types . 12 6.1 Grouping 12 6.2 Packing. 12 6.3 Integer Numbers 13 6.4 Floating-Point Numbers . 13 6.5 Character Encoding, S

3、equences, and Strings . 13 7 File Layout 14 7.1 File Extension . 14 7.2 High-Level File Layout . 14 7.3 Magic Number 14 7.4 Version Field 14 7.5 Header 15 7.6 Line Offset Table 17 7.7 Scan Line Storage 17 7.8 End-of-File Filler . 18 8 Predefined Attribute Types 18 8.1 General. 18 8.2 box2i . 18 8.3

4、chlist . 18 8.4 chromaticities . 19 8.5 compression . 19 8.6 double. 19 Page 1 of 36 pages SMPTE ST 2065-4:2013 SMPTE STANDARD ACES Image Container File Layout SMPTE ST 2065-4:2013 Page 2 of 36 pages 8.7 float . 19 8.8 half 19 8.9 int 19 8.10 lineOrder 20 8.11 keycode . 20 8.12 rational . 20 8.13 sh

5、ort . 21 8.14 string 21 8.15 stringVector 21 8.16 timecode 21 8.17 unsignedChar 23 8.18 unsignedInt 23 8.19 unsignedLong 23 8.20 unsignedShort 23 8.21 v2f 23 8.22 v3f 23 9 Predefined Attributes 24 9.1 General 24 9.2 acesImageContainerFlag 24 9.3 altitude . 24 9.4 aperture . 24 9.5 cameraFirmwareVers

6、ion . 24 9.6 cameraIdentifier . 24 9.7 cameraLabel 24 9.8 cameraMake 24 9.9 cameraModel . 25 9.10 cameraPosition 25 9.11 cameraSerialNumber . 25 9.12 cameraUpDirection 25 9.13 cameraViewingDirection 25 9.14 capDate . 26 9.15 captureRate . 26 9.16 channels 26 9.17 chromaticities . 27 9.18 comments 27

7、 9.19 compression 27 9.20 convergenceDistance 27 9.21 creator 27 9.22 dataWindow . 28 9.23 displayWindow . 28 9.24 expTime . 28 9.25 focalLength 28 9.26 focus 28 9.27 framesPerSecond 28 9.28 free . 28 9.29 imageDigestMD5 . 28 9.30 imageCounter 28 9.31 imageRotation 29 9.32 interocularDistance 29 9.3

8、3 isoSpeed 29 9.34 keyCode . 29 9.35 latitude . 29 9.36 lensAttributes . 29 9.37 lensMake . 29 9.38 lensModel 29 SMPTE ST 2065-4:2013 Page 3 of 36 pages 9.39 lensSerialNumber 29 9.40 lineOrder . 30 9.41 longitude 30 9.42 metadataDigestMD5 . 30 9.43 multiView . 30 9.44 originalImageFlag 30 9.45 owner

9、. 30 9.46 pixelAspectRatio . 30 9.47 recorderFirmwareVersion 30 9.48 recorderMake 31 9.49 recorderModel . 31 9.50 recorderSerialNumber . 31 9.51 reelName . 31 9.52 screenWindowCenter 31 9.53 screenWindowWidth . 31 9.54 storageMediaSerialNumber 31 9.55 timeCode . 31 9.56 timecodeRate 31 9.57 utcOffse

10、t 31 9.58 uuid 31 10 Attributes for Stereoscopic Images 32 11 Reader and Writer Requirements 32 Annex A Bibliography (Informative) . 33 Annex B Sample File (Informative) 34 SMPTE ST 2065-4:2013 Page 4 of 36 pages List of Tables Table 1 Integer Data Types 13 Table 2 Floating Point Data Types . 13 Tab

11、le 3 File Structure . 14 Table 4 Attribute Structure 15 Table 5 Required Attributes 16 Table 6 Scan Line Object . 17 Table 7 box2i Structure 18 Table 8 chlist Structure . 19 Table 9 chromaticities Structure . 19 Table 10 keyCode Structure and Values 20 Table 11 rational Structure . 20 Table 12 timec

12、ode Structure 21 Table 13 timeAndFlags Structure . 22 Table 14 userData Structure 22 Table 15 v2f Structure 23 Table 16 v3f Structure 23 Table 17 chromaticities Values . 27 Table 18 Names Of Stereoscopic Attributes 32 SMPTE ST 2065-4:2013 Page 5 of 36 pages Foreword SMPTE (the Society of Motion Pict

13、ure 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 Documents, including Standards, Recommended Practices, and En

14、gineering 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, IEC and ITU. SMPTE Engineering Documents are drafted in

15、 accordance with the rules given in Part XIII of its Operations Manual. SMPTE ST 2065-4 was prepared by Technology Committee 31FS. Intellectual Property At the time of publication, no notice had been received by SMPTE claiming patent rights essential to the implementation of this standard. However,

16、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 The ACES image container is a digital data file format that is designed for storing th

17、e individual frames of a motion picture during production and for archival. During production, it is important to maintain the highest possible image quality, and to minimize generational loss as images are repeatedly extracted from files, processed, and stored in new files. Fast random access to in

18、dividual frames is highly desirable. Storage space and data transmission bandwidth limitations tend to be of secondary concern. The ACES image container is not meant for distribution of motion pictures to theaters and home viewers, where representation of an entire movie as a single file, compact st

19、orage and data security take precedence. Each ACES image container file contains a single monoscopic or stereoscopic image. Moving images are represented as sequences of image container files, with a separate image container file for each frame. This allows each frame to be read or written individua

20、lly, without accessing other frames or any kind of enclosing image sequence container. The ACES image container file format is derived from the popular OpenEXR file format, and is readable by many OpenEXR readers. SMPTE ST 2065-4:2013 Page 6 of 36 pages 1 Scope This Standard specifies the layout of,

21、 and metadata in, files containing images that conform to SMPTE ST 2065-1, Academy Color Encoding Specification (ACES). 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

22、“. 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. Informative text does not contain any conformance keywords. All text in this document is, by default, normative, except: t

23、he Introduction, any section explicitly labeled as “Informative“ or individual paragraphs that start with “NOTE or EXAMPLE 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, “s

24、hould“ 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 is preferred but not necessarily required; or that (in the negative form) a certain possibility or course of act

25、ion 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 provision that is not defined at this time, shall not be used, and may be defined in the future. The keyword forbidden in

26、dicates reserved and in addition indicates that the provision will never be defined in the future. A conformant implementation according to this document is one that includes all mandatory provisions (“shall“) and, if implemented, all recommended provisions (“should“) as described. A conformant impl

27、ementation need not implement optional provisions (“may“) and need not implement them as described. 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 n

28、ext; followed by formal languages; then figures; and then any other language forms. 3 Normative References Note: All references in this document to other SMPTE documents use the current numbering style (e.g. SMPTE ST 12-1:2008) although, during a transitional phase, the document as published (printe

29、d or PDF) may bear an older designation (such as SMPTE 12M-1-2008). Documents with the same root number (e.g. 12-1) and publication year (e.g. 2008) are functionally identical. The following standards contain provisions that, through reference in this text, constitute provisions of this standard. At

30、 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 most recent edition of the standards indicated below. IEEE Std 754-2008, Standard for Flo

31、ating-Point Arithmetic IETF RFC 1321:1992, The MD5 Message-Digest Algorithm (Proposed Standard) IETF RFC 4122:2005, A Universally Unique Identifier (UUID) URN Namespace (Proposed Standard) SMPTE ST 2065-4:2013 Page 7 of 36 pages ISO 11664-1:2007 (CIE S 014-1/E:2006), Colorimetry Part 1: CIE Standard

32、 Colorimetric Observers SMPTE ST 12-1:2008, Television Time and Control Code SMPTE ST 254:2008, Motion-Picture Film (35-mm) Manufacturer-Printed Latent Image Identification Information SMPTE ST 268:2003, File Format for Digital Moving-Picture Exchange (DPX), Version 2.0 SMPTE ST 331:2011, Element an

33、d Metadata Definitions for the SDTI-CP SMPTE ST 2065-1:2012, Academy Color Encoding Specification (ACES) The Unicode Consortium. The Unicode Standard, Version 6.0.0, (Mountain View, CA: The Unicode Consortium, 2011. ISBN 978-1-936213-01-6) 4 Terms and Definitions For the purposes of this document, t

34、he following terms and definitions apply. 4.1 ACES image container file file compliant with this standard 4.2 alpha opacity proportion by which a pixel obscures the pixel behind it (from ISO/IEC 9592-1:1997) 4.3 byte order ordering of bytes for multi-byte data primitives within a file, such as 4-byt

35、e integers, or 8-byte floats 4.4 channel collection of all values of the same name in an image or in a part of an image 4.5 compositing combining two images into a single image (from ISO/IEC 15444-2:2004) 4.6 editor device that is both a compliant reader and a compliant writer and that updates files

36、, or reads files and writes new files with derived contents 4.7 exposure time time from the start of light exposure integration at a point on the sensor to the end of light exposure integration at that same point on the sensor 4.8 little-endian byte order byte order having increasing numerical signi

37、ficance with increasing byte address (from the least significant byte to the most significant byte) SMPTE ST 2065-4:2013 Page 8 of 36 pages 4.9 monoscopic image image containing a single view of the depicted scene, intended to be presented to the viewer on a 2D display device 4.10 “over“ compositing

38、 operation compositing, where a foreground RGB color F with an associated alpha value A over a background RGB color B, will produce a combined color C, where C = F + (1-A) * B (from Porter-Duff, 1984) 4.11 pixel aspect ratio pixel width divided by pixel height when the image is displayed with the in

39、tended aspect ratio, where the pixel width is the distance between the centers of two horizontally adjacent pixels on the display, and the pixel height is the distance between the centers of two vertically adjacent pixels on the display 4.12 pixel space two-dimensional Cartesian coordinate system ha

40、ving signed integer coordinates with x coordinates increasing from left to right and y coordinates increasing from top to bottom 4.13 reader device consuming files compliant with this standard 4.14 recorder device that stores image data and image metadata received from a digital capture system 4.15

41、RGB color model with red, green, blue components 4.16 scan line row of pixels, with all pixels having the same y coordinate 4.17 stereoscopic image image containing two separate views of the depicted scene, intended to be presented to the viewer on a 3D display device such that the left-eye view and

42、 right-eye view are visible only to the viewers left and right eye respectively 4.18 window axis-parallel rectangular region in pixel space, specified by the coordinates of two opposing corners, (xmin, ymin) and (xmax, ymax), where xmin alpha. For compatibility with OpenEXR, this file format does no

43、t impose such requirements on RGB. Other documents can contain workflow-specific requirements on preparing RGB values prior to storing them in the file. The above definition is not related to “straight alpha“ or “unassociated alpha“. Note 2: RGB alpha is useful for semi-transparent sources of light,

44、 such as fire with semi-transparent smoke, head-up displays, glow, lens flare, or window reflections. Note 3: For color corrections and other operations that work on “straight alpha“ instead of “premultiplied alpha“, any premultiplied alpha baked into the files RGB values can be removed by dividing

45、the RGB values with alpha. As the RGB values are in floating point, this can be done without loss of precision over a wide range of values, except for alpha = 0. This removal is not appropriate when alpha is not baked into the files RGB values, such as for fire, in which case other adjustments (if a

46、ny) can be more appropriate. 5.4 Display Window, Data Window Two windows specify the boundaries of the image: The display window shall define the window that is to be displayed. The data window shall define the window for which pixel data are available in the file. No specific spatial relationship b

47、etween the data window and the display window is required. The two windows may be coincident, they may overlap, or they may be completely disjoint. EXAMPLES: Assume that a motion picture is produced with a resolution of 2048 by 1080 pixels. The upper left and lower right corners of the display windo

48、w for all frames of the movie are at (0, 0) and (2047, 1079). For most images, in particular finished frames that will be part of the final product, the data window is the same as the display window, but for some images that are used in producing the finished frames, the data window differs from the

49、 display window. For a background plate that will be heavily post-processed, extra pixels beyond the edge of the display window are recorded. The upper left and lower right corners of the data window are at (-100, -100) and (2147, 1179). The extra pixels are not normally displayed. Their existence allows operations such as large-kernel blurs or simulated camera shake to avoid edge artifacts. Alternatively, while working on a computer-generated element, an artist can repeatedly render the same frame. To sa