S-2019-001pdf
S-2019-001pdf
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  1. © A M PA S ®SpecificationS-2019-001ACES Metadata File (AMF)The Academy of Motion Picture Arts and SciencesScience and Technology CouncilAcademy Color Encoding System (ACES) Project CommitteeMarch 10, 2021Summary: The ACES Metadata File (“AMF”) is a ‘sidecar’ XML file intendedto exchange the metadata required to recreate ACES viewing pipelines. This doc-ument specifies example use cases for AMF along with the data model and XMLtags needed for implementation.
  2. S-2019-001 ACES Metadata FileNOTICES©2021 Academy of Motion Picture Arts and Sciences (A.M.P.A.S.). All rights reserved. This document isprovided to individuals and organizations for their own internal use, and may be copied or reproduced in itsentirety for such use. This document may not be published, distributed, publicly displayed, or transmitted, inwhole or in part, without the express written permission of the Academy.The accuracy, completeness, adequacy, availability or currency of this document is not warranted or guar-anteed. Use of information in this document is at your own risk. The Academy expressly disclaims allwarranties, including the warranties of merchantability, fitness for a particular purpose and non-infringement.Copies of this document may be obtained by contacting the Academy at councilinfo@oscars.org.“Oscars,” “Academy Awards,” and the Oscar statuette are registered trademarks, and the Oscar statuette acopyrighted property, of the Academy of Motion Picture Arts and Sciences.This document is distributed to interested parties for review and comment. A.M.P.A.S. reserves the right tochange this document without notice, and readers are advised to check with the Council for the latest versionof this document.The technology described in this document may be the subject of intellectual property rights (includingpatent, copyright, trademark or similar such rights) of A.M.P.A.S. or others. A.M.P.A.S. declares that itwill not enforce any applicable intellectual property rights owned or controlled by it (other than A.M.P.A.S.trademarks) against any person or entity using the intellectual property to comply with this document.Attention is drawn to the possibility that some elements of the technology described in this document, orcertain applications of the technology may be the subject of intellectual property rights other than thoseidentified above. A.M.P.A.S. shall not be held responsible for identifying any or all such rights. Recipientsof this document are invited to submit notification to A.M.P.A.S. of any such intellectual property of whichthey are aware.These notices must be retained in any copies of any part of this document.Page 2March 10, 2021
  3. S-2019-001 ACES Metadata FileRevision HistoryDateDescription03/26/2020Initial Version03/10/2021Updateaces:transformTypeto include optionalaces:uuidandaces:fileel-ements to better support interchange.Update choice occurrences to disallow the possibility of empty transform tags.Remove redundantuuidelement associatedcdl:ColorCorrectionRef.Update type definitions to enable changes.Update UML diagrams and split for better readabilityRelated Academy DocumentsDocument NameDescriptionS-2014-002Academy Color Encoding System — Versioning SystemPage 3March 10, 2021
  4. S-2019-001 ACES Metadata FileTable of ContentsNOTICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Related Academy Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Terms and Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64.1 Why is metadata needed for ACES? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64.2 What is AMF? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85.1 Look Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85.2 On Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85.3 Dailies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85.4 VFX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95.5 Finishing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95.6 Archival . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 Data Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106.1 UML Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106.1.1 acesMetadataFile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106.1.2 amfInfo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106.1.3 clipId . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106.1.4 pipeline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116.1.5 pipelineInfo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116.1.6 inputTransform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126.1.7 lookTransform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136.1.8 outputTransform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136.2 Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146.2.1 Simple Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146.2.2 Complex Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166.3 Elements (by type) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216.3.1aces:acesMetadataFile. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216.3.2aces:authorType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256.3.3aces:cdlWorkingSpaceType. . . . . . . . . . . . . . . . . . . . . . . . . . . . 266.3.4aces:clipIdType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Page 4March 10, 2021
  5. S-2019-001 ACES Metadata File6.3.5aces:dateTimeType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306.3.6aces:infoType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316.3.7aces:inputTransformType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346.3.8aces:inverseOutputDeviceTransformType. . . . . . . . . . . . . . . . . . 386.3.9aces:inverseOutputTransformType. . . . . . . . . . . . . . . . . . . . . . 406.3.10aces:inverseReferenceRenderingTransformType. . . . . . . . . . . . . 426.3.11aces:lookTransformType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446.3.12aces:outputDeviceTransformType. . . . . . . . . . . . . . . . . . . . . . . 476.3.13aces:outputTransformType. . . . . . . . . . . . . . . . . . . . . . . . . . . . 496.3.14aces:pipelineInfoType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536.3.15aces:pipelineType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536.3.16aces:referenceRenderingTransformType. . . . . . . . . . . . . . . . . . 576.3.17aces:transformType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 596.3.18aces:versionType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 616.3.19aces:workingSpaceTransformType. . . . . . . . . . . . . . . . . . . . . . . 636.3.20 Imported Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Appendix A ACES Metadata File XSD Schema . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68Appendix B Sample ACES Metadata File XML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76Page 5March 10, 2021
  6. S-2019-001 ACES Metadata File1ReferencesThe following standards, specifications, articles, presentations, and texts are referenced in this text:Academy S-2014-002, Academy Color Encoding System - Versioning SystemSMPTE ST 2065-1:2012, Academy Color Encoding Specification (ACES)SMPTE ST 2065-4:2013, ACES Image Container File LayoutAcademy TB-2014-010, Design, Integration and Use of ACES Look Modification Transforms (LMTs)ISO 8601:2004, Data elements and interchange formats – Information interchange – Representation of datesand timesISO/IEC 11578:1996, Information technology – Open Systems Interconnection – Remote Procedure Call(RPC)SMPTE ST.2067-50 – Interoperable Master Format — Application #5 ACESSMPTE RDD 47 – Interoperable Master Format — Isochronous Stream of XML Documents (ISXD) PluginSMPTE ST.2067-9 – Interoperable Master Format — Sidecar Composition Map2Terms and DefinitionsThe following terms and definitions are used in this document.2.1DateTime(reference: ISO8601:2004) timestamp formatThe DateTime is specified in the following form ”YYYY-MM-DDThh:mm:ss{offset}” where:•YYYY indicates the year•MM indicates the month•DD indicates the day•T indicates the start of the required time section•hh indicates the hour•mm indicates the minute•ss indicates the second•{offset}time zone offset from UTCNOTE: All components are required.Example: 2014-11-20T12:24:13-8:002.2TransformIDString identifying the ACES transform. Please see the ACES System Versioning Specification for moreinformation on the format to use for TransformIDs.Page 6March 10, 2021
  7. S-2019-001 ACES Metadata File3ScopeThis document specifies the ACES Metadata File (“AMF”), a ‘sidecar’ XML file intended to exchange themetadata required to recreate ACES viewing pipelines.This specification supersedes TB-2014-009 – Academy Color Encoding System (ACES) Clip-level MetadataFile Format Definition and Usage (“ACESclip”). TB-2014-009 is now considered obsolete.4Introduction4.1Why is metadata needed for ACES?ACES defines a standard color encoding (SMPTE ST 2065-1) for exchange of images, along with InputTransforms to convert from different image sources to ACES, and Output Transforms in order to view ACESimages on different types of displays.However, when exchanging ACES images during production, there is often missing information required tofully describe the viewing pipeline or “creative intent” of that particular image.Examples of such information:•ACES Version –which version of ACES was used?•Look Transform –is there a creative look?•Output Transform –how was this viewed on a display?To maintain consistent color appearance, transporting this information is crucial. Additionally, this informa-tion serves as an unambiguous archive of the creative intent.4.2What is AMF?The ACES Metadata File (“AMF”) is a sidecar XML file intended to exchange the metadata required to recre-ate ACES viewing pipelines. It describes the transforms necessary to configure an ACES viewing pipelinefor a collection of related image files.An AMF may have a specified association with a single frame or clip. Alternatively, it may exist without anyassociation to an image, and one may apply it to an image. An application of an AMF to an image wouldtranslate its viewing pipeline to the target image.Images are formed at several stages of production and post-production, including:•Digital cameras•Film scanners•Animation and VFX production•Virtual production•Editorial and color correction systemsAMF can be compatible with any digital image, and is not restricted to those encoded in the ACES (SMPTEST 2065-1). They may be camera native file formats or other encodings if they have associated Input DeviceTransforms (IDTs) (using the<inputTransform>element) so they may be displayed using an ACESviewing pipeline.AMFs may also embed creative look adjustments as one or more LMTs (using the<lookTransform>elements). These looks may be in the form of ASC CDL values, or a reference to an external look file, suchas a CLF (Common LUT Format). Multiple<lookTransform>elements are allowed, and the order ofoperations in which they are applied shall be the order in which they appear in the AMF.Page 7March 10, 2021
  8. S-2019-001 ACES Metadata FileAMFs can also serve as effective archival elements. When paired with finished ACES image files, theyform a complete archival record of how image content is intended to be viewed (for example, using the<outputTransform>and<systemVersion>elements).AMFs do not contain “timeline” metadata such as edit points. Timeline management files such as EditDecision Lists (EDLs) or Avid Log Exchange files (ALEs) may reference AMFs, attaching them to editingevents and thus enable standardized color management throughout all stages of production.Figure 1 shows the overall structure of an AMF in simplified form.ACES Pipeline<pipeline>Pipeline Info<pipelineInfo>Input Transform<inputTransform>Look Transform<lookTransform>Output Transform<outputTransform>RRT<referenceRenderingTransform>ODT<outputDeviceTransform>Archived ACES Pipeline<archivedPipeline>...ACES Metadata File<acesMetadataFile>AMF Info<amfInfo>Clip ID<clipID>Look Transform<lookTransform>...Figure 1 – A simplified diagram showing the overall structure of an ACES Metadata File.Page 8March 10, 2021
  9. S-2019-001 ACES Metadata File5Use CasesACES Metadata Files (AMFs) are intended to contain the minimum required metadata for transferring infor-mation about ACES viewing pipelines during production, post-production, and archival.Typical use cases for AMF files are the application of “show LUT” LMTs in cameras and on-set systems,the capture of shot-to-shot looks generated on-set using ASC-CDL, and communication of both to dailies,editorial, VFX, and post-production mastering facilities.AMF supports the transfer of looks by embedding ASC-CDL values within the AMF file or by referencingsidecar look files containing LMTs, such as CLF (Common LUT Format) files.5.1Look DevelopmentThe development of a creative look before the commencement of production is common. Production usesthis look to produce a pre-adjusted reference for on-set monitoring. The creative look may be a packageof files containing a viewing transform (also known as a “Show LUT”), CDL grades, or more. There areno consistent standards specifying how to produce them, and exchanging them is complex due to a lack ofmetadata.AMF contains the ability to completely specify the application of a creative look. This automates the ex-change of these files and the recreation of the look when applying the AMF. In an ACES workflow, onespecifies the creative look as one or more Look Modification Transforms (LMT). AMF can include refer-ences to any number of these transforms, and maintains their order of operations.The input and output of an LMT is always a triplet of ACES RGB relative exposure values, as defined inSMPTE ST 2065-1. This will likely need a robust transform, such as CLF, that can handle linear input dataand output data.AMF offers an unambiguous description of the full ACES viewing pipeline for on-set look managementsoftware to load and display images as intended.5.2On SetBefore production begins, an AMF may be created and shared with production as a “look template” for useduring on-set monitoring or look management.Cameras with AMF support can load or generate AMFs to configure or communicate the viewing pipeline ofimages viewed out of the camera’s live video signal.On-set color grading software can load or generate AMFs, allowing the communication of the color adjust-ments created on set.5.3DailiesDailies can apply AMFs from production to the camera files to reproduce the same images seen on set. Thereis no single method of exchange between production and dailies. AMFs should be agnostic to the givenexchange method.It is possible, or even likely, that one will update AMFs in the dailies stage. For example, a dailies coloristmay choose to balance shots at this stage and update the look. Another example could be that dailies uses adifferent ODT than the one used in on-set monitoring.This specification does not define how one should transport AMFs between stages. Existing exchange formatsmay reference them, or image files themselves may embed them. One may also transport AMFs indepen-dently of any other files.Page 9March 10, 2021
  10. S-2019-001 ACES Metadata File5.4VFXThe exchange of shots for VFX work requires perfect translation of each shot’s viewing pipeline, or ‘colorrecipe’. If the images cannot be accurately reproduced from VFX plates, effects will be created with anincorrect reference.AMF provides a complete and unambiguous translation of ACES viewing pipelines. If they travel with VFXplates, they can describe how to view each plate along with any associated looks.VFX software should have the ability to read AMF to configure its internal viewing pipeline. Or, AMF willinform the configuration of third party color management software, such as OpenColorIO.5.5FinishingIn finishing, the on-set or dailies viewing reference can be automatically recreated upon reading an AMF.This stage typically uses a higher quality display, which may warrant the use of a different ODT than onespecified in an ingested AMF.AMF can seamlessly provide the colorist a starting point that is consistent with the creative intent of thefilmmakers on-set. This removes any necessity to recreate a starting look from scratch.5.6ArchivalAMF enables the ability to establish a complete ACES archive, and effectively serves as a snapshot of creativeintent for preservation and remastering purposes. All components required to recreate the look of an ACESarchive are meaningfully described and preserved within the AMF.One possible method for this could be the utilization of SMPTE standards such as ST.2067-50 (IMF App #5)– commonly referred to as “ACES IMF” – and SMPTE RDD 47 (ISXD) – a virtual track file containing XMLdata – in order to form a complete and flexible ACES archival package.Another method could be to use SMPTE ST.2067-9 (Sidecar Composition Map) which would allow linkingof a single AMF to a CPL (Composition Playlist) in the case where there is a single AMF for an entireplaylist.Page 10March 10, 2021
  11. S-2019-001 ACES Metadata File6Data ModelThis section describes the data intended for use within the ACES Metadata file.All top level structures shall be tagged as being within theacesnamespace with urnurn:acesMetadata:acesMetadataFile:v1.06.1UML DiagramThe following UML diagrams are segments of the complete UML diagram which is not included in thisdocument due to space constraints. To view the entire UML diagram in SVG format visit https://aces.mp/amfuml.6.1.1acesMetadataFileacesMetadataFilexs:complexTypeversion : xs:decimalxmlns : xs:stringamfInfoaces:infoTypeclipIdaces:clipIdTypepipelineaces:pipelineTypearchivedPipelineaces:pipelineType6.1.2amfInfoamfInfoaces:infoTypedescriptionxs:stringauthoraces:authorTypenamexs:stringemailAddressaces:emailAddressTypedateTimeaces:dateTimeTypecreationDateTimexs:dateTimemodificationDateTimexs:dateTimeuuiddcml:UUIDType6.1.3clipIdclipIdaces:clipIdTypeclipNamexs:stringsequenceaces:sequenceTypeidx : xs:stringmin : xs:nonNegativeIntegermax : xs:nonNegativeIntegerfilexs:anyURIuuiddcml:UUIDTypePage 11March 10, 2021
  12. S-2019-001 ACES Metadata File6.1.4pipelinepipelineaces:pipelineTypepipelineInfoaces:pipelineInfoTypeinputTransformaces:inputTransformTypeapplied : xs:boollookTransformaces:lookTransformTypeapplied : xs:booloutputTransformaces:outputTransformType6.1.5pipelineInfopipelineInfoaces:pipelineInfoTypedescriptionxs:stringauthoraces:authorTypenamexs:stringemailAddressaces:emailAddressTypedateTimeaces:dateTimeTypecreationDateTimexs:dateTimemodificationDateTimexs:dateTimeuuiddcml:UUIDTypesystemVersionaces:versionTypemajorVersionaces:singleDigitTypeminorVersionaces:singleDigitTypepatchVersionaces:singleDigitTypePage 12March 10, 2021
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