Interoperable Master Format: Difference between revisions

Revision as of 17:47, 26 May 2022

Revision as of 00:52, 3 June 2022

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The IMF family of standards is maintained by [[Society of Motion Picture and Television Engineers|SMPTE]].<ref name=":0">{{Cite journal |date=August 2021 |title=OV 2067-0-2021 - SMPTE Overview Document - Interoperable Master Format |url=https://ieeexplore.ieee.org/document/9521128/ |journal=OV 2067-0-2021 |pages=1–4 |doi=10.5594/SMPTE.OV2067-0-2021}}</ref> Its first edition was published in 2013.

IMF is closely related to [[Digital Cinema Package]] (“DCP”), leveraging several of the same standards for packaging and architecture.

= Architecture =

The core of IMF is the Composition, illustrated in the first image, which consists of a single Composition Playlist and a collection of Track Files. Each Composition corresponds to a single audio-visual master.

[[File:IMF Composition (CPL) Example.png|alt=An IMF Composition is defined by a Composition Play List|thumb|IMF Composition Example]]

Each Track File contains a single kind ofspecific essence corresponding to a single aspect of the presentation. ForTrack example,Files aare firstboth Trackorganized Fileand mightlimited containby theparameters primarysuch videoas programresolution, whilecolor aspace, secondframe mightrate, containaudio Spanishsound stereofield, audioetc. andTrack aFiles thirdof Englishdisparate parameters may not be mixed in a subtitlesComposition. Track Files use a constrained version of the MXF OP1a format [[Material Exchange Format]]<ref name=":1" />

The Composition Playlist is an [[XML]] document<ref>{{Cite journal |date=May 2020 |title=ST 2067-3:2020 - SMPTE Standard - Interoperable Master Format — Composition Playlist |url=https://ieeexplore.ieee.org/document/9097510/ |journal=ST 2067-3:2020 |pages=1–35 |doi=10.5594/SMPTE.ST2067-3.2020}}</ref>. It assembles the Track Files<ref>{{Cite journal |date=May 2020 |title=ST 2067-5:2020 - SMPTE Standard - Interoperable Master Format — Essence Component |url=https://ieeexplore.ieee.org/document/9099734/ |journal=ST 2067-5:2020 |pages=1–15 |doi=10.5594/SMPTE.ST2067-5.2020}}</ref> onto virtual tracks that are synchronized onto a timeline. It also contains metadata associated with that timeline.The combination of a Composition Playlist and the Track Files it references is called a Composition.

Each Composition represents a different version of an audio-visual work. Separating the Composition Playlist from the Track Files allows reuse of Track Files across multiple Compositions, as shown in the reuse example diagram. Versions[[File:IMF ofTrack aFile programRe-use can differ in small waysExample.svg|alt=IMF Thiscan componentre-based approach results in more efficient use ofTrack media,Files fewerto duplicatedminimize masterresource resources,usage andfor simplifiedversions workflowsof inaudio-viual mastering,works.|thumb|IMF qualityTrack control,File inventory, and distribution.Reuse]]

For example, a censored version of a film might remove a scene considered offensive in a particular territory. Using a new Composition Playlist which ignores the scene, the remainder of the media may be used without issuing a new master element.[[File:IMF Track File Re-use Example.svg|alt=IMF can re-use Track Files to minimize resource usage for versions of audio-viual works.|thumb|IMF Track File Reuse]]

= Specifications =

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== History ==

The need for IMF arose from various projects in the film and television industries<ref>{{Cite web |title=© 2011 AmberFin Limited Loose Coupling for Multipurpose Distribution Bruce Devlin Chief Technical Officer. - ppt download |url=https://slideplayer.com/slide/7416420/ |access-date=2022-04-01 |website=slideplayer.com}}</ref> that identified component-based working as a more efficient mechanism for handling the very large volumes of very large files created when delivering cinema and television content around the globe<ref>{{Cite web |last=Blog |first=Netflix Technology |date=2017-04-19 |title=The Netflix IMF Workflow |url=https://netflixtechblog.com/the-netflix-imf-workflow-f45dd72ed700 |access-date=2022-04-01 |website=Medium |language=en}}</ref>. With help from the [[Entertainment Technology Center]]<ref>{{Cite web |title=ETC |url=https://www.etcenter.org/imf-version-1-0-launches/ |access-date=2022-04-01 |website=www.etcenter.org}}</ref>, the [[Society of Motion Picture and Television Engineers|SMPTE]] created the first version of the standard in 2013. The IMF User Group (IMF UG) was created by the [[Hollywood Professional Association]] shortly after and the IMF UG fosters active discussions between content owners, technologists, logistics specialists and software providers on best current practisepractice for delivering large volumes of localisedlocalized content in a resource efficient waymanner. The IMF UG has created an IMF explainer in multiple languages<ref name=":3">{{Cite web |title=EXPLAINER: Interoperable Master Format (IMF) – IMF UG |url=https://www.imfug.com/explainer/ |access-date=2022-04-01 |language=en-US}}</ref>

== References ==