Interoperable Master Format: Difference between revisions

Revision as of 04:42, 21 October 2022

Revision as of 19:40, 23 October 2022

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'''Interoperable Master Format (IMF)''' is a [[Container format (computing)|container format]] for the [[Standardization|standardized]] digital delivery and storage of finished audio-visual masters, including movies, episodic content and advertisements.

In IMF, each kind of [[Essence (media)|essence]] (video, audio, subtitles, etc.) is stored in individual media files (“Track Files”) and the instructions for synchronizing these media files are stored in a separate playlist file (“Composition Playlist”).<ref name=":3" />. This component-based approach allows the large media files to be reused across multiple playlists, each representing a different version of the content..<ref>{{Cite web |last=2018-09-16T11:26:00+01:00 |title=IMF: A gateway to component-based workflows |url=https://www.ibc.org/thought-leadership/imf-a-gateway-to-component-based-workflows/3204.article |access-date=2022-05-20 |website=IBC |language=en}}</ref>

The IMF family of standards, ST 2067, 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.

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Each Track File contains a specific essence corresponding to a single aspect of the presentation. Track Files are both organized and limited by parameters such as resolution, color space, frame rate, audio sound field, etc. Track Files of disparate parameters may not be mixed in a Composition. 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. [[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]]

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IMF is organized into three main categories:

* core constraints,<ref name=":1" />, to which all IMF implementations conform and representing the bulk of the IMF standard;

* applications, which target specific use cases; and

* plug-ins, which contain optional technology that can be used across multiple applications.

The core constraints are specified in SMPTE ST 2067-2 (Core Constraints).<ref name=":1">{{Cite journal |date=May 2020 |title=ST 2067-2:2020 - SMPTE Standard - Interoperable Master Format — Core Constraints |url=https://ieeexplore.ieee.org/document/9097478/ |journal=ST 2067-2:2020 |pages=1–43 |doi=10.5594/SMPTE.ST2067-2.2020}}</ref>. An example of an application is Application #2E, which is specified in SMPTE ST 2067-21<ref name=":2">{{Cite journal |date=May 2020 |title=ST 2067-21:2020 - SMPTE Standard - Interoperable Master Format — Application #2E |url=https://ieeexplore.ieee.org/document/9097487/ |journal=ST 2067-21:2021 |pages=1–34 |doi=10.5594/SMPTE.ST2067-21.2020}}</ref> and targets studio masters. One of the plugins is the Immersive Audio Bitstream Level 0 Plug-in, which is specified in SMPTE ST 2067-201<ref>{{Cite journal |date=January 2021 |title=ST 2067-201:2021 - SMPTE Standard - Immersive Audio Bitstream Level 0 Plug-in |url=https://ieeexplore.ieee.org/document/9343937/ |journal=ST 2067-201:2021 |pages=1–14 |doi=10.5594/SMPTE.ST2067-201.2021}}</ref> and adds support for immersive sound.

= Example uses =

IMF is specified by professional content creators for delivery of their content, including: BBC,<ref>{{Cite web |title=TechnicalDeliveryStandardsBBCUHDiPlayerSupplement.pdf |url=https://www.dropbox.com/s/tkvwxksgy3izpca/TechnicalDeliveryStandardsBBCUHDiPlayerSupplement.pdf?dl=0 |access-date=2022-03-04 |website=Dropbox |language=en}}</ref>, Netflix<ref>{{Cite web |title=Netflix Branded Delivery Specifications v4.1 |url=https://partnerhelp.netflixstudios.com/hc/en-us/articles/214806618-Netflix-Branded-Delivery-Specifications-v4-1 |access-date=2022-03-04 |website=Netflix {{!}} Partner Help Center |language=en-US}}</ref> and Disney<ref>{{Cite web |date=2021-04-27 |title=Disney Media Tech Specs |url=https://mediatechspecs.disney.com/#/mastering/video/imf-master-packages |access-date=2022-03-04 |website=mediatechspecs.disney.com}}</ref>

In partnership with SMPTE, the DPP has published recommendations for broadcast workflows with IMF<ref>{{Cite web |title=DPP and SMPTE publish major updates to IMF documentation |url=https://www.thedpp.com/news/dpp-and-smpte-publish-major-updates-to-imf-specification |access-date=2022-09-02 |website=The DPP |language=en-GB}}</ref>

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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 practice for delivering large volumes of localized content in a resource efficient manner. 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>

{{SMPTE standards}}