The Interoperable Mastering Format

Dom Jackson, Telestream LLC

SMPTE Bits By The Bay 2017

May 2017

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Agenda

• Introduction to IMF and versioning

• Key concepts and terminology in IMF

• Elements of an IMF package

• Adoption

• The future

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It may not be a Tsunami in itself, but it is

certainly a big wave that is coming our

way

It’s also poorly understood

It’s fairly complicated

It can be difficult to deal with

Why are we talking about IMF today?

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“The IMF is a file-based framework that allows these high-quality

versions, called Compositions, to be efficiently represented,

managed, played back, processed and transformed on file-based

systems.”

SMPTE ST 2067-1 2016

So what is this IMF thing anyway?

IMF is likely to become one of the predominant

formats for B2B transfer of media in the supply chain.

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IMF was designed to handle the problems of

multiple versions of content in an efficient manner

A mainstream movie can end up with hundreds of

different versions

Creating and storing so many versions of a master

mezzanine file is expensive and unwieldy

Versions?

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So why is IMF so efficient?

IMF uses a single “Master” version of a piece of

content

To make other versions you just need the differences

from the Master

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Versions share most of the same basic

ingredients.

Only a few change from recipe to recipe to

make different ones

It’s a bit like baking a cake…

IMF

Key Concepts and Terms

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Packages

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IMP = IMF Master Package

• A package consisting of a packing list and all it’s assets.

Complete IMP

• A package containing all the assets required for one or more compositions.

• Sometimes also referred to as a Master Package

Package Types:

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Partial IMP

• A package that does not contain all the assets required for a composition

• Sometimes also referred to as a Supplemental Package

• Might be used to send assets for an additional language to an existing complete package.

Package Types:

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Simple IMP

• A package with continuous video and audio

tracks, no cuts or content substitutions.

Complex IMP

• A package where there are cuts or content

substitutions in the Video and / or Audio track.

Note: These are colloquial terms, not from the specification.

Package Types (Simple and Complex):

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Compositions

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Examples:

• Directors Cut:

Master Movie with “deletes scenes” added

back

• Lithuanian Airline version

Some scenes from Master Movie cut for

airline distributions

Additional Lithuanian audio and subtitles

Compositions = Versions

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Applications

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Different applications allow different video (and

possibly audio) encoding for different uses.

When people talk about IMF today they are talking

about App2 Extended

Applications:

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Current Applications:

• App 2 and App2 Extended: Jpeg 2000 Video to 4K

• App 3: SStP Video Codec (Sony HDCAM SR)

• App 4: Cinema Mezzanine, also Jpeg2000 video.

Applications:

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File Naming

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IMF assumes that filenames are fragile – they can get

changed

They are not reliable identifiers

Files are referred to by their UUID

Asset Map is designed to aid file discovery (but may not be

there)

Filenames are bad!

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JPEG 2000

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Very high quality (including lossless)

Royalty free

Resilient to errors

Supports any frame size, bit depth or color space

BUT – computationally expensive

Why JPEG2000?

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IMSC

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Internet Media Subtitling and Captioning

Timed Text XML format defined by W3C

“Native” Subtitle / Caption format for IMF (defined in the

specification)

In IMF, the XML is wrapped in MXF Data Essence Track

IMSC

Elements of an IMF Package

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Tracks contain the “essence” elements used to make compositions.

Tracks are single-essence MXF OP1A files

4 Types:

• Image (IMF-Speak for video) Tracks

• Audio Tracks

• Data Essence Tracks (IMSC XML)

• Ancillary Data Tracks (ST 436 VANC)

Tracks

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CPL is the “recipe” for a specific composition or version.

XML document specified in ST 2067-3

Specifies Video, Audio and Data elements to be included

in composition.

Has EDL-like functionality (combine video, audio and

data segments from multiple source tracks).

CPL – Composition Playlist

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XML Manifest of all of the elements in a package

Specified in the D-Cinema Specs ST 429-8

Primarily intended for use when an IMP is being

transmitted between locations

Not a permanent entity

Packing List

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XML Document detailing the paths of the track files

within the package used for resolving file locations in

a received package.

Specified in the D-Cinema Specs ST 429-9

Primarily intended for use when an IMP is being

transmitted between locations

Not a permanent entity

Asset Map

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Describes a set of transformations to be made on a

finished composition for specific endpoints

Examples:

• Image cropping and scaling

• Color transforms

• Audio mapping

Published Specification (ST 2067-100) currently has

limited practical use

OPL – Output Profile List

Adoption of IMF

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Adoption of IMF

Up until 2014 IMF was strictly a “Hollywood” thing

Fall of 2014, Netflix announce that all UHD submissions must

be IMF

January 2016, major studios begin distributing sample IMF

packages to the supply chain

NAB 2016, NABA announced IMF as their standard library

format

A number of major US broadcasters are now adopting IMF

Also seeing considerable interest outside North America

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Future developments

Possible update or new application for NABA

Possible update to OPL specification

Possible new applications with video codecs more appropriate for broadcast.

Challenges of IMF

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Challenges:

Not compact (J2K)

Complex multi-file structure

Not human friendly

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Questions?