“A few years ago we discovered the Inter-
operable Master Format (IMF), a standard cre-
ated by the Society of Motion Picture and Tele-
vision Engineers (SMPTE),” wrote Chris Fetner
and Brian Kenworthy in a Netflix Tech Blog
posting in late 2016 ( go2sm.com/netfliximf).
“By using this standard, Netflix is able to hold
a single set of core assets and the unique ele-
ments needed to make those assets relevant
in a local territory.”
“[Our global] supply chain needed an effi-
cient way to vault our masters in the cloud that
didn’t require a different version for every ter-
ritory in which we have our service,” Fetner
and Kenworthy wrote.
So what is IMF and where did it come from?
And what are the benefits and limitations of
IMF? This article highlights several of those key
areas, including the use of an extensible markup language (XML) and the material exchange
format (MXF), the audio- and video-track container format that underlies IMF.
“The goal behind IMF is to provide a single
interchangeable master file format primarily
for distribution,” says David Schleifer, Primestream’s chief operating officer.
Schleifer, who provided a good bit of detail
for last month’s article “MAM and DAM Evolve
Into the Cloud” ( go2sm.com/mam), noted that
Primestream strives to support the latest standards as a way to deliver new workflows and efficiencies their customers. However, he warned
that IMF isn’t exactly a universal format when
it comes to the acquisition and post-production
“We do not currently see IMF as a format in
the production process upstream from distribution,” says Schleifer, “but rather as a deliverable for the final product.”
Understanding IMF: Bits and Bobs
The IMF family of standards, according to
SMPTE, is maintained by its Media Packaging
and Interchange Committee 35PM. IMF is a
superset of MXF and XML, with the benefits of
both in addition to the ability to move beyond
MXF’s binary-based versioning (to what IMF
refers to as the Composite Playlist, or CPL).
A good overview of MXF and how it compares to IMF can be found in a blog post by
Dalet’s Bruce Devlin ( go2sm.com/daletimf).
The blog post argues that XML, which has been
used for everything from Microsoft Word to websites, is a more approachable option for creating playlists.
“There are maybe 20 or 30 really good MXF
binary programmers in the world today,” writes
Devlin. “XML is much more generic, and there
must be hundreds of thousands of top quality
XML programmers out there.”
In essence, IMF uses XML as a human-
readable way to represent various content ver-
sions while, according to Devlin, “maintaining
the proven AS02 media wrapping to store the
The entire standard resides under SMPTE
ST 2067 ( go2sm.com/smpteimf), with the most
recent versions being designated as 2016, such
as the Core Constraints standard, which is
In addition to the ST 2067-5 essence components—including audio, basic metadata, timed
text, and video—the SMPTE family of IMF standards also maintains a series of profile lists
( 100-103, currently) as well as key application
The profile lists, which were last updated in
2014, provide common image or audio definitions and macros, as well as common image
pixel color schemes.
The applications are where the heavy lifting—or at least the previous thoughtful constructing of typical use cases for the IMF container format—is done.
For instance, Application 2 is geared toward
“studio applications where a TV or movie title is
transformed into multiple content versions (air-
line edits, special edition, languages…) that are
made available to multiple consumer distribu-
tion channels (internet, optical media, broad-
cast…) across multiple territories and over the
span of many months to over a year.”
The Netflix Tech Blog post explains one of
the practical approaches to the Application
2 use case. In their blog post, Fetner and Ken-
worthy point out that that for certain titles,