In Broadcast - November 2017 - 56

56

www.inbroadcast.com | Vol: 7 - Issue 11 | November 2017

InMedia

Metadata Workflows:
One Format To Rule Them All
IMF is coming to broadcast. Contributing Editor
Adrian Pennington examines what this means
for post workflows and asks will it achieve the
simplicity intended...

B

y April next year there will be a
new file format to juggle with. This
one is intended to be the one format to
rule them all. SMPTE is working with
the Digital Production Partnership
(DPP) on joint development of an
Interoperable Master Format (IMF)
specification for broadcast and online.
The original SMPTE standard, ST
2067, developed in 2012, dealt with
file-based interchange of finished
multi-version audio-visual works.
That dealt with multi-language
requirements, including subtitles and
closed captions all of which can be
handled within one large IMP - the
interoperable master package.
The DPP then took the lead in
drawing up an IMF for broadcast, in
co-operation with the North American
Broadcasters Association (NABA) and
the EBU.
For broadcasters there are two
primary use cases: incoming, meaning
buying content masters for further
compliance processing; and outgoing,
which is sales mastering. The goal is
to implement a system that addresses
the myriad metadata requirements
of television and OTT while fitting
into broadcasters' sizeable existing
archives of content.
However, the jury seems out on how
successful the original IMF has been.
Paul Mardling, VP of Strategy, Piksel,
says "extremely successful" but others
are less sure.
"The original vision for IMF was
that movie studios would use it as
the primary format for archiving
content and delivering it to the supply
chain," says Dominic Jackson, Product
Manager, Enterprise Products at

"The original vision
for IMF was that movie
studios would use
it as the primary
format"
Dominic Jackson, Telestream

Telestream. "So far there may be
some archiving going on, but the use
of IMF as a 'live' delivery format isn't
really here yet. We are mostly at the
point where studios are distributing
'test' packages to ensure that
recipients can handle them correctly."
Dalet's Chief Media Scientist, Bruce
Devlin also claims take up within the
Hollywood community, however, there
is still a missing unifying aspect to IMF.
He cites two major components behind
this inability to truly make IMF a massmarket format.
"Each studio still has their own IMF
delivery standards, both input and
output specifications," he says. "The
broader content creative and delivery
community feels that IMF is really
more like five to six different flavours
of a similar standard, since they have
to make IMF Flavour A for Netflix,
IMF Flavour B for a major studio and
IMF Flavour C to feed their finishing/
transcoding tool."
The second missing aspect is the
lack of tools able to handle IMF.
"Componentised media workflows
like IMF are very powerful and
drastically simplify operations, but
they are very complex in the back
end. It requires a good platform and
adapted management tools to enable
simple, cost-effective solutions to
ingest, manage, search/find/retrieve
and transform IMF for the necessary
workflows. And very few platforms
have developed the data model and
toolset."
Such tools are expected to move
out of testing into actual use cases
and production over the first half of
2018. As they do, there shouldn't be
too much difference between the core
workflows for IMF version 1 and the
broadcast/online version but there are
changes.
The principle differences is the need
to transport ad break information
to support stitching of assets from
outside of the IMF container at
playout. "This opens the possibility of
creative teams defining different break

Simplicity for
post workflows?

patterns and cut points in the asset
depending on the required ad payload
and playout length requirement,"
explains Mardling. "There's also the
need to include the relationships
between assets in different IMF
containers to allow series and episode
information to be transmitted within
the container.
"There
are
effectively
two
approaches to IMF in the workflow
- early or late stitching," he says.
"In an early stitching scenario the
broadcaster flattens the IMF file to
the required formats on receipt.
This allows the rest of the broadcast
workflow to remain more or less
unchanged. In a late stitching scenario
the IMF is processed through the
workflow and in effect any edits are
simply reflected in an updated CPL.
Flattening does not need to occur until
final playout, potentially on the fly."
Any new version of IMF needs
to be backwards compatible with
current implementations. However,
the majority of broadcast archives
are currently flattened files, often in
multiple difficult to track versions.
According to Mardling, the principle
issue will be in the requirement for
updating tooling to work with IMF and
the risk that rendering technologies
may become obsolete.
"I'd expect groups like DPP to
work on defining standard metadata
sets for specific markets or groups
or broadcasters," says Jackson.
"These metadata sets will also need
to be extensible to include specific
metadata requirements for individual
broadcasters."
If IMF for broadcast is going to work,

"The broader content
creative and delivery
community feels that
IMF is really more like
five to six different
flavours of a similar
standard"
Bruce Devlin, Dalet

broadcasters and the kit suppliers will
be required to introduce new ways of
handling files.
"Most of the existing tools that
broadcasters use are not necessarily
very IMF friendly," says Jackson.
"The asset management systems,
transcoders, edit systems and the
like are all likely going to need some
upgrade to deal with IMF successfully.
Just the implications of the fact that
IMF is a group of files rather than a
single one are going to be significant
for broadcast supply chain, and that's
just the start of it."
Codec Issues
Deciding on a primary codec for the
format seems too thorny an issue to
be sorted. "ProRes in IMF seems to
be here to stay but I doubt that will
meet everyone's needs," says Jackson.
"Codec choice is too challenging to
agree on."
Mardling believes the issue is a
storm in a teacup: "As with other
similar standards, shims will be
required to ensure interoperability but
this should not be a major impediment
to adoption."
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