frames, it does add an extra layer of complexity in the form of XML files,” says Primestream’s
“These XML files are used to describe the
relationship between the different media and
their versions, and this extra metadata has more
value when the files are transported between
systems, and less value when production is occurring within a system or workflow that maintains the same and in many cases even more
metadata,” says Schleifer.
But what about editing the CPL, in the same
way an M3U8 or MPD manifest file for HLS or
MPEG-DASH, respectively, would be edited?
In theory, editing limitations should not be
a major roadblock, but editing itself will be an
important litmus test for IMF-compatible software tool vendors to overcome.
“Not many editing/archive/ingest/playout
components or systems in the production
workflow currently support IMF,” according
One step in the editing process would be to
properly modify IMF compositions created
with one of several available desktop CPL edit
solutions. Another would be meeting necessary
interoperability standards when it comes to
proper ingestion of complete or supplemental IMF packages.
Not only are storage and playback important,
but the included metadata in any IMF package
must be readable by both human and software
parsers. Therefore, the ability to index, search,
and retrieve key portions of an IMF package
are critical requirements.
Finally, editing also brings into focus the need
to properly allow updating of a CPL within an
existing IMF package, whether the package is
on the local machine where CPL edits are occurring or on a local server or stored in the cloud.
As such, the ability to upload and download
complete or partial packages as part of the
overall distribution scheme is critical. In some
instances, this distribution may also require
stripping away the IMF package itself in favor
of transcoded output. In other words, the final
deliverable may be the audio-video files rather
than a total IMF package.
Next Steps for IMF
In all the excitement around IMF, it’s easy to
forget that not only must the XML be extensible, but that the IMF packaging structure must
be flexible enough to handle new audio and video formats. Steps are underway to address 360°
video as well as VR video.
In addition, continued improvement around
packaging data XML—the XML within the IMF
that allows for asset mapping, packing lists, and
even practical constraints such as a volume index for movie and broadcast delivery compliance—will address VR video and other more
exotic use cases.
Already, there is an Application 2E, with the
E standing for Extended, which offers support for imaging that has wider color depth—
High Dynamic Range, or HDR—as well as larger
Specifically, Application 2E addresses “col-
orimetry specified in IEC 61966-2-4 and Rec-
ommendation ITU-R BT.2020” as well as “color
primaries specified in SMPTE RP 431-2.”
Following the HDR transfer function speci-
fied in ST 2084, IMF packages can now contain
HDR frames at a “maximum width and height
of 4096 and 3112 pixels, respectively,” to handle
both ultra-high-definition (UHD) as well as the
Digital Cinema Intitiatives 4K specifications.
On the vendor front, Prime Focus’ Sankaranarayanan says that the player portion, while
critical, is only one step in streamlining overall
“The IMF Media Player was just the first step
in our innovation-driven product roadmap towards IMF readiness,” says Sankaranarayanan.
“Our integrated software offerings offer smart
possibilities with automation, and are well-positioned to deliver more speed, more control and much lower Total Cost of Operations
(TCOP) to M&E companies. We know that IMF
will be a core technology in that future, and we
are already well underway.”
Tim Siglin is a streaming industry veteran and longtime
contributing editor to Streaming Media magazine.
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