CREATION
March 2016
15
within the subtleties
who have had years of content, including
captions, saved on tape.”
Although there were ways to digitise this
content and preserve the CC information,
Matrox found previous editing solutions “ill-
equipped” to preserve the content during the
editing process, thus leading the company
to develop a solution called Matrox 4VANC,
which allows editors to reserve CC informa-
tion as an audio track in FCP.
“The editor could lay his content down
on the timeline, trim and perform effects
such as colour correction, output to an SDI
monitor for preview and print back to tape,”
Maloney reveals. “We also worked with the
team at MacCaption to further enhance
the workflow, allowing users to import and
export Matrox 4VANC files into their closed
captioning authoring tool.”
When Adobe began including caption-
ing workflows directly into Premiere Pro,
Matrox also worked with Adobe to ensure
that broadcast customers could preview cap-
tions on an SDI monitor to ensure accuracy.
With well-defined standards to follow,
broadcasters may be well versed at offering
CC on live transmissions for their tradition-
al linear TV audiences.
Will the increasing reality of over-the-
top (OTT) herald a completely new CC
paradigm?
Maloney answers: “When dealing with
live content for OTT delivery, [offering
CC] becomes more complex because video/
audio and CC must be encoded and pack-
aged to be compatible with the many dif-
ferent types of devices that will access the
content.”
He goes on to illustrate that in a broad-
cast workflow, upstream of the linear and
non-linear delivery format of an asset sees all
deliverables derived from a mezzanine-level
asset. In a linear workflow, the file is output
from a broadcast video server with valid CC
information in the SDI stream, and sent to
the transmission server. In non-linear or
OTT workflows, the mezzanine file and
associated CC information are transcoded
into formats that Web and mobile devices
can read natively and hosted on a media
server for Web-based access.
Maloney adds: “It is not as big a chal-
lenge with episodic content because the
mezzanine-level files can be repurposed
offline, but the real-time nature of live TV
means captioning must be transcoded in
real time. The lack of a single standard for
delivering CC to the various player plat-
forms essentially means that all must be
supported.
“That requires a powerful real-time
transcoding solution, one that can take
the CC information directly from an SDI
stream, or from a primary encoder that
delivers a single format.”
For AJA, recent changes to the company’s
As IP infrastructures begin to
replace current conventional
broadcast plant infrastructures,
captioning will remain important.
The uncertainty, suggests AJA
Video Systems’ Thad Huston (left),
lies in how captioning metadata will
be transmitted.
software development kit (SDK) are designed
to improve the way ancillary data is passed
between SDI and a software application.
Thad Huston, product manager at AJA
Video Systems, tells APB: “This should be
something that is largely transparent to the
end-user, regardless if they’re using KONA
or lo with a non-linear editing (NLE) sys-
tem, a broadcast automation application,
or a streaming application. Mostly, this
change will only affect applications where
the user will [possibly] want to simultane-
ously use the video processing features of
the AJA hardware with ancillary data input
or output.”
Last September, AJA released version
12.3 drivers and software for its KONA,
T-TAP and lo line of video and audio input/
output devices, which include a range of
CC support for KONA 4 and lo 4K. In this
instance, AJA’s driver SDK version 12.3
changes the way that ancillary, or CC, data
is passed into and out of the hardware. It
allows users of AJA’s SDK to implement
better solutions for capture and output of
closed captions using ancillary data in their
software packages.
Where there was previously no CC fea-
tures in AJA Control Room, and only CC
output from Premiere Pro, the new update
adds CC capture and output in AJA Control
Room and Adobe Premiere Pro plug-ins, for
KONA 4 and lo 4K.
CC capture features for KONA 4 and lo
4K include capture with CC of all supported
file types, including QuickTime and image
sequences such as DPX. In AJA Control
Room, this CC capture function must be
turned on deliberately, while in the AJA
Premiere Pro capture plug-in, the system
is always on the lookout for the presence of
closed captioning, and to capture it if it exists.
CC output features for KONA 4 and
lo 4K include the optional decoding and
display of captions in AJA Control Room
on the Desktop Preview Screen. When a
file is played back on AJA Control Room,
it first looks for the MCC/SCC file. If none
is present, and the file is in QuickTime for-
mat, CC embedded in the CC track of the
QuickTime file will be used.
For Premiere Pro, when any CC is
available, and when ‘Enable Captions’ is
With well-defined standards to follow, broadcasters may
be well versed at offering CC on live transmissions for their
traditional linear TV audiences.
turned on, those captions are then output
automatically.
Another development worth monitoring
where CC is concerned is the video-to-
IP (VoIP) transmission, advises Matrox’s
Maloney, who adds that Matrox is actively
researching and de