remote production - going the distance

Remote Production is fast becoming more prevalent as many broadcasters
look to it as a means of generating a wider range of high-quality content.
However, this method of live broadcasting has its own very specific issues.
This white paper identifies those issues with regard to audio production and
offers a practical and cost effective solution.
An illustrative case study is included to give context to the discussion points
and demonstrates the application of the solution.
Putting Sound in the Picture
Remote production gives broadcasters
the ability to capture a wider range of
live events, such as regional sports,
news or music festivals, and mix
them in a remote facility hundreds or
thousands of miles away.
1. Speed; the single biggest issue.
Broadcast audio workflows rely on
effective monitor mixes with no latency.
This can be difficult to achieve when
your studio is hundreds or even
thousands of miles away.
Many of these events might be
of restricted interest, and may be
broadcast to a narrow audience
demographic. They may be regional
news events which require a lot of
content generation in a short space
of time. They may require temporary
infrastructures which need to be highly
To avoid the audio making a long
distance round-trip, on-site remote
production equipment should have
local DSP to generate monitor mixes
and IFBs with no latency. An operator
in a remote studio needs direct control
over channel functions such as mic
gains, aux send/monitor mix levels and
fader levels from the remote console
control surface.
Remote production technology
provides a realistic alternative for these
events – the production of high quality
content with fewer resources.
The barriers to effective remote
broadcasting are speed (or latency),
control and infrastructure.
There also needs to be a convenient
method for managing the DSP and
bus configuration on-site. It must be
simple for on-site engineers to setup IFB routing and remote monitor
mix levels at the venue, especially
considering that many remote
production broadcasts will not utilise
as many staff. These considerations
guarantee that venue infrastructure,
routing and monitor feeds are
functional prior to transmission. Local
DSP also means there is no latency for
commentary or talent monitoring.
With all DSP for monitor mixes taken
care of on-site, the studio transmission
console can concentrate purely on the
main programme mix.
2. Control; operators need real-time
control over mic gains, fader levels and
monitor mix levels.
Effective remote production requires
a simple method to control the
parameters of the remote production
unit from a control room located many
miles away, giving the operator control
over channels, busses and other
parameters from the studio control
In other words, the operator sits
behind a console that he is already
familiar with and assigns remote
channel paths to local faders, just like
any other channel.
This functionality should include
channel path fader levels and cuts, aux
send levels and ons, aux master levels
and cuts, VCA linking via the studio
console, as well as control over EQ,
dynamics and direct outputs.
The operator needs to independently
mix all the remote site IFBs and
aux buses in addition to the local
transmission mix on the studio
3. Infrastructure; or, which transport
to use to move signals around. Multiple
synced signals need to be moved in
real time, and often down the same
physical infrastructure. Audio, data and
video all need to be considered, as
well as multiple control protocols.
Infrastructures need to be versatile
to connect via a range of transports,
allowing the broadcaster to use a
preferred transport method. This
minimises initial expenditure and gives
confidence in using an established
transport mechanism. The studio
console mixing the transmission can
in turn assign these signals where
required on the desk, so workflows
are the same as any other broadcast.
Working in this way means the learning
curve is shallow and transitioning to a
remote production workflow causes
minimal disruption.
To address these issues Calrec has created the RP1. A 2U single box
solution, RP1 provides local DSP to enable the generation of monitor mixes
and IFBs with no latency. It gives an operator in a remote studio direct control
over channel functions such as mic gains, aux send/monitor mix levels and
fader levels. It also provides a mechanism to embed audio into existing
backhaul technologies, such as SDI or SMPTE 2022.
In addition, RP1 allows broadcasters to create low-cost on-site Hydra2
networks for all audio routing requirements. It provides connectivity to any
Calrec Hydra2 I/O box providing ways to adapt to the requirements of any
situation. Such connectivity also gives broadcasters access to Hydra2’s
inherent management features, such as port protection, alias files, and access
Fundamentally, it enables broadcasters to cover a greater number of
specialised events, such as regional or college sports and smaller
entertainment events, at significantly reduced costs, making it possible to
develop an increasingly wide range of content.
As our industry develops, these
transports need to develop too. The
flexibility to incorporate changing AoIP
and IP protocols like Dante, AES67
and even SMPTE 2022, is essential.
A remote production unit should
be flexible enough to deal with any
For full scalability, there should be
the ability to link multiple remote
production units to the same studiobased console. This is useful for
shows with multiple events happening
Calrec’s RP1 Remote Production Solution.
“Remote, or at home production, will no doubt increase over the next five years as technology
evolves to allow production teams to work from the same facility week in week out, especially
on longer form multi day events.”
Remote Produc tion - Going The Dist ance
Gordon Roxburgh, Technical Manager, Sky Sports

CALREC White Paper
The first connectivity test was the
control of the RP1 via a web browser.
Once RP1 is up and running it allows
several web clients to connect into
it using a Calrec application called
‘Calrec Assist.’
RP1 trial testing was carried out during
the ATP tennis finals. Connectivity
was between the O2 Arena in North
Greenwich, London, and Sky Studios
at Osterley, London in November
2016. The trial was set up in parallel to
the ATP Tennis live broadcast.
The RP1 unit was located in a technical
bay at the O2. 16 microphones from
around the court, umpire chair and
commentator positions were connected
to the RP1 via MADI.
Two instances of Calrec Assist were
setup; one at the O2 and the other
next to the console in Osterley. The
functions of the RP1 were setup and
controlled from both positions to prove
that parallel control could be achieved.
The RP1 took in the MADI data from
a DirectOut M.1k2 MADI router, which
was sent to one of four aux IFB outputs
and then sent back out of the RP1 unit
via MADI.
Each instance of Calrec Assist can
fully control any of the channels and
auxiliaries whilst other instances of
Calrec Assist were simultaneously
controlling other path parameters.
The MADI inputs were embedded into
SDI streams before being passed
through an SDI-Codec unit and fed into
a Cisco switch and sent via IP over 20
miles of fibre on a managed network
with a latency of no more than 40ms.
Camera Mics for either side of the net and Mics at ends of the court.
In a live scenario the remote channels
and transmission channels would be
mixed on the Artemis, thus allowing
the operator to control both the
transmission mix and the remote
production mix from the same surface.
The signals were received at Sky
Studios where the audio was
de-embedded and remotely mixed
on a Calrec Artemis console in Sky
Studio 8.
The main purpose of this trial was not
to show that audio could be passed
over IP to another site, but to prove that
the microphone channel inputs to the
RP1, and the IFB Auxiliary outputs
from the RP1 at the O2, could be
controlled over long distances in real
time over the same IP connection via
the Cisco Catalyst 2960 switch. Control
was tested both directly from the Host
console surface and from a GUI running
on a browser in a variety of locations
to the LAN1 port on the rear of the RP1.
The second method of controlling the
RP1 unit was achieved by mapping
the RP1 channels and auxiliaries on to
the Artemis Light control surface of the
Host console back at Sky Studio 8,
next door to the transmission console.
Apart from clearly identifying which
channels and auxiliaries were coming
from the remote site, the operator
could control these ‘remote’ paths in
the same way as its ‘local’ paths.
Umpire Chair Mics:- 2 rear Mics, 2 courtside Mics and the umpire Mic.
Commentator Position Mic & Headphones.
Calrec Assist allows the user to access and control all the functions of the
RP1 unit including:
• Show creation.
• Loading and saving Shows.
• Saving and loading memories within
• Configuring the virtual fader bed
for mono, stereo and surround input
• Configuring the IFBs for
commentator output feeds.
• Patching various I/O units to
channels and buses.
• Applying mic gain, phantom power,
trim, balance etc. to channel inputs.
• Controlling fader levels and Cut Aux
Sends and Direct Outputs.
• Having the ability to monitor and
meter the inputs and outputs of the
• Routing channels to various buses
as required.
The test showed that control was
achieved from both the host surface
and various instances of Calrec Assist.
While lag was recorded, this was
insignificant and had no effect on
“The RP1 allows us to re-invent the audio workflows for remote working, allowing critical
functionality to be remotely controlled from the main studio complex. With its Hydra2
network built in, it allows the RP1 to be the core of the OB audio facility, and not just an
add on ‘blackbox’.”
Gordon Roxburgh, Technical Manager, Sky Sports
Remote Produc tion - Going The Dist ance

CALREC White Paper
1. The RP1 Remote Production
Unit receives the mic inputs from
various locations around the
venue and commentary positions.
It outputs to stereo IFB monitor
headphones via Hydra2 I/O boxes
at the remote site.
RP1 is a 32-channel mixer with
channels that can be configured as
mono, stereo or 5.1. Any channel can
route to any of 12 aux buses, which
can be used to create local monitor
Routing capabilities are very flexible
thanks to a built-in 768 x 768 matrix
router. This router means that RP1 has
maximum physical output capacity of
704 signals using modular slots and
Hydra2 port on the rear of the unit.
Depending on the transport
infrastructure it is possible to have
all 704 signals transported from
the venue (say, on multiple MADI
streams), and patch additional mics
from the venue without touching the
channels (i.e. a direct input to output
patch). One need only add sources to
channels for IFB controls, which can
be set up through Calrec Assist.
This router provides a flexible way to
manage signals. Let’s say you need
three separate outputs for monitoring,
two separate mono sources locally
(e.g. channel and aux) and the ability to
send one monitor out on an embedded
You can send the RP1 monitor
output (and PFL) back to the studio
console and configure an external
input to listen to the monitor output
(or the PFL) of the RP1. You could
also bring some inputs and buses
back to the studio console using
any transportation method. You can
patch as many of the buses or inputs
sources as you want.
There are no limitations on the type
of I/O box connected to a H2Hub
network – I/O boxes can be any of
Calrec’s range of fixed format, modular
or Fieldbox I/O – but the H2Hub has
an upstream connection limitation to
a Calrec Router of 512 bi-directional
channels, so the total I/O connected
must not exceed 512 signals.
2. RP1 can contain SDI Embedder &
De-embedder modules.
With no built-in audio codec,
customers can use any existing
backhaul technology, which saves
time and money, and provides the
confidence of using familiar transports.
Calrec’s modular card slots allow
the user to send audio over long
RP1 can connect via analogue, AES,
MADI, SDI, as well as emerging
IP solutions such as AES67 and
Dante. The card slots in the rear of
the RP1 enable even more efficient
connectivity; embedder cards can be
directly plugged in the back of the
RP1, and a de-embedder card can be
plugged directly in the modular I/O at
the studio console.
3. Remote audio was sent to Host
console using SDI over video
codecs, J2K+AoIP.
RP1 can embed audio into existing
video transport mechanisms, and
using an established video transport
to embed the audio ensures that there
are no synchronisation issues. This
integrates seamlessly into established
workflows that the broadcaster is
Remote Produc tion - Going The Dist ance
already using, such as J2K for an
SDI source. RP1 works within the
parameters of existing broadcast
4. Studio programme audio feeds
can be returned to the remote
site using SDI over video codecs,
At the studio console, all the remote
I/O resources appear like any other
local I/O box, so workflows are the
same as any other broadcast. For
confidence and cues, video signals
can be sent from the studio to the
venue on the same transport. This
would normally be a feed of the
programme output to give a visual
reference for onsite talent.
5. Hydra 2 True Control data is
passed between the RP1 and the
Host console, or Calrec Assist via
IP ports.
The transport layer is UDP and TCP
with a network layer of IPv4. Although
latency depends on how far the data
must travel, Calrec control data needs
nothing more than a standard QoS
setting. Including network switch
delays, RP1 aims to achieve
a maximum round trip message time
of no more than 400-500ms.
6. Control of remote faders,
including mic Inputs, is managed
from the Host console by use of
control faders acting on remote
production channels.
Calrec’s RP1 uses a system called
True Control, which includes channel
path fader levels and cuts, as well
as aux send levels and ons, and
aux master levels and cuts. Future
development will include VCA linking
via the studio console, and control
over EQ, dynamics and direct outputs
via Calrec Assist.
RP1 uses UDP ports at both the
remote site and the venue, and
additional TCP connections at the
UDP ports are used for monitoring
device connectivity and status; TCP
connection is used for the control
protocol once connected, and for
Calrec Assist.
True Control allows an operator to
independently mix all the remote
site IFBs and aux buses in addition
to the local transmission mix on the

CALREC White Paper
studio console. In fact, Calrec’s True
Control provides the ability to link five
independent RP1 units to the same
studio-based console.
7. Control of remote auxiliaries
allow creation and adjustment of
IFB monitor feeds on the remote
site (with no round-trip IP delay).
These are managed from the Host
console by use of control auxes
acting on remote production buses.
There are 12 x aux buses on the RP1
for creating local monitor mixes and
IFBs for latency free mixing at the
Channel and input controls such as
mic gains and 48V phantom power
can be set from the Host console or
via Calrec Assist if console connection
is offline.
IFB/Aux outputs to the talent can
be mixed and monitored locally at
the venue, but there may be times
when the audio operator at the studio
console needs access to these mixes.
RP1 aux signals can be sent back to
the studio and routed into the studio
console as external inputs. This way
an audio operator can make a clear
distinction between monitoring an RP1
external aux output and an aux output
local to the studio.
8. Remote processing and routing
can be controlled from multiple
Host console surfaces or Calrec
Calrec’s True Control system makes
it simple to manage the transmission
mix as well as sending control signals.
RP1 channels and buses can be
assigned to the fader strip with IFB
routing, inputs and fader controls, so
there is no need to switch between the
desk and a PC screen for the remote
sources and the local mixing console
There may be several consoles at the
Host studio which all need control of
the RP1 sources at different times. It
is possible to do this on an ownership
Network protection is a broadcast
pre-requisite, and should be a central
consideration for key broadcast design
principals. While several consoles
can connect to any one RP1, only one
console can be connected at any one
time, and once set up all the operator
needs to do is hit the Connect button
on the console. Control must be
released before someone else can
take it. Should the connection be
lost, a different console can quickly
establish a new connection.
Calrec provides the ability to link five
RP1 cores to the same studio console,
all with independent True Control and
transmission mixes. There is also a
control room monitor output and AFL/
PFL functionality on channel paths and
auxiliary outputs.
For example, if the monitor and PFL
output are brought back from the
venue, these can be routed into the
Host console as external inputs;
Calrec Assist can be used to trigger a
PFL on the RP1 unit and listen to it via
the external input. The PFL activation
of the remote channels is achieved
through the fader-surface screen in
the Calrec Assist application – this is
accessible to the RP1 at the venue,
and also at the Host console.
There may be instances where this
open control may not be desirable,
such as during a live broadcast. In
this case the console software has a
“Block” switch, which prevents Assist
from making any fader and cut data
changes at the venue on channels
under True Control from the studio.
9. Calrec Assist can be used at the
Host console to modify infrequently
changed remote production
In contrast, RP1 also has an
“Independent” switch which ignores
any True Control data from the studio
console and allows operators at the
venue to set their own levels without
DSP and bus configuration can be
managed with Calrec Assist. This
enables all venue infrastructure,
routing and monitor feeds to be
checked prior to establishing the link
with the studio console.
Calrec Assist can adjust RP1 input
settings, such as gain, phantom power
and input, plus fader levels on studio
console meters.
Changes made through Assist, such
as changes to mic inputs feeding the
studio console, will be seen on the
studio console. It allows the user to
access and control other functions
too, such as show creation, I/O unit
patching to channels and buses,
routing, and saving and loading
memories. Calrec Assist has access to
the RP1 from the venue and the studio
This means if you are at the venue, you
can use the RP1 to set up and test
mics, for example, and you can use
Assist at the studio to do the same.
There is no hierarchy of influence with
Assist control messages – changes
can be made to the RP1 from any
Assist client, and the last message
received will affect the RP1 settings.
Remote Site
Calrec Assist
Onsite I/O
Network requirements to make Calrec
Assist at the studio work with a remote
RP1 are minimal. The RP1 at the
remote venue needs a data connection
back to the studio console, as well
as a VPN or direct link for other IP
devices. Calrec Assist only needs
200kbps with a max latency of around
one second to be manageable.
IP Network
Once the RP1 is on the Host studio
network it can be accessed by typing
the IP address of the RP1 unit into a
Chrome web browser. That means
it can be accessed via a corporate
network on an iPad or a PC/Mac, or
even on the studio console PC.
True Control
Video Sync
Meter Data
The trial use of RP1 in this
environment shows that it can solve
the problems identified in this paper,
and provides an efficient and cost
effective remote production solution.
Network I/O
6 7 8
Control Room I/O
Calrec Assist
Host Console
Control Room
* The numbers on the diagram refer to the points made in this section.
Remote Produc tion - Going The Dist ance

CALREC White Paper
“Remote, or at-home production,
will no doubt increase over the next
five years as technology evolves to
allow production teams to work from
the same facility week in, week out,
especially on longer-form multi-day
events. We are not going to see every
major soccer or cricket match being
remotely produced in the short term,
but key areas such as the remote
production of the presentation of
events will increase.
“The RP1 allows us to re-invent the
audio workflows for remote working,
allowing critical functionality to be
remotely controlled from the main
studio complex. With its built-in
Hydra2 network, it allows the RP1 to
be the core of the OB audio facility,
and not just an add-on ‘blackbox’.
“The key hurdles are no longer
technical, we can tick all of those
boxes now; the critical steps to a
remote production being a success is
to work with the production teams and
all the key stakeholders at the planning
stage to ensure we are all going in the
same direction.
“‘Flight Rules’ have to be defined to
ensure that everyone understands how
the programme being made differs to
a traditional Outside Broadcast. As
the event evolves these flight rules
evolve too and the programme gets
better and better.
“On events that are a longer distance
away, where latency becomes an
issue for simple conversations, its also
critical to work with the on-screen
10 Remote Produc tion - Going The Dist ance
talent to give them appreciation of the
RP1 Benefits
“Ultimately by being efficient and
working differently we can create a
better product. Allowing presentations
to break out from a studio environment
to the actual event will always be far
more engaging for our viewers.
“The production crew working back
at base likely have access to far more
resources than in an OB truck; for
example a producer before a show can
be working in a high end edit before
arriving in the gallery to make the live
Studio Operator has full control of remote resources.
Redundancy of power, audio and control as standard.
Specialised OB equipment and full audio team not needed for smaller events.
Small 2U Footprint with a wide variety of I/O options.
Cost effective and easy to set up/configure.
Multiple RP1 units can be connected to Host Console.
Real time control of latency-free commentary mixes.
Can be controlled standalone using a web browser from any IP connected location.
Gordon Roxburgh, Technical
Manager, Sky Sports

CALREC White Paper
Calrec Audio Ltd
Nutclough Mill
Hebden Bridge
West Yorkshire
England UK
Tel +44 (0)1422 842159
Fax +44 (0)1422 845244
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