One year ago,
Radio World asked several experts to discuss trends in the broadcast
codec technology arena (Jan. 2, 2013). It was a popular topic, so we
return to it now to learn more and find out what’s new in a set of
four Q&As. Replies were via email and have been edited for
Campbell, APAC/Americas APT Sales Director with WorldCast Systems,
comments. Watch the website for the rest in the series.
What’s the most
important recent development in codec technology?
I think the most significant would be the recent adoption of a
redundant streaming approach to counteract adverse network conditions
on lossy IP links. This approach is enabling broadcasters to utilize
cost-effective public Internet connections to replace or backup main
connections without any loss of quality compared to the traditional
(and substantially more expensive) synchronous connections such as
T1. It has opened up a new path for audio broadcasters and gained in
APT pioneered this
field when we launched SureStream technology back in 2010 and the
past year has seen a rise in “CopyStream” technologies from
competitors attempting to emulate its success and in some cases
retrofit it to legacy hardware. We are confident that SureStream
remains significantly ahead in terms of performance and
sophistication and will continue maintain our market-leading position
in this field. This is at least in part due to refinements and
feedback from our significant installed base. In fact, 2013 saw the
first large-scale telco deployment of the technology in a
country-wide network with over 100 codec units which represents a
landmark in the adoption of this approach.
broadcast users should be well familiar with audio over IP, but there
never seems to be enough information in the marketplace to meet the
level of interest.
are still plenty of misperceptions and misinformation. The one that
we still hear a lot is the fact that a link is declared free from
packet drop after an engineer does a PING test. Just because a PING
is completed is of little relevance in the IP codec world as the PING
test operates using TCP/IP whilst the audio codec, primarily (through
not exclusively) uses UDP/IP.
It’s these types
of persistent misperceptions that have prompted us to rewrite our
successful “Practical Guide to IP Audio.” We first released this
primer back in 2008/9 near the start of the IP audio phenomenon and
it soon became a must-read for engineers contemplating a migration to
IP audio transport. We are updating the guide and plan to have the
new version available before NAB 2014.
does the AES67 standard have?
advantages of the technology and the contributing technologies to the
standard are well documented. It negates the need for punch blocks,
patch panels and tons of cables in any facility and simply and
elegantly replaces them with Cat-5 Ethernet cable and off-the-shelf
switches. The sophistication of this solution combined with the
flexibility that AES67 offers in terms of audio routing and the
ease of connectivity to AES67 products makes it a “killer
Clearly as codecs
are a key element in moving audio channels between facilities, the
technology will have an impact on our range. Watch this space for
what we do!
What is the
“state of the art” in algorithms?
the risk of sounding like a broken record, you can’t really go past
Enhanced apt-X if you are looking for a “no compromise” solution.
No compromise in terms of audio fidelity and latency, the
characteristics of the algorithm remain markedly close to Linear PCM
and vastly superior to psychoacoustic algorithms, especially when it
comes to multiple encodes or tandem coding. Enhanced apt-X is still
being bought into globally by broadcasters, broadcast service
providers and telcos, where quality and audio fidelity are the prime
We have seen much
less demand and, in some territories, very little awareness for the
newer algorithms such as Opus. Licensing costs and availability of
the algorithm quite often outweigh the inherent qualities of the
algorithm in determining the market penetration, especially in our
quite small niche sector where we purchase in the hundreds and the
thousands rather than the millions like the consumer sector.
To generalize, I
think the holy trinity for broadcasters could be stated as Enhanced
apt-X, to be used where no compromise on quality, but bandwidth
constraints; Linear PCM, to be used where there are no bandwidth
constraints; and HE-AAC , to be used where the bandwidth is heavily
What is your
newest product or feature?
latest addition to our core audio-over-IP codec range is the
ScriptEasy remote control application. Known from our Audemat line of
remote control devices, ScriptEasy has been integrated into APT codec
units to deliver a unique way of offering advanced remote control,
which would previously only have been possible using external
remote control logic, it endows the codec with inbuilt intelligence
which can enable it to act how you wish it to when certain criteria
are met in the internal performance metrics or from up to five
external pieces of equipment. For example, you can trigger specific
line backups based on packet loss experienced, you can switch
schedule changes to receive local programming at specific times or
days and you can implement a different audio profile should your main
transmitter switch to the auxiliary.
These are just
examples; the true power of the application is that it can do what
you want it to do. … In the U.S. it is widely in use within the
Clear Channel group as the technology used to remotely control and
monitor all studio and transmitter sites throughout the country on
the Relio hardware platform.
How does the
decline in POTS, ISDN and other older services affect your users?
year we have had an announcement from Verizon in the northeast U.S.
that no more new installations will be undertaken for ISDN. No one
was shocked really; it’s to be expected as backbones continue to
change and the support personnel who know anything about ISDN
continue to dwindle. Those who have ISDN at studio and remote sites
(ballparks, concert venues etc.) continue to have service, albeit
I regularly speak
to many customers who want to make the transition to IP; however it’s
the age-old problem of budget vs. necessity. The engineer believes
it’s necessary to make the jump now, as ISDN is really on its last
legs; however management won’t make the investment as the ISDN
links have not yet been discontinued or no notice of discontinuation
of the service has been issued. So we continue on a gradual phased
transition as budgets become cyclically available.
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