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Since the first white papers and early builds of software grabbed by some eager innovators, we�re now seeing a broader range of HMP (Host Media Processing) products available in the market with better targeted features and stability as the classic software �version 2s� hit the streets from leading vendors.
But first let�s start by reviewing what
media processing is about and go on to
recap what HMP is and where it fits. A
variety of media processing functions
need to be taken care of as part of
designing and integrating a communications
platform, depending on the target
application. They range from recording
and playing back speech using an appropriate
compression or encoding scheme
to suit the telephony devices being used,
through DTMF recognition to fax
transmit and receive. The amount of
mathematical processing power required
to support each function is very much
dependent upon its complexity.
Historically, the only commercially
viable method of performing the high
number of computations required to
run the different algorithms was to use
digital signal processors, or DSPs. These
devices are still the mainstay of media
processing today and, unlike general
processors, they have the unique ability
to perform both multiply and accumulate
functions on a single clock pulse.
This efficiency enables high-density
designs to be achieved without causing
material impacts upon the host processor,
which is usually running the main
application.
General purpose processors on our
PCs and servers seem to creep up in
power every year. This point hasn�t been
lost on software engineers looking to
work on newer versions of algorithms
for media processing. While at any
point in time we would expect a DSP to
outperform a general purpose processor
executing like-for-like media processing
functions, the more important question
is, �Can the general purpose processor
support enough channels of media processing
required to do the job in the
communications system?� This fundamental
question can sometimes get lost;
it reminds me of a debate I heard comparing
two sporty looking high-powered
cars � each had some special attributes
like road-holding on corners, or raw
straight-line speed, but when you boiled
it down to a question of can it get me
from A to B safely in reasonable time,
the simple answer was yes, of course!
Few would deny the market trend is
for technology to migrate from TDM to
IP. In this context it means that no specialist
telephony hardware interface is
required any more, and the traffic will
arrive at the server via a low-cost NIC (News - Alert).
Now we�re talking for the first time
about having a media processing solution
with no specialist hardware! This
holds appeal for organizations with
strong software application abilities that
have found the prospect � or even the
experience � of integrating traditional
telecoms somewhat daunting. So maybe
we�re looking at a slightly different type
of developer who will eagerly embrace
HMP? So what is the profile of applications
being developed with HMP technology?
As with any new technology, many were
cautious, but they were happy to try the
basic functions at modest channel
counts. This has led to a number of
either embedded IVR functions on the
same server as the communication
application, or a standalone server configuration
to complement an all-new IP system. These key system/PBX (News - Alert)/contact
center solutions have typically been in
an enterprise environment where maximum
local control is achievable and
channel counts are frequently below 40
users. This arrangement has allowed a
proper exercising of the functionality to
everyone�s satisfaction and has allowed
feedback to the HMP vendors such that
key improvements can be made.
We mustn�t forget that the diffusion
of innovation follows a well-documented
and reproducible path, so there is a
high level of certainty that HMP technologies
have staked a firm claim and
will see high growth. Initially, this is
likely to be at the expense of DSP
boards with analog interfaces, which are
synonymous with low-density installations.
The T1/E1 density board space
will be eroded from the low end in due
course. But none of this will happen
without the main market players taking
appropriate steps to listen and act upon
customer feedback. This, in itself, can
be a challenge for those vendors who
take the simplistic view that if a product�s
average sell price is below $1,000,
then it will be sold via channel partners.
The simple alternative is to make the
product available on the vendor�s Web
site � but is technical support going to
be provided in the price of the Webbased
product sale? No one is claiming
that the technology is an order of magnitude
easier to understand than a hardware-
based DSP circuit card. Whichever
route to market is selected, the vendor
has to ensure feedback is managed and
support provided appropriately.
Another area worthy of note is the
licensing of the HMP product. Given
the ease of software distribution, and
the inevitable concerns about possible
illegal copying, there needs to have
been an appropriate amount of consideration
given to the balance necessary
to protect the vendor and the flexibility
needed by the developer and systems
integrator. There is an understandable
tension in trying to get this right and
given that the majority of HMP vendors
have a hardware-dominated background,
we are witnessing steady
improvements across the market. The
leading offerings have either an OEM
licensing arrangement to enable the
developer to embed an appropriate
number of channels � at their control
� or a software licence key that is generated
to match the platform upon
which the application is run.
To assist customers who fit the
�majority� profile � and that is the stage
of the market we are now in � most
HMP vendors are offering a free, timelimited
version of their product to
remove barriers to adoption. With typically
4-6 weeks� time to carry out product
evaluations, some vendors even offer
free technical or pre-sales support; there
is clearly a push to capture the mind
share of the development community.
Given that this is IP-based technology,
we anticipate an increasingly wide
range of devices that HMP will need to
be connected to, possibly with different
media and compression schemes. In
addition to the standard G.711 audio
codec, we�re seeing implementations of
an interesting range of codecs, including:
G.729, G.726, G.723, Speex and
iLBC, the Internet low bit-rate codec.
The iLBC codec was specifically developed
to accommodate the Internet�s
�bursty� transmission characteristics, and
is used in the widely-deployed Skype (News - Alert)
VoIP communications software. It is
worth spotting the mixture of audio
codecs that cover traditional wired and
wireless TDM networks, ensuring a
wider applicability for HMP products
than at initial launch.
And yes, there still seems to be a solid
market need for facsimile � particularly
for such sectors as financial services, so
support for the T.38 standard is common;
this ensures the developer can �tick
the box� when asked.
Having touched on audio and fax,
let�s not forget video. Those of us watching
the newer features coming through
on the latest host processors know that
every release of silicon brings us �new�
and �spectacular� graphics handling and
sets the expectation that we should be
seeing at least a few channels of video
from the HMP products too. Although
still in the �early days�, we can nevertheless
see the first products becoming
available capable of connecting with
�like-to-like� video devices; that is to say
no transcoding is performed, which
would demand intensive processing.
What of the future? We can reasonably
expect a continuous rise in the
number of channels and features that
can be supported on a single installation,
thus leading the system architect
to consider HMP as a serious alternative
when making technology selections for
more solutions.
As familiarity with the technology
increases, both from the HMP vendors
and the developers� perspective, we
would expect more insights into ways of
taking advantage of a software-only
architecture that lead to experiencebased
enhancements. One such area is
likely to be in methods of achieving distribution
amongst different servers to
provide both additional resilience and a
means of scaling a solution. These areas
of development should consolidate and
enhance the choice for designers to consider
incorporating either DSP or HMP
technologies in solutions.
All in all, you could argue that
HMP is just completing its �apprenticeship�
and is ready for a prime-time
audience. IT
Mike Matthews manages product lifecycles
and customer feedback, and is responsible
for the positioning of new products at
Aculab (News - Alert) (www.aculab.com). He manages the
link between customers and Aculab�s R&D,
oversees Aculab�s product roadmap, and
supports the company�s global sales force.
A well-known speaker, over the past 25
years he�s also had several roles in telecom
industrial consortia responsible for ensuring
equipment interoperability.
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