An IP World
Digital systems offer numerous advantages over analog technology
- By Matt Barnette, Adam Shane
- Mar 18, 2008
Video management systems
have evolved considerably
since the analog tape-based
VCRs that were prevalent nearly
10 years ago. Then, analog CCTV cameras
with coaxial cable typically were connected
to a multiplexer so multiple video
images could be displayed on a video monitor
simultaneously. These signals then
were recorded for review and archiving.
Today, digital systems afford many
advantages over analog-based video
recorders. In a digital system, video data is
represented by exact numbers in bits. The
digital data is processed, stored and distributed
by computers. In general, digital
video systems offer advantages in information
processing, including production of
higher-quality information, ease of copying
information without quality loss, higher
interactivity—ease of manipulation
leading to useful product features—ease of
storage and retrieval, ease of distribution
and higher security.
Going Digital
A DVR, in its simplest form, is a VCR
replacement box. A DVR records the same
analog video camera signals, not to a tape,
but to a computer with hard disk-based
storage. Recording with a DVR allows for
better video quality capture than older
VCRs and provides exponentially more
video storage space. The video can be
retrieved faster because the computer can
find, manage and replay video clips instantaneously.
When a DVR is connected to a
network, users can view live or recorded
video from any computer that has access.
DVRs offer all of this improved functionality
and conveniently require very little user
intervention.
For these reasons, DVRs have proliferated,
and the continuing evolution of video
management is now tending toward completely
digital systems. The goal is the
establishment of a fully digital solution
from the camera, at the edge of the network;
to a computer viewing the video,
located anywhere on the network; to a storage
device that collects the data for
retrieval and historical archiving. The
advantages of an all-IP digital video system
are numerous, including design, installation
and overall flexibility.
The dilemma facing customers and
system integrators tasked with installation
is how to implement a video surveillance
system that is capable of meeting current
and future needs while incorporating
existing products the customer may have
acquired in the past. Security manufacturers
have designed systems specifically to
address these issues. These systems allow
the customer to protect previous investments
by using the technology the customer
already has and integrating it
into current technologies, laying the
foundation for an all-digital solution in
the future.
DVR Design Advantages
DVRs are being used as transition storage
devices between the analog systems of yesterday
and the all-digital surveillance systems
of the future. Technological developments
in storage and computer networks
are making the deployment of fully digital
IP surveillance more cost-effective, and the
benefits of a DVR-based solution are
numerous:
• DVR-based solutions are easily understood
in design terms. The interface to
the video management software is via
the network and the DVR manufacturer’s
software interface. Connections
from camera to recorder are through
dedicated cables; the design element simply ensures a cable route is available.
In a technical sense, DVR-based
systems are easy to deploy.
• Network design is simple; a single network
connection point is required by
the DVR with a single IP address for
high camera concentrations. Network
bandwidth is low and only used when
the video is being viewed or streamed
over the network.
• Most DVRs have a built-in browser so
the occasional user can connect to live
and stored video with software loaded
on the PC.
• No network bandwidth is used when
recording because the video is being
transmitted to the DVR via a dedicated
cable.
• Easy storage calculation for video.
• Easy deployment—many buildings
have existing analog CCTV system
infrastructure, such as coaxial cable
routed to a central location.
• Easy expansion—software can be overlaid
on top of the DVR infrastructure
without equipment redundancy.
• Where video is required locally, a lowcost
monitor can be connected to the
DVR for viewing purposes.
THE DEBATE IS ON
ETHERNET-BASED IP NETWORKING VERSUS
COAXIAL-BASED ANALOG NETWORKING
By Nathan Wheeler
When cable television was introduced to the public, a fierce debate erupted about whether the
transmission medium would replace traditional open-air-based antenna television. Those in
favor of the new technology largely based their argument on a single precept—consumer
demand. To put it simply, people wanted and were ready for the channels, content and options
that cable television offered.
For the past several years, a similar debate based on the acceptance of a new transmission
technology has been going on in the security industry: traditional coaxial analog video networking
versus IP/data video networking. It is a
hot topic at trade shows, in conference
rooms and at training sessions worldwide,
and it will probably continue to be so for
years to come.
Consider the fact that basic surveillance
networks consist of three primary components—
cameras generating content, a wirebased
transmission medium for transporting
content and a recording device for data. Tune
out all of the background noise about functions
and feature sets, and what remains is a
simple platform of components upon which
rests the foundation of nearly every major
surveillance network deployed. Once
deployed, the question becomes very simple:
Which of the two systems offers more?
Security directors are always looking to
maximize the performance of a video surveillance
system in terms of both coverage and
image detail. With IP-based high-definition
multi-megapixel cameras, they now have this
ability like never before. A few years ago, the
concept of zooming in on recorded or
archived video to view and recover clear,
forensic, detailed information was exclusively
reserved to magicians on television shows
like “CSI.” Now, with cameras recording at
resolutions higher than the best available
monitors can display, forensic zooming and
analysis of recorded data have become as
simple as point and click.
With the introduction of Arecont Vision’s
patented 180-degree and 360-degree
panoramic cameras last year, it is now possible
to put multiple, multi-megapixel high-definition
cameras inside of a single camera
body—four separate 2 megapixel cameras,
each with its own CMOS image processor, all
operating over a single Cat-5 connection. For
the first time, security personnel can view a
sweeping landscape of imagery at amazingly
high resolution with a single camera.
The storage and bandwidth requirements
of these HD megapixel cameras has
been the most common issue preventing
widespread acceptance of implementing
systems based on IP megapixel technology.
With gigabyte switches and terabytes of
storage available for hundreds of dollars
rather than thousands, a valid argument
nearly ceases. Now, with the rollout of
megapixel cameras with H.264 compression,
the bandwidth and storage requirements
for IP megapixel cameras have
dropped tremendously. New H.264 megapixel
cameras now offer bandwidth that’s 25
times greater than conventional MPEG
megapixel devices, along with incomparable
resolution. As a result, the longstanding
arguments against IP
networking no longer
apply.
Nathan Wheeler is the
Western U.S. sales manager
for Arecont Vision. |
DVR Design Disadvantages
However, the move to digital recording
also can present some negative factors:
• Hidden cost—equipment costs may
look favorable, but cabling costs,
deployment and disruption may result
in higher total costs.
• System availability can be affected by a
single equipment failure because, to
achieve low equipment costs, DVRs use
high camera concentrations—16 cameras
or more.
• Equipment setup and programming is
required individually on all the DVRs as
well as with the management system,
which can add time to the configuration.
Single configuration changes cannot be
made by the management system, thus
requiring the user to log on to the DVR
and program locally.
• Video is stored on the DVR, and while
it can be viewed on the management
system, permanent archiving has to be
performed at the DVR directly.
• The security management system and
the DVR connect via a protocol called
an application programming interface.
The interconnection is limited by the
functionality the DVR manufacturer
provides. Often, manufacturers will not
expose all of the functionality through
the API to protect their intellectual
property or to keep their own software
solution’s advantage.
• Because the security management system
and the DVR are provided by different
manufacturers, keeping the products
compatible through future
upgrades and service packs might be
difficult. There is no guarantee that later
releases will be backward compatible.
• The system setup is generally static: the
DVR is set to a fixed frame rate, resolution
and record period prior to any reference
to the pictures being viewed.
This can lead to a compromise on the
retention period of recordings or an
increased cost of hardware to achieve
the storage required.
Common Ground
Select a video management system platform
that supports DVR integration from a
variety of manufacturers while supporting
IP cameras and edge encoders. By supporting
the whole spectrum of CCTV products,
the digital video management system can
incorporate the advantages of all systems and avoid the disadvantages.
“Superior video management systems
support the use of IP/network cameras,”
said Bob Sawyer, president of AMAG
Technology. “Additional camera support
will continue to be offered as technology
changes, taking advantage of new technologies
as they are introduced.”
There is no single point of failure—as
each camera is a separate intelligent entity,
there is no one place that can fail and bring
the system down. Redundancy or fault tolerance
can be built into the management
system, ensuring high reliability.
IP Design Disadvantages
When designing a system that uses IP cameras,
remember to take the following
advantages into consideration:
• Many new construction projects include
structured network cable throughout the
buildings, making deployment of
IP/network cameras a relatively trivial
matter. Additional cameras, temporary
solutions or single cameras in a location
easily can be implemented with minimal
installation.
• Improved image performance—As
there is no conversion of the video into
an analog signal prior to the MPEG-4
compression, the IP cameras generally
provide superior image quality.
Advanced features such as integrated
alarms, audio and motion detection now
are being built into the camera and
transmitted via IP over the network.
• Network PTZ cameras can be controlled
via the network without additional
cabling. A fixed camera easily can be
replaced by a PTZ model. No extra
cables have to be run for PTZ controls.
• PoE availability means a power cable
may not be needed. If the network supports
PoE, the camera can be powered
by the Ethernet connection, meaning
only one cable is needed for the entire
functionality of the device.
• Plug and play—IP cameras use a protocol
called UPnP, which detects the camera
when it is on a network. To set up
the camera, all the user has to do is plug
it into a network and use a PC to detect
and configure it. Bringing the camera
into a video management system
requires a modest amount of configuration,
but there is no need to perform the
configuration in two locations as is
done with DVRs.
• Less cost—While IP/network cameras
initially may seem more expensive,
prices will come down as they generally
do with all technology products.
When taking cabling costs into account,
there may be a price advantage to
installing IP cameras on a network with
the additional advantage of reduced
installation labor costs.
• Network cameras have built-in
browsers, allowing occasional users to
connect from anywhere on the network.
Network cameras generally support
firmware uploads, making functionality
improvements possible without equipment
redundancy.
• Tight integration with a security management
system means the whole power
and flexibility of the security system
can be applied to system design without
giving up on functionality.
IP Design Disadvantages
As with DVR systems, IP solutions also
feature their share of shortcomings to
consider:
• Network cameras use large amounts of
network bandwidth if not correctly configured.
Understanding the customer
requirements and bandwidth availability
is crucial to successful system implementation. However, this disadvantage
easily can be rectified by using a video
server that provides the ability to buffer
video at the edge of the network and
intelligently control bandwidth use.
• Without a video management system
supporting the network cameras, only
live
video may be viewed. A good video
system supplements the solution by
providing a means of storing video and
providing video replay.
• The system designer is forced to use the
camera manufacturers supported by the
software. NTSC and PAL present standards
that system designers can use to
provide universal support for analog
cameras. Presently, all network cameras
use different protocols, limiting the
ability to support large numbers of cameras
from different manufacturers in the
video management solution.
• Successful installation requires an
understanding of network technology
that is not common in the security
industry today.
Select a video management platform
that supports IP camera integration from a
number of product manufacturers and provides
the additional components to complement
the basic IP camera functionality,
such as storing and archiving video
deemed of value. The ability to tag, replay
and export video files from IP cameras is
missing from the basic solution.
Furthermore, introduction of video analytics
can offload the requirement to stream
video over the network. A video analytics
engine can determine when there is an
alarm in the video stream and send a message
to the security management system.
Deeply integrated solutions that encompass
digital video, video intelligence (analytics)
and video management, as well as
security management, resolve the shortcomings
of a single-product solution.
On the Edge
One of the disadvantages of the network
camera is that it requires new investment in
camera technology. Video servers, sometimes
called encoders, were introduced as a
way to make use of an existing analog
camera investment, and to provide support
for special-purpose cameras that are not
available in network camera versions—
extreme low light, thermal imaging, license
plate readers, extreme high zoom, highspeed
PTZ or explosion-proof housings.
These servers are boxes that take the analog
signal from a traditional CCTV camera
and transform—or encode—the signal so it
can be connected to a computer network.
A video server that sits on the edge is a
departure from the existing solution in a
number of important ways, such as onboard
storage. This enables many interesting
features, including store and forward
capability that allows video to be stored at
the edge of the network to not burden the
LAN with video traffic. The stored video
then can be forwarded to long-term storage
at times of low bandwidth use, at night or
on weekends.
Next, a video server on the edge of the
network provides a DSP-based solution to video compression. Since the algorithms
are in the software, they can be
updated and features can be enhanced.
DSP technology will follow general technology
trends, providing better performance
at lower cost over time. An application-
specific integrated circuit solution is
constrained to basic functionality that is
fixed in time, and dual processor solutions
are expensive. A video server that
sits on the edge is designed with future
capabilities in mind. Bidirectional audio
and compact flash interfaces are supported
in the hardware and can be implemented
in future versions of the device to provide
even more capability than is available
today.
When selecting a video server, choose
a company that has complete control of
the product development, functionality
and feature set. This gives the most flexibility
in designing and engineering solutions
for customers. Parameters of the
MPEG-4 compression are exposed to the
advanced user, for example, allowing the
system to be highly customized for different
networking conditions.
The Optimal Solution
There are advantages and disadvantages
to many of these components. How are
video system designers to choose? The
answer is, they don’t have to choose.
Modern video management systems support
multifunctional solutions in which
the entire spectrum of products—from
analog CCTV camera switcher matrix
systems to NVR/DVR systems to IP network
cameras—is supported.
This is the optimal solution because it
allows all of these components to be fully
integrated into a seamless package on the
network. Such systems integrate with
DVRs, IP cameras and video encoders,
including edge of network video servers,
to provide support for existing analog
infrastructure. Transitioning to digital
through a video server while supporting
legacy LAN architectures and adding IP
cameras allows users a scalable solution
both now and into the future. Cameras
can be brought into the system from disparate
sources, and live video can be displayed
simultaneously from all sources
side-by-side with stored video from various
sources, all while still making user
viewing easy.
Furthermore, such video management
system architecture is scalable. As the
number of cameras grows—from any or
all sources—the system remains stable.
Storage capacity can grow by simply
adding off-the-shelf computer technology.
The architecture is distributed to not
only allow this scalability but also to
provide support over the WAN—video
can be stored at the remote location and
transferred on-demand or on a schedule.
The system offers the ultimate in design
flexibility.
Finally, the video management system
must be deeply integrated into the
security management platform. Thus
video management becomes a seamless,
integral part of the alarm management,
identity management, and reporting and
review system.