In the IP world, each network camera captures an analog image but immediately
converts it to digital inside the camera. Some digital processing can happen
right at the camera, such as compression and motion detection. The digital video
stream is then broadcast over the IP network using Ethernet (CAT5) cable. The
power supply may be plugged in at the camera or can be run over the ethernet
cable by using Power-Over-Ethernet (POE) adapters. The CAT5 cable for each
camera is plugged into a switch which feeds into the network hub. As with all
network devices, some set-up needs to be done for each network camera to set up
its IP address and other identifying attributes.
Software is required on each PC that you want to view the cameras or playback
video. Another high powered PC is set up with the appropriate software to record
the cameras. Since communication standards are not consistently followed in this
industry yet, the viewing and recording software must be purchased from the same
vendor that sells the IP cameras. This can make switching or mixing camera
vendors very expensive.
The IP camera signal is broadcast over the Internet in the same way that a
DVR signal is. However, each camera is a separate stream and has its own IP
address or port. This can greatly affect bandwidth as we'll see below. When
viewing remotely each camera can be pulled up individually by its IP address. If
you want to see all of the cameras side-by-side, additional software (again,
from the same camera vendor) must be installed.
Which approach is more cost-effective?
For now, installing analog cameras coupled with DVRs is the most
cost-effective approach for most security applications. Later on, a couple of
scenarios will be introduced whereby an IP-based solution might be less
A typical medium quality analog dome camera sells retail for about $100 to
$200. A similar quality IP camera sells for at least twice that amount. Analog
cameras are available with many different features: varifocal lenses, high
resolutions, and long distance infrared, for example. Finding just the right
combination of features in a network camera for your application might be
difficult and very expensive. Sometimes you may have to buy an analog camera and
add a separate video server to do the job. Single-channel network video servers
currently start at about $300 retail.
IP advocates will point out that a digital video recorder is not required in
an IP solution. That is true, but some device will still be needed to record the
camera images. Typically that requires a high-powered PC with considerable hard
drive space. Often, that will cost as much as or more than a DVR. Even more
significant is the price of the recording software which tends to be expensive.
Licenses are typically based on number of cameras, and per user.
IP advocates may also point out that businesses often have IP networks in
place and therefore no additional cabling or hardware is needed. However, each
camera requires a port to plug into the switch, so more or bigger switches may
need to be purchased. POE adapters might need to be added. If the existing
network will not handle the load of the additional network devices, upgrades
might need to be made, thereby making the installation more expensive.
Finally, bandwidth on the network needs to be considered. Video uses a lot of
bandwidth. The bandwidth used by each camera varies by many factors including
the resolution, the compression method, and even the amount of movement in the
field-of-view. As a general rule, a camera using full CIF (352 x 288)
resolution, 30 frames per second (30 fps), and MPEG4 compression will require
about 720K bits per second (720Kbps). Therefore, if we put 100 IP cameras on a
network, we would use about 72Mbps more bandwidth. This number will double if
audio is also transmitted. It should come as no surprise, then, that some
companies have gone so far as to create an entirely separate IP network just to
run their camera system.
To make bandwidth matters worse for IP - many of the newest IP cameras are
coming out with 'megapixel' resolution. This is wonderful from the standpoint of
how much clarity and field-of-view can be captured, but it comes at a huge price
to bandwidth. A single 2-megapixel IP camera, running 30 fps with MPEG4
compression will use a whopping 6.5Mbps of bandwidth. These high-resolution IP
cameras also require a great deal of hard drive space to store the video. The
2-megapixel camera described above would require approximately 67 Gigs of hard
drive space to record one day's worth of video.
It's worth noting that DVRs will also use bandwidth if viewed remotely over a
network. However, the DVR will only use bandwidth if people are currently
viewing the cameras. Otherwise, they will not. Furthermore, a DVR will combine
several camera images into one video stream vs. a separate video stream for each
camera, as in IP. For example, a typical 16 camera DVR will combine its camera
images and throttle its output to a maximum 360Kbps. To run 16 similar IP
cameras on a network would generate about 11Mbps
Which approach is better quality?
There are poor quality components and good quality components no matter which
type of system is used. That being said, network cameras do offer some
technological advances in the areas of video quality and wireless installations.
Analog cameras cannot provide resolution above TV standards, the maximum being
about 0.4 megapixel. Resolution of IP cameras can be many times higher
(currently up to 3 megapixel) and they can capture a clearer image when objects
are moving. This could make a difference in high risk applications such as for
casinos and law enforcement. Wireless communication over IP networks has fewer
problems with interference, and encryption security is built into the
Which approach is easier to install and configure?
If an IP network is already in place at the installation site, and it can
handle the additional load of the new cameras, then IP cameras will be easier to
install. If additional RJ-45 jacks are needed to plug in the network cameras,
then the installer only has to run a CAT-5 cable from the camera to the nearest
switch. An inexpensive switch can be installed right at the nearest wall jack.
In contrast, each cable for analog cameras must be run all the way back to the
DVR. If upgrades need to be made to an existing IP network to handle the
additional load, obviously the installation would be more difficult.
The power for the cameras can be handled fairly easily with either
technology. For IP networks, use Power-Over-Ethernet (POE) transmitters to send
the power through the existing CAT-5 cable. For analog systems, use RG59 Siamese
cable to combine the video and power cables into one jacket. Either way, there
is no additional cabling for power. POE can run 300 feet without a repeater.
RG59 can be run 1000 feet without a repeater.
Once the cabling is in place, configuring the system is less difficult for
analog systems. With analog, you plug the cameras into the DVR and you've got
video. For IP cameras, you have to assign each camera a network address and open
up ports on the router. It's easier to set up cameras for internet viewing using
a DVR because access is provided to all cameras at once by using one external IP
address to the DVR.
What about wireless?
Analog wireless systems do not work well. This is because the government
regulates on which frequencies analog wireless devices can run and how strong
the signal can be. Interference from other wireless devices such as cell phones
can cause the camera video to be distorted. Interference is especially
problematic in buildings with florescent lighting.
Digital IP wireless is much better. The digital transmission does not get
interference from other analog wireless devices, and the 802.11x communication
standard used has encryption built in. Consequently, there is no problem with
unauthorized access to the video.
For what applications should I consider IP?
IP cameras should be considered for large installation sites that already
have a high bandwidth network installed - especially if the cameras will be
spread out over a wide area, or if wireless cameras will be used.
For large installations with many cameras, some installers still prefer a
multiple DVR solution to an IP solution. Software is bundled with higher-end
DVRs that allows you to view and record cameras from multiple DVRs. Using analog
cameras and multiple DVRs can be less costly than purchasing many IP cameras
along with the required software licenses. The multiple DVR solution also
provides better failover protection. If the network goes down in an IP based
system, video is lost from all the cameras. If the network goes down in an
analog system, the DVRs are still recording the cameras. If one DVR has a
problem, only the recorded video from the cameras on that particular DVR is
lost. In contrast, if the recording PC goes down in an IP system, all video
recording is stopped.
An even better solution may be to use a hybrid solution which combines the
use of analog and IP technology. Check out
VR Series Enterprise Hybrid Solution here.