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What features should I look for in a CCTV Digital Video Recorder (DVR)?
There are several factors that are critical to
consider when purchasing a DVR, especially when comparing price. The
most important factors to look at are the number of cameras
supported, frames per second (fps), compression technology, hard
drive space, network connection / remote viewing capability, motion
detection, scheduling, and ability to save video and audio to a CD
or flash drive. You should also look for easy and comprehensive
search capabilities and audio support. The setup and user
interface should be intuitive and easy to operate.
What is frames per second?
The frames per second (fps) relates to how many pictures
the DVR will record in a second. Real time recording is about
30 fps on each camera. To calculate the fps per camera take
the total fps in the system and divide it by the number of
video inputs. For example, a 60 fps digital video recorder
with 4 video inputs would result in about 15 fps per camera.
The technology has finally gotten to the point now where real
time recording is affordable. If you are recording cash
registers or something similar then you should definitely
invest in real time recording.
How many Frames Per Seconds will I see with an 8 Camera 120 FPS DVR (or any other DVR)?
There is no way to tell exactly how fast your
video will come across the Internet. The speed depends on your
connection to the Internet and the DVR's connection to the
internet as well. The same applies for a modem however the
speed of a modem is extremely slow and you will not be happy
with the performance over a modem connection.
How big a hard drive do I need?
The amount of hard drive space is very important
because it will limit how many days of recording you can store
before the system has to start recording over the oldest video. Each
DVR will have its storage capacity listed in the specifications. But
this calculation is just a rough estimate as there are many factors
that affect hard drive use. The most critical factor being the
compression format used by the DVR (for more info on compression
formats click here). But also the type of cameras that are connected
to the DVR make a difference (specifically the chip size and
resolution) and also the features that are selected on the DVR. If
you use the scheduling or motion detection features or tune down the
frame rate that will extend the storage capacity of the unit. Even
the field of view (what you are recording) will affect the storage
capacity - the more complex the image, the more hard drive space it
will take to capture the complexity.
How does a CCTV digital video recorder work?
A CCTV digital video recorder (or “DVR” for short) is essentially a computer that saves security video images to a hard drive.
Most security cameras in use today capture an analog picture. The DVR converts the analog signal to digital and then compresses it.
Many cameras can be connected to one DVR. DVRs
generally come with 4, 8, 16, or 32 camera inputs. The DVR will
allow you to view all of these images at once or one at a time, and
all of the video is saved to the hard drive. Additional switches,
quads, or multiplexors are not required.
Are security digital video recorders hard to install?
Not at all. You simply plug the cameras into the back
of the unit. For the PC-based: Plug in the power, monitor, keyboard
and mouse - just like a regular computer. You will receive
instructions on how to set up the machine with your shipment.
What comes with the DVR?
All of our DVRs come standard with an 250 gig hard drive.
They also include the software (for setup, local, and remote viewing), power cord, and documentation.
PC-based machines also come with the mouse and keyboard. You just need to add the cameras, whatever cable you need, and a monitor. For PC-based
machines you need a standard computer monitor. Also, we have on-site
technical support available at no additional cost.
Why doesn't the computer monitor come with the PC-based Digital Video Recorders?
We don't supply the computer monitor with the DVR
because frankly you can get one cheaper and easier locally. Large
computer stores such as Best Buy or CompUSA sell these monitors
practically at cost. And due to thier heavy weight, they are very
expensive to ship (and subject to damage). Also, we found that many
of our customers have spare computer monitors available.
How do I see pictures from a remote site?
You can view the camera video over the internet using
a modem which is slow but can display 1 or 2 frames every 5 seconds.
Better is a DSL or cable modem connection which can generally
display 1 frame per second. When viewing remotely, the refresh rate
is restricted by the communications medium (your internet connection
speed). When viewing or playing back locally, the display is
dependent of the unit's frame rate (fps). You will need a static ip
address available to assign to the DVR (more about this in your
documentation).
How many computers/people can I have connected to and viewing a DVR Remotely?
Up to 50 connections to the DVR can be made at a
single time. With a modem however there can be only 1 person
connected at one time due to phone line restrictions.
Should I purchase the card and software and
build my own digital video recorder or buy one
pre-built?
It is much better to
purchase a DVR system pre-built than to build one yourself.
There are many compatibility issues with DVR cards and related
software. They are very sensitive to the type of motherboard
in the computer, the cpu, the memory, even the video card
makes a difference! We had to test many different
configurations to find one that worked reliably. You also
don't want to be running any other software on the computer
that your DVR is running on so you need a dedicated computer
anyway. We have had so many customers call us that have had
problems installing cards in their own systems that we won't
even sell the cards separately anymore.
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