What features should I look for in a CCTV DVR?
All DVRs are
definitely not made equal! 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), hard drive space, network connection / remote viewing
capability, motion detection, scheduling, and ability to burn video and audio to
You need to be especially careful when purchasing embedded DVRs. Some do not
have even basic features such as remote viewing and CD burning and some have
very little hard drive space. At Discount Security Cameras we only offer DVRs
that meet these basic requirements.
The security digital video recorder that will work best for your application
will depend on several factors including the number of cameras that you will
have and the frames per second that you need. When determining the number of
camera inputs, it is important to consider future needs as well as current
The frames per second (fps) relates to how many pictures it 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. Real time recording is 30fps. 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 invest in
real time recording. If not, then a lessor recording speed should suffice. You
can still see a clear picture even though it will have a little hesitation or
jerkiness on playback.
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. The general rule of thumb is that each camera will use about 2
to 3 gigabytes (gigs) of hard drive space a day. Real Time and Embedded DVRs
tend to use about twice as much as that per day. So, for example a PC-Based 4
camera 60fps system with 120 gigs of hard drive space will use about 8 to 12 gig
total per day, giving you from 10 to 15 days of recordings before it needs to
start writing over the old video. Some embedded DVRs that our competitors offer
only have 80 gigs of hard drive space - this is only going to let you store a
few days of video.
Some features are going to affect the amount of hard drive space used. One
important feature is scheduling. There may be certain cameras that you only want
to record during working or daylight hours, the scheduling feature is what you
need to set this up. Another very important feature is motion detection. If you
can set up your recorder to only record when motion is detected this will
significantly extend your recording life.
Having a CD burner built into the machine is a very important feature because if
a problem is detected you need to be able to save it on a CD (typically in AVI
format) for others to be able to see it. If there is no CD burner on the machine
then make sure you have network ability so you can connect to it from another
machine so you can burn video that way.
Other features you should look for are the ability to view the cameras remotely
(more on this below), easy and comprehensive search capabilities (check out our
'Smart Search' technology), and audio support. The user interface should be easy
to operate. All of our PC-based systems come standard with these options.
What is the difference between a PC-based DVR
and an Embedded DVR?
A PC-based digital video recorder is basically a
personal computer that has been modified with hardware and software to work as a
DVR. An embedded digital video recorder is a machine that has been manufactured
specifically to work as a DVR. In embedded DVRs there is typically one circuit
board with simple software burned into the chip. There are advantages and
disadvantages to each type of DVR.
The advantages of an embedded digital video recorder is that they are extremely
stable and reliable since they contain fewer parts. The software is often
written in basic machine code or Linux code which tends to be more stable than
Windows software. Also the picture that you get on the monitor usually looks
better (especially when viewed full screen) than PC-based DVRs because there is
less compression. The disadvantages are that they have less options. Most do not
have remote viewing capability (ours do). They generally have slower recording
rates (we have some of the fastest available). Sometimes embedded DVRS do not
have a CD burner (ours do) so the only way to get video out of the machine is to
copy it via the LAN (if it has the connectivity) to another computer or to hook
up a VCR to it. Since they generally have less compression they use more hard
drive space so you can fit fewer days of recorded video on it. And you do not
have as many options to upgrade the hard drive space as the PC-based systems
(some do not allow you to upgrade the hard drive space at all).
The advantages of the PC-based digital video recorders is that you have many
more features and options available on the units. For example, some of the
options you get on the PC based machines that you don't get on the embedded is
Smart Search (see below), and the ability to set many options like motion
detection, pre and post recording frames, and compression options on a per
camera basis. You can completely control the PC-based DVR remotely via the
supplied software. The software is easily upgradeable when new enhancements are
made (upgrades are available on our web site for free). You interact with the
software via keyboard and mouse so its much easier to use (with the embedded
systems you set them up with buttons like a VCR). A CD Rom burner is included so
storing video off of the unit is easy. Compression is usually better so it uses
less hard drive space and you can customize how much hard drive space you want
on the unit.
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. Digital
compression results in a much better picture than analog compression and its
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
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. The DVR is setup using the intuitive
software that comes with the system.
What comes with the DVR?
Our PC-based DVRs come standard with an 120 gig
hard drive (except for the 32 channel system which comes with a 250 gig hard
drive). They also include the software (for setup, local, and remote viewing),
power cord, keyboard, mouse, and documentation. You just need to add the
cameras, whatever cable you need, and a standard computer monitor. Also, we have
full time on-site technical support available at no additional cost.
Why doesn't the computer monitor come with the
Digital Video Recorder?
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
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).
What is 'Smart Search'?
Our PC-based DVRs come standard with smart search
capability. This allows you to highlight one area of a captured image and look
for changes just to that area. For example, if an item is stolen off of a
counter... you can go to a moment in the video where the item is still on the
counter, then highlight the area around the item and search automatically
through the video for the moment in time when that particular area changes, that
is precisely when the item is removed and then view that part of the video.
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. One reason is because the pre-built
systems have more features and options than the cards that you can buy and
install 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.
How much hard drive space will I need?
There are many variables that factor into how
much hard drive space is used. The general rule of thumb is that each camera
will use about 2 gig of space per day. So for example, if you have an 8 camera
DVR you will use in the area of 16 gigs of hard drive space per day. If you are
using motion detection the hard drive usage will likely be less (especially if
there is little movement on each camera). The actual amount of hard drive space
used varies widely and depends to a large extent on how much movement there is
on the cameras. For example, a fast food restaurant (with a lot of activity)
will use a lot more hard drive space per day than an office with a few
employees. This is due to the way that the video is compressed for storage.
As mentioned above, the embedded DVRs use much more hard drive space than the
PC-based units, perhaps twice as much per camera, but again it varies from site
to site. Also, on some of the embedded DVRs you can reduce the recording frame
rate which will reduce the amount of hard drive space used (as well as the
quality of the video).
When the hard drive space is filled up, it will start over-writing the oldest
pre-recorded video. Each of our PC-based DVRs comes standard with a read/write
CDRom for saving video permanently.