digital video recorder that will work best for your application
will depend on 4 factors: the number of cameras that you will
have, the frames per second that you need, whether you want
a card, stand-alone or embedded system, and if you want remote
Number of cameras:
Be sure to purchase a DVR that supports the number of cameras
that you need now as well as what you may need in the future.
Frames Per Second (fps):
Calculate your fps per camera by taking the total fps of the
system and dividing it by the number of cameras that you have.
For example, a 4 camera system with 30 fps would give you
about 7 fps per camera. A low fps per camera (3 fps per camera)
is adequate for most security needs. If your application involves
money counting, as in casinos or bank telling, then you will
want to purchase the highest fps available.
Card, Stand-alone or
Card systems are good if you have a spare computer with the
compatible parts and operating system and the expertise and
time to build it, you can save yourself some money using this
do-it-yourself approach. Pre-built PC-based (standalone) systems
allow the convenience of just plugging in the cameras and
knowing that all of the hardware and software is compatible
and pre-tested. Embedded systems are convenient like the PC-based
systems. They are designed specifically for the DVR and so
remove the risk of operating system errors and lockups. However,
the embedded systems do not allow remote viewing and they
are only currently available in 30 fps.
You can view your cameras remotely either by connecting directly
to the system using a modem, or through the internet, or through
your companys network. The remote viewing feature is
not available in the embedded systems.