Do not lightly dismiss a consideration of whether your Video Surveillance system should be designed as either an IP-based or an Analog System. The determination of how the video signals sent from the cameras will be delivered to the viewer, whether observed in real-time or sent to a recorder for later review, is second only in importance to the specific purpose of each component in a surveillance system and how it relates to the overall goal.
Since the inception of television, Analog signals have been used to send video images to monitors, and eventually to video recorders. Such is also the case with video surveillance, its roots being a low cost version of the components used in TV.
Today, there are very few true Analog systems available. What is today meant by Analog Systems is rather that the camera captures the image and sends the video signal in a format that can be seen on an Analog television. That is where it ends. For recording, the signal is converted away from analog, either to a digital video signal (to be recorded on a Digital Video Recorder) or to an IP signal (to be recoreded on a Network Video Recorder).
Since it is an older tecnology, why is it still used? Primarily because Analog cameras are less costly than IP cameras. There are hundreds of brands competing for this business, thus driving cost down. And, in fact, analog cameras are more than adequate in certain environments, for example a small viewing area. There is also greater flexibility for the system designer with analog, since there are so many models to choose from and they all speak the "same language" as it were, being based on a signal that has been a standard for many years.
Some disadvantages to Analog cameras come with regard to certain features, such as digital zoom, which is greatly enhanced in IP cameras. Distance is an issue with Analog, and interference a concern. Signals may need to be processed and boosted along the way to keep integrity. And scalability, the ability to add more cameras to a system, is much more difficult with analog.
While a Video Surveillance system cannot reasonably be analog end-to-end, an IP System can be. This means that each camera gets an IP address on a network, which can then be accessed easily for image viewing, system set-up and maintenance. Adding cameras is as easy as installing a hub or router and assigning new addresses, thus making the system virtually infinitely scalable. Also the Recorder is IP technology.
The first advantage is that IP Cameras can utilize much greater resolution image pick-up devices. What may have taken 10, 20 or even 50 cameras with an Analog system can possibly now be accomplished with one camera. (See our Recorder page to learn of some additional advantages in the playback of images.)
Another advantages is that IP signals can be encrypted - keeping others from tapping in. Also, depending on the configuration of your network, IP systems can be run on existing cabling, possibly saving installation costs. However, higher resolution IP cameras do use substantial bandwidth, so be sure to consult with a systems designer to see if this is possible in your case.
Some disadvantages of IP include the recording formats. Unlike the single analog signal, there are a number of different standards being used - MPEG-4, MJPEG, H.264, and JPEG-2000. This limits your flexibility when adding components from other manufacturers. This limitation, along with the higher resolution video capabilities of the technology, tend to make IP cameras more costly. In fact, there are still no IP cameras that can match analog on a cost basis when it comes to effectively viewing a small area. However, when larger areas need to be viewed, a single IP camera replacing 10 or more analog cameras cuts down substantially on installation and operating cost.
In reality, unless the installation is quite small with little or no chance of ever expanding, or the area to be viewed are strictly composed of larger, open spaces, today's systems are usually a hybrid of the two, IP cameras and Network Recorders being combined with Analog cameras converted to IP for smaller viewing zones.