Choosing Analog Or IP Camera Systems For Video Surveillance (CCTV)
The discussion among security and surveillance video manufacturers, systems integrators, and end-users about the relative advantages and indications for different kinds of video installations is easy to oversimplify. Simplification aids end-user decision-making and furthers the business interests of equipment manufacturers and systems integrators. Industry writers also have good incentive to simplify information. The many motives include making a larger point, supporting a specific-case argument, and getting and keeping readers’ attention.
Simplification most often leads to statements like “IP video is more expensive than analog video,” which are true with so many exceptions that they are not actually true at all – studies sponsored by interested parties have shown the opposite to be true, and editors and bloggers have covered the studies’ findings widely. In fact, oversimplification often leads to an assertion and its opposite both being true.
In this paper we provide as simple as possible an explanation of the factors which indicate analog, IP, and hybrid IP/analog video systems respectively. This paper seeks to provide a reference for editors, end-users, and integrators who may need to evaluate a specific case or understand the general principles.
Ability to use an existing IT network – In some cases, digital video video systems with IP cameras can be plugged into the existing IP infrastructure. And other times the cost for the upgrade to the network to make it viable for video is easily managed. A user with an existing Ethernet network which is able to handle large amounts of data, who just needs a few cameras or plans to record low frame rates or low resolution, is a good case for a pure IP system. Recording at the “edge” of the network with only occasional requests for video over the main network may also provide a way to implement IP video on existing infrastructure.
Ability to move and add cameras easily – Users with fluctuating camera counts and locations can avoid the need to power down recording servers to add, move, or remove cameras. This means seamless, pain-free recording from existing cameras, rather than scheduled downtime with alternate-server recording or missed recording.
Ability to use facial recognition analytics – Facial recognition software depends on high-resolution images to be effective. Any camera being filtered for facial recognition should have more than the 704×576 pixels (PAL) or 720 x 480 pixels (NTSC) provided by an analog camera.
Need for video transmission over wide geographical range – Putting video on the IT network makes it possible to use switches, hubs, and routers to expand the network to a broader range. Analog cameras have significant transmission limits over wide surveillance areas, and they are not appropriate for some wide-area installations due to their need to be physically cabled to a DVR.
Need for camera-level redundant recording – Some IP cameras can provide redundancy by recording onto built-in memory cards.
Analog can meet user’s recording needs for a lower cost – There are many lower-end, low resolution IP cameras that are low in cost. But high-end IP and megapixel cameras are very expensive, and the disk capacity required to store the higher volume of video data is a very significant increased expense. Across a network array of hundreds or thousands of cameras this cost can be prohibitive. A large network of IP cameras will usually require the installation of a separate network so traffic doesn’t exceed bandwidth. An installation of just 40 cameras of 1000 Kbps-1 Mbps each will overtax many existing corporate networks. Many high-end analog cameras, though limited in resolution to 704×576 pixels (PAL) or 720 x 480 pixels (NTSC), use image processing, automatic back focus and imager sensitivity to produce images that are superior in quality and clarity to a similarly or higher-priced IP camera.
Network traffic exceeds the user’s existing capacity – IP camera recording and viewing will increase network traffic, especially with lots of IP cameras or with or megapixel cameras. If recording will exceed the existing network capacity, a user will need to add the costs of installing an additional network for the video to the operational and equipment costs of pure IP when comparing it to analog and analog-IP hybrid options.
Need for minimum latency – Latency is defined as the time it takes for an image captured at a camera source to be presented to a system user. Every camera has latency to a degree, because the data travels from one location to another. It is much greater for IP systems, however, because their signals need to be encoded at the source and then must travel through the network to the decoder in order to be presented to the user. Because analog signals are point-to-point (camera-to-monitor), they don’t have the additional latency caused by network routing and the encoding and the decoding process. Because of this they are typically preferred in industries such as gaming and corrections.
Wider camera variety and choice – There are a large variety of Analog cameras (for instance, mini covert cameras and pan-tilt-zoom cameras in various sizes and shapes) to choose from. With IP cameras, not every vendor has many varieties and not every vendor’s surveillance software supports others’ cameras. In many organizations, physical security staff takes care of the surveillance system administration as well as the overall security plan design and implementation, and there are no existing IT needs that require IT professionals.
Indications for choosing a hybrid IP/analog system
Ability to add IP camera recording to existing investments in analog – Where there is existing analog infrastructure, the hybrid approach allows the user to avoid expensive replacement of their existing analog cameras and wiring. Instead, the user can add IP cameras to their surveillance resources and record from both analog and IP cameras in the same DVR.
Minimal retraining expenses – Surveillance operators familiar with an existing analog-system user interface will be able to manage new IP cameras without disruptive and expensive retraining. Using hybrid DVR/NVR recording allows integration of IP cameras with little change to the end user’s normal routine.