IP systems.
The advent of the era of IP technologies is an indisputable fact, no one is trying to argue with this anymore. It should be recognized, however, that the massive demand for IP cameras is by no means evidence of the readiness of all manufacturers to saturate the CCTV market with products.
IP camera is a fairly broad concept. For many, an IP camera is a device that creates a digital video image and transmits it over an IP network for playback on a computer. Such a device often has only a purely external resemblance to equipment designed for professional CCTV systems, since the quality of the video module used leaves much to be desired.
In addition, IP cameras used in CCTV have a more complex encoder capable of generating multiple IP streams, supporting various network protocols that may be in demand when building large systems.
Simple IP cameras from the lower and middle price ranges are more in demand on the market. A completely natural stage in the development of IP video surveillance. Many probably remember how much demand there was 5-7 years ago for cheap, simple products from Asian manufacturers. However, today the trend is already quite clear: from the simplest IP entry points to IP systems.
Let's explain our idea.
Quite a few companies produce quite good IP cameras. They can be used to monitor various objects. But the camera itself is not a system, but only a part of it. A very important one, perhaps the main one in terms of receiving the original video information, but still a part.
As a rule, the manufacturer, creating a camera that generates and broadcasts a video stream to the network, presents the characteristics of this stream to the consumer. But in order to reproduce this stream, and even more so to record it, it is necessary to write quite complex software. In the West, this is done by independent integrator companies that produce literally universal software shells that can work with IP devices from different manufacturers. That is, the installer has the right to choose when purchasing equipment and software. It would seem that everything is simple. But often the specifications of the software manufacturer do not even mention such fundamental characteristics as resolution and recording speed, the number of simultaneously controlled video streams (IP cameras) and the number of users who can simultaneously work in the system. This does not happen at all because the manufacturer of the program is bad. It is just that the operation of the system depends on a number of factors. For example, on how correctly the network is built. After all, an IP network is a fairly complex system, and it often costs more than the video surveillance system itself. And the end result depends on how correctly the network is built, how correctly the installation is carried out, how correctly the software is used. So it is not at all necessary that you will get exactly the same stream during playback and recording, which the manufacturer of the IP camera mentioned in the specification for this device. Because he gave the values typical for connecting one camera to one computer. And this is not a deception. Agree, if the manufacturer of an analog TV camera states that it forms an image with a resolution of 560 television lines, this does not mean that when connecting the camera with a bad cable to a monitor at a distance of 500 meters, this image will retain its original resolution. Of course, a digital image cannot degrade because it is transmitted over a long distance over a digital network, but the network bandwidth may dictate more modest settings for the resolution and image transfer rate for your IP camera.
Such problems are largely inevitable if you build IP systems from elements produced by different manufacturers. It is no coincidence that leading companies strive to produce a functionally complete line of equipment and software needed to create an IP system. We are sure that this is the approach of the future.
The leading trend of the Western market of technical security equipment is complete solutions. We can be sure that in two or three years it will fully dominate in Russia. Therefore, from this point of view, today we should talk about video systems based on IP technologies.
Let's list the main components of the IP system.
- Sources of information: IP cameras or regular cameras connected to IP encoders.
- Network video recorders, which are usually separated from the workstation.
It is quite acceptable to use specialized DVRs in such systems, which have the ability to record both analog and digital video information streams and can be part of a single system.
- A workstation that is used to configure individual components of the system and to work with devices — visualization, programming, system management.
- Decoders and virtual matrices (switches), which are additional visualization devices for organizing monitoring centers.
- A server with administrative information, a single database and events of the entire system.
- The data transmission network itself, whose parameters and topology are calculated relative to the characteristics and topology of the system being created.
Let's say a little more about the components.
Any system starts with a device for receiving source information (video module or camera) and forming an IP stream of digital video (IP encoder).
In the vast majority of cases, video modules or cameras have the usual characteristics for CCTV. The higher they are, the closer this device is to a professional level. Obviously, it is useless to discuss the quality of an IP video system if the source of source information is bad.
The video stream obtained in this way must be digitized and compressed for subsequent transmission to the IP network. This is the function of the encoder. It can be implemented as a separate device installed in close proximity to the camera. It can also be built into the camera body.
The first approach gives greater freedom to the developer of the video surveillance system, since it allows choosing any camera from any manufacturer.
The advantage of the second approach is the compactness and completeness of the solution, allowing you to organize a single power supply, get rid of the use of additional connecting and mounting units, etc.
From our point of view, the distinction that currently exists is somewhat arbitrary, since an encoder (encoding network device) with an analog TV camera and an IP camera are essentially one device from the point of view of building an IP system.
The trend in modern IP camera production is to combine a video module and an encoder in one housing. We will allow ourselves to suggest that this trend will partly continue in the future. Separate IP encoders will be used in the construction of complex video surveillance systems for perimeter protection in severe weather conditions or at industrial facilities.
When discussing the issue of building large and complex video surveillance systems using IP networks, it is necessary to say a few words about the use of traditional digital recorders.
Until recently, there was a tendency on the market to build distributed systems based on DVR, connecting these devices over a network. The disadvantage of this approach is obvious. The system installer must constantly solve the issues of transmitting analog video over long distances, since it is not always possible to install a camera close to the recorder.
Currently, some installers seek to completely eliminate DVR, using only IP cameras when building distributed systems based on IP networks. This is not always justified both in terms of the cost of the system and in terms of its simplicity. If we have some relatively isolated object that allows for the installation of a local recording server, then in this case it makes sense to use a standard solution: analog video cameras connected to a DVR. In this case, it is necessary for the DVR to be part of a single surveillance system built on IP cameras.
The following components of the system are visualization devices — workstations, virtual matrices (switches), IP decoders. An IP decoder is a device for converting an IP stream into an analog video signal.
If we are talking about simple surveillance systems for small objects, then several IP cameras and a workstation — a computer with visualization and recording software — are enough. If we are talking about a professional video surveillance system, which involves the presence of several surveillance centers, a device is needed that takes a stream from the network and outputs it to an analog monitor.
What is a decoder for? The simplest example: you install a computer — a workstation, display 16 cameras on the screen. The ability to create an additional screen and connect a monitor depends not even on the capabilities of your computer's video card and IP system software, but on the bandwidth of the network segment to which the workstation is connected and on the computing power of the computer. So, if there are more than 100 cameras in the system, it is necessary to install several workstations, which will be difficult for one operator to manage. Of course, the operator will not be able to effectively monitor the object, looking at a large number of microscopic windows. The operator often needs a certain logic for displaying images. Some cameras should be displayed constantly, some on alarm, some the operator will display on the screen independently and view the details of what is happening. That is, we are talking about a multi-screen, not a multi-window display mode. In an IP system that has only a computer workstation accessing an IP encoder or an IP camera, the number of monitors is limited. The idea of creating a decoder that receives an IP stream from the network as input and an analog signal as output is inspired by the experience of using traditional analog video switches. The decoder converts the digital stream into a traditional CCTV composite signal, or a VGA signal for connecting to monitors. This device itself is not tied to a specific source of information. The decoder can be “connected” to a specific encoder or IP camera, which will send IP packets containing video information to it, and the decoder will convert them into an analog signal.
We will talk about other components of IP systems in the next issue.