DVR or PC — how important is it?
DVR or PC — how important is it?
The more clearly the requirements for the future system are defined, the narrower the range of software and hardware components from which the platform components will have to be selected. However, in many cases it is necessary to choose not only the manufacturer and the specific product, but also the concept of building the system. Concepts between which it is often necessary to choose are ready-made DVRs and software-based solutions.
MAIN TYPES OF PLATFORMS
First of all, it is necessary to determine the features of ready-made hardware solutions in the form of a DVR (digital video recorder or simply a video recorder) and solutions based on specialized software installed on personal computers*. It should be noted that DVRs can also be based on a personal computer platform — such DVRs are called PC-based, or on a specialized hardware platform with a specialized operating system — such DVRs are called non-PC-based.
* This does not refer to a computer used at home or in an office, but to an architecture based on the use of Intel-compatible processors. The computer itself can be, and often is, specialized, created specifically for the deployment of video surveillance systems.
There is an accepted division of DVR into four classes — budget, average, professional and Hi-End. The simplest non-PC DVRs have a low cost and can perform basic functions, such as recording and playing video, recording by motion detector. Such video recorders can be equipped with a USB port for saving the archive to external media and have the ability to broadcast video over the network. In non-PC DVRs of higher classes, it is possible to combine several devices into a network using special software that allows you to remotely configure video recorders and view video simultaneously from several DVRs on a personal computer. There is a function of recording to external disk arrays or network data storage and a function of controlling PTZ cameras. Video recorders of professional and Hi-End classes have the ability to set reactions to alarm events — send e-mail, SMS or MMS, turn on the buzzer, perform an action on the output relay, display the image of the «alarm» channel on a separate monitor, etc. Video analytics functions in non-PC DVRs are usually limited to a motion detector, which is already present in economy-class models, but has a more advanced implementation in higher-class models. Almost all DVRs have the ability to record audio, many have alarm inputs and outputs. Hi-End DVRs allow you to record live video (25 fps) on all channels.
The differences between PC*based DVR and systems based on a personal computer with specialized software (we will call them video servers to distinguish them from video recorders) are more in the marketing part than in the technical part. After all, PC-based DVRs are actually the same computer and software, except in different packaging: such DVRs are positioned by the manufacturer as ready-made solutions, while computer systems can be created directly by the company installing the video surveillance system based on software from one manufacturer and hardware components from other manufacturers.
The capabilities of video servers and PC-based DVRs are close: both can form the basis of both small local and large distributed systems with the most complex functionality, including all the functionality of a non-PC DVR and even more. Both can have powerful video analytics, which is sometimes carried out in separate hardware modules. One of the fundamental differences between video surveillance software and DVRs is that DVRs designed to work with IP equipment** support either only IP* devices from the same manufacturer, or an additional small set of devices from other manufacturers. The situation promises to change with the widespread use of a single data transmission standard for IP video equipment — ONVIF, but this has not happened yet. At the same time, independent manufacturers of software for IP video surveillance systems strive to support IP devices from many vendors. Therefore, the need to use IP*cameras from different manufacturers at the facility is a sufficient argument for choosing a computer system.
** They are called NVR, network video recorder.
RELIABILITY
There is an opinion that ready-made video recorders of famous brands are more reliable than computer systems due to their industrial design. This is partly true — DVRs of leading manufacturers are indeed reliable. However, the unreliability of computers is a thing of the past: there are many components of various capabilities and prices on the market, which allow you to create both inexpensive solutions for home use and highly reliable devices for industrial use. The question here is rather the degree of trust in the manufacturer: a priori, a large well-known vendor producing DVRs deserves more trust than an installation company assembling video servers. But, firstly, both video servers and, for example, PC-based DVRs are assembled from the same components, in essence. Secondly, there are many companies that specialize in assembling highly reliable video servers. Thus, when choosing between a DVR-based system and a PC-based system with specialized software based on the reliability parameter, the question primarily comes down to choosing a trustworthy installer who will be engaged in its implementation and maintenance.
DOES SIZE MATTER?
One of the fundamental characteristics of a video surveillance system is its size, or more precisely, the number of video cameras. Is it possible to recommend one or another type of system based on this parameter? It is better to say that the choice of platform depends primarily on the required functionality of the system, and only then on the size.
Economy-class video recorders are good for facilities with a small number of video cameras — such that they can be connected to one DVR, if high recording speed and various complex functions are not required. Such DVRs allow you to quickly and cost-effectively deploy and configure a video surveillance system that performs the simplest functions. If advanced functionality is required with a small number of cameras, you can install either a higher-class non-PC DVR, or a computer system, or a PC-based DVR. If complex video analytics is required, you will have to choose between a PC-based DVR and a computer system. However, it should be noted that PC*based DVRs from well-known manufacturers are expensive, and video analytics modules can also be purchased for an additional fee. At the same time, leading Russian and foreign software manufacturers offer free versions of their products for creating small video surveillance systems.
If the facility is small but requires the installation of more than one video recorder, the choice of platform type and specific product depends entirely on the required functionality of the system — it can be both a DVR and a software platform. If both types of platforms meet the requirements of the facility, it is worth considering that the computer system provides the ability to update and expand functionality by updating the software — DVRs do not provide for this. Advantage
The advantage of a video recorder is (possibly) its lower cost and the fact that it is a ready-made solution that is easier to implement. There is an opinion that it is also easier to use, but this is not entirely true.
This opinion is that computer systems are overloaded with functions, and this makes them more difficult to configure and less reliable. This is partly true, because until recently, video surveillance software from independent manufacturers was indeed more complex than the software installed on the DVR. But recently, the trend of creating user-friendly products has been gaining momentum. In the field of video surveillance, this trend has been embodied in software products that, with rich functionality, are no more difficult to configure and use, and perhaps even easier, than a DVR. This is achieved through a well-thought-out interface, as well as simple and quick access to all the most frequently used functions. As for the reliability of the software, it is ensured by the manufacturer's extensive experience and confirmed by a large number of successful projects — the user just needs to choose a trustworthy software provider.
INTEGRATION
So, we have considered small and medium systems. Which platform is better to use on large objects? Again, the choice depends on functionality. And when it comes to large systems, in addition to the already mentioned functions, another important factor arises — integration. It is on large objects that integrated systems are most in demand, combining video surveillance with an access control system, security and fire alarms and other security systems. In this area, software-based systems are the undisputed leaders. DVRs, primarily PC-based, can be used in integrated systems for working with video, but the basis of such a system in any case is specialized software.
Integration with some types of equipment is also common in medium-scale systems, for example, this can be integration with cash registers or ATMs for video monitoring of transactions. Both software and DVRs have such capabilities. But we emphasize once again that the widest opportunities for creating distributed integrated security systems, supplemented by powerful video analysis functions, are provided by software platforms. In addition, some of these platforms support scripting languages that allow you to configure arbitrarily complex operating algorithms. Thus, software-based systems provide the greatest flexibility, which is especially in demand when creating complex systems.
VIDEO ANALYTICS
As already mentioned, video analysis functions are most developed in computer systems and PC-based DVRs from leading manufacturers, and in the latter, video analytics is often placed in separate plug-in hardware modules. It should be noted that video analytics is developing faster in software products, because only such products provide the ability to quickly and easily update the system by updating the software or installing an additional software module on an existing hardware platform.
In addition, new technologies traditionally first appear in software and then are implemented in DVR. This is due to the fact that a more flexible software development process allows various innovations to be tested on software systems. And only when these innovations have firmly taken their place in software, they begin to be implemented in DVR. One example of new technologies currently implemented in some software products is intelligent search in the video archive, which does not require preliminary configuration of video detectors and allows you to find video recordings in the archive based on the parameters specified by the user at the time of creating the search query.
RESULTS
The choice of platform type for each specific project is determined by many factors related specifically to this project. And of course, it is not only and not so much the type of platform that is important, but its implementation. However, the conclusions that will be made can become a guideline when choosing the type of system.
In small (up to 16 cameras) and simple projects, when only the most basic video recording functions are required, inexpensive DVRs can be a good choice — this will allow you to quickly and with minimal costs deploy a video surveillance system.
If the project is small, but requires more extensive functionality, you should pay attention to free offers from leading Russian and foreign manufacturers of software for security systems. You can also use a higher-class DVR, but in this case, the video analytics functions will be limited.
In medium-scale projects, both computer systems and video recorders can be used — it all depends on the specific functions that are needed, the cost of specific systems and the choice of a reliable installer who will implement and maintain the system.
If integration with specialized equipment is required, for example, with cash terminals, you can use both ready-made specialized solutions «in hardware» and software products, which can also provide functionality for creating a fully integrated complex system.
In large projects, if there is no need for integration, non*PC video recorders can be used. However, if integration of video with other security systems (OPS, ACS) or advanced functionality in the field of video analytics and complex algorithms is required, the choice should most likely be made in favor of software solutions that are leaders in this field.
It should be noted that if the system includes more than one device, no matter whether it is a video server or a video recorder, it will most likely use software for video monitoring and configuration of several devices over the network.
If the system uses IP cameras from different manufacturers, there is no full-fledged alternative to software-based solutions yet. With the widespread introduction of the standard protocol (ONVIF), the situation may change. And finally, software products provide the widest opportunities in the field of video analytics.
In conclusion, we emphasize once again that a good system can be created on the basis of various platforms. Answering the question posed in the title of the article, it can be said that the most important thing is not the type of platform, but the qualifications of the installer, who will be able to correctly assess the customer's requirements and offer the optimal system for this project from a trustworthy manufacturer.
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D. Shelestov
Commercial Director of ITV | AxxonSoft
magazine «Security Algorithm» №1, 2011