DVRs, or DVRs, have firmly entered into modern life. What it is? A digital video recorder is a device that records and processes any type of video signal that comes from connected cameras. At the same time, recording is performed (if any) on the hard drive. At the same time, the image is output to a monitor or a remote device (via a local network to a backup monitor or to a mobile gadget if there is an Internet connection). This is the basic principle of the DVR.
What is this in practice? The DVR is a device whose architecture is closed. Thus, protection against possible external influences is provided, and durability is guaranteed.
To get started, you need to install the hard drive inside the device according to the instructions, and then connect through the available channels of the cameras with the basic settings of the DVR.
What is the difference between different DVRs?
What are these devices, and what are their characteristics? DVRs differ in a number of parameters that determine their power and purpose.
The number of video channels. At the rear of the recorder there are connectors to which you can connect video cameras via wires. Delivery options come in 4 types: to 8, 9 or 16 channels, depending on the DVR-recorder.
The number of channels is one of the main parameters. The larger their number, the larger the video surveillance network can be built without additional equipment and expenses.
At the same time, 4-channel DVRs are convenient to use for small networks (including home or in the store). 8-channel devices can already serve in cafes, restaurants, around the perimeter of a large house or in a production workshop. 16-channel can be used at larger facilities. In particular, it is possible to organize video surveillance on their basis in garage areas, supermarkets, on production sites or at a industrial base. For this, they often use Full HD DVR.
Write speed. The same important parameter. Image quality depends on it. Best if the video signal is recorded at a speed of 25 frames per second. In this case, all movements on the monitor when viewing will be smooth, and also nothing important will slip away at some point. However, most of the DVRs available on the market, in order to reduce the cost, can record 3-6 frames per second (these are the most low-cost Xiaomi DVR models). Which is quite enough to observe the situation.
Resolution of the video image. The parameter will affect how clear the picture will be. And with what maximum magnification after it will be possible to consider individual objects in frames.
There are several options for recording resolution: 720x576, 720x288, 360x288 pixels. A higher resolution automatically reduces the recording speed, especially if there are a large number of channels - due to the limitations that the architecture of the hard disk itself imposes as an array of data.
For example, the DVR MDR-8700 at a resolution of 720x576 can record 50 frames per second (6 per channel), at 720x288 the number of frames is already 100 (12.5 per channel), at 360x288 = 200. However, choose between quality and the recording speed is necessary for each separately, depending on the conditions and requirements. For example, the expensive Full HD DVR is unlikely to be needed for a small room.
Networking
Most registrars have the ability to connect over the network to configure access to third-party backup monitors through it (for example, not only at the security post, but also in the manager’s office or on his mobile device). Such an opportunity is very important for the person who wants to always be aware of what exactly is happening with the business object.
What is the principle of operation of the DVR? Instructions to it can be presented as follows. The DVR records data from the cameras on the installed hard drive. Accordingly, with an increase in the number of incoming signals from video cameras, the required hard disk capacity also increases significantly. So, the maximum number of channels that a DVR can support is 32 (DVRs with 16 channels are usually common). For a larger number, you will need to install several devices at the same time, or configure on the basis of a personal computer.
The DVR broadcasts the signal directly to the monitor, while the video image is being recorded in parallel. This allows the operator to simultaneously observe the current situation in order to respond on time. DVRs provide several options for watching videos at once. Among them, you can connect everything at once (or multi-screen). Modes are 2x3, 3x3, 4x4, as well as much more complex, like 1x5, when one screen is preferred, and the rest are located on the sides and bottom. You can also turn on one camera, scrolling the entire list one by one. Any screen in multi-mode can also be enlarged to large if necessary.
Each DVR has a set of multi-screens. However, this is not the main characteristic of high-quality DVR equipment. What does it mean? Much more attention should be paid to the following parameters of the DVR.
Observation frame rate
The DVR recorder relays the entire picture from the cameras in real time. Thanks to this, an excellent image is achieved, the picture in which changes at a frequency of 25 frames per second. It is to this frequency that the eye is accustomed to in connection with the operation of television equipment on it. This is how most of the common DVR brands work - Blackbox, Xiaomi, and so on. This allows the operator to timely consider any alarming situations and immediately give a signal, if necessary.
The number of frames in the record
However, at the same speed as when viewing, not all DVRs can record. There are those that can save all 25 frames per second. They stand out at a higher cost, sometimes noticeably more expensive. Most DVRs (Vehicle Blackbox, for example) can record perfectly at 3-8 frames per second, which is enough to detect important details. In this case, it will be possible to view frame-by-frame 3-8 freeze frames. This characteristic is most often referred to as the “cumulative recording frame rate”.
Video resolution
This parameter is indicated by two digits separated by a multiplication sign (720x480). The first digit is the number of horizontal dots at each point in time in the picture, the second is vertical. In most cases, the figure is not always correctly indicated correctly. Often, manufacturers can overestimate it to make their products more attractive on the market.
It is also worth noting that the resolution itself cannot be an absolute indicator of a high-quality picture. Even with good resolution, such camcorders can be installed that they cannot transmit a clear image. Therefore, you should approach the selection of any equipment as a whole, building the same type of video surveillance system, without overpaying in some positions and saving on others.
Network operation of the DVR
Most DVRs have an Ethernet connection to configure remote access to data. For example, it can be data transfer to a backup monitor. It is also possible to connect via special software via the Internet from a mobile phone or tablet. At the same time, the video is not just duplicated, the second person can view all the data in parallel, including finding a video clip in memory that was recorded several days ago. Today, mass-produced DVR Vehicle models are common that give users this opportunity.
Motion Detector
Good video recorders have the ability to record when there is any movement in the picture. This can be either a predefined area (for example, in front of a door or window), or any in the picture. In the event that the movement of an object (or even a shadow from an object) is detected, the DVR starts recording at an increased speed, which allows a more detailed frame-by-frame analysis of everything that was happening at a given time. If there is no movement, then in this case the recording may either not be conducted at all, or it may be made at a low frame rate per second. Thanks to this mode, you can significantly save space on your hard drive and at the same time not miss out on anything important that attackers could create at the enterprise or indoors. An example of such equipment is the DVR Vehicle GT300 A8.
Shapes and sizes
A very important characteristic of DVRs, among others, is the form factor. In other words - the type, size, weight and some other characteristics. The installation method is closely related to it, especially in a car. For obvious reasons, it is on this that convenience of use, as well as security, largely depend on how much the device will block the view.
You should also notice how much the registrar will stand out in an empty car. The low visibility of the device will not attract small thieves, nor will it attract the attention of unauthorized persons, who may seem safe to take any actions near the car. In this regard, DVR mirrors are very popular.
For many, an important condition is the ease of dismantling the DVR. This may be necessary either while driving to capture any important point that initially does not get into the review or when recording communication during a stop with the traffic police inspector.
Which devices are most in demand?
According to numerous reviews, the most popular can be called car DVRs. This is due to the fact that they have a low cost, and at the same time are able to provide significant assistance to the car owner, especially in disputed situations.
In addition, such devices can not only help to prove their case to the traffic police, but also capture any attempts of other people's illegal behavior. So, an attempt to steal property from the car will be immediately captured on video. Some devices have a wide viewing angle and can capture everything that happens around the car.
How to choose this device for a car?
On all the above characteristics, it is worth focusing more directly when choosing a device in the store. You should initially make up some gradation for yourself by their importance, giving greater preference to that device, which, all other things being equal, will be either smaller or faster to assemble.
Almost all modern recorders (including the Blackbox DVR) have a conventional suction cup on the windshield as a mount. It allows you to maintain your qualities for a long time. At the same time, you can easily change the location of the recorder in case of need (as the whole structure, and dismantling without a fixing bracket, which increases the durability of fixing the main holder).
Another mounting option is double-sided tape. This is often found on DVR Mirror devices. Practice shows that in this case the fixation is much longer. However, before starting the installation, it is required to accurately and accurately make all measurements. True, in this case, it will not be possible to quickly remove the registrar. After which additional cleaning of the glass may still be required.
Some recorders may have two cameras at the same time. In this case, the dimensions of the device will be slightly larger. However, it will be possible to simultaneously record what is happening in the cabin. Often in this case, you can even see what is happening on the sides of the car or even behind it. However, the internal camcorder has slightly worse performance. In the event that you want to shoot from several positions at once, you can purchase and install a modular recorder, which includes up to 4 different cameras. In this case, the picture can be displayed on a specially installed rear-view mirror in its side panel.
Final word
User reviews say the following. The best option for choosing a device is when the seller of the device will help not only with a story about the main characteristics, but also with a preliminary installation. In this case, you can pre-evaluate the registrar for interference, stealth and recording quality in a particular vehicle. Do not forget that even in the same type of car the picture may differ due to various interference, even when using the ultra-compact DVR Car Mirror.
At the same time, when you try the DVR, you can evaluate how you are satisfied with its viewing angle. Most models have an angle of 40 ° to 150 °. The most popular and widespread due to the optimal price / quality ratio is 120 °. Indeed, in this case, a wide range will allow you to capture what is happening on the sides of the car.
At the same time, two DVRs with the same angle of 120 ° may differ in reality. Some manufacturers are cunning and indicate this angle, starting not from the width of the screen, but from the diagonal. However, often with a large shooting angle, what is happening on the sides can be recorded with great distortion, which also does not cause positive emotions.
All that will be taken into account when choosing a registrar will allow you to use it longer and with greater benefit. And to have an additional factor in their favor in the event of an accident.