DVRs, or DVRs, have firmly entered 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. Recording is carried out (if available) on the hard disk. At the same time, the image is output to a monitor or a remote device (via a local network to a duplicate monitor or to a mobile gadget, if there is an Internet connection). This is the basic working principle of the DVR.
What is it like in practice? The video recorder is a device whose architecture is closed. In this way, protection from possible external influences is made, and the durability of the work is also guaranteed.
To get started, you need to install the hard drive inside the device according to the instructions, and then connect the video cameras via the available channels with the setup of the basic parameters of the DVR.
How are different DVRs different?
What are these devices and what are their characteristics? DVRs differ in a number of parameters that determine their power and purpose.
Number of video channels. At the back of the recorder there are connectors to which video cameras can be connected via wires. Delivery options are 4 types: to 8, 9 or 16 channels, depending on the DVR-recorder.
The number of channels is one of the main parameters. The greater 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 a 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 on larger objects. In particular, it is possible to organize video surveillance on their basis in garages, supermarkets, at production sites or at an industrial base. For this, Full HD DVR is more often used.
Write speed. The same important parameter. The quality of the image depends on it. It is best if the video signal is recorded at 25 frames per second. In this case, all movements on the monitor during viewing will be smooth, and nothing important will slip away at some point. However, most of the DVRs on the market, in order to reduce the cost, can record 3-6 frames per second (these are the most budget Xiaomi DVR models). Which is quite enough to observe the situation.
Video image resolution. The parameter will affect how clear the picture will be. And with what maximum magnification after it will be possible to consider individual objects on the frames.
There are several options for recording resolution: 720x576, 720x288, 360x288 pixels. Higher resolution automatically reduces the recording speed, especially when there are a large number of channels - due to the limitations imposed by the very architecture of the hard disk as a data array.
For example, DVR MDR-8700 at 720x576 resolution 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, it is necessary for everyone to choose between the quality and speed of recording, depending on the conditions and requirements. For example, an expensive Full HD DVR is unlikely to be needed for a small room.
Networking
Most registrars have the ability to connect over the network in order to configure access to third-party backup monitors through it (for example, not only at the guard 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 working principle of DVR? Instructions for it can be presented as follows. The video recorder records data from video cameras to the installed hard drive. Accordingly, with an increase in the number of incoming signals withvideo cameras, the required capacity of the hard disk also increases significantly. So, the maximum number of channels that a DVR can support is 32 (registrators with 16 channels are usually common). For more, either multiple devices installed at the same time, or a PC-based setup.
The video recorder broadcasts the signal directly to the monitor, while simultaneously recording a video image. This allows the operator to simultaneously observe the current situation in order to respond in time. DVRs provide several options for viewing video at once. Among them, you can connect all at once (or a multi-screen). Modes are 2x2, 3x3, 4x4, and also much more complex, like 1x5, when one screen is preferred, and the rest are located on the sides and below. It is also possible to turn on one camera by scrolling through the entire list one by one. Any screen in multi mode can also be enlarged to large if necessary.
Each DVR has its own 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.
Surveillance Frame Rate
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 in connection with work on it.television technology. This is how most common brands of DVR work - Blackbox, Xiaomi and so on. This allows the operator to consider any alarming situations in a timely manner and immediately give a signal if necessary.
Number of frames per recording
However, with the same speed as when viewing, not all DVRs are capable of recording. There are those who can save all 25 frames per second. They are distinguished by 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 reveal important details. In this case, it will be possible to view 3-8 still pictures frame by frame. This characteristic is most often referred to as "cumulative frame rate during recording".
Video recording resolution
This is a parameter that is indicated by two digits separated by a multiplication sign (720x480). The first digit is the number of dots horizontally at each moment in the picture, the second - vertically. 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 a 100% indicator of a quality picture. Even with good resolution, cameras may be installed such that they cannot transmit a clear image. Therefore, one should approach the choice of anyequipment in general, building the same type of video surveillance system, without overpaying in some positions and saving on others.
DVR network operation
Most DVRs have an Ethernet connection to set up remote data access. For example, it can be data transfer to a duplicate monitor. It is also possible to connect via special software via the Internet from a mobile phone or tablet. In this case, the video is not just duplicated, the second person can view all the data in parallel, including finding some video fragment in memory that was recorded several days ago. Today, mass-produced DVR Vehicle models are ubiquitous, giving users this ability.
Motion Detection
Good DVRs have the ability to record when any movement is noticed in the picture. This can be either a pre-set area (for example, in front of a door or window), or any one 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 view of everything that happened at a given time. If there is no movement, then in this case the recording may either not be conducted at all, or be performed 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 anything important that could be createdat the enterprise or in the premises by intruders. An example of such equipment is DVR Vehicle GT300 A8.
Shapes and sizes
A very important characteristic of DVRs, among others, is the form factor. In other words - type, size, weight and some other characteristics. The method of installation is closely related to it, especially in a car. For obvious reasons, the convenience of use, as well as security, depends on this in many respects - 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 petty thieves, and will not attract the attention of strangers who may find it safe to do anything 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 shoot some important moment that is not initially included in the review, or when recording a conversation during a stop with a traffic police inspector.
Which devices are in the most demand?
According to numerous reviews, DVRs designed for cars can be called the most popular. This is due to the fact that they have a low cost, and at the same time they are able to provide significant assistance to the car owner, especially in controversial situations.
In addition, such devices can not only help to prove their case to traffic police officers, but alsocapture any attempted illegal behavior of other people. So, an attempt to steal property from a car will be immediately captured on video. Some devices have a wide field of view and can capture everything that happens around the car.
How to choose this device for the car?
All of the above characteristics should be focused on directly when choosing a device in a store. You should initially make some gradation for yourself according to their importance, giving greater preference to the device that, other things being equal, will be either smaller or faster to assemble.
Almost all modern recorders (including DVR Blackbox) have a conventional suction cup on the windshield as a mount. It allows you to maintain its qualities for a long time. At the same time, you can easily change the location of the recorder if necessary (both the entire structure and dismantling without a fixing bracket, which increases the durability of the main holder fixation).
Another option for fastening can be double-sided tape. This is often found in DVR Mirror devices. Practice shows that in this case the fixation is much longer. However, before starting installation, it is required to clearly and accurately make all measurements. True, in this case it will not work out quickly to remove the registrar. After that, additional glass cleaning may be required.
Some registrars may have two video cameras at the same time. In this case, the dimensions of the device will be slightly larger. However, it will be possible to simultaneouslyrecord 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 video camera has slightly worse performance. In the event that you need 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.
Closing word
User reviews say the following. The best option in choosing a device is when the seller of the device will help not only with a story about the main characteristics, but also with pre-installation. In this case, you can pre-evaluate the registrar for interference, secrecy and recording quality in a particular car. It should not be forgotten that even in the same type of car, the picture may differ due to various interferences, even when using the ultra-compact DVR Car Mirror.
At the same time, when trying out the DVR, you can evaluate how satisfied you are with its viewing angle. Most models have an angle of 40° to 150°. The most popular and widespread due to the optimal ratio "price / quality" - 120 °. Indeed, in this case, a wide spectrum will allow you to capture what is happening on the sides of the car.
However, two DVRs with the same 120° angle may differ in reality. Some manufacturers are cunning and indicate this angle, starting not from the width of the screen, but fromdiagonals. However, often at a large shooting angle, what is happening on the sides can be recorded with great distortion, which also does not cause positive emotions.
Everything that will be taken into account when choosing a registrar will allow you to use it longer and more efficiently. And have an additional factor in your favor in the event of an accident.
