One of the most important criteria for determining whether to buy a DVR is the quality of the filming it provides, that is, the quality of the camera installed in it. If it is impossible to make out the license plates of the cars in front on the resulting video, then its legal value is very doubtful. It is also important how high-quality the image is obtained in cloudy weather and at night.

One of the most important characteristics is video resolution. It can be different — from 640x480 pixels to 1280x720 pixels (HD) and even higher, up to 1920x1080 pixels (Full HD). At the same time, it simply does not make sense to take a device with a resolution below HD these days, such savings will only be harmful.

But it should be noted that sometimes manufacturers artificially stretch the resulting image (this procedure is called interpolation). Thus, it turns out that the resolution is really high, but its quality leaves much to be desired. But usually only very “left” manufacturers do this.

In addition, the presence in the description of the device of the possibility of shooting high-resolution video does not mean at all that the device will do it with high quality. After all, there is such a thing as frame rate. The higher this indicator, the better, the image will be less “twitchy” (desired frequency is 30 frames / sec). That is, it may well turn out that an inexpensive device really provides 1280x720 pixels, but at a lower frame rate. The value of this option is questionable. However, 90% of modern devices provide 30 frames per second.  

No less important is such an indicator as the viewing angle — the larger it is, the more space in front of the car will be captured. This reduces the likelihood that any important moment will be off-screen. It is believed that the viewing angle should be at least 120 degrees. However, it also happens that an inexpensive model provides a wide viewing angle, but the image quality suffers, it becomes more difficult to distinguish individual details.

Most modern models record video cyclically, breaking it into separate pieces and gradually replacing old files with new ones. The size of these files is set in the device settings. At the same time, it will not be superfluous to have a G-sensor (accelerometer), with the help of which the device will be able to highlight difficult situations among others, focus on the shake that occurs during a sharp change in speed. These pieces of video will be saved in a separate folder and will never be deleted automatically. However, you should not rely on this function too much, it is better to always make copies.

If you often drive in the dark, then it's ok at all that the DVR has a night shooting mode conducted in the infrared range. Such a video will be discoloured, but it will still allow you to understand the situation.

Modern models are often equipped with all sorts of additional features. Such as GPS navigators, remote controls, radar detectors, the ability to connect a camera aimed at the cabin, etc. Many of these additions are not necessary, but can significantly increase the cost of the device. You must first decide what exactly you need and what will be a clear overkill. Among the useful options, it should be noted: the ability to display the current speed on the video, the ability of the mount to turn into the cabin (when communicating with the traffic police). A second camera aimed at the passenger compartment will not be superfluous — in which case this will make it possible to prove that at the time of the accident the driver was not talking on his mobile, but was looking at the road. As for the remote camera, it can be directed to the rear window.

And it should be noted that a good DVR should have a good mount. Such that it provides sufficient shock absorption, allows you to easily deploy the device in any direction and would not fall off when shaking. Mounts are different — on the windscreen, on the rear-view mirror, on the visor. In this case, it is considered optimal to mount on glass. So, the visor will “play” when shaking, which will immediately affect the quality of the video.

The quality and capabilities of modern video recorders are constantly growing. So, a few years ago, there were many models on the market that lacked such a useful option as a built-in screen that allows you to view the footage immediately after shooting. Today, such models are almost never found (an action camera can be deprived of a screen to increase reliability, but this is a slightly different story). No one is surprised by the possibility of shooting video with Full HD resolution or the presence of a GPS module.

But the general principle has remained unchanged — you should not buy a device that is too cheap, no matter how attractive its technical characteristics may seem. It may well turn out that the quality of the video he shoots will be so low that it will simply not be useful when analyzing an accident, that is, the purchase will be meaningless. However, the principle “the more expensive the better” also cannot be called correct, yet the registrar must correspond to the car in which it is installed. And on the market there are models worth more than $ 500. But this is already a clear overkill — on the market you can find good solutions, the cost of which falls within the range of 100 to 200 dollars.

Perhaps the most correct way to choose is to search for reviews about the model you like. Also, it will not be superfluous to look for examples of the captured video on YouTube (moreover, when viewing, do not forget to switch the video quality to maximum). The latter can be the final argument in favor or against the chosen model.

The kit often comes with special wires that allow you to connect the DVR directly to the car's electrical wiring. This turns the device into a kind of black box, and also allows you not to occupy the cigarette lighter, which is used to power, for example, a navigator or for its intended purpose. But even with this approach, it is highly desirable that the DVR still be equipped with a built-in battery — this will allow you to shoot even after the engine is turned off.