In the security industry, the current car DVR market is still chaotic, and users are not well-understood. There are thousands of companies making car DVRs all over the country. Therefore, it is often found that the ordinary DVR is used as a vehicle DVR.
Although the embedded system is used like the ordinary DVR, the vehicle-mounted DVR technology is more complicated than the ordinary DVR, and the key to be solved is also different. Therefore, the two are two completely different concepts. Vehicle-mounted DVR is applied to moving vehicles. Due to the different vehicle and road conditions, the vibration is relatively large, which has a great impact on the hard disk reading and writing data, and the damage to the equipment is very large. Therefore, anti-seismic technology has become the most basic requirement for vehicle-mounted DVR. At present, there are mainly measures such as damping the whole machine, damping the hard disk rack, and damping the hard disk.
Second, regulated power supply
Voltage stabilization is another important technology of vehicle-mounted DVR. During the driving process, the vehicle will have actions such as ignition, braking, and stepping on the accelerator. These behaviors will cause the output voltage of the vehicle to fluctuate with different amplitudes, which can easily cause the vehicle DVR to burn out. Therefore, the vehicle-mounted DVR must have a wide voltage input capability to adapt to this voltage change. At present, a wide voltage of 6 to 36V is generally used to meet the needs of mobile vehicles.
At the same time, it should also be noted that if the vehicle crashes and suddenly shuts down, the power supply on the vehicle is cut off. At this time, the on-board DVR must have the function of automatic power supply protection to ensure that the data in the hard disk will not be lost.
3. Heat dissipation
During the operation of the vehicle, the temperature difference changes greatly due to the environment and weather.
This puts high requirements on the heat dissipation performance of the car DVR. Therefore, if the heat dissipation performance is not good, the life of the product will be reduced, and it will also affect the monitoring effect. At present, some products are cooled by fans, and some are cooled by the fuselage. Therefore, when purchasing, it is best to run for a while, then measure the temperature of the body, and watch the actual effect of the image.
Fourth, image clarity
The clarity of the image directly affects the monitoring effect, so when buying a product, it depends on which processing chip the product uses, which compression format, and what resolutions are supported? At present, the products generally support CIF to D1, using D1 recording and CIF transmission. To observe the actual effect, you need to record a video at different resolutions to observe the video playback effect, whether the picture is clear and whether there is a delay.
Vehicle monitoring clarity
Fifth, interface firmness
In the car, due to braking, acceleration, bumps on the road, the vibration is relatively large. If the interface is not secure, the wiring may fall off at any time, causing image jitter, video loss, and power loss. Therefore, when buying products, you should carefully observe whether the interface is firm. I have seen in the test process that some manufacturers have collected most of the interfaces on the rear panel and replaced them with a multi-pin interface, which bundles all the data cables into a bundle, which plays a good role in the solidity of the interface.
Six, wireless transmission
In addition to being able to provide local recording and forensic data, the vehicle-mounted DVR also needs to send the obtained video information back to the control center in time, so that the control center can timely understand the situation on the vehicle and centralize management. Therefore, wireless transmission is particularly important.
Currently mainly uses mobile GPRS and China Unicom's CDMA network, but due to bandwidth and cost issues, real-time transmission cannot be achieved, and only 5 to 7 frames in CIF format can be transmitted within one second. Therefore, users can check whether the transmitted pictures are clear and smooth in the control center.
Vehicles are generally cleaned every day, especially on buses. After the bus enters the station, the staff will use water to rinse the car, and the water will be sprinkled on the device if you are not careful. If the waterproof performance is not good, water droplets may enter the interior of the chassis. The device is burnt out, so the waterproof performance of the car DVR cannot be ignored.
During the driving of the bus, the passengers on the bus go up and down, the dust is indispensable. Therefore, the product also puts forward high requirements on dust prevention. When purchasing products, users should try to choose products with fully enclosed shells and good interface tightness. Prevent dust from entering the chassis, so as not to affect the stability of the product operation.
Vehicle DVR products are pursuing miniaturized design. This is not only the beautiful appearance of the product, but also mainly to meet the small installation environment in the car. Due to the different models of large buses, small buses, and private cars, the interior space is also very different. Therefore, when purchasing products, you need to choose different sizes of car DVRs according to the model.
Ten, high integration
Vehicle DVR is not just a single product, it can not only be connected to the camera for surveillance recording, but also should have a rich interface, can be integrated in some large projects, so the space is greater. Therefore, you can check whether the interface is rich, whether some protocols are provided, whether it is convenient to upgrade, and whether it is compatible with the access platform.
Eleven, hard disk
Generally speaking, the hard disk space should be large enough, otherwise there will be no space in less than a month.
At the same time also need to have an interface, you can copy the data directly without disassembly. At the same time, to meet the needs of customers, the quality of the hard disk must be reliable, and it cannot be damaged within one month of use.
12. Alarm setting
Vehicles have always been a blind spot in the surveillance area, and vehicle-mounted DVR has just made up for this vacancy. Therefore, in addition to being able to record video, the car DVR should also have an alarm function. When an event occurs on the vehicle, the alarm signal can be uploaded to the control center through the alarm device installed in the vehicle. The control center can keep abreast of the situation and centrally dispatch. Therefore, you can check whether the car DVR has functions such as door opening recording and alarm recording.
Thirteen, temperature and humidity
Due to the indefinite changes in climate and weather, as well as the differences in the application environment of the products in the south and the north, for the vehicle-mounted DVR to operate normally, the impact of temperature and humidity actually encountered in these projects must be resolved. At present, some products have added smart thermometer functions. When the temperature in the car is lower than a certain value, the product will automatically start the heating device. When the temperature in the car is higher than a certain value, the product will automatically start the heat dissipation device to make the vehicle equipment operate normally.
14. Media Play
In the past, car DVRs mainly used video recording, and now it has diversified functions. Playing entertainment programs can not only meet the entertainment needs of passengers, but also bring new business opportunities to operating units. This function can receive radio and TV signals, can pre-store entertainment programs such as DVD and VCD, and can insert advertisements.
Fifteen, black box
Black box is also called 'motor vehicle driving recorder', it is one of the important functions of car DVR. It can record all the data of the whole process of motor vehicle operation, and can realize the management and supervision of the driver through the supporting computer software. When the vehicle speeds or other violations occur, the black box will send the information to the control center for early warning.
16. GPS positioning system
GPS positioning system is very important for buses, police vehicles and banknotes. It can implement unified deployment and timely grasp the specific location of vehicles. At present, most vehicle-mounted DVRs are only used as stand-alone units, but the products have reserved interfaces for GPS and other functional modules. GPS positioning module can be installed through the interface to achieve satellite positioning and remote control.