How to choose a hard disk video recorder?
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A selecting <br> <br> most digital monitoring host interface chosen as industrial chassis housing, to print delicate and beautiful appearance of the work, and I believe that the floppy drive with a mechanical power switch that locks up style to reduce human faults Must help. If you can open the cover, you should pay attention to what fan and power supply you are using. For example, the dedicated fan on the Pentium III CPU has an average time between failures of more than 3 years, and the average time between failures of the average fan may not be accurate. The digital monitoring host, which is continuously turned on, is a hidden trouble. In addition, pay attention to whether the rear interface connection mode is reliable and convenient.
In order to facilitate the operation, the interface should be all Chinese, and the main functions can be reflected at the main interface at a glance. It is recommended to select an intuitive operation interface that looks very professional and beautiful. It is best to be similar to the WINDOWS operation menu.
The function expansion is stronger, the main functions are divided into monitoring function, video function, alarm function, control function, network function, identity recognition function, work schedule function, if there is a matrix, the best duplex talkback, these two are many difficult Do it. The following is a one-by-one introduction.
Second, the function of diversification 1. Monitoring function Monitoring function is one of the main functions of the matrix host and the digital host, the monitoring function is nothing more than to see the scene, see the scene, if necessary, there should be voice, pay attention to whether the video and audio synchronization. Mainly through the definition, the real-time level and the display form to determine the monitoring effect, and television display is different, the effect of different video card and capture card observation is not the same, to compare the clarity of monitoring, there should be a good monitor Watch, I recommend SONY Trinitron and LG future windows and other several 15 ``-17`` high-definition monitor, like measuring the clarity of the CCD camera, it is recommended to use professional graphics test card and a higher number of lines The camera as an observation object accurately reads the horizontal and vertical resolutions that can be observed as the basis for monitoring the sharpness. Generally when the image exceeds 17 frames per second, it looks to the naked eye as a more real-time image, and the teller system and some special The surveillance site requires the image to reach 25 frames per second or higher. Usually, you can do some quick actions to observe this function, such as quick counting, clapping, and so on. This effect should be recorded as a record playback record. The display format is generally 1, 4, 7, 9, 10, 16 and other screens, and the screen can also be cut to full screen. The brightness, contrast, color, saturation and other parameters of each channel should be continuously adjustable. Otherwise, the multi-picture cannot be well viewed due to uneven light. This is also the place where the digital host is superior to the ordinary picture splitter.
When viewed in full screen, it can accurately reflect image quality, video speed, and graphics quality.
2, video:
The video effect is the core and vitality of the digital host. When you look at the real-time and clear images on the monitor, the playback effect recorded is not necessarily good. The most important effect of the forensics is to watch the video effects. In general, the video effect is better than the monitoring. The effect is more important. Sharpness and real-time visibility and monitoring are similar. The memory used for the unit time recording and the single frame memory are also the most important parameters reflecting the video effect. The memory occupied by unit time recording and the space occupied by a single frame have a decisive influence on how long the same hard disk can be recorded and the rate at which images are transmitted on the Internet. In the standard MPEG format, 600M is recorded every hour, while the MJPEG format records 16 pictures at the same time. In the standard case, it occupies 150M. The difference in the occupied space is quite large. The amount of memory for the static picture depends on the picture size of the picture compression ratio ( Picture quality) and graphics format. How much memory the dynamic picture occupies depends on the picture size of the picture compression ratio, image format and whether the picture changes and the speed of change, the author once tested on a digital host, the use of MJPEG format, the image size is set to 800 × 600, image motion accounted for 3K bytes, and 180 bytes when not moving.
In addition, some hosts for security monitoring should have a preset alarm recording function, which can filter out information that is not related to the alarm and not record it, greatly reducing the requirements for storage capacity. Some hosts also have the ability to automatically increase the number of recording frames after an alarm. This is also helpful for the storage of effective information.
A special reminder is that the same images look similar in quality and the space they occupy may vary greatly (70M-550M/Road/hour). At this time you can not see the machine monitoring interface display, can only be returned to the operating system (such as WINDOWS, NT, UNIX ...) to view the size of the file is accurate.
3, alarm function:
The alarm function mainly refers to the input alarm of the detector and the alarm of the image and video frame measurement. After the alarm, the system will automatically open the recording function and turn on the corresponding spotlight, alarm signal and network output signal through the alarm output function.
Image video frame detection alarm is a unique function of digital surveillance. He can easily set the video trigger area and sensitivity, and in a certain sense can play a role of the detector.
Auto-arming and disarming functions according to time zones, preset alarm recording functions and automatic addition of frames to alarm recordings are functions not provided by conventional alarm systems.
The output time of the alarm signal should be adjustable, and various alarm results should be clearly recorded in the computer.
4, control function:
Mainly refers to the camera through the host for the full range of camera head, lens control, which is generally completed through a dedicated decoder, mainly to observe whether the operation is flexible and reliable.
5, network function:
Through dial-up LAN access through a simple identification of the host can carry out a variety of monitoring video control operations, mainly to observe the connection speed and monitor video effects and whether to affect the operation of other software. This is equivalent to the sub-control function of the matrix system.
6, password authorization function:
In order to reduce the system's failure rate and illegal entry, passwords must be set for procedures such as stopping video recording, arming and disarming systems, and entering programming, so that unauthorized persons may not operate.
7. Work schedule The work time can be programmed for a certain time period of a certain camera. This is also a unique function of the digital host. It can pre-arrange the changes of holidays and work schedules into the program and can be used in a certain sense. Realize unattended.
8, more work:
The system can have the functions of simultaneous monitoring, recording, playback, network transmission, and backup, without affecting each other.
Third, stability, durability <br> <br> any product over time, environment, volume, etc. are likely to produce a lot of problems that people at first unexpected, digital host is no exception, try to be more familiar with and use The machine understands the following situation.
1, with the passage of time a, whether the phenomenon of death, which is a fatal weakness of many digital products. Believe that stability is overriding the truth When you have not tested for a long time, it is best to remove the chassis and look at the structure, to understand whether it is a high-quality real IPC, or just an external industrial chassis.
b. How long does the life of the fan and hard disk c. Whether or not the information is lost inexplicably, paying particular attention to whether or not there is a lost frame between the file package and the hard disk drive.
d, the average time between failures of the entire system is how long e, whether there will be a false alarm phenomenon 2, with the environmental changes a, the voltage instability, 180 ~ 250V voltage can work properly.
b. Whether the power supply voltage is unclean has an impact on the system c. Humidity, temperature, dust on the system's normal work d, Does the lightning cause damage to the internal circuit? Does the surrounding electrical interference affect the normal operation of the host? , Power failure, and the impact of abnormal operation on the system, how much? 3, with the batch changes whether the quality of the machine is good or bad, what factors are most likely to cause inconsistent batch quality