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What factors are affected by the network camera effect?
First, the lens
The lens is the first pass of video capture. The quality of the lens will naturally affect the effect of the video. Although there are many kinds of lenses, the effect on the video is very large. The price of the lens ranges from tens of yuan to several tens of thousands. However, in the field of surveillance, it is not enough to buy a lens of tens of thousands of dollars, so basically the lenses on the market are similar. However, the effect of the focal length of the lens on the video effect is worth noting, which means that you should consider whether to choose the model of the interchangeable lens, or consider whether to choose the lens for zooming.
Speaking of this, I have to mention that the zoom refers to the focal length of the lens can be changed. Some network cameras have a digital zoom function. Digital zoom means that you can zoom in on the video image without changing the sharpness of the image. It is of little value to the network camera. In particular, beware of some unprofessional sales people or JS stealing concepts.
Second, the image sensor
This is a key factor affecting video performance.
At present, there are two kinds of CMOS and CCD on the market. In terms of imaging, the imaging transparency and sharpness of the CCD are very good under the same pixel, and the color reproduction and exposure can ensure basic accuracy. Ordinary CMOS products tend to be generally transparent, and the color reproduction ability of the object is weak (the color of the object being monitored is quite different from that seen on the monitor, or even completely discolored), and the exposure is not very good, because Due to its own physical characteristics, there is still a gap between the imaging quality of ordinary CMOS and CCD.
CMOS video images are better artistic, just like people follow art photos. Everyone knows that art photos are beautiful but not realistic. People are often confused by their artistic effects and ignore the importance of clarity and fidelity. In fact, these two points are very important when monitoring the industry.
Third, the video compression algorithm
This is the most important factor in the network camera because it directly determines the video clarity, video fluency and video storage space.
After many years of understanding, this most important factor has always been avoided by the seller intentionally or unintentionally. The reason may be that it cannot be said to be in itself or has a shoddy motivation. But as a savvy buyer, you must understand it.
At present, the network cameras on the market mainly have two video compression algorithms, H.265 and H.264. H.265 is a new encoding protocol, which is an upgraded version of H.264. Their core difference can be seen in two steps: the same picture quality and the same code rate, H.265 is 50% less than the theoretical storage space occupied by H2.64. If the storage space is the same, it means that H.265 will be 30%~40% higher than the theoretical value of H2.64 at the same bit rate.
Fourth, the image format
The image format determines the actual pixels of the video image. It is divided into DVD format and VGA (640*480) format and CIF (352*288) format. The DVD image format family includes D1 (720*576 interlaced) and D2 ( 1048*720), D3 (1920*1080 interlaced), D4 (1280*720 progressive scan) and D5 (1920*1080 progressive scan) five image formats, currently the mainstream on the market is D1. Support D3 and D4's megapixels are also on the market, just because they use more bandwidth and are not widely used.
Different pixels in the same image format are different, and the video file size is different. If it is not the same image format, we can't determine the pros and cons of the webcam by the size of the hard disk required for the video. The image format of a webcam can often be adjusted, which means that if your hard disk space is not large enough, but you need to record for a long time, you can reduce the image format.
Five, frame rate
As we all know, any video file is composed of consecutive pictures. We call it a frame for a picture. For example, a one-second video consists of 25 consecutive pictures, and the frame rate is 25 frames/second. In the PAL system, 25 frames per second of video can be very realistic. If it is less than 25 frames, the motion in the video will not be coherent, and the lower the inconsistency, the even more jumping motion artifacts will appear. Therefore frame rate is very important in video surveillance. This parameter will be displayed on the video monitoring interface. Everyone must pay attention to this when purchasing products, because the cost difference of network cameras that can support 25 frames/second is also large.
Six, double stream
Some network cameras are designed to support two video signals, the so-called dual stream. The advantage of dual stream is that it can be more effectively protected against network congestion by using one stream stream, one stream stream storage and one channel stream for viewing and storage, thus better guaranteeing the smoothness of video on effective network bandwidth.
Seven, front-end storage
Some network cameras have an SD card slot or a USB mobile storage interface, which we call front-end storage. Front-end storage is often used in monitoring environments where bandwidth is not sufficient. Some environments are inconvenient to install broadband, use the function of the front-end storage, save the monitored video to play a certain monitoring effect, can not help but also a way.
Eight, product line
In most of the larger monitoring systems, multiple models are often used, because the video management software of various manufacturers is difficult to be compatible with other brands of network cameras. Therefore, when selecting a brand for a monitoring system, it is necessary to consider whether the brand has a rich product line to cope with various environmental needs and system solving capabilities. Such as support for infrared, support for WIFI wireless, support for POE, support for fiber access, support for pan/tilt, support for zoom, whether there is a video server for integration with some special analog cameras, and whether a video decoder can be connected to the video wall.
Nine, software features
Most monitoring systems require centralized management, so whether the video management software is powerful or not, is also a problem that must be considered when selecting products. There are many functional modules of the management software. Therefore, the identification of the advantages and disadvantages of the video management software requires comprehensive consideration. It is not possible to exaggerate a certain function, nor can it ignore a certain function.
In addition to the above nine, infrared night vision capability, ultra-low illumination, wide dynamics, strong light suppression and other functions are also some important parameters of the network camera. In summary, the selection of network cameras requires a certain level of expertise and more patience. If you don't choose expensive, you only choose the right one. I hope everyone can choose the right network camera.