The effect of network cameras is affected by many factors. The use of cameras in the market is already very extensive, and network cameras have become one of the most popular cameras. So what is it affected by?
1. The lens
The lens is the first step in video capture. The quality of the lens will naturally affect the effect of the video. There are many kinds of lenses, and they have a great influence on the video effect. The price of the lens ranges from tens of yuan to tens of thousands of yuan. But in the monitoring field, it is not necessary to buy a lens of tens of thousands of yuan, so basically the lenses on the market are almost the same. However, the impact 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 with an interchangeable lens or whether to choose a zoom lens when choosing a product. Having said that, I have to mention that zoom means that the focal length of the lens can be changed. Some network cameras have the function of digital zooming. Digital zooming means that the video image can be magnified and viewed without changing the clarity of the image at all, which is of little value to the application of network cameras. Especially we should note that some unprofessional sales staff or JS may steal concepts.
2. The image sensor
This is a key factor that affects the video effect. At present, there are two kinds on the market: CMOS and CCD. In terms of imaging, the imaging permeability and sharpness of CCD under the same pixel are very good, and its color reproduction and exposure can be guaranteed to be basically accurate. Ordinary CMOS products tend to have average permeability, and their ability to reproduce the color of the actual object is weak (the color of the monitored object is quite different from the one seen on the monitor. Or the object can be completely discolored), and the exposure is not very good. Due to its own physical characteristics, there is still a certain gap between the imaging quality of ordinary CMOS and CCD. CMOS video images have better artistic effects. Just like people taking artistic photos, everyone knows that artistic photos are beautiful but not realistic, but people are usually confused by their artistic effects and ignore the importance of clarity and fidelity. In fact, these two points are very important in the monitoring industry.
3. Video compression algorithm (also called video compression format)
This is the most important key factor in a network camera, because it directly determines video clarity, video fluency, and video storage space. After my researches for many years, this most important factor is always ignored by the sellers intentionally or unintentionally. The reason may be that the seller itself cannot tell the truth, or has a shoddy motive. But as a savvy buyer, you must understand clearly. Currently, the network cameras on the market mainly have two video compression algorithms: H.264 and MPEG4. The former has stronger compression ability and less video loss, so it is clearer and smoother. The former can support a frame rate of 25 frames per second, and the latter generally does not exceed 10 frames per second. This means that the latter's video is not coherent and not real-time; because the MPEG4 compression rate is not enough, if the video is done in full real-time, the code stream is too large, and it will be difficult to see remotely.
4. 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 five image formats: D1 (720*576 interlaced scan), D2 ( 1048*720), D3 (1920*1080 interlaced scan), D4 (1280*720 progressive scan) and D5 (1920*1080 progressive scan). The mainstream format currently on the market is D1. Network cameras which support D3 and D4 megapixels are also on the market, but because they occupy more bandwidth, they are not widely used.
The pixels of different image formats are different, and the size of the video file is also different. If it is not the same image format, we cannot determine the pros and cons of a network camera based on the size of the hard disk required for recording. The image format of a network camera 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 to achieve this.
5. Frame rate
As we all know, any video file is composed of continuous pictures. A picture is called one frame. For example, a one-second video is composed of 25 continuous pictures, and the frame rate at this time is 25 frames per second. In the PAL format, 25 frames per second video can perform very realistic actions. If it is less than 25 frames, the motion in the video will not be coherent enough. Therefore, the frame rate is very important in video monitoring. This parameter will be displayed on the video monitoring interface. This parameter is also avoided by many unprofessional salesmen. Everyone must pay attention to this when buying products, because the cost of network cameras which can support 25 frames per second or not is also quite different.
6. Dual stream
Some network cameras are designed to support two video signals, the so-called dual stream. The advantage of dual stream is that using one stream to watch and another one to store can prevent network congestion more effectively than using the same one stream for viewing and storage, so as to better ensure the smoothness of the video on the effective network bandwidth.
7. Front-end storage
Some network cameras have an SD card slot or USB mobile storage interface, which we call front-end storage. Front-end storage is often used in monitoring environments with insufficient bandwidth. In some environments, it is inconvenient to install broadband. Use the front-end storage function to save the monitoring video to achieve a certain monitoring effect. It is also a way for monitoring.
8. Product line
In most large monitoring systems, multiple models of products are often used, because the current video management software of various manufacturers is difficult to be compatible with other brands of network cameras. Therefore, when choosing a brand for the monitoring system, it is necessary to consider whether the brand has a rich product line to meet the needs of various environments, as well as system solution capabilities. For example, whether support infrared, support WIFI wireless, support POE, support fiber access, support PTZ system, support zoom, whether there is a video server so that it can be combined with some special analog cameras, and whether there is a video decoder that can be connected to the TV wall, etc.
9. Software function
Most monitoring systems need centralized management, so whether the video management software is powerful and the interface is user-friendly are also issues that must be considered during product selection. There are many functional modules of management software. Therefore, the evaluation of the pros and cons of video management software requires comprehensive consideration. A certain function cannot be exaggerated or ignored and it must be based on actual needs.
In addition to the above nine items, functions such as infrared night vision, ultra-low illumination, wide dynamic range, and strong light suppression are also some of the important parameters of network cameras. In summary, the selection of network cameras requires certain professional knowledge and patience. Don't choose the expensive one, just choose the right one. I hope you can choose your own suitable network camera.