Nowadays, the speed of development of network cameras is extremely fast. What is the reason? Let's do a comparison below.
The encoder's camera solution uses analog technology, analog video camera + analog transmission line. Its working principle is that the analog video signal is transmitted through an analog transmission line to an encoder, which is then digitized, coded, network transmitted, and stored.
As we all know, the analog camera output signal is a CVBS format video signal. Due to the constraints of the N/P system specification, the maximum resolution supported by the CVBS signal is D1, ie 704x576 for the P system or 704x480 for the N system. The highest pixel of CVBS is only about 360,000, and this pixel resolution is interlaced.
When the requirements on image quality are higher, such as megapixels, or progressive images (all CMOS outputs are line-by-line images), the standard CVBS signal transmission method cannot be achieved. Of course, dedicated transmission lines can be designed specifically for high-resolution images. However, this line needs to be implemented using Gigabit coaxial cable or optical fiber. Obviously, the high cost is unacceptable to manufacturers or users. Therefore, this kind of camera solution for encoders is difficult to design high-resolution products.
Another problem with analog transmission lines is that the loss of the analog signal during transmission is very large. As the transmission distance increases, the signal-to-noise ratio increases sharply. This causes the image quality to drop rapidly and introduces a lot of noise during transmission. This makes the encoder's video compression coding more difficult, but also makes the video code rate will increase exponentially, thus making it more difficult to transmit in a low-bandwidth network, but also makes the video storage hard disk space requirements increase, that is to say, Analog transmission not only makes image quality easily degraded, but also increases transmission and storage costs.
In addition, there is a problem with analog transmission lines: insecure! As we all know, the CVBS signal format is an open standard, and there is no encryption and authentication mechanism when video information is transmitted over a coaxial cable. As long as you know the location of the video cable, anyone can watch and switch videos by removing the barriers. We have seen some large movies in Europe and the United States, such as the scenes in the movies such as “Stolen Days,†“Emergency Landings,†and other crimes. Those perpetrators switched video signals by evading grafts to avoid video surveillance by video surveillance personnel. In other words, analog transmission lines cannot guarantee the security of video signals.
In contrast, because the network camera adopts the solution of the embedded camera, the image obtained by the camera photosensitive device does not need long-distance transmission, and is directly transmitted to the encoding module, which avoids the constraints of the N/P specification and avoids the CVBS signal to the image. The problem of limited resolution, which means that the network camera can provide high quality, low bit rate images, the image resolution can support more than megapixels, can also support progressive images. In addition, the network camera's video signal can be securely encrypted, which ensures the security of the transmission process, and can effectively prevent illegal users from eavesdropping and tampering.
We say why there are webcam products? This is the root cause.
Summary: Network cameras are an inevitable product of technological progress and are a necessary requirement for the development of surveillance cameras.
The encoder's camera solution uses analog technology, analog video camera + analog transmission line. Its working principle is that the analog video signal is transmitted through an analog transmission line to an encoder, which is then digitized, coded, network transmitted, and stored.
As we all know, the analog camera output signal is a CVBS format video signal. Due to the constraints of the N/P system specification, the maximum resolution supported by the CVBS signal is D1, ie 704x576 for the P system or 704x480 for the N system. The highest pixel of CVBS is only about 360,000, and this pixel resolution is interlaced.
When the requirements on image quality are higher, such as megapixels, or progressive images (all CMOS outputs are line-by-line images), the standard CVBS signal transmission method cannot be achieved. Of course, dedicated transmission lines can be designed specifically for high-resolution images. However, this line needs to be implemented using Gigabit coaxial cable or optical fiber. Obviously, the high cost is unacceptable to manufacturers or users. Therefore, this kind of camera solution for encoders is difficult to design high-resolution products.
Another problem with analog transmission lines is that the loss of the analog signal during transmission is very large. As the transmission distance increases, the signal-to-noise ratio increases sharply. This causes the image quality to drop rapidly and introduces a lot of noise during transmission. This makes the encoder's video compression coding more difficult, but also makes the video code rate will increase exponentially, thus making it more difficult to transmit in a low-bandwidth network, but also makes the video storage hard disk space requirements increase, that is to say, Analog transmission not only makes image quality easily degraded, but also increases transmission and storage costs.
In addition, there is a problem with analog transmission lines: insecure! As we all know, the CVBS signal format is an open standard, and there is no encryption and authentication mechanism when video information is transmitted over a coaxial cable. As long as you know the location of the video cable, anyone can watch and switch videos by removing the barriers. We have seen some large movies in Europe and the United States, such as the scenes in the movies such as “Stolen Days,†“Emergency Landings,†and other crimes. Those perpetrators switched video signals by evading grafts to avoid video surveillance by video surveillance personnel. In other words, analog transmission lines cannot guarantee the security of video signals.
In contrast, because the network camera adopts the solution of the embedded camera, the image obtained by the camera photosensitive device does not need long-distance transmission, and is directly transmitted to the encoding module, which avoids the constraints of the N/P specification and avoids the CVBS signal to the image. The problem of limited resolution, which means that the network camera can provide high quality, low bit rate images, the image resolution can support more than megapixels, can also support progressive images. In addition, the network camera's video signal can be securely encrypted, which ensures the security of the transmission process, and can effectively prevent illegal users from eavesdropping and tampering.
We say why there are webcam products? This is the root cause.
Summary: Network cameras are an inevitable product of technological progress and are a necessary requirement for the development of surveillance cameras.
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