Perspective Network Camera's Technical Features and Development Advantages

From the hardware structure, the network camera is based on the analog camera integrated video compression and network transmission processing module, so both the analog camera and video server technology features, but not the simple combination of the two, a unique structural design and The mode of implementation determines that it has its own technical characteristics. From the flow of data, the network camera looks like: lens->sensor->isp->encoder->network. To build a network camera, there are a lot of factors to consider when it comes to true video capture and stream transmission, including images. Quality, video capture, selection of codec chips, compliance criteria, network transmission, network security, etc.

Network camera technology features From the hardware structure, the network camera is based on the analog camera integrated video compression and network transmission processing module, so both the analog camera and video server technology features, but not the simple combination of the two, unique The design and implementation of the structure determine that it has its own technical characteristics.

1. Video Compression Video compression is the most basic technical requirement of network cameras. At present, the network camera's video processing chip is mainly ASIC, and video compression uses MPEG-2, M-JPEG, MPEG-4 and H. 264 scales, including H. 264 is the mainstream. Recently, the network camera based on TI Davinci chip has already been put on the market, Davinci is a SoC system, has the characteristic that ASIC handles high-efficiently, at the same time take into account the different flexibility of CPU, DSP, it has a main processing system of DSP, there is still another ARM9 subsystem, another very important characteristic is to have very abundant interface, these interfaces are useful for the development of the function of the network camera, the following certain characteristic is based on this characteristic possesses.

2. The highly integrated network camera has more than just the traditional analog camera image acquisition function. It is already a front-end processing system, and it has a considerable number of heterogeneous bus access functions, such as VOIP, alarms, and 232/485 serial devices. In addition, in addition to this, it is also possible to send alarm signals such as motion detection, video loss, lens coverage, storage abnormality, etc. to the back end via the network. Network camera can be embedded in the storage system, usually using an SD card. Currently, the capacity of the SD card varies from 8MB to 4GB. The SD card can be used as a temporary storage device for images in the event of a network failure. When the network is restored to normal, the video can be uploaded. , Can effectively guarantee the continuity and integrity of video data. Another use of the SD card is to store important alarm images locally and upload the backend at the same time so that no video data is lost due to unreliable transmission of the network.

3, Power over Ethernet (POE)

POE is a fast-growing and widely used network power supply technology in recent years. POE (Power Over Ethernet) refers to the existing Ethernet Cat. 5. In the case of no changes to the cabling infrastructure, in addition to the transmission of data signals for some IP-based terminals (such as IP phones, network cameras, etc.), DC power can be provided for such devices. In this way, the network camera no longer needs to be powered by other power sources. By using the UPS in a centralized manner (without interrupting the power supply), the equipment can be guaranteed to operate uninterrupted for a certain period of time (depending on the UPS), and simplification of the management is also facilitated. The IEEE802.3af standard is a new standard for POE based on Power over Ethernet (POE), which requires that the power consumption of a device powered by POE cannot exceed 12.95W.

Now, most vendors provide network switches that support PoE. If the corresponding normal switch equipment is installed, the function of PoE can be achieved simply by adding midspan to the switch. Among them, the main role of the midspan is to power the network cable.