Since the live recording is developing, more and more customers has specific requirements to HD live recording. New Intel CPU has better supported HD video and HD cameras have been applied gradually with prices getting lower and lower. Signal transmission has become the biggest problem for HD live recording. Previously, the component signals are transmitted by 3 coaxial cables. But since component signals are analog signals, when it is transmitted for long distance, the image will get obscure or even ripple or get doubled; HDMI is also a universal interface for HD signals. HDMI can transmit complete HD image with the transmission distance at 20~30 meters. The price for HDMI cable is often very expensive. But if you use extender to get longer transmission distance, the cost is increasing while the stability will not be the same as before. SDI interface for HD signals can solve the above problem very well. SDI interface has been widely used in radio and television. It is digital signals and supports embedded audio. The transmission is done by a 75 Ohms coaxial cable, which is widely used in cable TV and is easy to purchase for users. Signals of 1080p60 can be transmitted for 100m, while that of 1080i60 can be transmitted for more than 200m. The current universal PTZ meeting cameras for live recording have SDI interface. Cameras of medium level, produced by SONY/ Panasonic/Canon usually have SDI interface.
The Architecture of the Solution
For HD live recording requirements, Magewell has released XI102XE-HD video capture card, which can simultaneously capture 2-channel SDI signal and 1-channel universal HD video signal. The SDI fully supports SD/HD/3G standards and embedded audio. The 1-channel DVI-I universal HD supports VGA, DVI, HDMI, component, and CVBS input. The VGA capture has the best capability to automatically detect the resolution and has the image automatic adjustment engine and various video processing functions. The captured image is clear and can automatically detect the dynamic switch of various resolutions. The interface of the host machine adopts PCI-Express x4 with the actual transmission rate at 600-800MB/s. Magewell XI102XE-HD video capture card can simultaneously capture 2-channel SDI HD signals and 1-channel VGA signals. Instead of using multiple cards, it will help reduce the cost and improve the stability of the system. When capturing 3-channel HD signals. The power consumption is only 8W. It effectively reduces the power consumption and CPU occupancy. The scale and de-interlacing will be done within FPGA. The effective DMA transmission will further release the CPU so users can use it to do other work.