Real-time Video Capture Coding And Multi-link Switching Transmission System Based On FPGA

In recent years,with the continuous development of the integrated circuit industry and 5G network technology,the fields of remote driving and drones have also entered a stage of rapid development.At the same time,people’s demand for these applications is increasing day by day.Video information is one of the main information that needs to be captured in these application scenarios.In order to achieve accurate real-time control,the video transmission system is required to meet the conditions of clear video images,comprehensive information,low transmission delay and strong transmission reliability.However,the traditional video transmission systems has many problems,such as single video capture source,low resolution,single transmission network and poor real-time performance,which cannot meet the application requirements.This article adopts the hardware platform based on Xilinx Zynq Ultra Scale+MPSo C EV series chip design to realize the realization of real-time line video capture coding and multi-link transmission system.System design involves two parts:Programmable Logic(Progarmmable Logic,PL)and Processing System(PS).The PL part realizes the video acquisition and preprocessing,simulates the input of multiple video sources through video copying.At the same time,the integrated video codec unit of the PL part is used to encode multiple video streams in HEVC encoding,which improves system performance and Speed up the data processing speed.The PS part is equipped with a Linux platform,which mainly realizes the management of the PL side IP core,the transfer of encoding parameters and the transmission of the encoded code stream.The network transmission part uses 5G wireless network and wired Ethernet for transmission,and the automatic switch between the two networks ensures the realtime and reliability of code stream transmission.The software part of the system designed a multithreaded Linux application program,which read configuration files to get encoding parameters and start encoding.This program calls plug-ins in the GStreamer multimedia application framework.The acquisition,encoding and transmission are all independent plug-ins.The application layer combines each plug-in into a data processing pipeline to realize a complete video acquisition,coding and transmission system.DMABUF shared memory technology is used in data transmission between acquisition and encoding to realize zero copy of data,which reduces CPU occupation and system delay.A test platform was built on the hardware board designed in the laboratory,and each functional module in the system was tested first,and the complete code transmission system was integrated and tested under the premise of ensuring the normal function of each module.The test results show that the system can synchronously encode multi-channel 1080P/60 FPS video,and realize real-time transmission of encoded stream through free switching between 5G wireless network and wired Ethernet.This paper also introduces system power consumption and system delay as evaluation indicators to evaluate and analyze the performance of the system.The results show that the power consumption of the system is 7.764 W,and it can be further optimized.The multi-channel delay of the system is almost the same and less than200 ms,which meets the requirement of real-time transmission.The delay of the system is greatly affected by the decoding display of the receiver,which can be further improved by updating the hardware and software of the decoder.