Research And Design On Mornitoring System Of Video Stream Performance

Video on network is a kind of application technology based on stream media, and the development of stream media technology has brought rise to the network video. Meanwhile, video stream performance can be influenced by a variety of complex factors. For example, in the process of data collection, compression, processing, transmission and restoration, digital video data could generate different sorts of distortion, such as lossy compression technology will reduce video quality in the quantization process; in the BER channel transmission, channel error and data loss will increase the video distortion after its encoding; in packet switching network transmission, the network congestion will cause receiving data loss and excessive delay which increase distortion. Therefore, video stream quality evaluation receives widespread attention. Video service provider must be able to know and quantify the decreased video quality on time, and to measure video performance through effective evaluation method. In this situation, network video stream performance monitoring has become the research focus in this field.This paper mainly researches the evaluation method of video stream transmission performance, and designes the monitoring system. Then choose a video quality assessment method suitable for network transmission, test and analyze comprehensively the damage of video stream quality in laboratory access network environment. At last, combined with the testing methods and results, we design and develop a simple video monitoring system. The following will introduce main work we have done. 1. Research the existing subjective and objective video quality evaluation algorithm. Understand the new algorithms proposed currently, and advantages and disadvantages of each algorithm. Apply them to different scenarios according to demands.2. Research the main causes which produce video quality damage, and analyze the relations between the network transmission damage and video quality damage.3. Establish test platform in laboratory:build network video server and client; build WDM-PON access network system. Through the monitoring flow data obtained by test, analyze the video quality influenced by network transmission factors.4. Combined with the test methods and results, build development environment in Windows operation system. Design and develop video stream performance monitoring system, and through experiment, verify its monitoring results and assess its validity and availability.This paper is a summary of theoretical study and research development during autor's postgraduate period, its content as follows:The 1st chapter is Introduction section, which describes the research background and significance, introduces the emerging video stream media business and the access network technology to carry the business, and summarizes the research content and the structure of this paper.The 2nd chapter introduces the existing subjective and objective video quality evaluation algorithm, researches the advantages and disadvantages of each algorithm, analyzes the main causes which produce damage in the video network transmission and chooses suitable algorithm according to the research focus and the monitoring area.The 3rd chapter uses the typical network video application IPTV as the main research object, briefly introduces the system structure and main modules, emphatically elaborates the flow transmission technology, and according to the monitoring method in the situation of damage caused by network factors, does monitoring test in WDM-PON access network system, and analyzes the influence on video quality by network transmission factors. The 4th chapter elaborates a kind of simple monitoring system structure, analyzes video stream protocol stacks in network transmission, designs each system function modules, and by monitoring experiment, verifies the system function, assesses the validity and availability.The 5th chapter summarizes research achievements and work we have done, and prospects the further work and research direction in the future.