| Distance education has been widely developed in adult continuing education, enterprise training, exam remediation and other fields of training and education. All kinds of network training institutions release learning content through online learning system of distance education website. Learners can easily watch live and on-demand video courseware at any time and any place.However, with the further development of training services and Internet technology, distance education websites have many new problems to be solved in encoding, distribution, and content protection of video courseware. Firstly, the user scale of WebKit kernel browsers, such as Google Chrome and Safari, is quickly increasing. Android and other mobile operating systems are so popular that learning equipments have been gradually extended to tablet computers and so on. Courseware only learned in Windows system and IE browser has unable to meet the requirements of cross-browser and cross-system learning. Secondly, with the growth of learners, distance education websites have to pay more and more money in mirror servers and bandwidth when publishing streaming video and audio. On the premise of acceptable video and audio quality, E-learning websites hope to increase the compression rate of video and audio file in courseware. Besides, with limited network access, intranet users are often unable to watch live or on-demand internet video courseware distributed by streaming media transfer protocol, such as RTSP, MMS, RTMP and etc. Finally, digital right management systems of many distance education websites have complex setup requirements when first time learning protected courseware. The using process of DRM systems is always so difficult that E-learning websites need more simple protection scheme of courseware content. This paper bases on author's specific practice of reformation project in a training institution website, which including video courseware encoding, distribution, and content protection.With the realization of using HTTP protocol to simulate RTMP streaming protocol, overall design is proposed for distributing live and on-demand protected Flash video courses to meet the requirements of cross-platform and cross-browser distance learning and achieve the compatibility with the configuration of most firewalls and routers. This paper elaborates the specific realization of encoding, distribution and content protection progress, and validates the performance improvement by tests comparing with the widely used Windows Media streaming technology on media distribution and protection.The main study achievements of this paper are as follows.(1) On the aspect of video courseware content encoding, through the video and audio coding tests of different encoding parameters combination, this paper obtains the best Flash video container format and optimal encoding scheme. On the premise of clear and smooth playback, the bandwidth and storage resources of website servers can be mostly saved when using optimal parameter combinations to distribute live or on-demand video courseware.(2) On the aspect of Flash video courseware content distribution, specific deployment process and implementation are proposed for live and on-demand video distribution by using HTTP protocol to simulate RTMP streaming protocol. Based on the video distribution test, it comes to the conclusion that HTTP Dynamic Streaming technology can not only distribute streaming content to pass the intranet firewall, but also can meet the requirement of taking full advantage of caching services of video streaming distribution.(3) On the aspect of video courseware content protection, this paper proposes the specific deployment process and realization of protecting on-demand and live Flash video streaming based on the analysis of the merits and defects in mainstream digital copyright protection technologies. And through the video protection test, it comes to the conclusion that using Adobe Flash Access technology to build the DRM encryption system can obtain lower failure rate and more convenient operation experience. Comparing with other DRM technologies, Flash Access DRM technology can meet kinds of business modes in distance learning websites, and can effectively protect video and audio content of Flash courseware. |
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