Research Of Key Technologies For Wireless Video Adaptation Based On Content Analysis

In the information society, mobile digital media business has been using more widely. The traditional2G era of business, such as instant communication, mobile phone music, already cannot satisfy the requirement of modern user diversification. With the succession of3G network, the increase of wireless bandwidth and the strengthening of mobile terminal technology, mobile video business development is increasing rapidly. From users’perspective, mobile video services, such as mobile television, online MV and so on, conforms to modern people’s psychological need. Mobile phone, as a kind of mobile terminal, has wide application and the function of advanced Smartphone is also gradually popular. Therefore, we focus on mobile phone video. Since wireless network bandwidth is limited and differences of phone equipments are large, such as supporting different video format, video resources need appropriate adaption in order to transfer and display on a mobile terminal successfully. Combining with different network characteristics and terminal conditions, we provide video content with adaptive transmission and adaptation on the basis of content-based video analysis.Firstly, we analyze video resources based on content from two aspects of video static and dynamic characteristics. In static characteristics, we extract video key frames using the method of mutual information and analyze the interested region of key frames. The key frame plays an important role in the reconstruction of video content. This will be a great help to optimize the user’s visual experience if strengthening the protection of key frames in the process of video adapter. In dynamic characteristics, we calculate the motion energy difference between the video frames based on the three-step search block-matching method, in order to distinguish the importance degree of each frame in quantitative way. Secondly, according to the degree of importance of each frame in video resources, video frames can be divided into several quality layers. According to the video features, such as key frames and the value of MEDF, video frames can be divided into four level layers. Finally, we set up simulation test environment, using NOKIA n97emulator as test subject and establish home page of video adaptation for users’request. When the video format and resolution does not meet the requirements of the mobile terminal parameters, they can be adjusted using open source code of FFmpeg. In the last part of the experiment, we show some examples of video adaptation.