Security requirements analysis is a precondition to provide effective and appropriate safeguard for information systems. Based on the existing theories and approaches, this paper discusses the categories and analysis procedure of security requirements in information systems. And according to the basic steps of security requirements analysis, the security hazard analysis model and the security risk analysis model are presented here. At the end, the methods of security requirements specification and the corresponding improvements are also introduced.
主要介绍一种基于微软DirectX平台实现音频视频无线传输的系统,该系统利用Direct Play Voice实现音频传输,利用DirectShow实现视频传输。针对音频传输过程中延时、抖动现象,利用RTP协议包头时间戳和建立缓冲池的方法进行消除,提高音质;利用RTP/RTCP协议传输MPEG-4码流,提高视频质量。探讨了该系统的基本结构和实现细节,实际测试表明该系统音频和视频质量令人满意,具有稳定性好、占用带宽低等优点。
