Development And Implementation Of Mobile Video Monitoring System Based On Android Smart Phone

With the development of technology and the rising living standards, video monitoring system has been widely used and become networked, intelligent and high-definition. In recent years, Mobile video monitoring is an important research field because of the development of mobile communication networks and the popularity of Android smart phone. Mobile video monitoring system based on Android smart phone is researched in-depth in this thesis.The design of mobile video monitoring system is based on C/S architecture.The system is composed of three parts:Android mobile video capture terminal, Android mobile video monitoring client and the server. Android mobile video capture terminal is mainly for capturing video and audio through camera and microphone. It encodes video data into H.264 format and audio data into G.726 format then transmit them to the server via a wireless network. Android mobile video monitoring client decodes and plays audio and video data requesting from the server. Server is an intermediary between the client and the terminal, and it is responsible for the data transmission.The transmission protocol is designed based on the UDP protocol in this thesis. FFmpeg and X.264 are ported to Android through Android NDK.Android mobile video capture terminal realizes two types of video encoding, soft coding and hard coding.Soft coding is based on X.264. It is more flexible but low efficiency. It takes up CPU resources. Hard coding is based on MediaRecoder and encodes the data by hardware. It is efficient but poor in lexibility and portability. In order to ensure the real-time performance of system, hard coding is more suitable. The terminal also enables audio capture and codec, shoot and upload photos and GPS positioning.Android mobile video monitoring client recombines the video data by the frame number and package number. Then it decodes the video frame and displayes on the screen. The client enables remote control for the fixed cradle head camera of network video monitoring system. Three-dimensional spherical coordinate system is designed to display the deflected position of cradle head. Users can control the camera intuitively.The system is designed based on the analysis of data flow between server and terminal, server and client. There are two kinds of data, directly transmitting data and caching transmitting data. Different data transmitting mechanisms are designed for them.Finally, the paper summarizes the work and discusses the further research and improvement of the system.