Design And Implementation Of Screen Image Broadcast And Its Remote Control In LAN

Network technology is being employed increasingly far and wide in teaching. The network software for educational purposes largely emerges. It has become an important task for teachers and software company developing personnel who work on computer application technology or network technology teaching to study how to apply network technology to education in a better way.This paper discusses how to transmit the pictures on the teacher's host computer screen to the students' computers screens while demonstrating in the computer labs. It also discusses how to perform other relative long-distance control on students' computers. The network software system discussed in this paper is commonly called e-classroom.In order to accomplish the design of this network application development, this paper firstly discusses the theoretical foundation on the net application. Then it discusses the Winsock programming techniques and analyses the multicasting techniques in the process of the development, preparing for the subsequent designs.The third chapter is the core of the paper. It researches the compression algorithm of the screen pictures. It also researches the preparations of the both parties for transmission and receiving, the methods of joining the multicasting groups, the solutions to the broadcasting of the bigger-than-64K data packages, the receiving and assembly display for the receiving side to receive them and the disposal of allowing mistakes.The fourth chapter discusses the multithreading problems. When carrying out the transmission of the screen pictures and the mouse pictures, in order to guarantee the good synchronization of the mouse picture transmission, two threads must be started to conduct the two-way transmission separately.The paper also discusses the long-distance control of the clients over the host computers.The system discussed in the paper has been realized in the C++Builder design and acquires good running effects.