With the rapid development of global economy and information technology represented by multimedia computers and networks, there is no doubt that radio and television education should be open and modern. To realize the openness of distance education and the modernization of teaching, the first problem to be solved is how to develop distance education courses. How to realize the interaction or two-way communication between teachers and students?

First, the impact of multimedia technology on distance teaching materials

The application of multimedia technology fully combines the ideological, scientific and artistic nature of teaching materials, provides rich audio-visual environment for the teaching of various subjects, provides all-round and multi-dimensional information for the audience, improves the information transmission ratio between visual and auditory images, shortens the teaching time and expands the teaching scale. Modern teaching methods should not only impart knowledge to students and cultivate their study habits, but also cultivate their communicative ability, language ability and coping ability. Multimedia technology will provide a real and vivid learning and communication environment in this respect. Multimedia teaching materials provide knowledge, demonstration, practice, discussion and heuristic teaching methods at the same time, which is interesting and enlightening and can supplement the deficiency of practical teaching. At present, the CAI courseware provided by CCTV is mainly used in this field, such as mock trial, science and engineering experiment, accounting experiment, animal breeding and so on. Teachers can use the existing procedures to organize teaching, or dynamically organize and modify the teaching content, adjust the progress according to different people, promote students' active participation in training, stimulate their curiosity and cultivate their thinking creativity. Second, the influence of multimedia technology on the communication mode of distance program teaching

Modern multimedia technology makes the transmission process of distance education networked. In 1997 State of the Union address, US President Bill Clinton proposed: "By the year 2000, every classroom and library in the United States should be connected to the Internet, so that every child aged 12 can access the Internet." At present, almost all universities in the United States have established campus networks and are interconnected with the Internet. American educational technology magazines and international educational technology conferences are almost all about online education and virtual classrooms. Multimedia teaching design and so on.

Relying on the development of modern communication technology and multimedia computer technology, the network distance teaching mode greatly improves the scope and timeliness of educational communication, so that educational communication is not affected by time, place, national boundaries and climate. As long as the network is scattered, the courseware on the network leads there. Really broke the obvious campus boundaries and changed the traditional concept of "classroom". Students can break through the limitations of time and space and accept the guidance of teachers from different countries. You can get richer and more intuitive multimedia information besides the text, and the information in libraries all over the world can be shared. It can organize the teaching content according to the way of thinking of learners, and it can also be controlled and tested by learners themselves. The traditional teaching method has changed from one-way to two-way, realizing the two-way communication between teachers and students and between students in distance teaching. From popularization to personalization. Students' individual chemistry acquisition has been more fully reflected, and the feedback problem in distance teaching is no longer a difficult problem. There are two main transmission modes: 1. Online teaching mode Online teaching refers to the direct real-time teaching between teachers and students through the Internet. When surfing the Internet, students can use the browsing function to learn, or they can log in to the teacher's host computer through Telnet for interactive learning, and they can also use real-time discussions and remote meetings. In this teaching mode, information is transmitted and fed back instantly between teachers and students. Teachers can directly guide and supervise students' learning process and give teaching suggestions in person. According to students' feedback information, the teaching method is adjusted in time, and the teaching effect is good.

2. Offline teaching mode Offline teaching means that teachers send teaching materials to students through the Internet, and students study in offline time after receiving these materials. Mainly through FTP transmission corresponding teaching courseware and e-mail for teaching. Students download the materials they need to learn to the local hard disk according to the teacher's requirements, then open the courseware to learn, and then transfer the homework to the teacher's host computer, and the teacher corrects it and sends it back. This method is more flexible in learning time and saves the cost of surfing the Internet, but the feedback is not as timely as online teaching.

Combining online and offline teaching mode can give full play to the advantages of the two teaching modes, and it is a mode worth adopting in current distance education. For example, in the teaching process of China's Radio and TV University, it is very convenient and flexible to send some contents to students through the Internet. It is also possible to consider allowing students to transmit the corresponding teaching contents by visiting the TV University's homepage and using e-mail. With the development of hardware environment, it will gradually transition to Internet-based teaching methods. At present, the multimedia network teaching in China not only needs further improvement in hardware environment, but also puts forward higher requirements for teachers' quality.

Thirdly, the renewal of teachers' concept and the change of knowledge structure.

Modern educational technology emphasizes analyzing and solving teaching problems with systematic concepts, and pursues the optimization of teaching effect. The modernization of teaching media does not mean the optimization of teaching effect. What improves the teaching quality is not the use of superficial media at all, but the renewal of teachers' ideas. The application of modern information media in teaching must be supported by teaching experience and knowledge theory.

1. Updating teachers' concept Although multimedia computer-aided teaching has many obvious advantages, it is difficult to carry out teaching without the active participation and discussion of front-line teachers. Judging from the use of media by both the subject and the object in the process of educational communication, every media update is accompanied by the enhancement of communication function and the improvement of communication effect, and at the same time, higher requirements are put forward for the transmitter and receiver of education. Electronic communication requires both parties to have certain technical capabilities and environmental conditions. The development and innovation of media technology has formed a pair of contradictions with the traditional habits and psychological stereotypes of human beings using media to spread. This contradiction is mainly manifested in their adaptability and dependence on traditional media and their passive resistance to the use of new media. Most teachers have been accustomed to the unchanged teaching model for many years. The arrival of computer-aided teaching will make them feel pressure and re-establish the teaching concept of information. The huge and rapid information resources and brand-new interactive functions provided by computers make them have to re-recognize their own knowledge system, which is itself a revolution in self-knowledge. With the advent of teaching reform, teachers must change their traditional role of expressing teaching content in language in class. Before class, we should organize the design, production and processing of teaching information, be competent in the operation and control of classroom teaching courseware, ask and answer questions, and actively eliminate unfavorable factors such as students' attention shift or excessive dependence on the media. In fact, teachers play various roles, such as organizer, controller, coordinator and mentor.

2. Changes in teachers' knowledge structure Faced with the rapid development of educational technology in the new era, distance education institutions should train existing personnel in a planned way while increasing the number of multimedia computer personnel, network management designers and modern teaching staff. While improving the hardware environment, Heilongjiang Radio and TV University has issued a microcomputer training plan for all faculty members, and the school education technology center will also train the audio-visual education staff of municipal TV universities all over the province in stages and batches in production technology and CAI courseware knowledge. The three-level training mechanism established by educational technology departments can be used for our reference:

Level 1: (all teachers and audio-visual teaching staff) should master the theoretical knowledge of teaching design, teaching and learning, the knowledge of computer introduction and the use of general teaching software, such as Windows, Word, Power point, web browser, E-mail, etc.

Level 2: (full-time educational technology personnel and teaching and research personnel related to educational technology) should master the theory of computer-aided teaching and the knowledge of design, production and evaluation of teaching software. Such as Authware, the design of network homepage, the design, production and evaluation of multimedia CAI courseware, etc.

Level 3: (computer-aided educational design and development personnel, educational technology backbone personnel) should master the programming of teaching software and the use of related computer art and computer music software. Nonlinear editing system, etc.

In a word, the development of multimedia computer teaching system involves the all-round combination of computer, art, music, education, psychology and other majors. The future education is science and technology-oriented education, and its development trend will be characterized by computer multimedia intelligent education; It not only brings us broad prospects for the modernization of distance education, but also brings us new challenges for distance educators.