What are the characteristics of multimedia communication?

The characteristics of multimedia communication: 1. Integration refers to the ability to store, transmit, process, and display four types of information: content data information, multimedia and hypermedia information, script information, and specific application information. Ability. 2. Interactivity. 3. Synchronicity means that the images, sounds and text displayed on the multimedia communication terminal work in a synchronous manner.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

Multimedia communication refers to communication that can provide multimedia information transmission. The main body of the transmitted information is multimedia, that is, text, data, graphics, animation, images, sound, voice, video, etc., and different combinations of them , but must contain a time-based media such as voice or video.

Multimedia communication is the product of the combination and development of multimedia technology, computer technology, communication technology and network technology.

Conditions for multimedia communication

1. Information processing, computer and communication technology developed rapidly

In the early 1980s, famous computer companies in the United States, Japan and Europe began to devote themselves to the research of multimedia technology, making multimedia computer technology, including information compression Technologies such as coding, multimedia storage, and graphics synthesis and synchronization have developed rapidly. With the development of modern communication network technology (digital switching technology and transmission technology), multimedia communication technology combined with multimedia computer technology integrates various media information and realizes multimedia communication that fully develops, exchanges and utilizes information.

2. The demand for multimedia communications in the information society

In the 1990s, corporate competition has become increasingly fierce. In corporate business activities, information processing and communication have become more and more important. Advanced communication systems can shorten the time for products to be put on the market, improve services to users, reduce travel expenses, etc. Therefore, modern enterprises must rely on high-quality information and strong information acquisition capabilities to remain invincible. For individuals, as the living environment becomes increasingly complex and the pace of life becomes faster and faster, they hope that communication can ensure that they can obtain information at any time, and use computer-supported collaborative work (CSCW) to improve work efficiency. Therefore, the traditional communication system can no longer fully meet people's communication needs, and the only solution is to build a multimedia communication system.

Characteristics of multimedia communication

The key characteristics of multimedia communication are closely related to the key characteristics of multimedia, and not only information is reflected in the communication process The diversity and integration of carriers and systems also reflect the interactivity and synchronicity of communication methods. To sum up, the key characteristics of multimedia communication are reflected in the three aspects of integration, interactivity and synchronization of multimedia communication. Generally speaking, a communication system that has these three characteristics at the same time can be called a multimedia communication system.

1. Integration

Integration in a multimedia communication system refers to the ability to integrate content data information, multimedia and hypermedia information, script information and specific application information The ability to store, transmit, process, and display these four types of information.

Content Data information refers to information represented by a single media encoding standard, including text, two-dimensional and three-dimensional graphics, still images (continuous tone), binary images, sounds (voice, music, noise) and moving images (cartoons, moving images), etc. Multimedia and hypermedia information (MHI) are different from single-media information. They are structured information, consisting of structural framework and content data. Multimedia and hypermedia objects may be represented and encoded using their appropriate standards in a real-time exchange environment, using some representation standard for single media. Script information is a specific set of structured multimedia and hypermedia information linked by semantic relationships. It is necessary to provide a representation of the operation process of this set of multimedia information and the relationship with external processing modules. Different from the three types of low-level information mentioned above, specific application information is high-level information, which is closely related to the application and varies greatly depending on the application situation. It does not have a general representation method like the first three categories of information (for example, it can be defined and expressed by standards). Its representation method is based on the above three categories. Directory information is typical application-specific information.

2. Interactivity

Interactivity refers to the mutual control ability between people and systems in communication. In multimedia communication systems, interactivity has two aspects: one is the human-machine interface, which is the operating interface provided by the user terminal to the user when using the terminal of the system; the other is the interaction between the user terminal and the system application layer communication protocol.

The human-machine interface is the operation interface provided by the system to the user. Currently, the best human-machine interface that can be used in multimedia communication systems is a Windows-based human-machine interface. Window human-computer interface VI is an interface method based on icons. It can provide a variety of complex human-computer interfaces such as menus, buttons, selection boxes, list items, input fields, dialog boxes, sensitive areas, sensitive fields, etc. to meet the needs of Multimedia communication systems require complex interactive operations. It should be pointed out that the window-based human-machine interface interface in a multimedia communication system is very different from the PC window.

All operations of the PC window are local operations, while the window-based human-machine interface of the multimedia communication system is not a local operation at all, but an interactive operation between the local terminal and the remote host. Every action of it , such as popping up a menu, giving a list item, etc. are all controlled by the remote host, so it is a very complex communication process.

In addition to the human-machine interface, another aspect of interactivity in multimedia communication systems is the application layer communication protocol between the user terminal and the system. In a multimedia communication system, a variety of presentation media can be stored, transmitted, processed, and displayed, and there are complex synchronization relationships between these presentation media. Different presentation media can be transmitted to users in serial form, or they may be transmitted concurrently. The form is transmitted to the user so that the user terminal can reproduce the multimedia information according to the synchronization relationship.

Obviously, in multimedia communication systems, single-channel communication protocols are not enough, and multi-channel communication protocols that can support multiple channels working simultaneously are needed. In the multi-channel communication protocol, in addition to establishing a main channel to support the core interactive work of the system, several auxiliary channels must also be established to provide concurrent information transmission, thereby realizing a complete interactive process of multimedia communication.

Users of multimedia communication terminals have complete interactive control capabilities over the entire communication process. This is a major feature of multimedia communication systems and a major criterion for distinguishing multimedia communication systems from non-multimedia communication systems. For example, a digital color TV can process a variety of presentation media (image coding, sound coding), and can also display a variety of sensory media (pictures, text, sound), but users can not only switch channels to select programs , cannot effectively select and control its entire process, therefore, the color TV system is not a multimedia system. The Video on Demand (VOD) system is different. Users can effectively control the entire process, such as controlling playback, pause, fast forward, rewind, etc. Therefore, the VOD system is a multimedia communication system.

3. Synchronicity

Synchronicity means that the images, sounds and text displayed on the multimedia communication terminal work in a synchronous manner. For example, if the user wants to retrieve a fragment of an important historical event, the moving images (or still images) of the event are stored in the image database, and the text narrative and language description are placed in other databases. The multimedia communication terminal extracts the required information from different databases through different transmission channels, and synchronizes these sounds, images, and text to form a whole information presented to the user, so that the sounds, images, and text can be synchronized. And send the synchronized information to the user.

Synchronicity in multimedia communication systems is one of the most important features of multimedia communication systems. It can be said that whether the information is synchronized or not determines whether the system is a multimedia system or a multimedia system.

In multimedia communication systems, synchronization can be achieved at three levels: link level, presentation level and application level. However, not all multimedia communication systems must have all three levels of synchronization at the same time, but it must use at least one of these synchronization methods. Of course, the more synchronization methods are used, the better the performance of the system will be.

In short, for a multimedia communication system, the three characteristics of integration, interactivity and synchronization must coexist, and one is indispensable. Without one of them, it cannot be called a multimedia communication system.

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