What Are the Different Types of Multimedia Systems?

Multimedia system refers to a system that uses computer technology and digital communication network technology to process and control multimedia information. Broadly speaking, a multimedia system is an integrated information system that integrates telephone, television, media, and computer networks.

Chinese name: Multimedia system
Narrowly: Computer system with multimedia functions

Broadly divided: Integrated computer network and integrated information system
Including: Java framework layer, C language framework layer

Overview of multimedia systems

In a narrow sense, a multimedia system is a computer system with multimedia functions;

Broadly speaking, a multimedia system is an integrated information system that integrates telephone, television, media, and computer networks.

The multimedia system consists of two parts: 1. multimedia hardware system; 2. multimedia software system. The hardware system mainly includes: the main configuration of the computer and various external devices and control interface cards (including multimedia real-time compression and decompression circuits) with various external devices. The software system includes multimedia driver software, multimedia operating system, and multimedia data processing software. , Multimedia authoring tools and multimedia applications.

Android's multimedia system mainly includes Java framework layer, C language framework layer (Media API) and OpenCore. The Java framework layer is connected to the Java application layer. The middle of the Java framework layer and the C language framework layer is the Java local calling part (Media JNI). The core of the C language part of the Android multimedia part is the media library, which mainly provides a framework for media players and media recorders. The media library provides the interface to the upper layer through JNI, and the lower layer is implemented through Packet Video.

Multimedia system multimedia information type

Overview of multimedia systems

Multimedia information includes many different forms such as text, graphics, images, sound, film and television, animation, etc. Due to the different content and format of different types of media, the corresponding content management and processing methods are also different, and the amount of storage varies greatly.

Multimedia system text

Words are the main form of communication between people in the real world and the main medium for information exchange between people and computers. In computers, words are represented by binary codes, that is, different binary codes are used to represent different words. Commonly used characters include Western and Chinese characters.

(1) Western character encoding. In the computer, the Western language is represented by an ASCII (American Standard Code for Information Interchange) code. The ASCII code includes a total of 128 characters, including uppercase and lowercase English letters, punctuation marks, Arabic numerals, mathematical symbols, control characters, etc. One ASCII code occupies one byte and is composed of 7-bit binary number encoding.

(2) Chinese character coding. Chinese character encoding includes: Chinese character input encoding, Chinese character inner code, and Chinese character modulo code.

Chinese character input coding. Western languages can be input directly into the computer through the keyboard, but Chinese characters are different. To input Chinese characters using the keyboard, you must design corresponding input encoding methods for Chinese characters, such as Microsoft Pinyin input method, Wubi input method, and so on.

Chinese character code. No matter what encoding is used to input Chinese characters, each Chinese character is represented in the computer by a unique encoding-Chinese character internal code, which is an in-machine code used to store, exchange, and retrieve Chinese character information. The current Chinese character encoding is two-byte, three-byte or even four-byte. Among them, GB231280 (Chinese Standard Code for National Standard Information Interchange, abbreviated as National Standard Code) is a two-byte code, which represents one Chinese character by two 7-bit binary number codes. Inside the computer, Chinese and Western encodings coexist. In order to be able to distinguish each other, the national standard code specifies the highest byte of both bytes as 1, and the highest byte of the byte used by ASCII code is 0, and then software ( Or hardware).

Chinese character code. The glyph code is a glyph code of the Chinese character expressed by a dot matrix, and it is an output form of the Chinese character. According to the different requirements of Chinese character output, the number of dot matrix is also different. Simple Chinese characters are 16 × 16 dot matrix, enhanced Chinese characters are 24 × 24 dot matrix, 32 × 32 dot matrix, or even higher. Therefore, the information volume of the font lattice is very large, and the storage space is also large. For example, each Chinese character of a 16 × 16 dot matrix takes 32 bytes, and each Chinese character of a 32 × 32 dot matrix takes 128 bytes.

It can be seen that the input coding of Chinese characters, the internal code of Chinese characters, and the character code are three types of codes used in computers for input, internal processing, and output.

The traditional text input method is to use a keyboard for input. You can input text directly to the computer through a handwriting input device, or you can automatically recognize text for input by using optical symbol recognition (OCR) technology. The ideal input method is to use voice to input, so that the computer can understand the human language and convert it into the code inside the machine. At the same time, the computer can pronounce according to the text and truly realize "human-computer dialogue". This is exactly multimedia Problems that technology needs to address.

Multimedia system graphics

Graphics refer to geometric figures represented by points, lines, areas, and three-dimensional space. In geometry, geometric elements are usually represented by vectors, so graphics are also called vector graphics. Vector graphics are represented by a set of instructions. These instructions are used to describe various attributes and parameters such as the shape, position, and color of the lines, rectangles, circles, arcs, curves, etc. that make up a picture.

Multimedia system image

An image is a matrix whose elements represent a point in space, called a pixel. The color and brightness of each pixel are represented by a binary number. This image is also called a bitmap. For black-and-white images, use a 1-bit value. For gray-scale images, 4-bit (16 types of gray levels) or 8-bit (256 types of gray levels) are commonly used to represent the brightness of a point, and color images have multiple description methods. . Bitmap images are suitable for images with more detailed performance, richer levels and colors, and large amounts of detail.

Multimedia system sound

Sound is an important part of multimedia information and an indispensable medium for expressing thoughts and emotions. The sound mainly includes three types of waveform sound, voice and music. Sound is a kind of vibration wave. Wave sound is the most general form of sound. It contains all sound forms. Voice is a wave sound with rich language connotation. People can abstract and extract specific components of speech In order to achieve an understanding of its meaning, it is a special medium in sound; music is a symbolized sound. Compared with speech, its form is more standardized. ways of expression.

Multimedia system film and television

The human eye has a biological phenomenon of "visual dwelling", that is, after observing the object, the image of the object will remain on the retina of the eye for a short time. Therefore, if you play an image that changes the position and shape of an object slightly each time at a fast enough speed, your eyes will feel the object moving continuously. Video (Video) systems (such as movies and television) are dynamic images generated by applying this principle. This image is called a frame, and it is the basic unit of video information.

The traditional broadcast and television system uses an analog storage method. To process the film and television with a computer, the analog film and television must be converted into digital film and television. Digital film and television system is an information system that records the continuously changing image information in a digital manner, and can be played back under the control of application programs, and even special effects can be added through editing operations.

Multimedia system animation

Animation is similar to film and television, and is composed of a frame of still images arranged in a certain order. Each frame is slightly different from the adjacent frames. When the frames are continuously played at a certain speed, the visual persistence characteristics cause continuous Dynamic effects.

The main difference between computer animation and film and television is similar to the difference between graphics and images, that is, the generation of frame pictures is different. Computer animation is the use of computers to represent the behavior and actions of real and simulated objects over time. It is a continuous picture drawn using computer graphics technology. It is an important branch of computer graphics; digital film and television mainly refers to analog signal sources (such as TV, movie, etc.) A mixture of digitized images and synchronized sound. In multimedia applications, there is a tendency to mix computer animation with digital film and television.

Multimedia System Hypertext and Hypermedia

In today's information society, information continues to increase rapidly and the types are constantly increasing. In addition to text, numbers, graphics, images, sounds, movies, and other multimedia information has occupied an increasing proportion in the field of information processing. Massive multimedia information is effectively organized and managed to facilitate people's retrieval and viewing, which has become an important subject. The emergence of hypertext / hypermedia technology has made this issue better solved, and it has become the core technology of information retrieval on the Internet.

Human memory is a network structure constructed in an associative way. There are multiple paths in the mesh structure, and different association searches will inevitably lead to different paths. The network information structure cannot be managed with the traditional text form, and it is necessary to adopt an information management technology one level higher than the text-hypertext.

Hypertext can be simply defined as a technology that collects, stores, and browses discrete information, and establishes and represents the relationship between information. Conceptually, the information that has formed a web is generally referred to as a hypertext, and the system that manages it is called a hypertext system.

Hypertext has a non-linear network structure. This structure can connect related information blocks according to the associative thinking mode of the human brain, and open other links through defined chains such as "hot words" and "hot zones" in the information blocks. Some related media information for users to browse.

With the development of multimedia technology, in addition to text, media information in hypertext can also be multimedia information such as sound, graphics, images, film and television, so the concept of "hypermedia" is introduced, hypermedia-multimedia + hypertext. The two concepts of "hypertext" and "hypermedia" are generally not strictly distinguished and can usually be regarded as synonyms.

The composition of multimedia systems

1. Multimedia hardware systems At present, the most common multimedia hardware systems are multimedia personal computers (MPC) based on the IBMPC series and computers based on Apple Macintosh.

2. Multimedia software system Software system is the soul of multimedia technology. Its function is to enable users to organize and use multimedia data conveniently and effectively. Multimedia software can be divided according to its functions: system software, which is the basic operating system of personal computers, such as Windows series software; editing software, which is software for collecting, organizing and editing various media data, such as word processing software , Audio-visual processing software, etc. Creative software is a program used to integrate and assemble multimedia materials and set interactive control, including language-based creative software such as Visual Basic and tool-based cooperative software such as Tool Book; Multimedia application software refers to The multimedia products compiled by using the above software are called multimedia teaching materials or multimedia courseware. ^[1]