In the computer industry, media has two meanings: first, it refers to the carrier of information, such as language, text, image, video, audio and so on; Secondly, it refers to the carriers that store information, such as ROM, RAM, magnetic tape, magnetic disk, optical disk, etc. At present, the main carriers are CD-ROM, VCD and web pages. Multimedia is a new thing in recent years, which is developing and improving rapidly.
What we call media in multimedia technology mainly refers to the former, that is, using computers to digitize words, graphics, images, animations, sounds and videos, and integrate them on a certain interactive interface, so that computers have the ability to display different media forms interactively. It has greatly changed people's traditional way of obtaining information and conforms to people's reading way in the information age.
Characteristics of multimedia
Multimedia is a man-machine interactive information exchange and communication medium combining more than two kinds of media, which has the following characteristics:
1. Diversity of information carriers: relative to computers, it refers to the diversity of information media;
2. The interactivity of multimedia means that users can interact with various information media of computers, thus providing users with a means to control and use information more effectively;
3. Integration refers to the comprehensive processing of various information media with computers as the center, including the integration of information media and the integration of equipment for processing these media.
4. Digitalization-Media exists in digital form.
5. Real-time-sound and moving images (video) change with time.
Characteristics of multimedia technology:
1, which can complete the processing and transmission of multimedia information related to content, such as sound, moving images, text, graphics, animation, etc.
2, interactive work, rather than simple one-way or two-way transmission;
3, network connection, that is, all kinds of media information are transmitted through the network, rather than by means of storage carriers such as optical disks.
Application of multimedia technology
In recent years, multimedia technology has developed rapidly, and the application of multimedia system has entered all fields of human life with strong penetration, such as games, education, archives, books, entertainment, art, stocks and bonds, financial transactions, architectural design, family, communication and so on. Among them, video games are the most widely used and earliest, and millions of teenagers and even adults are fascinated by them. This shows the power of multimedia. The electronic shopping guide touch screen in shopping malls and post offices is also an example, which greatly facilitates people's lives. In recent years, there are multimedia products for teaching, and one-on-one professional professors have benefited many students. Because of this, many discerning enterprises have seen this form, and even used its interactive ability to add e-commerce, self-maintenance, teaching and other functions, which is convenient for customers and promotes promotion.
It can be said that any enterprising enterprise cannot do without this latest high-tech product. First, the wide application of multimedia is bound to take root and blossom in all walks of life. Second, with the popularity of computers, a new generation of young people who have grown up in the computer environment have become accustomed to this form. As a forward-looking enterprise, they will not give up this future consumer. Third, because multimedia information technology has become very popular abroad.
1, multimedia introduction
Ordinary computer application systems can handle information such as words, data and graphics, while multimedia computers can handle information such as images, sounds, animations and videos in addition to the above types of information, thus creating a new era of computer application.
The significance of the application of multimedia technology lies in:
Computers can handle the most direct and universal information in human life, thus greatly expanding the application fields and functions of computers.
Make the human-computer interaction interface and means of the computer system more friendly and convenient, and non-professionals can also use and operate the computer conveniently.
Multimedia technology closely combines audio-visual technology, computer technology and communication technology, laying a new cornerstone for the development of information processing technology.
Multimedia technology has been developed for many years. So far, the basic technology of sound, video and image compression has gradually matured, and the products have entered the market. Nowadays, popular technologies such as pattern recognition, MPEG compression and virtual reality are gradually maturing, and I believe they will enter the market soon.
2. Multimedia technology
Multimedia technology covers a wide range, mainly including:
Audio technology: audio sampling, compression, synthesis and processing, speech recognition, etc.
Video technology: video digitization and processing.
Image technology: image processing, dynamic generation of images and graphics.
Image compression technology: image compression, dynamic video compression.
Communication technology: the transmission of sound, video and images.
Standardization: multimedia standardization.
The following describes the development of major multimedia technologies.
2. 1 audio technology
Audio technology developed earlier, and some technologies were mature and commercialized several years ago, and even entered the home, such as digital audio. Audio technology mainly includes audio digitization, speech processing, speech synthesis and speech recognition.
Audio digitization is a mature technology at present, and multimedia sound cards are designed with this technology, and digital audio also adopts this technology to replace the traditional analog mode to achieve ideal sound effects. Audio sampling includes two important parameters, namely sampling frequency and sampling data bits. Sampling frequency refers to the number of times sound is sampled per second, and the upper limit of human hearing is about 20KHz. At present, the commonly used sampling frequencies are 1 1KHz, 22KHz and 44KHz. The higher the sampling frequency, the better the sound quality and the larger the amount of data stored. The sampling frequency of CD records is 44. 1KHz, which has achieved the best auditory effect at present. The number of sampling data bits is the data representation range of each sampling point. At present, there are three commonly used types: 8-bit, 12-bit and 16-bit. Different sampling data bits determine different sound quality. The higher the number of samples, the larger the stored data and the better the sound quality. CD records adopt dual-channel 16-bit sampling, and the sampling frequency is 44. 1KHz, reaching the professional level.
Audio processing involves a wide range, but the main aspect focuses on audio compression. At present, the latest MPEG speech compression algorithm can compress sound six times. Speech synthesis refers to the synthesis of text into language. At present, the synthesis level of several foreign speakers has reached the practical stage, and Chinese synthesis has also developed by leaps and bounds in recent years. The most difficult and attractive technology in audio technology is speech recognition. Although it is only in the experimental research stage at present, its broad application prospect makes it one of the research hotspots.
2.2 Video technology
Although video technology has not been developed for a long time, its application scope has been very large, and products combined with MPEG compression technology have begun to enter the home. Video technology includes video digitization and video coding technology.
Video digitization is to convert analog video signals into digital signals that can be processed by computers through analog-to-digital conversion and color space transformation, so that computers can display and process video signals. At present, there are two sampling formats: y: u: v4:1:kloc-0/and Y:U:V4:2:2. The former is the main format adopted by early products, Y:U:V4:2:2.
Video coding technology is to encode digitized video signals into TV signals for recording on video tapes or playing on TV. Different application environments can adopt different technologies. The coding technology from low-end game consoles to broadcast TV stations has matured.
2.3 image compression technology
Image compression has always been one of the technical hotspots, and its potential value is very considerable. It is an important basis for computer processing images and videos and network transmission. At present, ISO has formulated two compression standards, namely JPEG and MPEG.JPEG. These two compression standards are for still images and are suitable for continuous tone color or grayscale images. It includes two parts: one is lossless coding based on DPCM (Spatial Linear Prediction) technology, and the other is distortion algorithm based on DCT (Discrete Cosine Transform) and Huffman coding. The former has no distortion in image compression, but the compression ratio is very small. At present, the latter algorithm is mainly used, and the image is lossy, but the compression ratio is very large, and the distortion can hardly be seen when compressed by about 20 times.
MJPEG refers to MotionJPEG, which uses JPEG algorithm to compress video signals at a speed of 25 frames per second to complete the compression of dynamic video.
MPEG algorithm is a compression algorithm suitable for dynamic video. It not only encodes a single image, but also removes the inter-frame redundancy by using the correlation principle in the image sequence, which greatly improves the compression ratio of the image. Usually, the image quality is high, and the compression ratio is as high as 100 times. The disadvantage of MPEG algorithm is that the compression algorithm is complex and difficult to realize.
3. Introduction of multimedia products
At present, there are many multimedia products on the market. Hardware products mainly include the following categories: sound card, speech synthesis card, CD-ROM, video card, video coding card, still image compression card, dynamic image compression card, etc. Software products include multimedia application system making tools, multimedia information consulting systems, multimedia databases, etc. Choose suitable products according to different requirements when applying.
3. 1 multimedia audio products
Sound card is one of the largest multimedia products on the market at present. Its main function is to store sound samples in a computer or convert digitized sound into analog signals. Usually it also has MIDI music synthesizer and CD-ROM controller, and high-end products also have DSP devices. The typical product of sound card is sound blaster card series.
As for the speech synthesis card, Chinese synthesis card has been developed in China, which can play the text synthesis speech. At present, there is no mature product for speech recognition.
Using the same technology as CD-ROM, CD-ROM can store information such as sound and image in CD-ROM for access. It has become one of the important multimedia products because of its large capacity and no wear in use. At present, the development of MO technology has produced a high-speed CD-ROM which can be read and written, and its application prospect is very broad. Now the biggest application market is CD program (title).
3.2 Multimedia video and compression products
The video card can convert TV video signals into digital signals, and display them on VGA after being superimposed with VGA signals. At the same time, it can capture video images for storage or a small window semi-dynamic continuous tool, so that application development can get rid of many programming problems of multimedia products. MIS (Information Management) system has always been a widely used computer application system. The development of multimedia technology makes the development of multimedia MIS system a reality. At present, multimedia can easily make powerful multimedia application systems without programming.
Information consultation in transportation, tourism and other industries and professional fields also has broad application prospects.