Several types of common multimedia file formats

Common multimedia file Format types Multimedia technology fundamentally changed the past character-based computer processing, dynamic image, sound to the computer brought infinite vitality. The core of multimedia technology is the use of computer integrated processing of sound, text, images and other multimedia information, making the computer more entertaining, more humane. 3. Figure (Common image filename suffix)

BMP (*.bmp): a bitmap (BitMap) file format, which is a set of dots (pixels) consisting of images that are commonly used in standard bitmap formats under Windows systems. Its structure is simple, not compressed, the general image file will be relatively large. Its greatest benefit is that it can be "accepted" by most software and can be called a universal format. Often applied to Windows wallpapers and more.
GIF (*.gif): Graphic Interchange Format (graphics interchage format) (. gif): Supports 256 colors. Divided into static GIF and animated GIF two kinds, support transparent background image, suitable for a variety of operating systems, "size" is very small, many small animations on the web are GIF format. In fact, GIF is to save a number of images as an image file, thus forming an animation, so in the final analysis, GIF is still a picture file format.
JPEG (*.jpg,*.jpeg): is one of the most widely used image formats, it uses a special lossy compression algorithm, will not be easy to be detected by the human eye of the image color removed, so as to achieve a larger compression ratio (can reach 2:1 or even 40:1), but the damaged image can not be restored after compression. Commonly used in Web pages, is now also the preferred format for digital cameras to save images. So "petite, looks great", especially by the internet favor.
PSD: Image processing Software "mobile" Photoshop special image format, image files are generally large.
PNG: Similar to JPG format, there are many images in the Web page that are in this format, the compression ratio is higher than GIF, the image transparency is supported, and the alpha channel can be used to adjust the transparency of the image.

Common Audio file formats

Audio files are usually divided into two categories: sound files and midi files, sound files refers to the sound input device recorded by the original sound, directly recorded the real sound of binary sampling data, usually large file, while the midi file is a musical playing instruction sequence, equivalent to the score, because does not contain sound data, Its file size is small.
1. sound files
Digital audio is the same as CD music, the real digital signal is saved, playing through the sound card to restore the signal to a pleasant sound. However, the sound files generated by storing the sound information are quite large, so the vast majority of sound files use different audio compression algorithms to obtain smaller files as much as possible while maintaining sound quality unchanged.
Wave file ——. Wav
The wave format is a sound file format developed by Microsoft Corporation that holds the audio information resources of the Windows platform and is widely supported by the Windows platform and its applications. The file size is large and is used for storing short sound fragments.
MPEG Audio File ——. mp1/. mp2/. Mp3.mp4
MPEG is the English abbreviation of the motion image Expert Group (Moving Picture Experts Group), which represents the MPEG motion image compression standard, where the audio file format refers to the audio portion of the MPEG standard, the MPEG audio layer. MPEG Audio file compression is a lossy compression, depending on the compression quality and coding complexity can be divided into three layers (MPEG audio layer 1/2/3), respectively, corresponding to MP1, MP2 and MP3 three kinds of sound files. MPEG Audio Coding has a high compression rate, MP1 and MP2 compression rate of 4:1 and 6:1~8:1, while MP3 compression rate is up to 10:1~12:1, that is, one minute CD-quality music, uncompressed 10MB storage space, And after MP3 compression encoding only about 1MB, while its sound quality basically remains undistorted, therefore, the most used is the MP3 file format.
RealAudio file ——. ra/.rm/. Ram
The RealAudio file is a new streaming audio (streaming) file format developed by RealNetworks company, which is included in the audio, video compression specification RealMedia developed by RealNetworks Company, It is mainly used for transmitting audio information in real time on a low-speed WAN. Depending on the network connection rate, the sound quality of the client is not the same: for a 14.4Kbps network connection, the amplitude modulation (AM) quality is achieved. ; For a 28.8Kbps connection, you can achieve broadcast-grade sound quality, and if you have ISDN or a faster line connection, you can get CD-quality sound.
2. midi Files
MIDI file ——. Mid/. Rmi
MIDI is an acronym for Musical Instrument Digital Interface (musical instrument digital Interface), a unified international standard for digital music/electronic synthesis instruments, which defines the way in which music signals are exchanged by computer music programs, synthesizers and other electronic devices, It also provides a protocol for data transfer between electronic musical instruments and computer-connected cables and hardware and equipment for different manufacturers, which can be used to create digital sounds for different instruments and to simulate common instruments such as cello, violin and piano. MIDI files are more compact than sound files that hold real sampled data, and their file sizes are usually much smaller than sound files.
　　
Common Video file formats
Generalized video files can be divided into two categories, namely, animation files and image files: Animation file refers to a number of interrelated frame still images composed of image sequences, these still images are continuously played to form a set of animation, usually used to complete a simple dynamic process demonstration; image files, mainly those containing real-time audio, The multimedia information of the video information usually comes from the video input device, because it contains a lot of audio and video information.
1. Animation files
GIF file ——. Gif
GIF is the abbreviation for the Graphics Interchange Format (Graphic Interchange Format) and is a high compression color image file format introduced by CompuServe company in the 80 's. Most of the color animation files used on the Internet today are GIF files of this format. In Flash, you can export your design in GIF format.
2. Image files
AVI file ——. Avi
AVI is an acronym for Audio Video Interleaved, which is a digital audio and video file format developed by Microsoft Corporation. AVI files are mainly used in multimedia CD-ROM, to save movies, TV and other image information, and sometimes appear on the Internet, for users to download and enjoy the new film of Wonderful pieces.
QuickTime file ——. mov/. Qt
QuickTime is an audio, video file format developed by Apple Computer to hold audio and video information with advanced video and audio capabilities.
MPEG file ——. mpeg/. mpg/. Dat
MPEG file format is an international standard of motion image compression algorithm, it uses lossy compression method to reduce the redundant information in motion image, and guarantee the dynamic refresh rate of 30 frames per second, which has been supported by almost all computer platforms. MPEG compression standard is designed for motion images, the basic method is to collect and save the first frame of information in unit time, and then only store the rest of the frame relative to the first frame changes in the part, so as to achieve the purpose of compression. MPEG average compression ratio of 50:1, up to 200:1, compression efficiency is very high, while the image and sound quality is very good, and on the microcomputer has a uniform standard format, compatibility is quite good.
RealVideo file ——. RM
RealVideo file is a new streaming video file format developed by RealNetworks company, which is mainly used for real-time transmission of active video images on low-speed WAN, and can adopt different compression ratios according to the different data rate of network, so as to realize real-time transmission and real-time playback of image data. To play the video image while downloading while the data is being transferred, instead of having to download and play it as most video files do. Currently, there are many websites on the internet that use RealVideo technology to carry out live broadcasts of major events.

Classroom Exercises:

First, the following documents are classified by different types, at least two files per class.
Qi Xiang. mp3, Shenzhou sixth. jpg, index.html, fairy tale. RM, Dongba Road Map, BMP, Birch forest, MP3, learning methods and techniques. Doc, Information Technology module. txt, our love. wav, Rogue Rabbit. gif, that big high school. htm, information technology. asp
Text file:
Web file:
Picture file:
Audio/Video files:
Please tell me what common software can be edited to process the above files? Say at least one of each category. (Audio/Video write-play software or editing software is available.) ）
Example: the information technology module. TXT can be processed using Notepad.

Second, all the information in the computer (including audio, video, etc.) is stored and transmitted in digital form, and the uncompressed data information usually occupies huge storage space. For example, a 640x480 65536-color (16-bit) image has a data volume of about 600KB, while a minute CD-quality audio file typically requires about 10MB of storage space. Therefore, data compression must be performed on these multimedia messages.
Please read the previous study material carefully, say which of the above multimedia files belong to the compression class? What is the meaning of compression?
Extended Exercise:
Third, in addition to the text mentioned in the multimedia files, you also know which multimedia file types and processing software? Please briefly describe and give excellent links to network resources and share with you.
Requirements: Please edit the answer to the above questions in Notepad, verify the error after the article "comment", the user name please enter your name, if you are not a growth blog user, password can be omitted.

Several types of common multimedia file formats