File format refers to the file coding type and file structure. For example, ASCII files, binary files, JPG image files, HTML files, EXE files. File format is an agreement on file coding mode and file structure, which is easy to distinguish. Just like a key opens a lock, different files should be read, displayed, written, opened or run in different ways.
The input and output formats of data define the type of data (integer, floating point, character and structure). . . ) and input/output mode and type conversion mode.
The data transmission format defines the data transmission.
The definition and convention of format is equivalent to the rules and regulations of the game. What game to play, what rules (format) to use, without rules, without Fiona Fang, everything will be in a mess. A pile of keys can't open a pile of locks.
take for example
Picture format gif, jpg, jpeg
Audio format mpeg rm wma mp3 wav
Video formats AVI, MOV, RM and so on.
Introduce the longest ones in detail.
1.AVI format
Its full English name is Audio Video Interleaved, that is, audio and video interleaved format. It was introduced by Microsoft in 1992, and is known and familiar with people together with Windows3. 1. The so-called "audio and video interleaving" means that video and audio can be intertwined and played simultaneously. The advantage of this video format is that it has good picture quality and can be used across multiple platforms. But its disadvantage is that it is too big, and what is worse is that the compression standards are not uniform. Therefore, it is often encountered that the high version of Windows media player cannot play the AVI format video encoded and edited earlier, and the low version of Windows media player cannot play the latest AVI format video encoded and edited. In fact, the solution is also very simple, and we will give the solution in the later part of video conversion and video restoration.
2.DV-AVI format
The full English name of DV is Digital Video Format, which is a family digital video format jointly proposed by Sony, Panasonic, JVC and other manufacturers. At present, very popular digital cameras use this format to record video data. It can transmit video data to the computer through the IEEE 1394 port of the computer, and can also record the edited video data from the computer back to the digital camera. So is the file extension of this video format. Avi, so we used to call it DV-AVI format.
3.MPEG format
Its full English name is Moving Picture Expert Group, which is the format of moving picture expert group. VCD, SVCD and DVD that we often watch at home are all in this format. MPEG file format is the international standard of moving image compression algorithm, which uses lossy compression to reduce redundant information in moving images. MPEG compression method goes further, that is, most of the same parts of two adjacent images are retained, and the redundant parts in the latter image and the previous image are removed, so as to achieve the purpose of compression. At present, there are three compression standards of MPEG format, namely MPEG- 1, MPEG-2 and MPEG-4. In addition, MPEG-7 and MPEG-2 1 are still in the research and development stage.
MPEG- 1: formulated in 1992, it is an international standard designed for digital storage media moving images and audio coding with data transmission rate below 1.5Mbps, which is also the VCD production format we usually see. The file extensions of this video format include. mpg，。 mlv，。 mpe，。 Mpeg and. Dat file in VCD.
MPEG-2: Based on 1994, the design goal is advanced industrial standard image quality and higher transmission rate. This format is mainly used for DVD/SVCD production (compression), as well as some HDTV (high definition television broadcasting) and some demanding video editing and processing. The file extensions of this video format include. mpg，。 mpe，。 mpeg，。 M2v and. Vob file on DVD.
MPEG-4:MPEG-4 was established by 1998 and is specially designed for playing high-quality video of streaming media. It can compress and transmit data with extremely narrow bandwidth through frame reconstruction technology, and obtain the best image quality with the least data. The most attractive thing about MPEG-4 is that it can save small-capacity video files close to DVD quality. The file extensions of this video format include. asf，。 Mov, DivX, AVI, etc.
4.DivX format
This is another video coding (compression) standard derived from MPEG-4, which is what we usually call DVDrip format. It adopts MPEG-4 compression algorithm and integrates MPEG-4 and MP3 technologies. To put it bluntly, it is a video format formed by using DivX compression technology to compress the video image of DVD with high quality, and compressing the audio with MP3 or AC3 at the same time, then synthesizing the video and audio, and adding corresponding plug-in subtitle files. Its picture quality is almost the same as that of DVD, and its volume is only a fraction of that of DVD.
5.MOV format
A video format developed by Apple. The default player is Apple's QuickTimePlayer. It has the characteristics of high compression ratio and perfect video definition, but its biggest feature is cross-platform, that is, it can support not only MacOS but also Windows series.
6.ASF format
Its full English name is Advanced Streaming format, which is a video format introduced by Microsoft to compete with the current Real Player. Users can play directly with Windows Media Player that comes with Windows. Because it adopts MPEG-4 compression algorithm, the compression rate and image quality are very good.
7.WMF format
Its full English name is Windows Media Video, and it is also a file compression format introduced by Microsoft. It adopts independent coding mode and can directly watch video programs on the Internet in real time. The main advantages of WMV format include: local or network playback, extensible media types, scalable media types, multilingual support, environmental independence, rich inter-stream relationships and scalability.
8.RM format
The audio and video compression standard formulated by network companies is called Real Media. Users can use RealPlayer or RealOne Player to play network audio and video resources that meet the technical specifications of RealMedia, and RealMedia can also set different compression ratios according to different network transmission rates to realize real-time transmission and playback of image data on low-rate networks. Another feature of this format is that users can use RealPlayer or RealOne Player to realize play online without downloading audio and video content.
9.RMVB format
This is a new video format extended from the RM video format upgrade. Its advantage lies in that the RMVB video format breaks the way of average compressed sampling in the original RM format, and makes reasonable use of code rate resources on the basis of ensuring the average compression ratio, that is to say, static scenes with little action can leave more bandwidth space, and when there are fast-moving scenes, these bandwidths will be used. In this way, on the premise of ensuring the quality of still images, the image quality of moving images is greatly improved, thus achieving a delicate balance between image quality and file size.
1965 was born in Jingyanggang. His real name is Wang Taiyong. 1984 graduated from Texas medical college, majoring in laboratory medicine. 1986 started writing, and 1987 published his works. He has published more than 200 poems in newspapers and periodicals at home and abroad, such as Poetry Magazine, Star Poetry Magazine, Poetry Magazine, Poet God and Vineyard, and won many awards. He is the author of I'm glad you came, The Blind Touch the Elephant and Local Accent. In addition, tens of thousands of words of poetics and cultural prose are scattered in major newspapers and periodicals in China. He is a member of Shandong Writers Association, vice chairman of Dezhou Writers Association, and a top-notch professional and technical talent in Decheng District of Dezhou City. Now he works in the Policy Research Office of Decheng District Committee of Dezhou City.
format
Piaget called it cognitive structure format. Format is a dynamic psychological structure. On the one hand, it is different from the static knowledge structure, on the other hand, it does not have the nature of physiological anatomy. At first, the format was just some isolated and simple unconditional reflections, such as grasping and sucking, but through adaptation and organizing functions, the format itself became more complicated and merged with each other to form a new format. The process of cognitive development is the process of increasingly complex formats and the integration of different formats.