What are the formats for pictures and music? What do they mean? Can't figure it out?

First, the BMP format

BMP is the abbreviation of the English Bitmap (bitmap), which is the standard image file format in the Windows operating system, and can be supported by a variety of Windows applications. With the popularity of the Windows operating system and the development of rich Windows applications, the BMP bitmap format has rightly been widely used. This format is characterized by the richness of the image information contained, almost no compression, but this leads to its inherent shortcomings - occupy too much disk space. Therefore, BMP is currently more popular on a single machine.

Second, the GIF format

GIF is an acronym for Graphics Interchange Format. As the name suggests, this format is used to exchange pictures. As a matter of fact, in the 1980s, CompuServe, a famous online information service organization in the United States, developed this GIF image format in response to the limitations of network transmission bandwidth at that time.

The GIF format is characterized by a high compression ratio and less disk space occupation, so this image format was quickly and widely used. Initially, GIF is simply used to store a single still image (called GIF87a), and later with the development of technology, you can simultaneously store a number of still images to form a continuous animation, making it one of the few formats that support 2D animation at that time (known as GIF89a), and in the GIF89a image can be specified in the transparent area, so that the image has a non-trivial display effect, which makes GIF even more beautiful. This makes the GIF scenery. Currently on the Internet a large number of colorful animation files are mostly in this format, also known as GIF89a format files.

In addition, taking into account the actual situation of network transmission, the GIF image format also increased the gradual display mode, that is, in the image transmission process, the user can first see the general outline of the image, and then with the transmission process continues to gradually see the details of the image, thus adapting to the user's "from the hazy to clear" viewing psychology. Currently, a large number of colorful animation files on the Internet are mostly in this format.

But GIF has a small drawback, namely, it can not store more than 256 color images. Nevertheless, this format is still widely used on the Internet, which is inseparable from the advantages of short GIF image files, fast download speed, and the availability of many image files of the same size to form animations.

Third, JPEG format

JPEG is also a common image format, it is developed by the Joint Photographic Experts Group (Joint Photographic Experts Group) and named "ISO 10918-1", JPEG is just a common name. JPEG file extension .jpg or . jpeg, its compression technology is very advanced, it uses lossy compression to remove redundant images and color data, to get a very high compression rate at the same time to show a very rich and vivid image, in other words, it is the least amount of disk space to get a better image quality.

At the same time, JPEG is a very flexible format, with the ability to adjust the image quality, allowing you to use different compression ratios for this kind of file compression, for example, we can up to 1.37MB BMP bitmap file compression to 20.3KB. Of course, we can find a balance between the image quality and file size.

Because of JPEG's superior quality and outstanding performance, it is also widely used, especially on the Web and CD-ROM readers, where it can certainly be found. Currently all types of browsers support JPEG as an image format, because the JPEG format has a smaller file size and faster download speeds, making it possible for Web pages to provide a large number of beautiful images in a shorter download time, and JPEG has become the most popular image format on the Web at the same time as a matter of course.

Four, JPEG2000 format

JPEG 2000 is also responsible for the development of the JPEG organization, which has an official name called "ISO 15444", compared with JPEG, it has a higher compression rate and more new features of the new generation of still image compression technology.

JPEG2000 is an upgraded version of JPEG, with a compression rate about 30% higher than JPEG. Unlike JPEG, JPEG2000 supports both lossy and lossless compression, while JPEG can only support lossy compression. Lossless compression to save some important pictures is very useful. JPEG2000 is an extremely important feature is that it can achieve progressive transmission, which is the same as the GIF "gradual display", that is, the first transmission of the outline of the image, and then gradually transmit the data, and constantly improve the quality of the image, so that the image from the hazy to a clear display, and do not have to be the same as in the current JPEG, from the top to the bottom of the slowly!

In addition, the image quality can be improved continuously, so that the image from hazy to clear display, instead of like the current JPEG, from top to bottom slowly.

In addition, JPEG2000 supports the so-called "region of interest" feature, which allows you to specify the compression quality of the region of interest on the image, and to select the specified part to decompress first. The advantages of JPEG 2000 over JPEG are obvious, and it is backward compatible, so it will soon replace the traditional JPEG format.

JPEG2000 can be used in the traditional JPEG market, such as scanners, digital cameras, and so on, as well as in newer areas, such as networked transmissions, wireless communications, and so on.

V. TIFF format

TIFF (Tag Image File Format) is a widely used image format in the Mac, which is jointly developed by Aldus and Microsoft, initially designed for cross-platform storage of scanned images. It is characterized by a complex image format and a large amount of stored information. Because it stores so much information at the subtle level of the image, the quality of the image can be improved, so it is very conducive to the reproduction of the original.

The format has two forms of compression and non-compression, in which the compression can be stored using the LZW lossless compression scheme. However, due to the complex structure of the TIFF format, compatibility is poor, so sometimes your software may not be able to correctly recognize the TIFF file (now the vast majority of software has solved this problem). It is also very easy to port TIFF files to Macs and PCs, so TIFF is now one of the most widely used image file formats on microcomputers.

Six, PSD format

This is the famous Adobe image processing software Photoshop special format Photoshop Document (PSD). PSD is actually Photoshop graphic design a "draft map", which contains a variety of layers, channels, masks and other design samples, so that the next time you open the file. It contains a variety of layers, channels, masks and other design samples, so that the next time you open the file can modify the previous design. Photoshop supports a variety of image formats, PSD access speed is much faster than other formats, but also very powerful. Since Photoshop is becoming more and more widely used, there is reason to believe that this format will gradually become popular as well.

VII. PNG format

PNG (Portable Network Graphics) is an emerging network image format. At the end of 1994, due to Unysis announced that GIF has a patented compression method, requiring the development of GIF software authors must pay a fee, which prompted the birth of free png image format. png at the beginning of the combination of GIF and JPG two of the strengths of the intention to replace the two formats in one fell swoop. 1996 October 1 by the PNG to the international network of alliances and get Recommended standards, and most of the drawing software and browsers began to support PNG image browsing, since the PNG image format revitalization.

PNG is currently the format that guarantees the least distortion, which draws on the strengths of both GIF and JPG, with a rich storage format and the color patterns of both GIF and JPG; it is also characterized by the ability to compress the image file to the limit to facilitate network transmission, but retains all the information related to the quality of the image, because PNG is a lossless compression to reduce the size of the file, which is not the same as sacrificing image quality for the quality of the image, which is the same as sacrificing the image for the quality of the file, which is the same as sacrificing the quality of the image for the quality of the file. This is different from JPG, which sacrifices image quality for high compression rate; its third feature is that it displays very fast, and it only needs to download 1/64th of the image information to display a low-resolution preview image; fourthly, PNG also supports the production of transparent images, which are very useful in the production of webpage images, we can set the background of the image to be transparent, and replace the transparent color with the color information of the webpage itself, so that the transparent color can be replaced by the transparent color. We can set the background of the image to transparent, and use the color information of the web page itself to replace the transparent color, so that the image and the web page background can be harmoniously blended together.

The disadvantage of PNG is that it does not support animation effects, if you can strengthen in this area, it can be a complete alternative to GIF and JPEG. Macromedia's Fireworks software is the default format of PNG, and now more and more software to support this format, and on the network is also more and more cut-off popular.

Eight, SWF format

The use of Flash we can create a suffix name for the SWF (Shockwave Format) of the animation, this format of the animation image can be a relatively small volume to express the rich multimedia form. In the transmission of images, do not have to wait until the file is downloaded to watch, but can be downloaded while watching, so especially suitable for network transmission, especially in the case of poor transmission rates, but also to achieve better results. Facts have also proved this point, SWF has been applied to a large number of WEB pages for multimedia presentations and interactive design. In addition, SWF animation is produced by vector technology, so no matter how many times the picture is enlarged, the picture will not be damaged in any way. In summary, SWF format works with its high-definition picture quality and small size, by more and more web designers favor, but also more and more become the mainstream of web animation and webpage image design and production, has become the de facto standard of online animation.

Nine, SVG format

SVG can be regarded as the hottest image file format, its full name is Scalable Vector Graphics, meaning scalable vector graphics. It is based on XML (Extensible Markup Language), developed by the World Wide Web Consortium (W3C) alliance. Strictly speaking, it should be an open-standard vector graphics language that allows you to design exciting, high-resolution Web graphics pages. Users can depict images directly in code, open SVG images with any word processing tool, make images interoperable by changing parts of the code, and readily insert them into HTML to be viewed through a browser.

It provides the current popular network format GIF and JPEG can not have the advantage: you can arbitrarily enlarge the graphic display, but never at the expense of image quality; the word in the SVG image to retain the state of editable and searchable; on average, the SVG file is much smaller than the JPEG and GIF format files, and therefore download very quickly. It is believed that the development of SVG will provide a new image standard for the Web.

Other non-mainstream image formats:

1, PCX format

PCX format is the ZSOFT company in the development of image processing software Paintbrush developed a format, which is a compressed format, taking up less disk space. Because the format has been around for a long time and has the ability to be compressed and in full color, it is still relatively popular.

2, DXF format

DXF (Autodesk Drawing Exchange Format) is a vector file format in AutoCAD, which stores files in ASCII code, and is very accurate in terms of the size of the representation. Many software programs support the input and output of the DXF format.

3, WMF format

WMF (Windows Metafile Format) is a common metafile format in Windows, belonging to the vector file format. It has a short file, pattern modeling features, the entire graphic is often spliced by the various independent components, and its graphics tend to be more rough.

4, EMF format

EMF (Enhanced Metafile) is Microsoft in order to make up for the lack of the use of WMF developed a Windows 32-bit extension of the metafile format, which also belongs to the vector file format, the purpose of which is to make the metafile more acceptable

5, LIC (FLI/FLC) format

5. ) format

Flic format developed by Autodesk, FLIC is FLC and FLI collectively: FLI is the original animation file format based on 320 × 200 resolution, while FLC uses a more efficient data compression technology, so it has a higher compression ratio than FLI, and its resolution has improved a lot.

6, EPS format

EPS (Encapsulated PostScript) is a format that is less common among PC users, while Apple Mac users use more. It is an ASCII file format described in the PostScript language and is mainly used for typesetting, printing, and other output tasks.

7, TGA format

TGA (Tagged Graphics) file is developed by the U.S. Truevision for its display cards, an image file format, has been accepted by the international graphics, graphics industry. TGA structure is relatively simple, belongs to a graphic, image data in a common format, in the field of multimedia has a great impact, is a computer-generated images to the TV, the TV, and so on. influence, is a computer-generated image to television conversion of a preferred format.

Music Formats:

Music Formats at a Glance

Classic WAVE

The WAVE file, the most classic Windows multimedia audio format, is widely used, and uses three parameters to represent sound: the number of bits sampled, the sampling frequency, and the number of channels.

There are mono and stereo channels, and the sampling frequency is generally 11025Hz (11kHz), 22050Hz (22kHz), and 44100Hz (44kHz).WAVE file occupies the capacity=(sampling frequency×number of sampling bits×voice channel)×time/8(1 byte=8bit).

Traditional MOD

MOD is a wavetable-like music format, but with a MIDI-like structure, using real samples and a small size. In the old DOS days, MOD was often used as background music for games. Nowadays MODs can contain many tracks and come in numerous formats such as S3M, NST, 669, MTM, XM, IT, XT and RT.

MIDI for computer music

MIDI is short for Musical Instrument Data Interface, which uses digital recordings of sounds played by instruments (each note is recorded as a number), and then, when played, these recordings are synthesized by FM or wavetable synthesis: FM synthesis simulates the sound of a musical instrument by a multiple frequency FM synthesis simulates the sound of an instrument by mixing sounds from multiple frequencies; wavetable synthesis stores a sample of the instrument's sound in the sound card's wavetable, and produces the sound by removing it from the wavetable during playback.

The leader of MP3

MP3 can be said to be a big name, which uses MPEG Audio Layer 3 technology to compress the sound with a compression rate of 1:10 or even 1:12, with a sampling rate of 44kHz and a bit rate of 112kbit/s.

MP3 music is digitally stored music, and if you want to play it, you must have the appropriate digital decoder to play it. There must be a corresponding digital decoding playback system, generally through specialized software for MP3 digital music decoding, and then reduced to waveform sound signal playback output, this software is called MP3 player, such as Winamp.

Online RA series

RA, RAM and RM are Real's mature network audio format, using "audio streaming" technology, so it is very suitable for Internet broadcasting. You can add copyright, artist, producer, mail, and song title information to your productions.

RA can be called the dominant multimedia distribution on the Internet, suitable for real-time playback on the Internet, and is currently the best format for listening to Internet music online.

VQF with high compression ratio

VQF, or TwinVQ, is an audio compression technology developed by Nippon Telegraph and Telephone and Yamaha.

VQF's audio compression ratio is nearly double that of standard MPEG audio compression, reaching 1:18 or higher. In contrast, the popular compression formats like MP3 and RA are generally only about 1:12. But it still won't affect the sound quality. When VQF compresses music at 44kHz-80kbit/s audio sample rate, it will sound better than 44kHz-128kbit/s MP3, and when compressed at 44kHz-96kbit/s, the music will be close to 44kHz-256kbit/s MP3.

Mini-Disc MD

MD (i.e. MiniDisc) is a complete portable music format introduced by SONY in 1992, and the compression algorithm it uses is the ATRAC technology (the compression ratio is 1:5).MD is further divided into recordable MD (Recordable, with two heads, magnetic and laser) and single-player MD (Pre-recorded, laser only).

The powerful editing function is the strong point of MD, you can quickly select the song, track moving, merging, splitting, deleting and song name editing and other functions, more personalized than the CD, you can always have a belong to their own MD album.MD's products include MD Walkman, MD bedside stereo, MD car stereo, MD recording card holder, MD camera gun, and MD drive.

Music CD

that is, CD recordings, a CD can play about 74 minutes of sound files, Windows system comes with a CD player, in addition to most of the software that comes with the sound card provides CD playback, and there are even some CD-ROM drives detached from the computer, as long as the power is connected to the computer can be used as a stand-alone CD player.

WMA

Microsoft is developing its own networked multimedia services platform that promotes ASF (Audio Steaming format), an open standard that supports data transfer over a wide variety of networks and protocols. It supports audio, video, and a range of other multimedia types. And WMA, which stands for Windows Media Audio, is the equivalent of an audio-only ASF file.

WMA files can be compressed up to 1:18 in 80kbps, 44kHz mode, which is basically the same as VQF. And the compression speed is double than MP3. So it should be more competitive than VQF.

Free music format Vorbis

In order to prevent the rise of royalties charged by MP3 music companies, programmers at GMGI's iCast have developed a new free music format, Vorbis, whose sound quality can be comparable to, or even superior to, that of MP3, and which will be distributed over the Web and can be downloaded freely without fear of involving infringement issues. But MP3 is already very popular on the Internet, and Microsoft's Windows Media technology is starting to gain popularity, so the future of Vorbis still doesn't look promising.

Other audio formats

AIF/AIFF: Apple developed a sound file format that supports the MAC platform and 16-bit 44.1kHz stereo sound.

AU: SUN's AU compressed sound file format, only supports 8-bit sound, is a commonly used sound file format on the Internet, mostly created by SUN workstations.

CDA: CD track file.

CMF: A MIDI-like sound file developed by CREATIVE.

DSP: Short for Digital Signal Processing. By improving the signal processing method, the sound quality will be greatly improved and the songs will be more pleasing to the ear.

S3U: MP3 playback file list

RMI: MIDI instrument sequences

Lossy compression:

AAC: Second only to MPC in sound quality at high bit rates, with great appearances at both high and low bit rates. It's just too slow to encode!

MPC: average performance at low bitrate, not as good as Mp3Pro encoded MP3 and OGG, best sound quality at high bitrate, fast encoding speed!

OGG: Best sound quality at low bitrate, also good at high bitrate. Slightly slower encoding speed.

MP3(MP3Pro): sound quality second to OGG at low bitrates, otherwise same as MP3

WMA: average at both high and low bitrates, no VBR support, up to 192Kbit/s

Lossless compression:

FLAC: compression rate worst of the four, encoding speed good, platform support very good.

PAC: slightly slower encoding speed, third highest compression rate, good platform support.

APE: fastest encoding speed, best compression rate, average platform support.

WV: very fast encoding speed, second best compression rate of the four species, Windows platform support only