CD Format: Sound of Nature
What is the audio format with the best sound quality in the world today? Of course it's a CD. Therefore, when it comes to audio formats, CD is naturally the pioneer. In the "Open File Type" of most playback software, you can see the *.cda format, which is the CD audio track. The standard CD format is a sampling frequency of 44.1K, a rate of 88K/second, and 16 quantization bits. Because the CD track can be said to be approximately lossless, its sound is basically faithful to the original sound, so if you are a If you are an audiophile, CD is your first choice. It will make you feel the sound of nature. CDs can be played in CD players or replayed using various playback software on computers. A CD audio file is a *.cda file. This is just index information and does not actually contain sound information. Therefore, regardless of the length of the CD music, the "*.cda file" seen on the computer is 44 bytes long. . Note: You cannot directly copy *.cda files in CD format to the hard disk for playback. You need to use audio track capture software such as EAC to convert the CD format files into WAV. This conversion process will only occur if the quality of the CD drive is acceptable and the parameters of EAC are set. If done properly, it can be said to be basically lossless audio capture. It is recommended that everyone use this method.
WAV: lossless music
It is a sound file format developed by Microsoft. It conforms to the PIFFResource Interchange FileFormat file specification and is used to save audio information resources of the WINDOWS platform. It is used by WINDOWS supported by the platform and its applications. The "*.WAV" format supports multiple compression algorithms such as MSADPCM and CCITTALAW, and supports a variety of audio bits, sampling frequencies and channels. The standard format WAV file is the same as the CD format, with a sampling frequency of 44.1K and a rate of 88K/sec. , 16 quantization bits. As you can see, the sound file quality of WAV format is almost the same as that of CD. It is also a widely popular sound file format on PCs. Almost all audio editing software "knows" WAV format.
By the way, here is the AIFF (Audio InterchangeFileFormat) format developed by Apple and the AU format developed for UNIX systems. They are very similar to WAV and are also supported by most audio editing software. These are some common music formats.
MP3: Popular fashion
The MP3 format was born in Germany in the 1980s. The so-called MP3 refers to the audio part of the MPEG standard, which is the MPEG audio layer. According to the difference in compression quality and encoding processing, it is divided into 3 layers, corresponding to the three types of sound files: "*.mp1/"*.mp2"/"*.mp3". What needs to be reminded is: the compression of MPEG audio files It is a kind of lossy compression. MPEG3 audio encoding has a high compression rate of 10:1~12:1, while basically keeping the low audio part without distortion, but sacrificing the quality of the high audio part from 12KHz to 16KHz in the sound file in exchange for the file. The size and length of music files stored in *.mp3 format are generally only 1/10 of *.wav files, and the sound quality is inferior to CD format or WAV format sound files due to their small file size and good sound quality. ; So when it came out, there was no other audio format that could compete with it, thus providing good conditions for the development of the *.mp3 format. Until now, this format is still very popular, and its status as a mainstream audio format is difficult to achieve. Shaken. However, the copyright problem of MP3 music has never been solved, because MP3 does not have copyright protection technology. To put it bluntly, anyone can use the MP3 format to compress the sampling frequency of music. There are many options, you can use a sampling frequency of 64Kbps or lower to save space, or you can use a 320Kbps standard to achieve extremely high sound quality. We use the MP3 encoder equipped with Fraunhofer II SMpeg Lyaer3 (the best encoder now) MusicMatchJukebox6.0. Encoding a 3-minute song at 128Kbps results in a 2.82MB MP3 file. The default CBR (fixed sampling frequency) technology can sample a song at a fixed frequency, while VBR (variable sampling frequency) can. You can increase the sampling frequency to obtain higher sound quality when the music is "busy", but the resulting MP3 file may not be playable on some players. We set the VBR level to be basically the same as the sound quality of the previous CBR file. Same, the generated VBRMP3 file is 2.9MB
MIDI: Composer’s Favorite
People who often play music should often hear the word MIDI (Musical Instrument Digital Interface), MIDI allows. Digital synthesizers and other devices exchange data. The MID file format is inherited from MIDI.
A MID file is not a piece of recorded sound, but a set of instructions that records sound information and then tells the sound card how to reproduce the music. Such a MIDI file only uses about 5 to 10KB for each minute of music stored. Today, MID files are mainly used for original instrumental works, amateur performances of popular songs, game soundtracks, and electronic greeting cards, etc. *The playback effect of .mid files completely depends on the level of the sound card. *The biggest use of the .mid format is in the field of computer composition. *.mid files can be written using music composition software, or music played by an external sequencer can be input into the computer through the MIDI port of the sound card to create *.mid files.
WMA: The most powerful enemy
WMA (Windows MediaAudio) format is a heavyweight player from Microsoft. It has a tough background and its sound quality is better than MP3 format and even better than RA. format, which is the same as the VQF format developed by Japan's YAMAHA company. It achieves a higher compression rate than MP3 by reducing data traffic but maintaining sound quality. The compression rate of WMA can generally reach about 1:18. One advantage is that content providers can add anti-copy protection through DRM (Digital Centers Management) solutions such as Windows Media Centers Manager 7. This built-in copyright protection technology can limit the playback time, playback times, and even playback machines, etc. This is good news for music companies that are troubled by piracy. In addition, WMA also supports audio streaming (Stream) technology, suitable for online playback on the Internet. As Microsoft's pioneer in seizing online music, it can be said that it is technologically leading and has strong popularity. What's more convenient is that there is no need to install an additional player like MP3, and the Windows operating system and Windows Media Player are seamless. Bundling allows you to play WMA music directly as long as you install the Windows operating system. The new version of Windows Media Player 7.0 adds the function of directly converting CD discs to WMA sound format. In the new operating system Windows XP, WMA is the default Encoding format, everyone knows what happened to Netscape, and now the "wolf" is coming again. WMA is a format that allows you to adjust the sound quality during recording. In the same format, the sound quality is comparable to CD, and the compression rate is higher and can be used for network broadcasting. Although it is not very popular on the Internet now, it has been recognized and strongly supported by more and more sites due to Microsoft's large-scale promotion. In the field of online music, it is close to *.mp3. In terms of online radio, it is also becoming more popular. Divide the world created by Real. Therefore, almost all audio formats feel the pressure of WMA format.
RealAudio flowing melody
RealAudio is mainly suitable for online music appreciation on the Internet. Most users are still using 56Kbps or lower rate Modem, so typical playback Not the best sound quality. Some download sites will prompt you to choose the best Real file based on your Modem speed. There are currently several real file formats: RA (RealAudio), RM (RealMedia, RealAudioG2), RMX (RealAudioSecured), and more. The characteristic of these formats is that the sound quality can change with different network bandwidths, ensuring that most people can hear smooth sound, so that listeners with richer bandwidth can get better sound quality.
With the general improvement of network bandwidth recently, Real Company is launching a CD-quality format for Internet broadcasting. If your RealPlayer software cannot handle this format, it will remind you to download a free upgrade package. Many music websites provide trial versions of songs in Real format. The latest version now is RealPlayer9.0. The 39th issue of "Computer News" also introduced RealPlayer9.0 in detail, so I won't go into details here.
VQF: The end of the world
Another format from Yamaha is *.vqf. Its core is to achieve a higher compression ratio by reducing data traffic but maintaining sound quality. It is said that it is also very advanced technically, but due to poor publicity, this format is difficult to use. ＊.vqf can be played with Yamaha player. At the same time, Yamaha also provides software to convert *.wav files to *.vqf files.
Common formats include WMA, MP3, and MIDI.