Overview of music format:
Classic wave
WAVE file, as the most classic Windows multimedia audio format, is widely used. It uses three parameters to represent sound: number of sampling bits, sampling frequency and number of channels.
There are mono and stereo channels, and the sampling frequency is generally11025hz (11khz), 22050Hz(22kHz) and 44 100Hz(44kHz). Capacity of waveform file = (sampling frequency × sampling bits × number of channels) × time /8( 1 byte =8bit).
Traditional mode
MOD is a music format similar to wave table, but its structure is similar to MIDI, and it adopts real sampling, which is very small. In the previous DOS era, MOD was often used as the background music of games. At present, MOD can contain multiple tracks in various formats, such as S3M, NST, 669, MTM, XM, IT, XT, RT and so on.
Computer music MIDI
MIDI is the abbreviation of musical instrument data interface, which records the sound played by musical instruments digitally (each note is recorded as a number), and then synthesizes these records through FM or wave table when playing: FM synthesis is to mix the sounds of multiple frequencies to simulate the sound of musical instruments; Wave table synthesis is to store the sound samples of musical instruments in the sound card waveform table, and take them out from the waveform table to produce sound when playing.
Long tou Lao da MP3
MP3 is very famous. It adopts the third layer technology of MPEG audio, and compresses the sound with the compression ratio of 1∶ 10 or even 1∶ 12. The sampling rate is 44kHz and the bit rate is112kbit/s.
MP3 music is stored in digital form. If you want to play it, you must have a corresponding digital decoding and playing system. Generally, MP3 digital music is decoded by special software, and then restored to waveform sound signal for playback and output. This software is called MP3 player, such as Winamp.
Online overlord RA series
RA, RAM and RM are all mature network audio formats of Real Company, which adopt "audio streaming" technology and are very suitable for network playback. You can add information such as copyright, singer, producer, email, song title, etc.
RA is the overlord of Internet multimedia communication, suitable for real-time playing on the Internet, and the best format for listening to online music at present.
VQF with high compression ratio
VQF (TwinVQ) is an audio compression technology developed by Nippon Telegraph and Telephone Company and Yamaha Company.
The audio compression rate of VQF is nearly twice that of standard MPEG audio, which can reach about1:18 or even higher. The popular compression formats such as MP3 and RA are only about 1: 12. But it will not affect the sound quality. When VQF compresses music at the audio sampling rate of 44kHz-80kbit/s, its sound quality will be better than that of MP3 at 44kHz- 128kbit/s, while when it is compressed at 44kHz-96kbit/s, the music will be close to that of MP3 at 44 kHz-256 kbit/s. ..
Mini CD MD
MD (MiniDisc) is a complete portable music format introduced by Sony in 1992, and its compression algorithm is ATRAC technology (compression ratio is 1∶5). MD is divided into MD (recordable MD (with magnetic head and laser head) and pre-recorded MD (with laser head only).
Powerful editing function is the strength of MD, which can quickly select songs, move tracks, merge, split, delete and edit titles. More personalized than CD, you can have your own MD album at any time. MD products include MD walkman, MD bedside stereo, MD car stereo, MD recording deck, MD camera gun and MD driver.
Music CD
That is, CD records, a CD can play audio files for about 74 minutes. Windows comes with a CD player. In addition, the software that comes with most sound cards provides CD playback function. Some optical drives can even be used as independent CD players as long as they are connected to the power supply.
WMA with unlimited potential
When Microsoft develops its own network multimedia service platform, it mainly promotes ASF (Audio Stream Format), which is a standard that openly supports data transmission on various networks and protocols. It supports audio, video and a series of other multimedia types. WMA is the abbreviation of Windows Media Audio, which is equivalent to ASF file containing only audio.
The compression ratio of WMA file can reach 1∶ 18 at 80kbps and 44kHz, which is basically the same as VQF. The compression speed is twice that of MP3. So it should be more competitive than VQF.
Free music format Vorbis
In order to prevent the patent fees charged by MP3 music companies from rising, programmers of iCast company in GMGI have developed a new free music format Vorbis, whose sound quality is comparable to or even better than MP3. Moreover, it will be published through the internet and can be downloaded for free, without worrying about infringement. However, MP3 has become very popular on the Internet, and Microsoft's Windows Media technology has also become popular, so the prospect of Vorbis is still not optimistic.
Other audio formats
Aif/aiff: sound file format developed by Apple, which supports MAC platform and 16-bit 44.438+0 kHz stereo.
AU: SUN's AU compressed sound file format only supports 8-bit sound, which is a common sound file format on the Internet and is mostly created by SUN workstation.
CD audio track file.
CMF: A MIDI-like sound file developed by a creative company.
DSP: Short for Digital Signal Processing. By improving the signal processing method, the sound quality will be greatly improved and the song will sound better.
S3U:MP3 play file list
RMI:MIDI musical instrument sequence
Lossy compression:
AAC: The sound quality is second only to MPC at high bit rate, and the appearance is good at high bit rate and low bit rate. The coding speed is too slow!
MPC: The performance at low bit rate is not as good as that of OGG encoded by MP3 and Mp3Pro. At high bit rate, the sound quality is the best and the coding speed is fast!
OGG: The sound quality is the best at low bit rate, and the high bit rate is also good. The coding speed is a bit slow.
MP3(MP3Pro): At low bit rate, the sound quality is not as good as OGG, and it is the same as MP3 in other aspects.
WMA: Both high and low bit rates are common, and VBR is not supported, with a maximum of192kbit/s.
Lossless compression:
FLAC: Among the four, the compression ratio is the worst, the coding speed is good, and the platform support is good.
PAC: The coding speed is slightly slower, the compression rate is third, and the platform support is good.
APE: The coding speed is the fastest, the compression rate is the best, and the platform support is average.
WV: The coding speed is very fast, and the compression rate ranks second among the four, only supporting the Windows platform.