About Audio
Audiohas multiple meanings.
The LiveAudio in Netscape Navigatir browsers supports Audio format sound files.
InMiniTool, you are able toedit your audio for videoquickly.
In some aspects it can be referred to as vibration of a wave filter.
Today, you’re free to get audio books easily.
As a professional term, audio refers to all sounds that human can hear even including noise.
The audio is just the sound stored in the computer.
The acoustic characteristic of the sound can be stored in the form of computer hard disk files.
The process is also composed of sampling and quantization.
Therefore, the maximum bandwidth of audio is 20KHZ, so the sampling rate needs to be between 40-50KHZ.
Moreover, more quantization bits are needed for each sample.
The standard for audio digitization is a signal-to-noise ratio of 16-96 db per sample.
The PCM is modulated by linear pulse coding, and each quantization step has an equal length.
This standard is used in the production of audio files.
Main Audio Formats
Just as images have multiple file formats, audio files come in many formats.
Main audio formats include CD, WAV, MP3, MIDI, WMA, RealAudio, VQF, OGF.
However, the *.cda file is just an index message for it doesnt contain sound information.
It is used to store audio information resources on Windows platform and supported by Windows platform and other applications.
WAV supports MSADPCM, CCITTALAW and other compression methods, as well as multiple audio digits.
The sampling frequency, channel, speed and quantization bit of WAV are the same as that of CD.
MP3:It refers to the audio section in MPEG standard, MPEG audio layer.
The quality is in exchange for the size of the file.
It achieves higher compression ratio than MP3 by reducing the data traffic but maintaining sound quality.
Versions above Windows Media Player 7.0 add converting the CD to WMA sound format feature.
InWindow XPoperating system, WMA is the code format by default.
The WMA format can adjust the sound quality when recording.
Audio formats like WAV, MP3 mentioned above are able to be recovered by the software.
