What is a codec?
A codec is a software component that translates video or audio between its uncompressed form and compressed form. A codec is used to compress digital audio files by discarding redundant data. MP3 encoders and decoders are audio codecs. The compression of a WAV or AIFF file to MP3 format using a MPEG layer III audio codec is encoding, similarly, an MP3 file can be 'decompressed' or decoded to WAV or AIFF format using a separate codec. There are also codecs for WMA, QuickTime 4 Streaming Audio, RealAudio and other audio formats. As a form of compression, MP3 is based on a psycho-acoustic model which recognizes that the human ear cannot hear all the audio frequencies on a recording. The human hearing range is between 20Hz to 20Khz and it is most sensitive between 2 to 4 KHz. When sound is compressed into an MP3 file, an attempt is made to get rid of the frequencies that can't be heard. As such, this is known as 'destructive' compression. After a file is compressed, the data that is eliminated in the creation of the MP3 cannot be replaced. Recommended Link:
Terran Interactive-Codec Central | 
