Audio signals can be compressed based on audio compression technology. Audio compression technology refers to the use of appropriate digital signal processing techniques for the original digital audio signal stream (PCM encoding) to reduce (compress) its code rate without loss of useful information or negligible loss. It is called compression coding. It must have a corresponding inverse transform called decompression or decoding. Audio signals may introduce a large amount of noise and certain distortion after passing through a codec system.
In the field of audio compression, there are two compression methods, lossy compression and lossless compression. Commonly known MP3, WMA, and OGG are called lossy compression. As the name implies, lossy compression reduces the audio sampling frequency and bit rate, and the output audio file will be smaller than the original file. Another type of audio compression is called lossless compression, which is the subject matter to be said. Lossless compression can compress the volume of the audio file less than 100% of all the data of the original file, and restore the compressed audio file to achieve the same size and the same code rate as the source file. The lossless compression formats are APE, FLAC, WavPack, LPAC, WMALossless, AppleLossless, La, OpTImFROG, Shorten, and the common, mainstream lossless compression formats are APE and FLAC.