APE is one of the popular digital music file formats. Different from MP3 lossy compression, APE is a lossless audio compression technology, that is, the audio data files read from the audio CD are compressed into APE format, and then the files in APE format are restored, and the restored audio files are exactly the same as before compression, without any loss. The file size of APE is about half that of CD, and APE can save a lot of resources.

APE is actually a lossless compressed audio format. Huge WAV audio files can be "slimmed down" by the software Monkey Audio and compressed into APE. Sometimes it is used for network audio file transmission, because the compressed APE file capacity is less than half of the WAV source file, which can save transmission time. More importantly, the WAV file obtained after decompression and restoration of monkey's audio can be exactly the same as the source file before compression. Therefore, APE is called "lossless audio compression format" and Monkey's audio is called "lossless audio compression software". Unlike using professional data compression software such as WinZip or WinRAR to compress audio files, compressed APE audio files can be played directly. Monkey's Audio will install an "in_APE.dll" plug-in in Winamp, so Winamp can also play APE files.