Monkey's Audio

Monkey's Audio is a an algorithm and file format for lossless audio data compression. Monkey's Audio does not discard data during the process of encoding, unlike lossy compression methods such as AAC, MP3, Vorbis and Musepack.

Data file compression is employed in order to reduce bandwidth, file transfer time, and/or storage requirements. A digital recording (such as a CD) encoded to the Monkey's Audio format can be decompressed into an identical copy of the original audio data. As with the FLAC and Apple Lossless format, files encoded to Monkey's Audio are typically reduced to about half of the original size, with data transfer rates and bandwidth requirements being reduced accordingly.

Monkey's Audio's advantages are slightly better compression rates compared to FLAC and WavPack, as well as multithreading/multicore support. Monkey's Audio main drawbacks are the fact that it employs a symmetric algorithm, meaning the decoding takes comparable resources to encoding, which makes it unsuitable for all but the fastest portable players (via Rockbox firmware), and that it has limited support on software platforms other than Windows; on other platforms only decoding is officially supported by third-party programs. Although the original source code is freely available, the license is not considered to be an open source one. A GPL version of the decoder has been independently written for Rockbox and then included in ffmpeg.

Monkey's Audio files use the filename extension .ape for audio, and .apl for track metadata.