Monkey's Audio MIME Type

What does audio/x-ape mean?

The audio/x-ape media type identifies audio compressed with Monkey's Audio, usually in an .ape file. Monkey's Audio is lossless: decoding restores the same audio samples that went into the encoder rather than approximating them as MP3 or AAC does.¹

An APE file normally begins with the ASCII signature MAC , or bytes 4D 41 43 20. That signature is useful for identifying the format when an extension or HTTP header is missing.²

Where did Monkey's Audio come from?

Matthew T. Ashland released Monkey's Audio in 2000. The project's license and copyright history begin in that year, and its own version history identifies version 1.0 as the first public release.⁴⁵

Early files used the .mac extension. Version 3.00 changed the default extension to .ape, which is the one current software expects.⁵ This history explains why FFmpeg still recognizes .mac alongside .ape, although .mac is ambiguous and uncommon today.²

The format and its reference implementation have continued to evolve. Some older bitstream revisions have required compatibility code, so an APE decoder's age matters more than the filename alone suggests. The official version history, for example, records changes to backward compatibility and decoding of old files.⁵

How to open an .ape file

Use a player with an explicit Monkey's Audio decoder:

• Monkey's Audio is the reference application. It can compress, decompress, verify, and convert APE files.⁶
• VLC media player lists APE among its supported audio codecs.⁷
• foobar2000 2.0 includes Monkey's Audio decoding. Earlier foobar2000 versions use its Monkey's Audio Decoder component.⁸
• FFmpeg can decode APE input and convert it to another audio format.²

Current web browsers do not provide native Monkey's Audio playback. MDN's web audio codec guide covers the codecs intended for browser media delivery and does not include APE.⁹ Renaming the file to .mp3 or .flac does not help because the encoded stream remains Monkey's Audio.

Support in Poly

Poly recognizes .ape filenames and maps them to audio/x-ape. It classifies the file as audio, stores it, and routes it to the in-app audio player.

The current processing path has an important limitation. Poly's audio loader uses Symphonia, and the enabled Symphonia formats and codecs do not include Monkey's Audio. As a result:

• The browser-based player is shown, but the browser normally cannot decode the stream.
• Duration, tags, embedded cover art, and waveform data are not extracted.
• Automatic transcription and audio-similarity indexing cannot complete.
• The file remains searchable by its filename, but not by speech or acoustic content.
• The Poly agent cannot read or summarize the audio because no transcript or decoded audio content is available.

This is more limited than Poly's support for MP3, FLAC, AAC, and other decodable audio formats. Convert the file before uploading when playback, transcription, content search, or agent access is important.

Converting APE without losing audio quality

FLAC is usually the best interchange target. Both formats are lossless, so decoding APE and encoding FLAC preserves the decoded samples while improving compatibility. WAV also preserves the samples, but it is normally much larger because the audio is uncompressed.

With FFmpeg, a typical lossless conversion is:

ffmpeg -i input.ape -map_metadata 0 output.flac

For an uncompressed copy:

ffmpeg -i input.ape output.wav

Use MP3, AAC, or Opus only when smaller delivery files matter more than perfect reconstruction. Those targets are lossy. Keep the APE or a lossless FLAC master if you may need to convert again.

APE, FLAC, and WAV compared

All three can preserve the same decoded samples, but they solve different practical problems.

Compression level does not change the audio quality of a valid APE file. It trades encoding and decoding work for file size. The Monkey's Audio help recommends its High setting and notes that Extra High or Insane takes more time for only a small additional size reduction.⁶ That is a workflow choice, not a quality setting like the one in a lossy encoder.

Is an .apl file the same thing?

No. An .apl file is an APE Link. It points to a range within another audio file, often for a disc image paired with a CUE sheet. It is not a self-contained Monkey's Audio stream. foobar2000 documents .APE and .APL separately for this reason.⁸

Keep the referenced audio file with an .apl file. Converting or copying the link by itself will not recover the recording.

Integrity and safe handling

Modern APE files include cyclic redundancy checks that the reference application can use for quick or full verification.⁶ A successful CRC check is useful evidence against accidental corruption. It is not a cryptographic signature and does not establish who created the file.

Treat an APE file from an unknown source like any other complex media input. Decode it with maintained software, avoid obsolete plugins, and keep the original until a conversion has been verified. Tags and embedded artwork can also carry information you may not want to publish, so review metadata before sharing a converted file.