What is APE?
Complete guide to the APE file format
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What is APE?
APE (Monkey's Audio) is a lossless audio compression format created by Matthew T. Ashland and released in 2000. It stores audio data with no quality loss - the decoded audio is bit-for-bit identical to the original source - while achieving compression ratios that are often higher than FLAC. APE files typically reduce CD audio to about 40 to 60% of the original uncompressed size, with higher compression modes achieving even greater reductions at the cost of significantly longer encoding and decoding time.
Monkey's Audio is particularly popular in audiophile communities and on certain peer-to-peer networks where lossless music archiving is valued. The format has a companion CUE sheet (.cue file) workflow where an entire CD is stored as a single large APE file alongside a CUE sheet that marks the track positions - a common approach for lossless CD rips. The main drawback of APE is that its highest compression modes are extremely CPU-intensive, making fast playback and seeking difficult on older hardware.
How Monkey's Audio Compresses
Monkey's Audio uses adaptive linear prediction followed by range/entropy coding of the residuals to pack audio losslessly, reconstructing the original samples exactly on decode.[2] Its compression levels (such as Fast, Normal, High, Extra High, and Insane) trade encoding and decoding speed for slightly smaller files, with the highest modes demanding substantial CPU time.[1]
APE vs FLAC and Practical Trade-offs
Monkey's Audio often edges out FLAC slightly on compression ratio, but the difference is small and comes at a cost in computational symmetry: APE decoding is far heavier than FLAC's, which affects battery life and seeking on low-power devices.[3] APE is also less widely supported in hardware players and non-Windows software, partly because its reference implementation was historically Windows-centric.[3]
Limitations
Unlike some lossless formats, Monkey's Audio offers limited error resilience, so corruption in a file can render large portions undecodable, a concern for long-term archiving.[3] Its appeal remains strongest among collectors prioritizing maximum compression of full-disc rips paired with CUE sheets.[1]
Technical Details
APE vs Other Audio Formats
| Feature | APE | FLAC | WAV |
|---|---|---|---|
| Compression | Lossless[1] | Lossless | Uncompressed |
| Compression ratio | High[2] | Moderate | None |
| CPU usage | High[3] | Low | Minimal |
| License | Proprietary (free)[2] | Open | Open |
| Device support | Limited | Wide | Wide |
| Best for | Max compression | Lossless archiving | Editing |
Monkey's Audio (APE) achieves slightly higher compression than FLAC but is more CPU-intensive and less widely supported.
Pros and Cons
Advantages
Often compresses audio slightly more than FLAC, especially at higher compression levels.
Lossless format with bit-perfect decoded output identical to the source.
Widely used in audiophile circles for archiving CD rips with maximum compression.
Works well with CUE sheets for storing complete CD albums as a single file with embedded track markers.
Disadvantages
The highest compression modes (“High” and “Insane”) are extremely CPU-intensive, causing issues on older hardware.
The Monkey's Audio license restricts commercial use and open-source distribution, limiting widespread adoption.
APE files are not suitable for streaming because they do not support efficient random-access seeking.
Fewer media players and devices support APE natively compared to FLAC, requiring plugins on many platforms.
When to Use APE
Here are the most common situations where APE is the right choice:
CD Archiving
Use APE with a CUE sheet to create high-compression, bit-perfect archives of CD audio collections.
Audiophile Storage
Store high-resolution audio downloads in APE when maximum compression is more important than broad compatibility.
Long-Term Archiving
Suitable for archival storage on desktop systems where CPU-intensive decoding is not a concern.
Convert to FLAC
If you encounter APE files, convert them to FLAC for better compatibility without any quality loss.
Convert APE Files
Need to convert your APE files? Use our free online converter.
Try Audio Converter FreeFrequently Asked Questions about APE
Is APE better than FLAC?
APE can achieve slightly higher compression than FLAC, but FLAC is faster to decode, has better software support, and uses a more open license. For practical use, FLAC is the better choice.
Does converting APE to FLAC lose quality?
No. Both are lossless formats. Converting from APE to FLAC is a lossless transcoding operation - the decoded audio is identical in both formats.
Why is APE so slow?
APE uses a computationally expensive algorithm especially at compression levels 4 (High) and 5 (Insane). These levels can take many times longer to decode than FLAC, making real-time playback difficult on slow hardware.
What is a CUE sheet?
A CUE sheet (.cue file) is a text file that describes the track layout of a CD. When paired with a single APE file containing the entire album, the CUE sheet tells your media player where each track starts and ends.
Can I play APE on my phone?
APE is not natively supported on iOS or Android. Use a third-party player like VLC (Android) or convert APE files to FLAC or AAC for mobile use.