AFPK File

What are AFPK files and how to open them

Are you having problems opening an AFPK file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your AFPK files.

What is an AFPK file?

An .AFPK file is an Audfprint Peak file.

Audfprint Peak files are binary data files generated by the audfprint utility to store a compact representation of an audio recording's fingerprint peaks. They serve as precomputed summaries of audio features, allowing faster comparison and matching: instead of reprocessing an audio file, audfprint can load its AFPK file into its landmark-based fingerprint database and use it to detect similarity with queries. These files help avoid repeated full audio analysis, speeding up tasks like finding duplicate tracks.

The audfprint program, originally developed by Daniel P. W. Ellis at Columbia University, produces AFPK files using its "precompute peaks" mode. After detection of spectral peaks ("peaks" or "landmarks") in an audio waveform, it writes out time-bin pairs (times and frequency bin indices) to the AFPK file. Later, audfprint reads these peak-only files to build or augment fingerprint databases, and to match new audio against them based on shared landmark sets.

An AFPK file begins with the ASCII signature audfprintpeakV00 at byte offset zero. Following the header, the file holds a sequence of fixed-length binary records, each representing one peak by storing two integers: the time (in frames or sample units) and the spectral bin (frequency index) of that peak. These allow reconstruction of key landmark data without needing full audio or hash tables.

How to open AFPK files

Important: Different programs may use files with the AFPK file extension for different purposes, so unless you are sure which format your AFPK file is, you may need to try a few different programs.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Last updated: August 17, 2026

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