pHash is an implementation of various perceptual hashing algorithms. A perceptual hash is a fingerprint of an audio, video, or image file that is mathematically based on the audio or visual content contained within. Unlike cryptographic hash function

These routines implement a landmark-based audio fingerprinting system that is very well suited to identifying small, noisy excerpts a large number of items. It is based on the ideas used in the Shazam music matching service, which can identify seemin