Acoustic fingerprint matching catches the same recording even when the filename, tag, format, or bitrate disagree. Mac & Windows, no DJ software required.
You probably have several copies of the same song scattered across formats: a 320 kbps MP3 from one purchase, a FLAC from a CD rip, an iTunes Plus M4A from an old library, maybe a 192 kbps version still hanging around from a decade ago. Filename-based tools (dupeGuru, Gemini) see four different files. Tag-based tools (most music-app dedupe) see four different files. None of them match the same recording across formats — because the fingerprint they use isn't acoustic.
Supported today
Rekordbox · Serato DJ · VirtualDJ (incl. Favorite Folders) on Windows 10+ and macOS (Apple Silicon + Intel).
Acoustic fingerprinting reads the audio waveform itself and produces a compact hash that's stable across formats — a 320 kbps MP3, a 192 kbps re-encode, and a FLAC of the same recording all produce nearly identical fingerprints, even with different tags or filenames. MLD layers quality awareness on top: every copy shows its bitrate, duration, and real file size, and the per-group Quality Check scores the actual audio (1–10) so you can verify the keeper against the spectrum, not just the label. Borderline fingerprint matches are flagged for review instead of auto-grouped — your ears stay the final judge.
A content-based hash derived from the actual audio signal. Two files with different tags, bitrates, or filenames match if they contain the same audio. Chromaprint is the open-source algorithm MLD uses — also used by MusicBrainz Picard.
First pass on a 10,000-track library: 10–30 minutes (audio decoding is the bottleneck). Results are cached, so subsequent scans are instant.
No. The fingerprint reflects the actual audio. Different mixes, different masters, and remixes generate different fingerprints — only acoustic-twin copies match.
Yes. Any folder path works, including USB drives and SMB/AFP/NFS mounts. Scan speed depends on disk speed, but functionality is identical.
No. Fingerprints are computed locally and stay on your machine. Audio files never leave the computer.
Free tier covers scanning and detection. Pro is a one-time lifetime license — paid once, no subscription. Current founding pricing is on the homepage.
