Ircamchord: Automatic Chord Estimation

Ircamchord: Automatic Chord Estimation

Ircamchord software estimates automatically the temporal succession of music chords (C-Major, C-minor, …) that makes up a piece of music.

Target users and customers

One of the most important perceptual aspects of popular music is the succession of chords over time. Two tracks based on the same chord succession are perceived very similar and sometimes indicate a cover-version of the same composition. Automatic estimation of chord succession can therefore be used to perform search by similarity and play-list generation.
It can therefore benefit to music providers, online music portals.

Chord notation is also very popular for beginner musicians (a very large amount of guitar tabs are accessible and used over the web). Estimating automatically the chord succession of a given track can therefore be beneficial for personal users through the inclusion of the technology in local software.

Application sectors

  • Online music providers
  • Online music portals
  • Music players developers
  • Music software developers


Ircamchord performs the automatic estimation of the chord succession of a music track using a 24 chord dictionary (C-Major, C-minor…).

For this, the harmonic content of a music file is first extracted in a beat-synchronous way. A statistical model (double-state hidden Markov model) representing music theory (chord transition), expected downbeat positions and estimated local-key is used for a precise estimation.

Technical requirements:

Ircamchord is available as software or as a dynamic library for Windows, Mac OS-X and Linux platform.

Conditions for access and use:

Ircam Licence




Contact details:

Frédérick Rousseau

Sound Analysis/Synthesis
1 Place Igor-Stravinsky
75004 Paris