Chordify is a free online music service – made for and by music enthusiasts – that transforms music from YouTube, Deezer, SoundCloud or your private collection, into chords. Our service automatically recognises chords from the audio signal, and aligns them to the music in a simple and intuitive player. Chordify is a cutting edge service that helps both novice and trained musicians to play the music they want to play, making state-of-the-art music technology available to the public at large.
Experience a simple and beautiful chord extractor that helps you play any song. Click here
Technology behind Chordify
We’ve done our best to make our website simple and easy to use, even though there is some complex technology behind Chordify. Our website is built using up to the minute web development techniques, like HTML5 audio etc.
Behind the scenes, we use the sonic annotator for extraction of audio features. More specifically, we extract the NNLS chroma features developed by Matthias Mauch using the Chordino VAMP plugin. These features describe the tonal content of a piece of music. Next, a Haskell program HarmTrace then takes these features and computes the chords. For this to happen, HarmTrace uses a model of Western tonal harmony to aid in the chord selection. At beat positions where the audio matches a particular chord well, this chord is used in the final transcription. However, where there is uncertainty about the sounding chords at a specific position in the song, the HarmTrace harmony model will select the correct chords based on the rules of tonal harmony.
Chordify fosters open-source software. Not only do we use open-source software packages like GHC, PHP, SoX, sonic annotator and MongoDB, but we also give back a large share of the in-house developed technology to the music information retrieval research community via open-source software projects like HarmTrace and scientific publications.
Chordify could not have been realised without the support of Utrecht University.