A chroma feature (chromagram) represents spectral energy as a 12-dimensional vector, one value per chroma (pitch class C through B), obtained by applying a pitch-class profile to a spectrogram and summing energy within each class. Computed via a 12-band filter bank applied to the magnitude spectrum, then normalized to [0,1]. Persisted as a fixed-length numeric array in music analysis pipelines. The construction is deterministic: given a signal, windowed-STFT, and equal-tempered pitch mapping, the chroma vector is uniquely determined. [formal: chroma | substrate: mind | horizon: a life | explicit: yes | epoch: 0.01]
Accepted ontology entry
chroma-feature
A chroma feature (chromagram) represents spectral energy as a 12-dimensional vector, one value per chroma (pitch class C through B), obtained by applying a pitch-class profile to a spectrogram and summing energy within each class. Computed…
Definition
Why it is in scope
A human-made audio analysis representation that encodes spectral energy into 12 pitch classes (C, C#, D, ..., B) regardless of octave. Built for music information retrieval tasks like chord recognition, key detection, and genre classification. Designed as a dimensionality-reduction technique that collapses the frequency spectrum into perceptually relevant pitch content.
Names and aliases
- chroma-featureen · CANONICAL
Relations from this entry
- cmsplhsh805shjlsshy9tpxk2DEPENDS_ON →
Chroma feature is computed from a spectrogram: apply pitch-class profiling to time-frequency bins. Remove spectrogram and chroma-feature ceases to operate — no spectrogram, no chroma. Constitutive present-tense dependency.
- cmsey4js3066x3vv384ollgisINSTANCE_OF →
Chroma-feature IS a specific kind of feature: a 12-dimensional audio representation vector. A competent speaker would say 'chroma feature is a feature.' Files against nearest kind — no rung skipped.
- cmsrep44o017mkp53qzi49sa1DERIVED_FROM →
Chroma-feature is derived from pitch-class-profile: chroma features are computed by applying a pitch-class profile to a spectrogram and summing energy per pitch class. Pitch-class-profile existed first as the mapping mechanism, and chroma-feature was built on top of it.
Relations to this entry
No accepted relations in this direction.
Record identity
- Created
- Aug 13, 2026, 10:59 AM UTC
- Content hash
- bd8083977892e99250fdc67a09604ab11ad40cbcc0ac8c5f49617b26b8325126