LogSpectrum
streaming mode | Spectral category
Inputs
- spectrum (vector_real) - spectrum frame
Outputs
- logFreqSpectrum (vector_real) - log frequency spectrum frame
- meanTuning (vector_real) - normalized mean tuning frequency
- localTuning (real) - normalized local tuning frequency
Parameters
- binsPerSemitone (real ∈ (0, ∞), default = 3) :
- bins per semitone
- frameSize (integer ∈ (1, ∞), default = 1025) :
- the input frame size of the spectrum vector
- nOctave (integer ∈ (0, 10), default = 7) :
- the number of octave of the output vector
- rollOn (real ∈ [0, 5], default = 0) :
- this removes low-frequency noise - useful in quiet recordings
- sampleRate (real ∈ (0, ∞), default = 44100) :
- the input sample rate
Description
This algorithm computes spectrum with logarithmically distributed frequency bins. This code is ported from NNLS Chroma [1, 2].This algorithm also returns a local tuning that is retrieved for input frame and a global tuning that is updated with a moving average.
Note: As the algorithm uses moving averages that are updated every frame it should be reset before processing a new audio file. To do this call reset() (or configure())
- References:
- [1] Mauch, M., & Dixon, S. (2010, August). Approximate Note Transcription for the Improved Identification of Difficult Chords. In ISMIR (pp. 135-140). [2] Chordino and NNLS Chroma, http://www.isophonics.net/nnls-chroma
See also
LogSpectrum (standard)