Class: Muze::Feature::Context

Inherits:
Object
  • Object
show all
Defined in:
lib/muze/feature/context.rb

Overview

Lightweight cache for feature extractors that share the same STFT.

Constant Summary collapse

DEFAULT_FEATURES = 
%i[
  melspectrogram
  chroma_stft
  spectral_centroid
  spectral_bandwidth
  spectral_rolloff
  spectral_flatness
  rms
  zero_crossing_rate
].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(y:, sr: 22_050, n_fft: 2048, hop_length: 512, center: true, pad_mode: :reflect) ⇒ Context

Returns a new instance of Context.



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# File 'lib/muze/feature/context.rb', line 20

def initialize(y:, sr: 22_050, n_fft: 2048, hop_length: 512, center: true, pad_mode: :reflect)
  @y = y
  @sr = sr
  @n_fft = n_fft
  @hop_length = hop_length
  @center = center
  @pad_mode = pad_mode
  @cache = {}
end

Instance Attribute Details

#center ⇒ Object (readonly)

Returns the value of attribute center.



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# File 'lib/muze/feature/context.rb', line 18

def center
  @center
end

#hop_length ⇒ Object (readonly)

Returns the value of attribute hop_length.



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# File 'lib/muze/feature/context.rb', line 18

def hop_length
  @hop_length
end

#n_fft ⇒ Object (readonly)

Returns the value of attribute n_fft.



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# File 'lib/muze/feature/context.rb', line 18

def n_fft
  @n_fft
end

#pad_mode ⇒ Object (readonly)

Returns the value of attribute pad_mode.



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# File 'lib/muze/feature/context.rb', line 18

def pad_mode
  @pad_mode
end

#sr ⇒ Object (readonly)

Returns the value of attribute sr.



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# File 'lib/muze/feature/context.rb', line 18

def sr
  @sr
end

#y ⇒ Object (readonly)

Returns the value of attribute y.



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# File 'lib/muze/feature/context.rb', line 18

def y
  @y
end

Instance Method Details

#extract(features: DEFAULT_FEATURES) ⇒ Object 



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# File 'lib/muze/feature/context.rb', line 42

def extract(features: DEFAULT_FEATURES)
  features.each_with_object({}) do |feature, results|
    results[feature] = fetch(feature)
  end
end

#fetch(feature) ⇒ Object 



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# File 'lib/muze/feature/context.rb', line 48

def fetch(feature)
  @cache[feature] ||= case feature
                      when :melspectrogram then Muze::Feature.melspectrogram(sr:, s: power, n_fft:, hop_length:)
                      when :chroma_stft then Muze::Feature.chroma_stft(sr:, s: magnitude, n_fft:, hop_length:)
                      when :spectral_centroid then Muze::Feature.spectral_centroid(s: magnitude, sr:, n_fft:, hop_length:)
                      when :spectral_bandwidth then Muze::Feature.spectral_bandwidth(s: magnitude, sr:, n_fft:, hop_length:)
                      when :spectral_rolloff then Muze::Feature.spectral_rolloff(s: magnitude, sr:, n_fft:, hop_length:)
                      when :spectral_flatness then Muze::Feature.spectral_flatness(s: magnitude, n_fft:, hop_length:)
                      when :spectral_flux then Muze::Feature.spectral_flux(s: magnitude, sr:, n_fft:, hop_length:)
                      when :spectral_entropy then Muze::Feature.spectral_entropy(s: magnitude, sr:, n_fft:, hop_length:)
                      when :spectral_crest then Muze::Feature.spectral_crest(s: magnitude, sr:, n_fft:, hop_length:)
                      when :spectral_slope then Muze::Feature.spectral_slope(s: magnitude, sr:, n_fft:, hop_length:)
                      when :spectral_decrease then Muze::Feature.spectral_decrease(s: magnitude, sr:, n_fft:, hop_length:)
                      when :poly_features then Muze::Feature.poly_features(s: magnitude, sr:, n_fft:, hop_length:)
                      when :tonnetz then Muze::Feature.tonnetz(chroma: fetch(:chroma_stft), sr:, n_fft:, hop_length:)
                      when :rms then Muze::Feature.rms(s: magnitude)
                      when :zero_crossing_rate then Muze::Feature.zero_crossing_rate(y, frame_length: n_fft, hop_length:)
                      else
                        raise Muze::ParameterError, "Unsupported feature: #{feature}"
                      end
end

#magnitude ⇒ Object 



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# File 'lib/muze/feature/context.rb', line 34

def magnitude
  @cache[:magnitude] ||= Muze.magphase(stft).first
end

#power ⇒ Object 



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# File 'lib/muze/feature/context.rb', line 38

def power
  @cache[:power] ||= (magnitude**2).cast_to(Numo::SFloat)
end

#stft ⇒ Object 



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# File 'lib/muze/feature/context.rb', line 30

def stft
  @cache[:stft] ||= Muze.stft(y, n_fft:, hop_length:, center:, pad_mode:)
end