Class: Topaz::TempoCalculator

Inherits:
Object
  • Object
show all
Defined in:
lib/topaz/tempo_calculator.rb

Overview

Calculate tempo given timestamps

Constant Summary collapse

THRESHOLD =

Optimal number of ticks to analyze

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Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ TempoCalculator

Returns a new instance of TempoCalculator.



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# File 'lib/topaz/tempo_calculator.rb', line 10

def initialize
  @tempo = nil
  @timestamps = []
end

Instance Attribute Details

#tempo ⇒ Object (readonly)

Returns the value of attribute tempo.



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# File 'lib/topaz/tempo_calculator.rb', line 8

def tempo
  @tempo
end

#timestamps ⇒ Object (readonly)

Returns the value of attribute timestamps.



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# File 'lib/topaz/tempo_calculator.rb', line 8

def timestamps
  @timestamps
end

Instance Method Details

#calculate ⇒ Float?

Analyze the tempo based on the threshold

Returns:

  • (Float, nil) —

    The tempo as a float, or nil if there’s not enough data to calculate it



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# File 'lib/topaz/tempo_calculator.rb', line 17

def calculate
  tempo = nil
  if @timestamps.count >= 2
    limit_timestamps
    deltas = get_deltas
    sum = deltas.inject(&:+)
    average = sum.to_f / deltas.count
    bpm = ppq24_millis_to_bpm(average)
    @tempo = bpm
  end
end