Class: Pitch

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

Constant Summary collapse

SEMITONE_NAMES = 
%w[C C# D D# E F F# G G# A A# B]
NUM_SEMITONES = 
SEMITONE_NAMES.count

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(semitone, octave) ⇒ Pitch

Returns a new instance of Pitch.



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# File 'lib/pitch.rb', line 63

def initialize(semitone, octave)
  @semitone = case semitone
  when Numeric
    semitone
  when String
    SEMITONE_NAMES.index(semitone)
  else
    raise ArgumentError
  end
  @octave = octave
end

Instance Attribute Details

#octave ⇒ Object

Returns the value of attribute octave.



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# File 'lib/pitch.rb', line 6

def octave
  @octave
end

#semitone ⇒ Object

Returns the value of attribute semitone.



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# File 'lib/pitch.rb', line 5

def semitone
  @semitone
end

Class Method Details

.new_from_midi(arg) ⇒ Object 



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# File 'lib/pitch.rb', line 30

def self.new_from_midi(arg)
  case arg
  when Numeric
    new_from_midi_num(arg)
  when String
    new_from_midi_name(arg)
  else
    raise ArgumentError
  end
end

.new_from_midi_name(name) ⇒ Object 



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# File 'lib/pitch.rb', line 46

def self.new_from_midi_name(name)
  semitone, octave = parse_name(name)
  new(semitone, octave + 1)
end

.new_from_midi_num(num) ⇒ Object 



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# File 'lib/pitch.rb', line 41

def self.new_from_midi_num(num)
  semitone, octave = SEMITONE_NAMES[num % NUM_SEMITONES], (num / NUM_SEMITONES)
  new(semitone, octave - 1)
end

.new_from_spn(spn) ⇒ Object 



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# File 'lib/pitch.rb', line 51

def self.new_from_spn(spn)
  semitone, octave = parse_name(spn)
  new(semitone, octave)
end

.parse_name(name) ⇒ Object 



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# File 'lib/pitch.rb', line 56

def self.parse_name(name)
  semitone_name, octave = name.match(/^(.*?)(-?\d+)$/).captures
  semitone = SEMITONE_NAMES.index(semitone_name)
  octave = octave.to_i
  [semitone, octave]
end

.read_from_file(file) ⇒ Object 



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# File 'lib/pitch.rb', line 11

def self.read_from_file(file)
  out, _ = run_command(
    'aubiopitch',
    '--samplerate', 48000,  # doesn't work with higher sample rates?
    '--input', file,
    '--pitch-unit', 'midi',
  )
  values = out.split(/\n/).map { |line| line.split(/\s+/).last.to_f }.reject(&:zero?)
  raise "Couldn't detect pitches" if values.empty?
  value = (values.sum / values.count).round
  new_from_midi_num(value)
end

.run_command(*args) ⇒ Object 



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# File 'lib/pitch.rb', line 24

def self.run_command(*args)
  TTY::Command.new(printer: :quiet).run(
    *args.flatten.compact.map(&:to_s),
    only_output_on_error: true)
end

Instance Method Details

#+(n) ⇒ Object 



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# File 'lib/pitch.rb', line 100

def +(n)
  self.class.new_from_midi_num(to_midi_num + n)
end

#-(n) ⇒ Object 



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# File 'lib/pitch.rb', line 104

def -(n)
  self + (-n)
end

#==(other) ⇒ Object 



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# File 'lib/pitch.rb', line 75

def ==(other)
  other &&
    @octave == other.octave &&
    @semitone == other.semitone
end

#to_midi_name ⇒ Object 



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# File 'lib/pitch.rb', line 81

def to_midi_name
  to_s(offset: -1)
end

#to_midi_num ⇒ Object 



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# File 'lib/pitch.rb', line 85

def to_midi_num
  ((@octave + 1) * NUM_SEMITONES) + @semitone
end

#to_s(offset: 0) ⇒ Object 



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# File 'lib/pitch.rb', line 93

def to_s(offset: 0)
  '%s%d' % [
    SEMITONE_NAMES[@semitone],
    @octave + offset,
  ]
end

#to_spn ⇒ Object 



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# File 'lib/pitch.rb', line 89

def to_spn
  to_s
end

#write_to_file(file, duration: 5, rate: 48000, depth: 24) ⇒ Object 



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# File 'lib/pitch.rb', line 108

def write_to_file(file, duration: 5, rate: 48000, depth: 24)
  self.class.run_command(
    'sox',
    '--null',
    '--rate', rate,
    '--bits', depth,
    file,
    'synth', duration, 'pluck', to_spn,
  )
  file
end