Class: TorchAudio::Transforms::MFCC

Inherits:
Torch::NN::Module
  • Object
show all
Defined in:
lib/torchaudio/transforms/mfcc.rb

Constant Summary collapse

SUPPORTED_DCT_TYPES = 
[2]

Instance Method Summary collapse

Constructor Details

#initialize(sample_rate: 16000, n_mfcc: 40, dct_type: 2, norm: :ortho, log_mels: false, melkwargs: {}) ⇒ MFCC

Returns a new instance of MFCC.

Raises:

  • (ArgumentError) 


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# File 'lib/torchaudio/transforms/mfcc.rb', line 6

def initialize(sample_rate: 16000, n_mfcc: 40, dct_type: 2, norm: :ortho, log_mels: false, melkwargs: {})
  super()

  raise ArgumentError, "DCT type not supported: #{dct_type}" unless SUPPORTED_DCT_TYPES.include?(dct_type)

  @sample_rate = sample_rate
  @n_mfcc = n_mfcc
  @dct_type = dct_type
  @norm = norm
  @top_db = 80.0
  @amplitude_to_db = TorchAudio::Transforms::AmplitudeToDB.new(stype: :power, top_db: @top_db)

  @melspectrogram = TorchAudio::Transforms::MelSpectrogram.new(sample_rate: @sample_rate, **melkwargs)

  raise ArgumentError, "Cannot select more MFCC coefficients than # mel bins" if @n_mfcc > @melspectrogram.n_mels

  dct_mat = F.create_dct(@n_mfcc, @melspectrogram.n_mels, norm: @norm)
  register_buffer('dct_mat', dct_mat)

  @log_mels = log_mels
end

Instance Method Details

#forward(waveform) ⇒ Object 



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# File 'lib/torchaudio/transforms/mfcc.rb', line 28

def forward(waveform)
  mel_specgram = @melspectrogram.(waveform)
  if @log_mels
    mel_specgram = Torch.log(mel_specgram + 1e-6)
  else
    mel_specgram = @amplitude_to_db.(mel_specgram)
  end

  Torch
    .matmul(mel_specgram.transpose(-2, -1), @dct_mat)
    .transpose(-2, -1)
end