Module: TorchAudio::Functional

Defined in:
lib/torchaudio/functional.rb

Class Method Summary collapse

Class Method Details

.amplitude_to_DB(amp, multiplier, amin, db_multiplier, top_db: nil) ⇒ Object 



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# File 'lib/torchaudio/functional.rb', line 230

def amplitude_to_DB(amp, multiplier, amin, db_multiplier, top_db: nil)
  db = Torch.log10(Torch.clamp(amp, min: amin)) * multiplier
  db -= multiplier * db_multiplier

  db = db.clamp(min: db.max.item - top_db) if top_db

  db
end

.biquad(waveform, b0, b1, b2, a0, a1, a2) ⇒ Object 



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# File 'lib/torchaudio/functional.rb', line 136

def biquad(waveform, b0, b1, b2, a0, a1, a2)
  device = waveform.device
  dtype = waveform.dtype

  output_waveform = lfilter(
      waveform,
      Torch.tensor([a0, a1, a2], dtype: dtype, device: device),
      Torch.tensor([b0, b1, b2], dtype: dtype, device: device)
  )
  output_waveform
end

.complex_norm(complex_tensor, power: 1.0) ⇒ Object 



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# File 'lib/torchaudio/functional.rb', line 54

def complex_norm(complex_tensor, power: 1.0)
  complex_tensor.pow(2.0).sum(-1).pow(0.5 * power)
end

.compute_deltas(specgram, win_length: 5, mode: "replicate") ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/torchaudio/functional.rb', line 92

def compute_deltas(specgram, win_length: 5, mode: "replicate")
  device = specgram.device
  dtype = specgram.dtype

  # pack batch
  shape = specgram.size
  specgram = specgram.reshape(1, -1, shape[-1])

  raise ArgumentError, "win_length must be >= 3" unless win_length >= 3

  n = (win_length - 1).div(2)

  # twice sum of integer squared
  denom = n * (n + 1) * (2 * n + 1) / 3

  specgram = Torch::NN::Functional.pad(specgram, [n, n], mode: mode)

  kernel = Torch.arange(-n, n + 1, 1, device: device, dtype: dtype).repeat([specgram.shape[1], 1, 1])

  output = Torch::NN::Functional.conv1d(specgram, kernel, groups: specgram.shape[1]) / denom

  # unpack batch
  output = output.reshape(shape)
end

.create_fb_matrix(n_freqs, f_min, f_max, n_mels, sample_rate, norm: nil) ⇒ Object 



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# File 'lib/torchaudio/functional.rb', line 58

def create_fb_matrix(n_freqs, f_min, f_max, n_mels, sample_rate, norm: nil)
  if norm && norm != "slaney"
    raise ArgumentError, "norm must be one of None or 'slaney'"
  end

  # freq bins
  # Equivalent filterbank construction by Librosa
  all_freqs = Torch.linspace(0, sample_rate.div(2), n_freqs)

  # calculate mel freq bins
  # hertz to mel(f) is 2595. * math.log10(1. + (f / 700.))
  m_min = 2595.0 * Math.log10(1.0 + (f_min / 700.0))
  m_max = 2595.0 * Math.log10(1.0 + (f_max / 700.0))
  m_pts = Torch.linspace(m_min, m_max, n_mels + 2)
  # mel to hertz(mel) is 700. * (10**(mel / 2595.) - 1.)
  f_pts = (Torch.pow(10, m_pts / 2595.0) - 1.0) * 700.0
  # calculate the difference between each mel point and each stft freq point in hertz
  f_diff = f_pts[1..-1] - f_pts[0...-1]  # (n_mels + 1)
  slopes = f_pts.unsqueeze(0) - all_freqs.unsqueeze(1)  # (n_freqs, n_mels + 2)
  # create overlapping triangles
  zero = Torch.zeros(1)
  down_slopes = (slopes[0..-1, 0...-2] * -1.0) / f_diff[0...-1]  # (n_freqs, n_mels)
  up_slopes = slopes[0..-1, 2..-1] / f_diff[1..-1]  # (n_freqs, n_mels)
  fb = Torch.max(zero, Torch.min(down_slopes, up_slopes))

  if norm && norm == "slaney"
    # Slaney-style mel is scaled to be approx constant energy per channel
    enorm = 2.0 / (f_pts[2...(n_mels + 2)] - f_pts[:n_mels])
    fb *= enorm.unsqueeze(0)
  end

  fb
end

.DB_to_amplitude(db, ref, power) ⇒ Object 



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# File 'lib/torchaudio/functional.rb', line 239

def DB_to_amplitude(db, ref, power)
  Torch.pow(Torch.pow(10.0, db * 0.1), power) * ref
end

.dither(waveform, density_function: "TPDF", noise_shaping: false) ⇒ Object 



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# File 'lib/torchaudio/functional.rb', line 125

def dither(waveform, density_function: "TPDF", noise_shaping: false)
  dithered = _apply_probability_distribution(waveform, density_function: density_function)

  if noise_shaping
    raise "Not implemented yet"
    # _add_noise_shaping(dithered, waveform)
  else
    dithered
  end
end

.gain(waveform, gain_db: 1.0) ⇒ Object 



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# File 'lib/torchaudio/functional.rb', line 117

def gain(waveform, gain_db: 1.0)
  return waveform if gain_db == 0

  ratio = 10 ** (gain_db / 20)

  waveform * ratio
end

.highpass_biquad(waveform, sample_rate, cutoff_freq, q: 0.707) ⇒ Object 



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# File 'lib/torchaudio/functional.rb', line 148

def highpass_biquad(waveform, sample_rate, cutoff_freq, q: 0.707)
  w0 = 2 * Math::PI * cutoff_freq / sample_rate
  alpha = Math.sin(w0) / 2.0 / q

  b0 = (1 + Math.cos(w0)) / 2
  b1 = -1 - Math.cos(w0)
  b2 = b0
  a0 = 1 + alpha
  a1 = -2 * Math.cos(w0)
  a2 = 1 - alpha
  biquad(waveform, b0, b1, b2, a0, a1, a2)
end

.lfilter(waveform, a_coeffs, b_coeffs, clamp: true) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/torchaudio/functional.rb', line 174

def lfilter(waveform, a_coeffs, b_coeffs, clamp: true)
  # pack batch
  shape = waveform.size
  waveform = waveform.reshape(-1, shape[-1])

  raise ArgumentError unless (a_coeffs.size(0) == b_coeffs.size(0))
  raise ArgumentError unless (waveform.size.length == 2)
  raise ArgumentError unless (waveform.device == a_coeffs.device)
  raise ArgumentError unless (b_coeffs.device == a_coeffs.device)

  device = waveform.device
  dtype = waveform.dtype
  n_channel, n_sample = waveform.size
  n_order = a_coeffs.size(0)
  n_sample_padded = n_sample + n_order - 1
  raise ArgumentError unless (n_order > 0)

  # Pad the input and create output
  padded_waveform = Torch.zeros(n_channel, n_sample_padded, dtype: dtype, device: device)
  padded_waveform[0..-1, (n_order - 1)..-1] = waveform
  padded_output_waveform = Torch.zeros(n_channel, n_sample_padded, dtype: dtype, device: device)

  # Set up the coefficients matrix
  # Flip coefficients' order
  a_coeffs_flipped = a_coeffs.flip([0])
  b_coeffs_flipped = b_coeffs.flip([0])

  # calculate windowed_input_signal in parallel
  # create indices of original with shape (n_channel, n_order, n_sample)
  window_idxs = Torch.arange(n_sample, device: device).unsqueeze(0) + Torch.arange(n_order, device: device).unsqueeze(1)
  window_idxs = window_idxs.repeat([n_channel, 1, 1])
  window_idxs += (Torch.arange(n_channel, device: device).unsqueeze(-1).unsqueeze(-1) * n_sample_padded)
  window_idxs = window_idxs.long
  # (n_order, ) matmul (n_channel, n_order, n_sample) -> (n_channel, n_sample)
  input_signal_windows = Torch.matmul(b_coeffs_flipped, Torch.take(padded_waveform, window_idxs))

  input_signal_windows.div!(a_coeffs[0])
  a_coeffs_flipped.div!(a_coeffs[0])
  input_signal_windows.t.each_with_index do |o0, i_sample|
    windowed_output_signal = padded_output_waveform[0..-1, i_sample...(i_sample + n_order)]
    o0.addmv!(windowed_output_signal, a_coeffs_flipped, alpha: -1)
    padded_output_waveform[0..-1, i_sample + n_order - 1] = o0
  end

  output = padded_output_waveform[0..-1, (n_order - 1)..-1]

  if clamp
    output = Torch.clamp(output, -1.0, 1.0)
  end

  # unpack batch
  output = output.reshape(shape[0...-1] + output.shape[-1..-1])

  output
end

.lowpass_biquad(waveform, sample_rate, cutoff_freq, q: 0.707) ⇒ Object 



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# File 'lib/torchaudio/functional.rb', line 161

def lowpass_biquad(waveform, sample_rate, cutoff_freq, q: 0.707)
  w0 = 2 * Math::PI * cutoff_freq / sample_rate
  alpha = Math.sin(w0) / 2 / q

  b0 = (1 - Math.cos(w0)) / 2
  b1 = 1 - Math.cos(w0)
  b2 = b0
  a0 = 1 + alpha
  a1 = -2 * Math.cos(w0)
  a2 = 1 - alpha
  biquad(waveform, b0, b1, b2, a0, a1, a2)
end

.mu_law_decoding(x_mu, quantization_channels) ⇒ Object 



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# File 'lib/torchaudio/functional.rb', line 43

def mu_law_decoding(x_mu, quantization_channels)
  mu = quantization_channels - 1.0
  if !x_mu.floating_point?
    x_mu = x_mu.to(dtype: :float)
  end
  mu = Torch.tensor(mu, dtype: x_mu.dtype)
  x = ((x_mu) / mu) * 2 - 1.0
  x = Torch.sign(x) * (Torch.exp(Torch.abs(x) * Torch.log1p(mu)) - 1.0) / mu
  x
end

.mu_law_encoding(x, quantization_channels) ⇒ Object 



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# File 'lib/torchaudio/functional.rb', line 32

def mu_law_encoding(x, quantization_channels)
  mu = quantization_channels - 1.0
  if !x.floating_point?
    x = x.to(dtype: :float)
  end
  mu = Torch.tensor(mu, dtype: x.dtype)
  x_mu = Torch.sign(x) * Torch.log1p(mu * Torch.abs(x)) / Torch.log1p(mu)
  x_mu = ((x_mu + 1) / 2 * mu + 0.5).to(dtype: :int64)
  x_mu
end

.spectrogram(waveform, pad, window, n_fft, hop_length, win_length, power, normalized) ⇒ Object 



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# File 'lib/torchaudio/functional.rb', line 4

def spectrogram(waveform, pad, window, n_fft, hop_length, win_length, power, normalized)
  if pad > 0
    # TODO add "with torch.no_grad():" back when JIT supports it
    waveform = Torch::NN::Functional.pad(waveform, [pad, pad], "constant")
  end

  # pack batch
  shape = waveform.size
  waveform = waveform.reshape(-1, shape[-1])

  # default values are consistent with librosa.core.spectrum._spectrogram
  spec_f = Torch.stft(
    waveform, n_fft, hop_length: hop_length, win_length: win_length, window: window, center: true, pad_mode: "reflect", normalized: false, onesided: true
  )

  # unpack batch
  spec_f = spec_f.reshape(shape[0..-2] + spec_f.shape[-3..-1])

  if normalized
    spec_f.div!(window.pow(2.0).sum.sqrt)
  end
  if power
    spec_f = complex_norm(spec_f, power: power)
  end

  spec_f
end