Source code for TTS.utils.audio.processor

from io import BytesIO
from typing import Dict, Tuple

import librosa
import numpy as np
import scipy.io.wavfile
import scipy.signal

from TTS.tts.utils.helpers import StandardScaler
from TTS.utils.audio.numpy_transforms import (
    amp_to_db,
    build_mel_basis,
    compute_f0,
    db_to_amp,
    deemphasis,
    find_endpoint,
    griffin_lim,
    load_wav,
    mel_to_spec,
    millisec_to_length,
    preemphasis,
    rms_volume_norm,
    spec_to_mel,
    stft,
    trim_silence,
    volume_norm,
)

# pylint: disable=too-many-public-methods


[docs] class AudioProcessor(object): """Audio Processor for TTS. Note: All the class arguments are set to default values to enable a flexible initialization of the class with the model config. They are not meaningful for all the arguments. Args: sample_rate (int, optional): target audio sampling rate. Defaults to None. resample (bool, optional): enable/disable resampling of the audio clips when the target sampling rate does not match the original sampling rate. Defaults to False. num_mels (int, optional): number of melspectrogram dimensions. Defaults to None. log_func (int, optional): log exponent used for converting spectrogram aplitude to DB. min_level_db (int, optional): minimum db threshold for the computed melspectrograms. Defaults to None. frame_shift_ms (int, optional): milliseconds of frames between STFT columns. Defaults to None. frame_length_ms (int, optional): milliseconds of STFT window length. Defaults to None. hop_length (int, optional): number of frames between STFT columns. Used if ```frame_shift_ms``` is None. Defaults to None. win_length (int, optional): STFT window length. Used if ```frame_length_ms``` is None. Defaults to None. ref_level_db (int, optional): reference DB level to avoid background noise. In general <20DB corresponds to the air noise. Defaults to None. fft_size (int, optional): FFT window size for STFT. Defaults to 1024. power (int, optional): Exponent value applied to the spectrogram before GriffinLim. Defaults to None. preemphasis (float, optional): Preemphasis coefficient. Preemphasis is disabled if == 0.0. Defaults to 0.0. signal_norm (bool, optional): enable/disable signal normalization. Defaults to None. symmetric_norm (bool, optional): enable/disable symmetric normalization. If set True normalization is performed in the range [-k, k] else [0, k], Defaults to None. max_norm (float, optional): ```k``` defining the normalization range. Defaults to None. mel_fmin (int, optional): minimum filter frequency for computing melspectrograms. Defaults to None. mel_fmax (int, optional): maximum filter frequency for computing melspectrograms. Defaults to None. pitch_fmin (int, optional): minimum filter frequency for computing pitch. Defaults to None. pitch_fmax (int, optional): maximum filter frequency for computing pitch. Defaults to None. spec_gain (int, optional): gain applied when converting amplitude to DB. Defaults to 20. stft_pad_mode (str, optional): Padding mode for STFT. Defaults to 'reflect'. clip_norm (bool, optional): enable/disable clipping the our of range values in the normalized audio signal. Defaults to True. griffin_lim_iters (int, optional): Number of GriffinLim iterations. Defaults to None. do_trim_silence (bool, optional): enable/disable silence trimming when loading the audio signal. Defaults to False. trim_db (int, optional): DB threshold used for silence trimming. Defaults to 60. do_sound_norm (bool, optional): enable/disable signal normalization. Defaults to False. do_amp_to_db_linear (bool, optional): enable/disable amplitude to dB conversion of linear spectrograms. Defaults to True. do_amp_to_db_mel (bool, optional): enable/disable amplitude to dB conversion of mel spectrograms. Defaults to True. do_rms_norm (bool, optional): enable/disable RMS volume normalization when loading an audio file. Defaults to False. db_level (int, optional): dB level used for rms normalization. The range is -99 to 0. Defaults to None. stats_path (str, optional): Path to the computed stats file. Defaults to None. verbose (bool, optional): enable/disable logging. Defaults to True. """ def __init__( self, sample_rate=None, resample=False, num_mels=None, log_func="np.log10", min_level_db=None, frame_shift_ms=None, frame_length_ms=None, hop_length=None, win_length=None, ref_level_db=None, fft_size=1024, power=None, preemphasis=0.0, signal_norm=None, symmetric_norm=None, max_norm=None, mel_fmin=None, mel_fmax=None, pitch_fmax=None, pitch_fmin=None, spec_gain=20, stft_pad_mode="reflect", clip_norm=True, griffin_lim_iters=None, do_trim_silence=False, trim_db=60, do_sound_norm=False, do_amp_to_db_linear=True, do_amp_to_db_mel=True, do_rms_norm=False, db_level=None, stats_path=None, verbose=True, **_, ): # setup class attributed self.sample_rate = sample_rate self.resample = resample self.num_mels = num_mels self.log_func = log_func self.min_level_db = min_level_db or 0 self.frame_shift_ms = frame_shift_ms self.frame_length_ms = frame_length_ms self.ref_level_db = ref_level_db self.fft_size = fft_size self.power = power self.preemphasis = preemphasis self.griffin_lim_iters = griffin_lim_iters self.signal_norm = signal_norm self.symmetric_norm = symmetric_norm self.mel_fmin = mel_fmin or 0 self.mel_fmax = mel_fmax self.pitch_fmin = pitch_fmin self.pitch_fmax = pitch_fmax self.spec_gain = float(spec_gain) self.stft_pad_mode = stft_pad_mode self.max_norm = 1.0 if max_norm is None else float(max_norm) self.clip_norm = clip_norm self.do_trim_silence = do_trim_silence self.trim_db = trim_db self.do_sound_norm = do_sound_norm self.do_amp_to_db_linear = do_amp_to_db_linear self.do_amp_to_db_mel = do_amp_to_db_mel self.do_rms_norm = do_rms_norm self.db_level = db_level self.stats_path = stats_path # setup exp_func for db to amp conversion if log_func == "np.log": self.base = np.e elif log_func == "np.log10": self.base = 10 else: raise ValueError(" [!] unknown `log_func` value.") # setup stft parameters if hop_length is None: # compute stft parameters from given time values self.win_length, self.hop_length = millisec_to_length( frame_length_ms=self.frame_length_ms, frame_shift_ms=self.frame_shift_ms, sample_rate=self.sample_rate ) else: # use stft parameters from config file self.hop_length = hop_length self.win_length = win_length assert min_level_db != 0.0, " [!] min_level_db is 0" assert ( self.win_length <= self.fft_size ), f" [!] win_length cannot be larger than fft_size - {self.win_length} vs {self.fft_size}" members = vars(self) if verbose: print(" > Setting up Audio Processor...") for key, value in members.items(): print(" | > {}:{}".format(key, value)) # create spectrogram utils self.mel_basis = build_mel_basis( sample_rate=self.sample_rate, fft_size=self.fft_size, num_mels=self.num_mels, mel_fmax=self.mel_fmax, mel_fmin=self.mel_fmin, ) # setup scaler if stats_path and signal_norm: mel_mean, mel_std, linear_mean, linear_std, _ = self.load_stats(stats_path) self.setup_scaler(mel_mean, mel_std, linear_mean, linear_std) self.signal_norm = True self.max_norm = None self.clip_norm = None self.symmetric_norm = None @staticmethod def init_from_config(config: "Coqpit", verbose=True): if "audio" in config: return AudioProcessor(verbose=verbose, **config.audio) return AudioProcessor(verbose=verbose, **config) ### normalization ###
[docs] def normalize(self, S: np.ndarray) -> np.ndarray: """Normalize values into `[0, self.max_norm]` or `[-self.max_norm, self.max_norm]` Args: S (np.ndarray): Spectrogram to normalize. Raises: RuntimeError: Mean and variance is computed from incompatible parameters. Returns: np.ndarray: Normalized spectrogram. """ # pylint: disable=no-else-return S = S.copy() if self.signal_norm: # mean-var scaling if hasattr(self, "mel_scaler"): if S.shape[0] == self.num_mels: return self.mel_scaler.transform(S.T).T elif S.shape[0] == self.fft_size / 2: return self.linear_scaler.transform(S.T).T else: raise RuntimeError(" [!] Mean-Var stats does not match the given feature dimensions.") # range normalization S -= self.ref_level_db # discard certain range of DB assuming it is air noise S_norm = (S - self.min_level_db) / (-self.min_level_db) if self.symmetric_norm: S_norm = ((2 * self.max_norm) * S_norm) - self.max_norm if self.clip_norm: S_norm = np.clip( S_norm, -self.max_norm, self.max_norm # pylint: disable=invalid-unary-operand-type ) return S_norm else: S_norm = self.max_norm * S_norm if self.clip_norm: S_norm = np.clip(S_norm, 0, self.max_norm) return S_norm else: return S
[docs] def denormalize(self, S: np.ndarray) -> np.ndarray: """Denormalize spectrogram values. Args: S (np.ndarray): Spectrogram to denormalize. Raises: RuntimeError: Mean and variance are incompatible. Returns: np.ndarray: Denormalized spectrogram. """ # pylint: disable=no-else-return S_denorm = S.copy() if self.signal_norm: # mean-var scaling if hasattr(self, "mel_scaler"): if S_denorm.shape[0] == self.num_mels: return self.mel_scaler.inverse_transform(S_denorm.T).T elif S_denorm.shape[0] == self.fft_size / 2: return self.linear_scaler.inverse_transform(S_denorm.T).T else: raise RuntimeError(" [!] Mean-Var stats does not match the given feature dimensions.") if self.symmetric_norm: if self.clip_norm: S_denorm = np.clip( S_denorm, -self.max_norm, self.max_norm # pylint: disable=invalid-unary-operand-type ) S_denorm = ((S_denorm + self.max_norm) * -self.min_level_db / (2 * self.max_norm)) + self.min_level_db return S_denorm + self.ref_level_db else: if self.clip_norm: S_denorm = np.clip(S_denorm, 0, self.max_norm) S_denorm = (S_denorm * -self.min_level_db / self.max_norm) + self.min_level_db return S_denorm + self.ref_level_db else: return S_denorm
### Mean-STD scaling ###
[docs] def load_stats(self, stats_path: str) -> Tuple[np.array, np.array, np.array, np.array, Dict]: """Loading mean and variance statistics from a `npy` file. Args: stats_path (str): Path to the `npy` file containing Returns: Tuple[np.array, np.array, np.array, np.array, Dict]: loaded statistics and the config used to compute them. """ stats = np.load(stats_path, allow_pickle=True).item() # pylint: disable=unexpected-keyword-arg mel_mean = stats["mel_mean"] mel_std = stats["mel_std"] linear_mean = stats["linear_mean"] linear_std = stats["linear_std"] stats_config = stats["audio_config"] # check all audio parameters used for computing stats skip_parameters = ["griffin_lim_iters", "stats_path", "do_trim_silence", "ref_level_db", "power"] for key in stats_config.keys(): if key in skip_parameters: continue if key not in ["sample_rate", "trim_db"]: assert ( stats_config[key] == self.__dict__[key] ), f" [!] Audio param {key} does not match the value used for computing mean-var stats. {stats_config[key]} vs {self.__dict__[key]}" return mel_mean, mel_std, linear_mean, linear_std, stats_config
# pylint: disable=attribute-defined-outside-init
[docs] def setup_scaler( self, mel_mean: np.ndarray, mel_std: np.ndarray, linear_mean: np.ndarray, linear_std: np.ndarray ) -> None: """Initialize scaler objects used in mean-std normalization. Args: mel_mean (np.ndarray): Mean for melspectrograms. mel_std (np.ndarray): STD for melspectrograms. linear_mean (np.ndarray): Mean for full scale spectrograms. linear_std (np.ndarray): STD for full scale spectrograms. """ self.mel_scaler = StandardScaler() self.mel_scaler.set_stats(mel_mean, mel_std) self.linear_scaler = StandardScaler() self.linear_scaler.set_stats(linear_mean, linear_std)
### Preemphasis ###
[docs] def apply_preemphasis(self, x: np.ndarray) -> np.ndarray: """Apply pre-emphasis to the audio signal. Useful to reduce the correlation between neighbouring signal values. Args: x (np.ndarray): Audio signal. Raises: RuntimeError: Preemphasis coeff is set to 0. Returns: np.ndarray: Decorrelated audio signal. """ return preemphasis(x=x, coef=self.preemphasis)
[docs] def apply_inv_preemphasis(self, x: np.ndarray) -> np.ndarray: """Reverse pre-emphasis.""" return deemphasis(x=x, coef=self.preemphasis)
### SPECTROGRAMs ###
[docs] def spectrogram(self, y: np.ndarray) -> np.ndarray: """Compute a spectrogram from a waveform. Args: y (np.ndarray): Waveform. Returns: np.ndarray: Spectrogram. """ if self.preemphasis != 0: y = self.apply_preemphasis(y) D = stft( y=y, fft_size=self.fft_size, hop_length=self.hop_length, win_length=self.win_length, pad_mode=self.stft_pad_mode, ) if self.do_amp_to_db_linear: S = amp_to_db(x=np.abs(D), gain=self.spec_gain, base=self.base) else: S = np.abs(D) return self.normalize(S).astype(np.float32)
[docs] def melspectrogram(self, y: np.ndarray) -> np.ndarray: """Compute a melspectrogram from a waveform.""" if self.preemphasis != 0: y = self.apply_preemphasis(y) D = stft( y=y, fft_size=self.fft_size, hop_length=self.hop_length, win_length=self.win_length, pad_mode=self.stft_pad_mode, ) S = spec_to_mel(spec=np.abs(D), mel_basis=self.mel_basis) if self.do_amp_to_db_mel: S = amp_to_db(x=S, gain=self.spec_gain, base=self.base) return self.normalize(S).astype(np.float32)
[docs] def inv_spectrogram(self, spectrogram: np.ndarray) -> np.ndarray: """Convert a spectrogram to a waveform using Griffi-Lim vocoder.""" S = self.denormalize(spectrogram) S = db_to_amp(x=S, gain=self.spec_gain, base=self.base) # Reconstruct phase W = self._griffin_lim(S**self.power) return self.apply_inv_preemphasis(W) if self.preemphasis != 0 else W
[docs] def inv_melspectrogram(self, mel_spectrogram: np.ndarray) -> np.ndarray: """Convert a melspectrogram to a waveform using Griffi-Lim vocoder.""" D = self.denormalize(mel_spectrogram) S = db_to_amp(x=D, gain=self.spec_gain, base=self.base) S = mel_to_spec(mel=S, mel_basis=self.mel_basis) # Convert back to linear W = self._griffin_lim(S**self.power) return self.apply_inv_preemphasis(W) if self.preemphasis != 0 else W
[docs] def out_linear_to_mel(self, linear_spec: np.ndarray) -> np.ndarray: """Convert a full scale linear spectrogram output of a network to a melspectrogram. Args: linear_spec (np.ndarray): Normalized full scale linear spectrogram. Returns: np.ndarray: Normalized melspectrogram. """ S = self.denormalize(linear_spec) S = db_to_amp(x=S, gain=self.spec_gain, base=self.base) S = spec_to_mel(spec=np.abs(S), mel_basis=self.mel_basis) S = amp_to_db(x=S, gain=self.spec_gain, base=self.base) mel = self.normalize(S) return mel
def _griffin_lim(self, S): return griffin_lim( spec=S, num_iter=self.griffin_lim_iters, hop_length=self.hop_length, win_length=self.win_length, fft_size=self.fft_size, pad_mode=self.stft_pad_mode, )
[docs] def compute_f0(self, x: np.ndarray) -> np.ndarray: """Compute pitch (f0) of a waveform using the same parameters used for computing melspectrogram. Args: x (np.ndarray): Waveform. Returns: np.ndarray: Pitch. Examples: >>> WAV_FILE = filename = librosa.example('vibeace') >>> from TTS.config import BaseAudioConfig >>> from TTS.utils.audio import AudioProcessor >>> conf = BaseAudioConfig(pitch_fmax=640, pitch_fmin=1) >>> ap = AudioProcessor(**conf) >>> wav = ap.load_wav(WAV_FILE, sr=ap.sample_rate)[:5 * ap.sample_rate] >>> pitch = ap.compute_f0(wav) """ # align F0 length to the spectrogram length if len(x) % self.hop_length == 0: x = np.pad(x, (0, self.hop_length // 2), mode=self.stft_pad_mode) f0 = compute_f0( x=x, pitch_fmax=self.pitch_fmax, pitch_fmin=self.pitch_fmin, hop_length=self.hop_length, win_length=self.win_length, sample_rate=self.sample_rate, stft_pad_mode=self.stft_pad_mode, center=True, ) return f0
### Audio Processing ###
[docs] def find_endpoint(self, wav: np.ndarray, min_silence_sec=0.8) -> int: """Find the last point without silence at the end of a audio signal. Args: wav (np.ndarray): Audio signal. threshold_db (int, optional): Silence threshold in decibels. Defaults to -40. min_silence_sec (float, optional): Ignore silences that are shorter then this in secs. Defaults to 0.8. Returns: int: Last point without silence. """ return find_endpoint( wav=wav, trim_db=self.trim_db, sample_rate=self.sample_rate, min_silence_sec=min_silence_sec, gain=self.spec_gain, base=self.base, )
[docs] def trim_silence(self, wav): """Trim silent parts with a threshold and 0.01 sec margin""" return trim_silence( wav=wav, sample_rate=self.sample_rate, trim_db=self.trim_db, win_length=self.win_length, hop_length=self.hop_length, )
[docs] @staticmethod def sound_norm(x: np.ndarray) -> np.ndarray: """Normalize the volume of an audio signal. Args: x (np.ndarray): Raw waveform. Returns: np.ndarray: Volume normalized waveform. """ return volume_norm(x=x)
[docs] def rms_volume_norm(self, x: np.ndarray, db_level: float = None) -> np.ndarray: """Normalize the volume based on RMS of the signal. Args: x (np.ndarray): Raw waveform. Returns: np.ndarray: RMS normalized waveform. """ if db_level is None: db_level = self.db_level return rms_volume_norm(x=x, db_level=db_level)
### save and load ###
[docs] def load_wav(self, filename: str, sr: int = None) -> np.ndarray: """Read a wav file using Librosa and optionally resample, silence trim, volume normalize. Resampling slows down loading the file significantly. Therefore it is recommended to resample the file before. Args: filename (str): Path to the wav file. sr (int, optional): Sampling rate for resampling. Defaults to None. Returns: np.ndarray: Loaded waveform. """ if sr is not None: x = load_wav(filename=filename, sample_rate=sr, resample=True) else: x = load_wav(filename=filename, sample_rate=self.sample_rate, resample=self.resample) if self.do_trim_silence: try: x = self.trim_silence(x) except ValueError: print(f" [!] File cannot be trimmed for silence - {filename}") if self.do_sound_norm: x = self.sound_norm(x) if self.do_rms_norm: x = self.rms_volume_norm(x, self.db_level) return x
[docs] def save_wav(self, wav: np.ndarray, path: str, sr: int = None, pipe_out=None) -> None: """Save a waveform to a file using Scipy. Args: wav (np.ndarray): Waveform to save. path (str): Path to a output file. sr (int, optional): Sampling rate used for saving to the file. Defaults to None. pipe_out (BytesIO, optional): Flag to stdout the generated TTS wav file for shell pipe. """ if self.do_rms_norm: wav_norm = self.rms_volume_norm(wav, self.db_level) * 32767 else: wav_norm = wav * (32767 / max(0.01, np.max(np.abs(wav)))) wav_norm = wav_norm.astype(np.int16) if pipe_out: wav_buffer = BytesIO() scipy.io.wavfile.write(wav_buffer, sr if sr else self.sample_rate, wav_norm) wav_buffer.seek(0) pipe_out.buffer.write(wav_buffer.read()) scipy.io.wavfile.write(path, sr if sr else self.sample_rate, wav_norm)
[docs] def get_duration(self, filename: str) -> float: """Get the duration of a wav file using Librosa. Args: filename (str): Path to the wav file. """ return librosa.get_duration(filename=filename)