preprocessing.py

import numpy as np
import torch
import librosa

from sklearn.base import BaseEstimator, TransformerMixin
from typing import Callable, Optional

class ReductionTransformer(BaseEstimator, TransformerMixin):
    def __init__(self, windows_number: int = 300, statistique = np.mean):
        self.windows_number = windows_number
        self.statistique = statistique

    def fit(self, X: np.ndarray, y = None):
        return self

    def fit_transform(self, X: np.ndarray, y = None) -> np.ndarray:
        self.fit(X, y)
        return self.transform(X, y)

    def transform(self, X: np.ndarray, y = None) -> np.ndarray:
        X_ = X.copy()
        *c_, size_ = X_.shape
        windows_size_ = size_//self.windows_number
        metrique_clip = X_[..., :self.windows_number*windows_size_]
        return np.apply_along_axis(self.statistique,
                    axis=-1,
                    arr=metrique_clip.reshape((*c_, self.windows_number, windows_size_)))

    def inverse_transform(self, X: np.ndarray) -> np.ndarray:
        raise NotImplementedError

class MeanTransformer(BaseEstimator, TransformerMixin):
    def __init__(self, windows_number: int = 300):
        self.windows_number = windows_number
        self.windows_size = 0

    def fit(self, X: np.ndarray, y = None):
        return self

    def fit_transform(self, X: np.ndarray, y = None) -> np.ndarray:
        self.fit(X, y)
        return self.transform(X, y)

    def transform(self, X: np.ndarray, y = None) -> np.ndarray:
        X_ = X.copy()
        *c_, size_ = X_.shape
        windows_size_ = size_//self.windows_number
        self.windows_size = windows_size_
        metrique_clip = X_[..., :self.windows_number*windows_size_]
        return np.mean(metrique_clip.reshape((*c_, self.windows_number, windows_size_)), axis=-1)

    def inverse_transform(self, X: np.ndarray) -> np.ndarray:
        original_size = self.windows_size*self.windows_number
        X_reconstruct = np.interp(
            x  = np.arange(start=0, stop=original_size, step=1),
            xp = np.arange(start=0, stop=original_size, step=self.windows_size),
            fp = X
        )
        return X_reconstruct

class StdTransformer(BaseEstimator, TransformerMixin):
    def __init__(self, windows_number: int = 300):
        self.windows_number = windows_number

    def fit(self, X: np.ndarray, y = None):
        return self

    def fit_transform(self, X: np.ndarray, y = None) -> np.ndarray:
        self.fit(X, y)
        return self.transform(X, y)

    def transform(self, X: np.ndarray, y = None) -> np.ndarray:
        X_ = X.copy()
        *c_, size_ = X_.shape
        windows_size_ = size_//self.windows_number
        metrique_clip = X_[..., :self.windows_number*windows_size_]
        return np.std(metrique_clip.reshape((*c_, self.windows_number, windows_size_)), axis=-1)

    def inverse_transform(self, X: np.ndarray) -> np.ndarray:
        raise NotImplementedError

class MfccTransformer(BaseEstimator, TransformerMixin):
    def __init__(self, sr: int = 22050, N_MFCC: int = 12, hop_length: int = 1024, reshape_output: bool = True):
        self.sr = sr
        self.N_MFCC = N_MFCC
        self.hop_length = hop_length
        self.reshape_output = reshape_output

    def reshape(self, X: np.ndarray) -> np.ndarray:
        X_ = X.copy()
        c_, *_ = X_.shape
        return X_.reshape(c_, -1, self.N_MFCC)

    def fit(self, X: np.ndarray, y = None):
        return self

    def fit_transform(self, X: np.ndarray, y = None) -> np.ndarray:
        self.fit(X, y)
        return self.transform(X, y)

    def transform(self, X: np.ndarray, y = None) -> np.ndarray:
        X_ = X.copy()
        c_, *_ = X_.shape
        mfcc = librosa.feature.mfcc(y=X_, 
            sr=self.sr,
            hop_length=self.hop_length,
            n_mfcc=self.N_MFCC
        )
        if self.reshape_output:
            mfcc = mfcc.reshape(c_, -1)

        return mfcc

    def inverse_transform(self, X: np.ndarray) -> np.ndarray:
        X_reconstruct = librosa.feature.inverse.mfcc_to_audio(
            mfcc = X,
            n_mels = self.N_MFCC,
        )
        return X_reconstruct

class MelTransformer(BaseEstimator, TransformerMixin):
    def __init__(self, sr: int = 22050, N_MEL: int = 12, hop_length: int = 1024, reshape_output: bool = True):
        self.sr = sr
        self.N_MEL = N_MEL
        self.hop_length = hop_length
        self.reshape_output = reshape_output

    def reshape(self, X: np.ndarray) -> np.ndarray:
        X_ = X.copy()
        c_, *_ = X_.shape
        return X_.reshape(c_, -1, self.N_MEL)

    def fit(self, X: np.ndarray, y = None):
        return self

    def fit_transform(self, X: np.ndarray, y = None) -> np.ndarray:
        self.fit(X, y)
        return self.transform(X, y)

    def transform(self, X: np.ndarray, y = None) -> np.ndarray:
        X_ = X.copy()
        c_, *_ = X_.shape
        mel = librosa.feature.melspectrogram(y=X,
            sr=self.sr,
            hop_length=self.hop_length,
            n_mels=self.N_MEL
        )
        if self.reshape_output:
            mel = mel.reshape(c_, -1)

        return mel

    def inverse_transform(self, X: np.ndarray) -> np.ndarray:
        X_reconstruct = librosa.feature.inverse.mel_to_audio(
            M = X,
            sr = self.sr,
            hop_length = self.hop_length
        )
        return X_reconstruct

class TorchTransform(BaseEstimator, TransformerMixin):
    def __init__(self):
        pass

    def fit(self, X: np.ndarray, y = None):
        return self

    def fit_transform(self, X: np.ndarray, y = None) -> torch.Tensor:
        self.fit(X, y)
        return self.transform(X, y)

    def transform(self, X: np.ndarray, y = None) -> torch.Tensor:
        return torch.tensor(X).unsqueeze(dim=1)

    def inverse_transform(self, X: torch.Tensor) -> np.ndarray:
        return np.array(X.squeeze(dim=1))

class ShuffleTransformer(BaseEstimator, TransformerMixin):
    def __init__(self, p: float = 0.005):
        self.p = p

    def fit(self, X: np.ndarray, y = None):
        return self

    def fit_transform(self, X: np.ndarray, y = None) -> np.ndarray:
        self.fit(X, y)
        return self.transform(X, y)

    def transform(self, X: np.ndarray, y = None) -> np.ndarray:
        will_swap = np.random.choice(X.shape[0], int(self.p*X.shape[0]))
        will_swap_with = np.random.choice(X.shape[0], int(self.p*X.shape[0]))
        if hasattr(X, "copy"):
            X_ = X.copy()
        elif hasattr(X, "clone"):
            X_ = X.clone()
        else:
            X_ = X
        X_[will_swap, ...] = X_[will_swap_with, ...]
        return X_

    def inverse_transform(self, X: np.ndarray) -> np.ndarray:
        raise NotImplementedError