音频数据预处理：切片、序列化和降采样

import os
import librosa
import numpy as np
from tqdm import tqdm

#clean_train_folder = 'data/test/clean_trainset_56spk'
#noisy_train_folder = 'data/test/noisy_trainset_56spk'
#clean_test_folder = 'data/test/clean_testset'
#noisy_test_folder = 'data/test/noisy_testset'
#serialized_train_folder = 'data/test/serialized_train_data'
#serialized_test_folder = 'data/test/serialized_test_data'

clean_train_folder = 'D:/test_module/SEGAN/data/clean_trainset'
noisy_train_folder = 'D:/test_module/SEGAN/data/noisy_trainset'
clean_test_folder = 'data/test2/clean_testset'
noisy_test_folder = 'data/test2/noisy_testset'
serialized_train_folder = 'data/test2/serialized_train_data'
serialized_test_folder = 'data/test2/serialized_test_data'



window_size = 2 ** 14  # about 1 second of samples
sample_rate = 16000


def slice_signal(file, window_size, stride, sample_rate):
    '''
    Helper function for slicing the audio file
    by window size and sample rate with [1-stride] percent overlap (default 50%).
    '''
    wav, sr = librosa.load(file, sr=sample_rate)
    hop = int(window_size * stride)
    slices = []
    for end_idx in range(window_size, len(wav), hop):
        start_idx = end_idx - window_size
        slice_sig = wav[start_idx:end_idx]
        slices.append(slice_sig)
    return slices


def process_and_serialize(data_type):
    '''
    Serialize, down-sample the sliced signals and save on separate folder.
    '''
    stride = 0.5

    if data_type == 'train':
        clean_folder = clean_train_folder
        noisy_folder = noisy_train_folder
        serialized_folder = serialized_train_folder
    else:
        clean_folder = clean_test_folder
        noisy_folder = noisy_test_folder
        serialized_folder = serialized_test_folder
    if not os.path.exists(serialized_folder):
        os.makedirs(serialized_folder)

    # walk through the path, slice the audio file, and save the serialized result
    for root, dirs, files in os.walk(clean_folder):
        if len(files) == 0:
            continue
        for filename in tqdm(files, desc='Serialize and down-sample {} audios'.format(data_type)):
            clean_file = os.path.join(clean_folder, filename)
            noisy_file = os.path.join(noisy_folder, filename)
            # slice both clean signal and noisy signal
            clean_sliced = slice_signal(clean_file, window_size, stride, sample_rate)
            noisy_sliced = slice_signal(noisy_file, window_size, stride, sample_rate)
            # serialize - file format goes [original_file]_[slice_number].npy
            # ex) p293_154.wav_5.npy denotes 5th slice of p293_154.wav file
            for idx, slice_tuple in enumerate(zip(clean_sliced, noisy_sliced)):
                pair = np.array([slice_tuple[0], slice_tuple[1]])
                np.save(os.path.join(serialized_folder, '{}_{}'.format(filename, idx)), arr=pair)


def data_verify(data_type):
    '''
    Verifies the length of each data after pre-process.
    '''
    if data_type == 'train':
        serialized_folder = serialized_train_folder
    else:
        serialized_folder = serialized_test_folder

    for root, dirs, files in os.walk(serialized_folder):
        for filename in tqdm(files, desc='Verify serialized {} audios'.format(data_type)):
            data_pair = np.load(os.path.join(root, filename))
            if data_pair.shape[1] != window_size:
                print('Snippet length not {} : {} instead'.format(window_size, data_pair.shape[1]))
                break


if __name__ == '__main__':
    process_and_serialize('train')
    data_verify('train')
    process_and_serialize('test')
    data_verify('test')

该代码首先定义了用于处理音频的参数，包括窗口大小、采样率等。然后定义了一个辅助函数slice_signal()，用于对音频文件进行切片处理。该函数将音频文件读入到内存中，然后按照指定的窗口大小和重叠率进行切片，并返回一个列表，其中包含所有切片。

接下来的函数process_and_serialize()用于对切片后的音频数据进行序列化和降采样处理，并将处理后的数据保存在新的文件夹中。该函数首先根据数据类型（训练集或测试集）确定输入和输出文件夹，然后遍历输入文件夹中的所有文件，依次对每个文件进行切片、序列化和降采样处理，并将处理后的数据保存在输出文件夹中。处理后的文件名格式为[原始文件名]_[切片编号].npy。

最后的函数data_verify()用于验证处理后的数据是否符合预期。该函数首先根据数据类型确定输入文件夹，然后遍历文件夹中的所有文件，依次读入数据，并检查每个数据是否符合预期（即长度是否为窗口大小）。如果发现某个数据不符合预期，则输出错误提示并终止程序运行。