esc50.py

import os
import datasets
import typing as tp
from pathlib import Path

SAMPLE_RATE = 44_100
EXTENSION = '.wav'


class ESC50(datasets.GeneratorBasedBuilder):
    """
    The ESC50 dataset
    """
    def _info(self):
        return datasets.DatasetInfo(
            description='Environmental sound classification dataset',
            features=datasets.Features(
                {
                    # "filepath": datasets.Value("string"), 
                    "audio": datasets.Audio(sampling_rate=SAMPLE_RATE), 
                    "label": datasets.ClassLabel(names=GENRES), 
                }
            ),
        )

    def _split_generators(self, dl_manager):
        data_dir = dl_manager.download_and_extract("ESC-50-master.zip")
        return [
            datasets.SplitGenerator(
                name=datasets.Split.TRAIN, 
                gen_kwargs={
                    "data_dir": data_dir, 
                    "split": 'train'
                }, 
            ), 
        ]

    def _generate_examples(self, data_dir, split):
        _, _walker = fast_scandir(data_dir, [EXTENSION], recursive=True)

        for idx, fileid in enumerate(_walker):
            yield idx, {
                # 'filepath': fileid, 
                'audio': fileid, 
                'fold': default_find_fold(fileid), 
                'label': default_find_classes(fileid)
            }


def default_find_classes(audio_path):
    id_ = Path(audio_path).stem.split('-')[-1]
    return ESC50_ID2LABEL.get(int(id_))


def default_find_fold(audio_path):
    fold = Path(audio_path).stem.split('-')[0]
    return int(fold)


def fast_scandir(path: str, exts: tp.List[str], recursive: bool = False):
    # Scan files recursively faster than glob
    # From github.com/drscotthawley/aeiou/blob/main/aeiou/core.py
    subfolders, files = [], []

    try:  # hope to avoid 'permission denied' by this try
        for f in os.scandir(path):
            try:  # 'hope to avoid too many levels of symbolic links' error
                if f.is_dir():
                    subfolders.append(f.path)
                elif f.is_file():
                    if os.path.splitext(f.name)[1].lower() in exts:
                        files.append(f.path)
            except Exception:
                pass
    except Exception:
        pass

    if recursive:
        for path in list(subfolders):
            sf, f = fast_scandir(path, exts, recursive=recursive)
            subfolders.extend(sf)
            files.extend(f)  # type: ignore

    return subfolders, files