Find silences in audio samples

find_silence.py

import numpy as np

def find_silences_of_minimum_length(data: np.array, min_length: int) -> Generator[Tuple[int, int], None, None]:
    """
    Get a (start, stop) tuple for each detected silence of minimum length.

    The start is inclusive, and the stop is exclusive, to match Python's list slicing.

    >>> list(find_silences_of_minimum_length([1,0,1], 1))
    [(1, 2)]

    >>> list(find_silences_of_minimum_length([1,0,1], 2))
    []

    >>> list(find_silences_of_minimum_length([1,0,0,1], 1))
    [(1, 3)]

    >>> list(find_silences_of_minimum_length([1,0,0,1], 2))
    [(1, 3)]

    >>> list(find_silences_of_minimum_length([1,0,0,1], 3))
    []

    >>> list(find_silences_of_minimum_length([0,0,0,0,1,0,1,0,0,1,0,0,0,1,0,0,0,0,1], 1))
    [(0, 4), (5, 6), (7, 9), (10, 13), (14, 18)]

    >>> list(find_silences_of_minimum_length([0,0,0,0,1,0,1,0,0,1,0,0,0,1,0,0,0,0,1], 2))
    [(0, 4), (7, 9), (10, 13), (14, 18)]

    >>> list(find_silences_of_minimum_length([0,0,0,0,1,0,1,0,0,1,0,0,0,1,0,0,0,0,1], 3))
    [(0, 4), (10, 13), (14, 18)]
    """
    if min_length < 1:
        raise ValueError("Minimum length must be >= 1")

    for start, stop in find_all_silences(data):
        if stop - start >= min_length:
            yield start, stop


def find_all_silences(data: np.array) -> Generator[Tuple[int, int], None, None]:
    """
    Get a (start, stop) tuple for each detected silence.

    The start is inclusive, and the stop is exclusive, to match Python's list slicing.

    >>> list(find_all_silences([1,0,1]))
    [(1, 2)]

    >>> list(find_all_silences([1,0,0,1]))
    [(1, 3)]

    >>> list(find_all_silences([0,0,0,0,1,0,1,0,0,1,0,0,0,1,0,0,0,0,1]))
    [(0, 4), (5, 6), (7, 9), (10, 13), (14, 18)]
    """
    t_first_zero = None

    for t, sample in tqdm(enumerate(data)):
        is_zero = np.all(sample == 0)

        if is_zero:
            # Sample is silent
            if t_first_zero is None:
                # The silence starts at this samples.
                t_first_zero = t
            else:
                # This sample just continues the silence.
                pass
        else:
            # Sample is not silent.
            if t_first_zero is not None:
                # This sample broke the silence.
                yield t_first_zero, t
                t_first_zero = None
            else:
                # It was already not silent.
                pass