def get_length(filename):
    """
    Gets the length (s) of a video using ffprobe.

    Parameters
    ----------
    - filename : str

        Path to the video file to be measured.

    Returns
    -------
    - float

        The length of the input video file in seconds.
    """
    import subprocess
    result = subprocess.run(['ffprobe', '-v', 'error', '-show_entries',
        'format=duration', '-of', 'default=noprint_wrappers=1:nokey=1',
        filename], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
    return float(result.stdout)
