def _build_split_command(input_file, output_audio_file):
    """
    Creates a list for each bit of the command line to run
    since it is a list the command line is secure and can
    run with file names that are not formatted correctly.
    or doesn't need any explicit formatting.

    Downmixing to single channel audio(mono) without losing any data

    Parameters
    ----------
    input_file : str
        input video file name and path
    output_audio_file : str
        output audio file name and path

    Returns
    ---------
    _CMD
        command line to pass to the subprocess

    Examples
    ----------
    The command created spits the video file into an audio file, The file paths
    are kept same. The command goes like this

    `ffmpeg -y -i input.mkv output.wav`

        '-y' : FFmpeg option for 'yes override'. Override the output file it exists
        '-i' : FFmpeg option for 'input file'. Input file can be multiple

    """
    return [
        'ffmpeg',
        '-y',
        '-i',
        "'" + str(input_file) + "'",
        '-ac',
        '1',
        "'" + str(output_audio_file) + "'"
    ]