def _init_globals() ->None:
    """
    Initialize all global variables declared by this submodule.
    """
    global WRITER_BASENAME_TO_CONTAINER_FILETYPE_TO_CODEC_NAMES
    WRITER_BASENAME_TO_CONTAINER_FILETYPE_TO_CODEC_NAMES = {'ffmpeg': {
        'avi': ('libx264', 'libxvid', 'mpeg4', 'h263', 'mpeg2video'), 'gif':
        ('gif',), 'mkv': None, 'mov': None, 'mp4': None, 'ogv': (
        'libtheora',), 'webm': ('libvpx',)}, 'avconv': None, 'mencoder':
        None, 'convert': {'gif': (None,)}}
    codec_names = WRITER_BASENAME_TO_CONTAINER_FILETYPE_TO_CODEC_NAMES
    codec_names['ffmpeg']['mp4'] = ('libx264', 'hevc') + codec_names['ffmpeg'][
        'avi'][1:]
    codec_names['ffmpeg']['mov'] = codec_names['ffmpeg']['mp4']
    codec_names['ffmpeg']['mkv'] = codec_names['ffmpeg']['webm'] + codec_names[
        'ffmpeg']['ogv'] + codec_names['ffmpeg']['mp4']
    codec_names['avconv'] = codec_names['ffmpeg']
    codec_names['mencoder'] = codec_names['ffmpeg']
