python - 動画全体をダウンロードせずにオンライン動画の長さを取得する方法は?

Question

ビデオの長さと解像度を取得するために、次の関数があります。

def getvideosize(url, verbose=False):
try:
    if url.startswith('http:') or url.startswith('https:'):
        ffprobe_command = ['ffprobe', '-icy', '0', '-loglevel', 'repeat+warning' if verbose else 'repeat+error', '-print_format', 'json', '-select_streams', 'v', '-show_streams', '-timeout', '60000000', '-user-agent', BILIGRAB_UA, url]
    else:
        ffprobe_command = ['ffprobe', '-loglevel', 'repeat+warning' if verbose else 'repeat+error', '-print_format', 'json', '-select_streams', 'v', '-show_streams', url]
    logcommand(ffprobe_command)
    ffprobe_process = subprocess.Popen(ffprobe_command, stdout=subprocess.PIPE)
    try:
        ffprobe_output = json.loads(ffprobe_process.communicate()[0].decode('utf-8', 'replace'))
    except KeyboardInterrupt:
        logging.warning('Cancelling getting video size, press Ctrl-C again to terminate.')
        ffprobe_process.terminate()
        return 0, 0
    width, height, widthxheight, duration = 0, 0, 0, 0
    for stream in dict.get(ffprobe_output, 'streams') or []:
        if dict.get(stream, 'duration') > duration:
            duration = dict.get(stream, 'duration')
        if dict.get(stream, 'width')*dict.get(stream, 'height') > widthxheight:
            width, height = dict.get(stream, 'width'), dict.get(stream, 'height')
    if duration == 0:
        duration = 1800
    return [[int(width), int(height)], int(float(duration))+1]
except Exception as e:
    logorraise(e)
    return [[0, 0], 0]

ただし、一部のオンライン動画にはdurationタグが付いていません。その期間を取得するために何かできますか？