すいません、万年初心者です。
Youtubeの動画をコマンドで落とそうと思って、
youtube-dl を使ったんですが、落ちないんですが、

youtube-dl https://youtu.be/DLfen9rjfvI(中国天津の爆発動画)
[youtube] Setting language
[youtube] DLfen9rjfvI: Downloading video webpage
[youtube] DLfen9rjfvI: Downloading video info webpage
[youtube] DLfen9rjfvI: Extracting video information
Traceback (most recent call last):
File "/usr/bin/youtube-dl", line 4645, in <module>
main()
File "/usr/bin/youtube-dl", line 4636, in main
_real_main()
File "/usr/bin/youtube-dl", line 4620, in _real_main
retcode = fd.download(all_urls)
File "/usr/bin/youtube-dl", line 869, in download
ie.extract(url)
File "/usr/bin/youtube-dl", line 1135, in extract
return self._real_extract(url)
File "/usr/bin/youtube-dl", line 1406, in _real_extract
url_map = dict((ud['itag'][0], ud['url'][0] + '&signature=' + ud['sig'][0]) for ud in url_data)
File "/usr/bin/youtube-dl", line 1406, in <genexpr>
url_map = dict((ud['itag'][0], ud['url'][0] + '&signature=' + ud['sig'][0]) for ud in url_data)
KeyError: 'sig'
何ででしょうかね、(確か前はDL出来た覚えが有るんですが、、)