[niconico] unable to download links that start with live/live2

[KindredMantis]

Checklist

• I'm reporting a broken site support issue
• I've verified that I'm running youtube-dl version 2020.06.16.1
• I've checked that all provided URLs are alive and playable in a browser,
• I've checked that all URLs and arguments with special characters are properly quoted or escaped
• I've searched the bugtracker for similar bug reports including closed ones
• I've read bugs section in FAQ

Verbose log

[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['-v', '--no-geo-bypass', '-u,', '--username', 'PRIVATE', '-p,', '--password', 'PRIVATE', 'https://live2.nicovideo.jp/watch/lv326842348?ref=top_rookie']
[debug] Encodings: locale cp1252, fs mbcs, out cp850, pref cp1252
[debug] youtube-dl version 2020.06.16.1
[debug] Python version 3.4.4 (CPython) - Windows-10-10.0.18362
[debug] exe versions: none
[debug] Proxy map: {}
[generic] lv326842348?ref=top_rookie: Requesting header
WARNING: Falling back on generic information extractor.
[generic] lv326842348?ref=top_rookie: Downloading webpage
[generic] lv326842348?ref=top_rookie: Extracting information
ERROR: Unsupported URL: https://live2.nicovideo.jp/watch/lv326842348?ref=top_rookie
Traceback (most recent call last):
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpspbsbtmq\build\youtube_dl\YoutubeDL.py", line 797, in extract_info
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpspbsbtmq\build\youtube_dl\extractor\common.py", line 530, in extract
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpspbsbtmq\build\youtube_dl\extractor\generic.py", line 3382, in _real_extract
youtube_dl.utils.UnsupportedError: Unsupported URL: https://live2.nicovideo.jp/watch/lv326842348?ref=top_rookie

Verbose log

[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['-v', '-u,', '--username', 'PRIVATE', '-p,', '--password', 'PRIVATE', 'https://live2.nicovideo.jp/watch/lv326814636']
[debug] Encodings: locale cp1252, fs mbcs, out cp850, pref cp1252
[debug] youtube-dl version 2020.06.16.1
[debug] Python version 3.4.4 (CPython) - Windows-10-10.0.18362
[debug] exe versions: none
[debug] Proxy map: {}
[generic] lv326814636: Requesting header
WARNING: Falling back on generic information extractor.
[generic] lv326814636: Downloading webpage
[generic] lv326814636: Extracting information
ERROR: Unsupported URL: https://live2.nicovideo.jp/watch/lv326814636
Traceback (most recent call last):
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpspbsbtmq\build\youtube_dl\YoutubeDL.py", line 797, in extract_info
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpspbsbtmq\build\youtube_dl\extractor\common.py", line 530, in extract
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpspbsbtmq\build\youtube_dl\extractor\generic.py", line 3382, in _real_extract
youtube_dl.utils.UnsupportedError: Unsupported URL: https://live2.nicovideo.jp/watch/lv326814636

Description

I'm trying to download from niconico but whenever I use a link thats starts with "live" or "live2" it falls back to the generic information extractor, while for other niconico links that DON'T start with "live" or "live2" it will use the niconico extractor as it should. I think the bug is that it doesn't recognize live/live2 links as niconico links. It's hard to provide live/live2 links because they expire over time. the link that I provided in this report is probably also expired unless you have premium for niconico. go to https://live.nicovideo.jp/ and click any available video/stream and I still get the same issue. ( sometimes it's required to remove everything that comes after the question mark in the link, including the question mark), I have tried several links to make sure it's not just one specific video that might be bugged

[rolyli]

Someone made a fork with the ability to download live videos. See #17415.

[yuusakuri]

That fork no longer works.
Probably because the URL is live2.nicovideo.jp.