Repository: yt-dlp
Issue: Request extractor for DG Premium
Labels: site-request,account-needed,can-share-account

### Checklist

- [X] I'm reporting a new site support request
- [X] I've verified that I'm running yt-dlp version **2021.12.01**. ([update instructions](https://github.com/yt-dlp/yt-dlp#update))
- [X] I've checked that all provided URLs are alive and playable in a browser
- [X] I've checked that none of provided URLs [violate any copyrights](https://github.com/ytdl-org/youtube-dl#can-you-add-support-for-this-anime-video-site-or-site-which-shows-current-movies-for-free) or contain any [DRM](https://en.wikipedia.org/wiki/Digital_rights_management) to the best of my knowledge
- [X] I've searched the [bugtracker](https://github.com/yt-dlp/yt-dlp/issues?q=) for similar issues including closed ones. DO NOT post duplicates
- [X] I've read the [guidelines for opening an issue](https://github.com/yt-dlp/yt-dlp/blob/master/CONTRIBUTING.md#opening-an-issue)
- [X] I've read about [sharing account credentials](https://github.com/yt-dlp/yt-dlp/blob/master/CONTRIBUTING.md#are-you-willing-to-share-account-details-if-needed) and am willing to share it if required

### Region

Americas, Europe

### Example URLs

- Single video: https://www.dg-premium.com/premium_video/alice-sara-ott-mischa-maisky-chihiro-yamanaka-mori-building-digital-art-museum/
- Single video: https://www.dg-premium.com/premium_video/daniel-barenboim-leads-berlin-staatskapelle-string-quartet-in-schumann-piano-quintet/


### Description

Request extractor for DG Premium, Deutsche Grammophon's site for new and old concerts.  Site requires an account, but a lot of videos seem to be free (I've purchased on video and have played multiple videos with no problem).  

### Verbose log

```shell
yt-dlp --cookies-from-browser firefox -v -F "https://www.dg-premium.com/premium_video/alice-sara-ott-mischa-maisky-chihiro-yamanaka-mori-building-digital-art-museum/"
[debug] Command-line config: ['--cookies-from-browser', 'firefox', '-v', '-F', 'https://www.dg-premium.com/premium_video/alice-sara-ott-mischa-maisky-chihiro-yamanaka-mori-building-digital-art-museum/']
[Cookies] Extracting cookies from firefox
[debug] Extracting cookies from: "/Users/[redacted]/Library/Application Support/Firefox/Profiles/ayieh32f.default-1616072711057/cookies.sqlite"
[Cookies] Extracted 250 cookies from firefox
[debug] Encodings: locale UTF-8, fs utf-8, out utf-8, err utf-8, pref UTF-8
[debug] yt-dlp version 2021.12.01 [91f071af6]
[debug] Python version 3.10.0 (CPython 64bit) - macOS-12.0.1-x86_64-i386-64bit
[debug] exe versions: ffmpeg 4.4.1 (setts), ffprobe 4.4.1, rtmpdump 2.4
[debug] Optional libraries: Cryptodome, mutagen, sqlite, websockets
[debug] Proxy map: {}
[debug] [generic] Extracting URL: https://www.dg-premium.com/premium_video/alice-sara-ott-mischa-maisky-chihiro-yamanaka-mori-building-digital-art-museum/
[generic] alice-sara-ott-mischa-maisky-chihiro-yamanaka-mori-building-digital-art-museum: Requesting header
WARNING: [generic] Falling back on generic information extractor.
[generic] alice-sara-ott-mischa-maisky-chihiro-yamanaka-mori-building-digital-art-museum: Downloading webpage
[generic] alice-sara-ott-mischa-maisky-chihiro-yamanaka-mori-building-digital-art-museum: Extracting information
[debug] Looking for video embeds
ERROR: Unsupported URL: https://www.dg-premium.com/premium_video/alice-sara-ott-mischa-maisky-chihiro-yamanaka-mori-building-digital-art-museum/
Traceback (most recent call last):
  File "/usr/local/Cellar/yt-dlp/2021.12.1/libexec/lib/python3.10/site-packages/yt_dlp/YoutubeDL.py", line 1329, in wrapper
    return func(self, *args, **kwargs)
  File "/usr/local/Cellar/yt-dlp/2021.12.1/libexec/lib/python3.10/site-packages/yt_dlp/YoutubeDL.py", line 1398, in __extract_info
    ie_result = ie.extract(url)
  File "/usr/local/Cellar/yt-dlp/2021.12.1/libexec/lib/python3.10/site-packages/yt_dlp/extractor/common.py", line 597, in extract
    ie_result = self._real_extract(url)
  File "/usr/local/Cellar/yt-dlp/2021.12.1/libexec/lib/python3.10/site-packages/yt_dlp/extractor/generic.py", line 3813, in _real_extract
    raise UnsupportedError(url)
yt_dlp.utils.UnsupportedError: Unsupported URL: https://www.dg-premium.com/premium_video/alice-sara-ott-mischa-maisky-chihiro-yamanaka-mori-building-digital-art-museum/
```