This is a bit long but it’s actually very noob friendly, it’s only using 1 ffmpeg command at the end and you just have to copy/paste it (so install ffmpeg if you don’t have it).
1- Open the url of the video you want to keep in your browser.
2- Press F12 to open the dev/debug tools.
3- Click on the “Network” tab and make sure the network log is actually recording (it should say “Recording network activity…”).
4- Press CTRL+R to reload the page while the dev/debug tools window is still open.
5- In the Filter box at the top, write : session
6- You should now see session_ids appearing under the “Name” list, click on it.
7- On the right, where you see the “Headers, Payload, Preview, etc…” tabs, click on the “Response” tab and copy your session_id (the orange part without including the ").
8-Add your session ID at the end of this link:
https://hls-auth.cloud.stream.co.jp/auth/index.m3u8?session_id=
9-Copy/Paste the full link in your browser to get the index.m3u8 file, save it somewhere on your computer. (note that if you have an HLS player extension enabled like “Native MPEG-Dash + HLS Playback”, it will try play the m3u8 directly so disable that extension).
10- Now that you have that index.m3u8 file saved, open “command prompt” or “powershell”, navigate to the correct path where you saved the m3u8 file and use ffmpeg with the following command:
ffmpeg -protocol_whitelist file,http,https,tcp,tls,crypto -i index.m3u8 -c copy video.ts
This was a “I’m too dumb to use yt-dlp, streamlink or tools that requires commands lines” so I kept it simple on purpose. For more advanced stuff: Downloading from fanclub sites for free