This is 1:1 real-time. A 10-minute song takes 10 minutes. The quality is identical to what you hear, but you risk recording system sounds (email dings, notifications).
: Widely considered the best for high-quality audio extraction. Once you have the video file, you can drag it into File > Export > Export as WAV . Note that you may need to install the FFmpeg library to import certain video formats. yt-dlp (Command Line) niconico to wav
Based on user reviews and technical reliability, here are the most effective ways to handle Niconico audio: (Highly Recommended) This is 1:1 real-time