Based on user reviews and technical reliability, here are the most effective ways to handle Niconico audio: (Highly Recommended)
Conversion should strictly be for personal, offline listening. Redistributing converted WAV files, especially for commercial use, often violates Niconico's terms of service and Japanese copyright law.
Unlike YouTube, Niconico Douga (2006–present) historically limited video quality and used aggressive as low as 64kbps AAC-LC for comments-synced streaming. This created unique sonic artifacts:
: An essential free, open-source editor. Once you have a video file, you can drag it into Audacity to export the audio as a 16-bit WAV .
Search for a "Niconico downloader" online if you prefer not to install software, though these can be less stable. Step 2: Convert to WAV