I had ended up using ffmpeg a few times for this (i think inspired by the link you gave there) because it's often easier to share video than just audio on mainstream social media
A few details of what worked for me and the output shown here:
https://discourse.mozilla.org/t/tts-audio-to-video-trick-usi...
But Astrofox looks much cooler and massively more sophisticated.
The key to all audio/music visualizations is the Fast Fourier Transform. Hook a FFT implementation to a graphics library and you are set.
Re:Astrofox – Turn Audio into Videos
by userhacker on Thursday July 07, 2022 @05:37PM
(#32019806)
You can use revoldiv.com. If you go to export and choose audiogram, it will convert the audio/video you uploaded to text and create an audiogram.
vvvv not open source but has a free version:
Youtube video of Astrofox: https://www.youtube.com/watch?v=IbvuniqNPPw