audacity

https://www.howtogeek.com/217348/how-to-record-the-sound-coming-from-your-pc-even-without-stereo-mix/

https://github.com/ExistentialAudio/BlackHole

https://www.youtube.com/watch?v=K7UE8fZjox4

 https://support.apple.com/en-us/HT208721

https://blogs.reed.edu/ed-tech/recording-your-macs-video-screen-with-audio/

https://rogueamoeba.com/loopback/buy.php

https://filmora.wondershare.com/screen-recorder/quicktime-record-screen-audio.html

https://techpp.com/2020/01/28/macos-record-internal-audio-screen-recording/

https://www.macupdate.com/app/mac/14067/soundflower

https://atomisystems.com/screencasting/record-screen-windows-10/

https://superuser.com/questions/1509341/how-to-record-a-full-screen-with-only-internal-audio-on-windows-10

https://www.easeus.com/screen-recording-tips/internal-audio-recorder.html

https://www.howtogeek.com/217348/how-to-record-the-sound-coming-from-your-pc-even-without-stereo-mix/

https://www.howtogeek.com/howto/39532/how-to-enable-stereo-mix-in-windows-7-to-record-audio/

https://www.howtogeek.com/217348/how-to-record-the-sound-coming-from-your-pc-even-without-stereo-mix/

https://manual.audacityteam.org/man/tutorial_recording_computer_playback_on_windows.html#:~:text=WASAPI%20loopback%20has%20a%20big%20advantage%20over%20stereo,loopback%20when%20there%20is%20an%20active%20signal%20present.