I am looking for a way to process the audio data of a (YouTube) video in advance to implement some audio visualisation. For this I am looking for a way to get the PCM data of buffered audio of the video element.

While it is fairly easy to make an Audiobuffer that loads and plays an audio file, I have trouble finding the buffered data of the video stream and copying it into a buffer.

Note that because I'm implementing this on a different piece of software with a CEF based built in browser, I'm currently executing the JS on the webpage, as if via the console.