FFplay + Audio = Interesting Observation

I ordered an extremely cheap capture card by an unknown manufacturer that is supposedly able to record up to FHD60 (couldn’t get that to work yet but works perfectly fine at HD60/FHD30 with an acceptable quality and above all as simple driverless audio/video inputs instead of through disgusting buggy Windows applications that don’t work with Wine or VMs, even if FHD60 doesn’t work, this is still very much worth the weight compared to "proper" capture cards from the big corps that cost hundreds of Bucks (at least if it doesn’t break in a month)) and I wrote an FFmpeg script to record, screenshot and live view its input. To be able to hear sound during live view as well, I tried creating a second FFplay process that has the audio input as its… input, and I was indeed able to hear the sound. This also opened a second window that seemingly displays the audio spectrum similarly to how it’s displayed in a DAW piano roll. Fascinating.