How to capture video stream with audio spectrum display?

Question

Video processing

The task is to monitor the health of TV channels, now with the help of VLC we capture short segments of video from each channel, then we process the resulting files (we cut a couple of seconds on each side and overlay the text name of the channel), combine them into a matrix and display them on the screen. As a result, we have a dynamic picture, which shows the absence of an image or interference on the channel, but, unfortunately, the sound is not monitored in any way. Alternatively, you can visualize the sound and superimpose as a spectrum on the image of each channel. But here's how to do it?

Answer 1

In vlc, as far as I remember, it is possible to output sound to a file. In the processing stage, add an image overlay of the spectrum of the processed sound.