[IDEA] waveform visualisation in web player ?

[Nutul]

You might want to inspect the element on the Webpage and see if you can determine what code is being used to render the waveform.

If  they are using an already developed Open Source project on GitHub for this code, I'll have a look at it.

I think those are images generated on the server side, as you need to examine the whole track to be able to draw the thing.