provide a working demo that facilitates the use of the tool

[nicopace]

What I expected:

Write now, the proposed example in the readme is not a complete example... it lacks a way to format data.

It is not clear how to structure the data that is pushed into the visualization.

I would expect a way to tell: sample (in dB) and timestamp (so I can receive information asynchronously).

What I found:

no working example that facilitates the use of the code.

[konsumer]

I am not a maintainer of this project, but I found it so useful, I'd like to help.

Did you have a look at the demo? At the bottom is a spectrogram.push() which is pushing the FFT audio-analyzer data, in a single slice of time. This is pretty standard for spectrograms, implemented in other languages. I'm not sure why you expect it to be dB + time, but that's not what a spectrogram does.

A spectrogram is a visual representation of the spectrum of frequencies of sound or other signal as they vary with time or some other variable.

The demo is doing FFT analysis to give you a visualization of the spectrum of frequencies that is playing as the music scrolls by the playhead (the right edge of the color.)

I must say, this is the nicest looking 2D spectrogram implemented in GLSL that I have seen, but it's pretty standard.

Also, as a sidenote, @dfcreative made this code for free. @dfcreative doesn't owe you the thing you have in your head (ill-conceived or not.) If you think it should do something else, submit a PR, or ask a question about how to get what you want (which @dfcreative is also not obligated to answer or integrate) or make your own, with free inspiration, that works the way you think this should. That's the cost of free software.

[nicopace]

You are very right @knosumer... wasn't polite at all in the way I pointed the issue, I'm sorry @dfcreative .
I was actually working on using the spectrogram for another purpose... showing spectrum analysis done using wireless cards, so the samples don't come from a web api but from a web hook.
I did some reviews of other visualization tools here, maybe you find them useful.

https://blog.freifunk.net/2017/06/26/choosing-spectrogram-visualization-library-javascript/