Serve sampled signals using InteractNext and Mux

[rob-luke]

This might be way outside the scope of SampledSignals.jl, but I thought I would ask...

I would like to serve a web page that can play audio stored in a SampleBuf, similar to how you can press pause/play/stop etc in jupyter. Ideally the user could modify some parameters using interact.

Below is a minimum (not) working example. It runs and the generated web page has the interact buttons, but it shows an error saying SampleBuf display requires javascript. Do you know of a way to serve generated audio to a web page?

using InteractNext, WebIO, SampledSignals

Fs = 16000

ui = @manipulate for time_seconds = [1, 2, 3]
    x = randn(Fs * time_seconds, 2);  
    a = SampleBuf(x, Fs)
end

using Mux
responder(req) = ui
webio_serve(page("/", responder))

[ssfrr]

In order for the javascript display stuff to work there's some initialization code that needs to be part of the DOM. In a jupyter notebook that happens when you run using SampledSignals (it dumps the proper js initialization code into the output of that cell). If you look at the code for embed_javascript() you can see how it works.

If you can get that output dumped to the DOM inside of the Mux page than the audio display should work as it does in the notebook.

Doing streaming audio to the browser is definitely more complicated, as you'd need to open up a websocket or something to continuously pass the generated audio through. One of the things I've done in the past is use PortAudio.jl to output the sound directly from Julia (not going through the browser), but still control the process with Interact sliders. Of course this only works if you're working locally, and the computer you're running Julia on is the same as the one you're sitting at.

[rob-luke]

Thanks for the information @ssfrr. I will take a look at embed_javascript().

I have been using PortAudio.jl with Interact locally and it works perfectly, thanks for the great packages.