Envelope-follower NPM

envelope-follower

An audioWorklet that gets an envelope follower for a signal. Here is a demo..

Installing

npm i envelope-follower

Then, it will be in modules/envelope-follower in your project.

You can use it in your web page like so:

audioContext.audioWorklet.addModule('modules/envelope-follower.js')
.then(useWorklet)
.catch(handleError);

function useWorklet() {
  var envelopeFollowerNode = new AudioWorkletNode(
    audioContext,
    'envelope-follower-processor',
    { processorOptions: { smoothingFactorUp: 0.5, smoothingFactorDown: 0.99 } }
  );
  // Connect a source and dest to it here.
}

A higher smoothingFactor makes the follower less sensitive to changes in the signal, either when it's rising or falling.

Getting the demo running

Once you have this source code on your computer, you can get it running by doing the following.

Install Node 10 or later.
From the root directory of the project (the same one this README file is in), run this command: npm i
Then, run make run. It should then say something like Your application is ready~! Local: http://0.0.0.0:7000
- On Windows, you may not have make. In that case, you can run npm run dev.
- Go to http://0.0.0.0:7000 (or http://localhost:7000) in your browser. The web app will be running there.