Simple volume meter - Revisited

A new implementation of Chris Wilson's volume meter.

Although still available for use in some browsers, the ScriptProcessorNode API has been marked as deprecated.

Its main drawbacks have been:

• Lack of detailed specification. This leads to browsers having their own implementations with inconsistent results when used in different environments.

• Use of the main JS thread. When this thread is tasked with some intensive UI-related task, things like stuttering or drop-outs may be noticed. In general, using the main thread for both UI and DOM-related as well as audio processing can make an app less responsive.

This implementation uses the AudioWorklet API which allows user-supplied scripts for audio processing to run in the Web Audio API thread without blocking the main (UI) thread.

A deep-down explanation of this concept is available here.

Show me the code!

• main.js : get mic access through the getUserMedia API, receive messages from the processor and visualize the info available

• volmeter-processor.js : this is where the background magic happens

Show me the demo!

I cheated a bit here, you'll need python 3. Just clone and run

python3 -m http.server 3001

then open localhost:3001 and see the tool at work.