https://webaudio.github.io/web-audio-api/#AnalyserNode
Most of the interface is naively implemented. Container types
probably need adjusted (Vector<double> is used for all the processing).
A Fourier Transform is needed, but that's waiting on either a 3rd
party library or a complex number type.
There are lots of simple miscellaneous filters that need to be applied.
It could be reasonable to implement from scratch, supposing that
it can be parallelized. It might be hard to find one library with
everything. Not my call though.
Some additional scaffolding around blocks and render quanta is
probably needed before this is developed much further, which
probably comes in at the level of the AudioNode.
Co-authored-by: Tim Ledbetter <tim.ledbetter@ladybird.org>