AnalyserNode

The AnalyserNode is an interface in the Web Audio API that represents a node in the Web Audio processing graph that can perform analysis on the audio data flowing through it. It's a type of AudioNode that allows developers to access the raw audio data of a stream for purposes such as visualization, measurement, or other real-time audio analysis.

When an AnalyserNode is inserted into the audio graph, it intercepts the audio buffer as it passes through. It doesn't modify the audio itself, but rather provides methods to retrieve snapshots of the audio data. This data can be accessed in two primary forms: time-domain data and frequency-domain data.

Time-domain data is typically retrieved as an array of byte values representing the amplitude of the audio signal at discrete points in time. This is often referred to as waveform data. Frequency-domain data, on the other hand, is represented as an array of byte values corresponding to the magnitude of different frequency components within the audio signal. This is commonly known as FFT (Fast Fourier Transform) data.

Developers can configure the AnalyserNode to specify the size of the analysis window, which affects the resolution of the frequency data. The AnalyserNode is crucial for creating audio visualizations, such as oscilloscopes and spectrum analyzers, and for implementing audio reactive effects in web applications. It does not process audio in the traditional sense of effects like distortion or reverb; its sole purpose is analysis.