Visualizer

Real-time FFT (and optional PCM) frames for building audio visualizations. Get the singleton with getVisualizer():

import { getVisualizer } from 'react-native-queue-player';

const viz = getVisualizer();

const unsubscribe = viz.subscribe(
  { fftSize: 1024, updateIntervalMs: 33 },
  (frame) => {
    // frame.fft is an ArrayBuffer of fftSize/2 magnitudes
  },
  (reason) => {
    // 'hls-source' | 'visualization-disabled'
  },
);

// later
unsubscribe();

Methods

subscribe(
  config: VisualizerConfig,
  onFrame: (frame: VisualizerFrame) => void,
  onError: (reason: VisualizerErrorReason) => void,
): () => void

getSubscriberCount(): number

When the last subscriber disposes, native FFT processing stops.

Types

type VisualizerConfig = {
  fftSize: 256 | 512 | 1024 | 2048;
  updateIntervalMs: number;
  includeSamples?: boolean; // also deliver raw PCM
};

type VisualizerFrame = {
  fft: ArrayBuffer;       // length fftSize / 2
  samples?: ArrayBuffer;  // length fftSize, when includeSamples is true
  sampleRate: number;
};

Notes

• Visualization must be enabled at configure({ visualizationEnabled: true }) (the default). Disabling it skips the audio-tap chain, and subscribe reports 'visualization-disabled'.
• HLS sources can't be tapped; the error callback reports 'hls-source'.

In React, see useVisualizerState, which throttles frames and hands you typed Float32Arrays.