p5.SoundFile loadSound() autoplay behavior after library upgrade

Autoplay Behavior in p5.sound

No, loadSound() should not automatically start playback, regardless of library upgrades. Modern browsers strictly enforce autoplay policies, so any attempt to trigger audio without a preceding user gesture (such as a click or key press) will be blocked by the browser engine, not by the p5.js library.

The Technical Constraint

The underlying Web Audio API requires the AudioContext to be in a running state. By default, browsers initialize this context as suspended. While a library upgrade might change how the AudioContext is instantiated, it cannot bypass the browser's requirement for a user gesture to resume that context.

Should loadSound() Add an autoPlay Parameter?

An optional autoPlay flag would not solve the underlying problem: the browser would still block playback without a gesture. Adding such a parameter risks implying behavior the library cannot reliably deliver, so the safer design is to keep loadSound() as a pure loading operation and require explicit playback from a gesture handler.

Recommended Implementation Strategy

Decouple loading from playback:

1. Preload: Use preload() so the p5.SoundFile is fully buffered before the sketch starts.
2. Gesture trigger: Call .play() inside a user-initiated event handler.

let mySound;

function preload() {
  mySound = loadSound('audio.mp3');
}

function mousePressed() {
  // This user gesture resumes the AudioContext and starts playback
  mySound.play();
}

Backward Compatibility and Upgrades

When upgrading p5.js and p5.sound, avoid relying on implicit timing or auto-start workarounds. The safest strategy is to explicitly manage the AudioContext state. If you encounter a suspended context after an upgrade, resume it within a gesture:

function mousePressed() {
  if (getAudioContext().state === 'suspended') {
    getAudioContext().resume();
  }
  mySound.play();
}

Verification

To check whether an upgrade changed behavior or the browser is blocking audio, open the browser console. A warning such as "The AudioContext was not allowed to start" indicates a browser policy restriction rather than a library bug. Also confirm the p5.sound version in your script tag matches your p5.js core version, since mismatched versions are a common source of post-upgrade issues.

Diagnostic question: Are you calling .play() inside setup() or draw() without a preceding user interaction? If so, moving it into a gesture handler is the fix.