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schedule stop DECAY in the future for firefox

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Firefox at this time cannot smoothly schedule audio parameter changes
to happen immediately. Immediately scheduled changes clip when firefox
tries to catch up. Smoothly fading out a sound immediately instead of
clipping the end of the sound, in firefox at this time clips the sound
between where the fade out starts and where firefox catches up and
finishes the scheduled fade.
This commit is contained in:
Michael "Z" Goddard 2018-06-25 10:46:54 -04:00
parent a79684a720
commit fb355abb7d
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GPG key ID: 762CD40DD5349872
4 changed files with 25 additions and 12 deletions
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11
src/AudioEngine.js
View file

@ -113,6 +113,17 @@ class AudioEngine {
return 0.025;
}
/**
* Some environments cannot smoothly change parameters immediately, provide
* a small delay before decaying.
*
* @see {@link https://bugzilla.mozilla.org/show_bug.cgi?id=1228207}
* @const {number}
*/
get DECAY_SOON () {
return 0.05;
}
/**
* Get the input node.
* @return {AudioNode} - audio node that is the input for this effect

3
src/SoundPlayer.js
View file

@ -245,7 +245,8 @@ class SoundPlayer extends EventEmitter {
taken.finished().then(() => taken.dispose());
taken.volumeEffect.set(0);
taken.outputNode.stop(this.audioEngine.audioContext.currentTime + this.audioEngine.DECAY_TIME);
const {audioContext, DECAY_TIME, DECAY_SOON} = this.audioEngine;
taken.outputNode.stop(audioContext.currentTime + DECAY_SOON + DECAY_TIME);
}
/**

6
src/effects/VolumeEffect.js
View file

@ -38,9 +38,9 @@ class VolumeEffect extends Effect {
this.value = value;
const {gain} = this.outputNode;
const {audioContext: {currentTime}, DECAY_TIME} = this.audioEngine;
gain.setValueAtTime(gain.value, currentTime);
gain.linearRampToValueAtTime(value / 100, currentTime + DECAY_TIME);
const {audioContext: {currentTime}, DECAY_TIME, DECAY_SOON} = this.audioEngine;
gain.setValueAtTime(gain.value, currentTime + DECAY_SOON);
gain.linearRampToValueAtTime(value / 100, currentTime + DECAY_SOON + DECAY_TIME);
}
/**

17
test/SoundPlayer.js
View file

@ -20,10 +20,10 @@ tap.test('SoundPlayer', suite => {
suite.beforeEach(() => {
audioContext = new AudioContext();
audioEngine = new AudioEngine(audioContext);
// sound will be 0.1 seconds long
audioContext.DECODE_AUDIO_DATA_RESULT = audioContext.createBuffer(2, 4410, 44100);
// sound will be 0.2 seconds long
audioContext.DECODE_AUDIO_DATA_RESULT = audioContext.createBuffer(2, 8820, 44100);
audioContext.DECODE_AUDIO_DATA_FAILED = false;
const data = new Uint8Array(44100);
const data = new Uint8Array(0);
return audioEngine.decodeSoundPlayer({data}).then(result => {
soundPlayer = result;
});
@ -88,13 +88,13 @@ tap.test('SoundPlayer', suite => {
inputs: [outputNode.toJSON()]
}], 'output node connects to gain node to input node');
audioContext.$processTo(audioEngine.DECAY_TIME / 2);
audioContext.$processTo(audioEngine.DECAY_SOON + audioEngine.DECAY_TIME / 2);
const engineInputs = help.engineInputs;
t.notEqual(engineInputs[0].gain.value, 1, 'gain value should not be 1');
t.notEqual(engineInputs[0].gain.value, 0, 'gain value should not be 0');
t.equal(outputNode.$state, 'PLAYING');
audioContext.$processTo(audioEngine.DECAY_TIME);
audioContext.$processTo(audioEngine.DECAY_SOON + audioEngine.DECAY_TIME + 0.001);
t.deepEqual(help.engineInputs, [{
name: 'GainNode',
gain: {
@ -180,18 +180,19 @@ tap.test('SoundPlayer', suite => {
t.equal(soundPlayer.outputNode.$state, 'PLAYING');
t.equal(help.engineInputs[0].gain.value, 1, 'old sound connectect to gain node with volume 1');
audioContext.$processTo(audioContext.currentTime + 0.001);
const {currentTime} = audioContext;
audioContext.$processTo(currentTime + audioEngine.DECAY_SOON + 0.001);
t.notEqual(help.engineInputs[0].gain.value, 1,
'old sound connected to gain node which will fade');
audioContext.$processTo(audioContext.currentTime + audioEngine.DECAY_TIME + 0.001);
audioContext.$processTo(currentTime + audioEngine.DECAY_SOON + audioEngine.DECAY_TIME + 0.001);
t.equal(soundPlayer.outputNode.$state, 'PLAYING');
t.equal(firstPlayNode.$state, 'FINISHED');
t.equal(help.engineInputs[0].gain.value, 0, 'faded old sound to 0');
t.equal(log.length, 1);
audioContext.$processTo(audioContext.currentTime + 0.2);
audioContext.$processTo(currentTime + audioEngine.DECAY_SOON + audioEngine.DECAY_TIME + 0.3);
// wait for a micro-task loop to fire our previous events
return Promise.resolve();