NEW271227
AudioContext attached nodes can be collected 
https://bugs.webkit.org/show_bug.cgi?id=271227
Summary AudioContext attached nodes can be collected
youenn fablet
Reported 2024-03-19 02:52:02 PDT
AudioContext attached nodes can be collected, which can have an impact on audio rendering/now playing info. For instance in current LayoutTests/media/now-playing-webaudio.html: <!doctype html> <html> <head> <meta charset="utf-8"> <title>Testing basic video exchange from offerer to receiver</title> <script src="../resources/testharness.js"></script> <script src="../resources/testharnessreport.js"></script> </head> <body> <script> function waitFor(delay) { return new Promise(resolve => setTimeout(resolve, delay)); } async function waitForCriteria(test, criteria) { let counter = 0; while (!criteria() && ++counter < 100) await waitFor(50); } promise_test(async test => { if (!window.internals) return; navigator.audioSession.type = "playback"; let context = new AudioContext(); await waitFor(100); assert_false(!!internals.nowPlayingState.uniqueIdentifier); let oscillator = null; let gainNode = context.createGain(); oscillator = context.createOscillator(); oscillator.type = 'square'; oscillator.frequency.setValueAtTime(440, context.currentTime); oscillator.connect(gainNode); gainNode.gain.value = 0.1 internals.withUserGesture(() => { context.resume(); }); await waitFor(100); assert_false(!!internals.nowPlayingState.uniqueIdentifier); gainNode.connect(context.destination); await waitForCriteria(test, () => { return !!internals.nowPlayingState.uniqueIdentifier; }); assert_true(!!internals.nowPlayingState.uniqueIdentifier, "active now playing"); context.suspend(); await waitForCriteria(test, () => { return !internals.nowPlayingState.uniqueIdentifier; }); assert_false(!!internals.nowPlayingState.uniqueIdentifier, "inactive now playing"); context.resume(); await waitForCriteria(test, () => { return !!internals.nowPlayingState.uniqueIdentifier; }); assert_true(!!internals.nowPlayingState.uniqueIdentifier, "active now playing again"); }, "AudioContext as the now playing info source"); promise_test(async test => { if (!window.internals) return; const identifier = internals.nowPlayingState.uniqueIdentifier; let mediaElement = document.createElement("audio"); document.body.appendChild(mediaElement); await waitFor(100); assert_equals(internals.nowPlayingState.uniqueIdentifier, identifier, "AudioContext identifier"); await waitFor(100); assert_equals(internals.nowPlayingState.uniqueIdentifier, identifier, "AudioContext identifier 2"); mediaElement.src = "content/test.wav"; await waitForCriteria(test, () => { return internals.nowPlayingState.uniqueIdentifier !== identifier; }); assert_not_equals(internals.nowPlayingState.uniqueIdentifier, identifier, "HTMLMediaElement identifier"); const mediaElementIdentifier = internals.nowPlayingState.uniqueIdentifier document.body.removeChild(mediaElement); await waitForCriteria(test, () => { return internals.nowPlayingState.uniqueIdentifier !== mediaElementIdentifier; }); assert_equals(internals.nowPlayingState.uniqueIdentifier, identifier, "AudioContext identifier 3"); }, "HTMLMediaElement will become the now playing info source over playing AudioContext"); </script> </body> </html>
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Radar WebKit Bug Importer
Comment 1 2024-03-19 02:52:22 PDT
<rdar://problem/125000113>
youenn fablet
Comment 2 2025-01-31 08:49:24 PST
Looking a bit more, calling start() fixes the issue. I am not sure whether it makes a difference to have a node that disappears or keeping a node that is not started. When plugging a MediaStream destination node, this has the internal effect of audioSamplesAvailable being no longer called (but maybe this should be handled by MediaStream destination node itself).
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