Bug 169849

Summary:	Web Audio ScriptProcessorNode pauses, emits hum after switching audio output device
Product:	WebKit	Reporter:	Brooke Vibber <bvibber>
Component:	Web Audio	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	hartman.wiki, jer.noble, webkit-bug-importer
Priority:	P2	Keywords:	InRadar
Version:	WebKit Nightly Build
Hardware:	Mac
OS:	macOS 10.12

Description Brooke Vibber 2017-03-18 12:28:09 PDT

We're using Web Audio's ScriptProcessorNode to play audio files that have been decoded in JavaScript dynamically; it works quite well except when the audio output device is changed during playback.

On my MacBook Pro running macOS 10.12.3, I can reproduce this by plugging or unplugging a USB speaker during playback; both directions produce similar results:
* audio stops on the old device
* on the new device, a humming noise may be emitted
* audioprocessing events are no longer delivered

When switching back to the original output device, audioprocessing events continue being delivered, and audio continues as expected.

Simplified test case: https://brionv.com/misc/audio.html

Same results with Safari 10 release version, Technical Preview, and WebKit Nightly.

Comment 1 Radar WebKit Bug Importer 2017-03-19 13:47:25 PDT

<rdar://problem/31137513>

Comment 2 Jer Noble 2017-03-19 20:26:31 PDT

This sounds suspiciously like a bug we fixed in iOS last year; I must have done it in a platform specific area of the Web Audio code. Should be relatively easy to port over.