Bug 181939

Summary:

AudioBufferSourceNode start method causes OfflineAudioContext to start running

Product:

WebKit

Reporter:

yotammann

Component:

Web Audio

Assignee:

Jer Noble <jer.noble>

Status:

RESOLVED FIXED

Severity:

Major

CC:

commit-queue, eric.carlson, jer.noble, spwilliamsiam, webkit-bug-importer, yotammann

Priority:

Keywords:

InRadar

Version:

Safari 11

Hardware:

iPhone / iPad

OS:

iOS 11

Attachments:

Description	Flags
Patch	none

Description yotammann 2018-01-22 12:31:57 PST

The OfflineAudioContext.state should be "suspended" and not increment the currentTime until `startRendering` is invoked. The issue is that as soon as AudioBufferSourceNode.start is invoked, the OfflineAudioContext.state returns "running" and the OfflineAudioContext.currentTime starts incrementing usually much faster than real time. This makes it impossible to schedule anything after an AudioBufferSourceNode is started since the scheduled time will usually be in the past. 

Test case: https://jsfiddle.net/3h8e3bcg/

Should print to the console: "should be suspended: suspended" then "should still be suspended: suspended"

PASSES on Chrome, Firefox and Safari 11 on Desktop. 

FAILS on Safari on iOS 11. prints: "should be suspended: suspended" then "should still be suspended: running"

Comment 1 Radar WebKit Bug Importer 2018-01-22 16:56:58 PST

<rdar://problem/36755393>

Comment 2 Sam Williams 2018-03-25 14:40:50 PDT

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But really, please do fix soon, as this bug is SO ANNOYING!!!
https://jsfiddle.net/ayunami2000/c5xdL6xL/
This is where I discovered the bug. Everything else in the JSFiddle works, but offlineAudioContext's oncomplete event never fires.
Also, https://codepen.io/tomduncalf/pen/GmvPNp works on iOS!!!

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Comment 3 Jer Noble 2018-03-26 11:14:07 PDT

Created attachment 336527 [details]
Patch

Comment 4 Eric Carlson 2018-03-27 08:52:00 PDT

Comment on attachment 336527 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=336527&action=review

> LayoutTests/webaudio/offlineaudiocontext-restriction.html:18
> +var calledResumeWithUserGesture = false;

Nit: this isn't used.

Comment 5 WebKit Commit Bot 2018-04-02 08:40:25 PDT

Comment on attachment 336527 [details]
Patch

Clearing flags on attachment: 336527

Committed r230158: <https://trac.webkit.org/changeset/230158>

Comment 6 WebKit Commit Bot 2018-04-02 08:40:26 PDT

All reviewed patches have been landed.  Closing bug.