Bug 216093

Summary:

Don't modify the response when creating a ConvolverNode

Product:

WebKit

Reporter:

Chris Dumez <cdumez>

Component:

Web Audio

Assignee:

Chris Dumez <cdumez>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

eric.carlson, ews-watchlist, glenn, jer.noble, peng.liu6, philipj, sergio, webkit-bug-importer

Priority:

Keywords:

InRadar

Version:

WebKit Nightly Build

Hardware:

Unspecified

OS:

Unspecified

See Also:

https://bugs.webkit.org/show_bug.cgi?id=216118

Bug Depends on:

Bug Blocks:

212611

Attachments:

Description	Flags
Patch	none
Patch	eric.carlson: review+

Description Chris Dumez 2020-09-02 13:38:01 PDT

When creating a ConvolverNode with normalization (the default), the ConvolverNode was modifying the supplied AudioBuffer containing the desired impulse response. This happens because the normalization factor was applied to the buffer, convolver stages were computed, and then the normalization was undone.  Due to floating-point roundoff, this can (and does) modify the buffer.

Comment 1 Chris Dumez 2020-09-02 13:50:06 PDT

Created attachment 407798 [details]
Patch

Comment 2 Chris Dumez 2020-09-02 13:55:41 PDT

Created attachment 407801 [details]
Patch

Comment 3 Peng Liu 2020-09-02 14:33:36 PDT

Comment on attachment 407801 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=407801&action=review

> Source/WebCore/platform/audio/FFTFrame.cpp:175
> +

Nit. There is an extra blank line here?

> LayoutTests/webaudio/convolvernode-unmodified-buffer.html:33
> +            // response if it hasn't been fixed not to do that.

Nit. The comment sounds strange.

> LayoutTests/webaudio/convolvernode-unmodified-buffer.html:53
> +            // better be unmodified.

Ditto.

Comment 4 Chris Dumez 2020-09-02 15:12:04 PDT

Committed r266492: <https://trac.webkit.org/changeset/266492>

Comment 5 Radar WebKit Bug Importer 2020-09-02 15:13:14 PDT

<rdar://problem/68235985>