Bug 192422

Summary:

BiquadFilterNode.getFrequencyReponse gives all 1's

Product:

WebKit

Reporter:

Component:

Web Audio

Assignee:

Nobody <webkit-unassigned>

Status:

NEW

Severity:

Normal

CC:

jer.noble, webkit-bug-importer

Priority:

Keywords:

InRadar

Version:

Safari 12

Hardware:

iPhone / iPad

OS:

iOS 12

Attachments:

Description	Flags
Frequency response as returned by WebKit / iOS	none
Frequency response as returned on Chrome (exactly same code / setup)	none

Reported 2018-12-05 12:19:29 PST

getFrequencyResponse doesn't seem to be working. No matter what I do, the frequency response array is filled with all 1s (obviously, I'm using non-flat filter settings). Chrome working correctly (fills in the actual frequency response).

Attachments
Frequency response as returned by WebKit / iOS (1.92 MB, image/jpeg) 2018-12-05 12:24 PST, ae	no flags	Details
Frequency response as returned on Chrome (exactly same code / setup) (167.29 KB, image/png) 2018-12-05 12:24 PST, ae	no flags	Details
View All Add attachment proposed patch, testcase, etc.

Comment 1 2018-12-05 12:24:15 PST

Created attachment 356639 [details] Frequency response as returned by WebKit / iOS

Comment 2 2018-12-05 12:24:55 PST

Created attachment 356640 [details] Frequency response as returned on Chrome (exactly same code / setup)

Comment 3 2018-12-05 12:27:03 PST

(the screenshots show a white noise source running through the "Spectral EQ" insert FX, which shows a spectrum analyser (AnalyserNode) and applies a single EQ with some gain and center frequency at 1500 Hz. The AnalyserNode is after the EQ. In Chrome, the frequency response curve (blue) as returned by FilterNode.getFrequencyResponse exactly corresponds to the observed spectrum. In WebKit, it is just flat (all 1s)).

Comment 4 2018-12-06 04:09:57 PST

The EQ is a BiquadFilterNode of type 'peaking', frequency 1500, gain 20, and Q 1. Calling getFrequencyResponse on this filter gives a flat (all 1) response. Also, the phase response is all 0 (wrong too).

Radar WebKit Bug Importer

Comment 5 2018-12-06 10:07:56 PST

<rdar://problem/46526644>

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