Bug 192422 - BiquadFilterNode.getFrequencyReponse gives all 1's
Summary: BiquadFilterNode.getFrequencyReponse gives all 1's
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: Web Audio (show other bugs)
Version: Safari 12
Hardware: iPhone / iPad iOS 12
: P2 Normal
Assignee: Nobody
URL:
Keywords: InRadar
Depends on:
Blocks:
 
Reported: 2018-12-05 12:19 PST by ae
Modified: 2018-12-06 10:07 PST (History)
2 users (show)

See Also:


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

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Description ae 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).
Comment 1 ae 2018-12-05 12:24:15 PST
Created attachment 356639 [details]
Frequency response as returned by WebKit / iOS
Comment 2 ae 2018-12-05 12:24:55 PST
Created attachment 356640 [details]
Frequency response as returned on Chrome (exactly same code / setup)
Comment 3 ae 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 ae 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).
Comment 5 Radar WebKit Bug Importer 2018-12-06 10:07:56 PST
<rdar://problem/46526644>