[Webkit-unassigned] [Bug 105912] New: Biquad filter: The phase response is incorrect

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=105912

           Summary: Biquad filter: The phase response is incorrect
           Product: WebKit
           Version: 528+ (Nightly build)
          Platform: PC
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: Normal
          Priority: P2
         Component: Web Audio
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: kaustubh.j at samsung.com
                CC: crogers at google.com


The phase change of frequency values is not happening as expected.
Verified on Webkit-r137862.

Please find the example below here:

----------------------------------------------------------------------------------------------------------
       var duration = 2.0;
       var sampleRate = 44100.0;
       function {
            context = window.AudioContext;
            numberOfFrames = duration * sampleRate;
            filter = context.createBiquadFilter();
            source = context.createBufferSource();
......
            fre = new Float32Array(numberOfFrames);
            mag = new Float32Array(numberOfFrames);
            pha = new Float32Array(numberOfFrames);
......
            buffer = context.createBuffer(1,numberOfFrames, sampleRate);
            data = buffer.getChannelData(0);
......
            // data filled with random values 
        // for e.g. data[i] = Math.sin(440.0 * Math.PI * i / sampleRate);
......
            source.buffer = buffer;
            filter.type = 7;
            filter.frequency.value = 495.0;
            filter.getFrequencyResponse(fre, mag, pha);
.......
            source.connect(filter);
            filter.connect(context.destination);
.......
        }
        var result = (pha[numberOfFrames/2] != pha[(numberOfFrames/2) - 1]);
        assert_true(result, "Check if BiquadFilterNode.ALLPASS filter changes the phase relationship");
----------------------------------------------------------------------------------------------------------

Expected behaviour: 'pha[numberOfFrames/2]' is not equal to 'pha[(numberOfFrames/2) - 1]' and result == true
Current Result: The value of result is coming as False.
Observed behaviour: pha[numberOfFrames/2] = pha[(numberOfFrames/2) - 1] = 0;

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