Extending supported sample rate from 3.0KHz to 192.0KHz for OfflineAudioContext.

Source/platform/audio/HRTFPanner.cpp

Index: Source/platform/audio/HRTFPanner.cpp
diff --git a/Source/platform/audio/HRTFPanner.cpp b/Source/platform/audio/HRTFPanner.cpp
index 04e410dba233decde70c91472d12cf7ba6103ab3..b9077cc2d3164eeb7a41c38c0072c346c05bdc5a 100644
--- a/Source/platform/audio/HRTFPanner.cpp
+++ b/Source/platform/audio/HRTFPanner.cpp
@@ -45,6 +45,8 @@ const double MaxDelayTimeSeconds = 0.002;
 const int UninitializedAzimuth = -1;
 const unsigned RenderingQuantum = 128;
 
+const size_t fftSizes[] = { 64, 128, 256, 512, 1024, 2048, 4096 };
+
 HRTFPanner::HRTFPanner(float sampleRate, HRTFDatabaseLoader* databaseLoader)
     : Panner(PanningModelHRTF)
     , m_databaseLoader(databaseLoader)
@@ -79,8 +81,24 @@ size_t HRTFPanner::fftSizeForSampleRate(float sampleRate)
     // The HRTF impulse responses (loaded as audio resources) are 512 sample-frames @44.1KHz.
     // Currently, we truncate the impulse responses to half this size, but an FFT-size of twice impulse response size is needed (for convolution).
     // So for sample rates around 44.1KHz an FFT size of 512 is good. We double the FFT-size only for sample rates at least double this.
-    ASSERT(sampleRate >= 44100 && sampleRate <= 96000.0);
-    return (sampleRate < 88200.0) ? 512 : 1024;
+    ASSERT(sampleRate >= 3000 && sampleRate <= 192000);

[Raymond Toy, 2014/09/05 05:18:30]

I think you should use AudioBuffer::minAllowedSampleRate() instead of 3000.

[KhNo, 2014/09/05 05:32:39]

Yes, I agree with that. However, current implementation can not call method
module method.(AudioBuffer.cpp is in module/) from plotform/ to module/.
So, now I'm preparing the next patch set of it. I will clean up all sample rate
numeric to use get one method after remove dependancy libmodule and libplatform.

+
+    int index = 6;
+
+    if (sampleRate <= 5512.5)
+        index = 0;
+    else if (sampleRate <= 11025)
+        index = 1;
+    else if (sampleRate <= 22050)
+        index = 2;
+    else if (sampleRate <= 44100)
+        index = 3;
+    else if (sampleRate <= 88200)
+        index = 4;
+    else if (sampleRate <= 176400)
+        index = 5;
+
+    return fftSizes[index];

[Raymond Toy, 2014/09/05 05:18:30]

Since this is so simple, I think you should just delete the fftSizes array and
instead of setting the index, just return the actual FFT size.

[KhNo, 2014/09/05 05:32:39]

Done.

 }
 
 void HRTFPanner::reset()