The HRTF panner uses significant memory for the responses and requires a fair...

The HRTF panner uses significant memory for the responses and requires a fair amount of processing to implement. For low-end mobile devices, this can be an issue. Since the default panner model is HRTF, the creation of the panner can cause the responses to be loaded.

Perhaps the default should be changed to equalpower, which doesn't consume significant memory and is much less intensive in processing power.

This is an incompatible change with the current spec.

See also: https://github.com/WebAudio/web-audio-api/issues/368

BUG=424356

Review URL: https://codereview.chromium.org/652073003

git-svn-id: svn://svn.chromium.org/blink/trunk@183925 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/webaudio/pannernode-basic-expected.txt

@@ -16,7 +16,7 @@ PASS coneOuterAngle default value is 360.
 PASS coneOuterAngle value is set to 166.66.
 PASS coneOuterGain default value is 0.
 PASS coneOuterGain value is set to 0.35.
-PASS PannerNode defaults to 'HRTF' panningModel.
+PASS PannerNode defaults to 'equalpower' panningModel.
 PASS PannerNode defaults to 'inverse' distanceModel.
 PASS panningModel: 'equalpower' is settable.
 PASS panningModel: 'HRTF' is settable.

third_party/WebKit/LayoutTests/webaudio/pannernode-basic.html

@@ -102,10 +102,10 @@ function runTest() {
     else
         testFailed("coneOuterGain value should be set to 0.35.");
 
-    if (panner.panningModel === "HRTF")
-        testPassed("PannerNode defaults to 'HRTF' panningModel.");
+    if (panner.panningModel === "equalpower")
+        testPassed("PannerNode defaults to 'equalpower' panningModel.");
     else
-        testFailed("PannerNode should default to 'HRTF' panningModel.");
+        testFailed("PannerNode should default to 'equalpower' panningModel.");
 
     if (panner.distanceModel === "inverse")
         testPassed("PannerNode defaults to 'inverse' distanceModel.");

third_party/WebKit/Source/modules/webaudio/PannerNode.cpp

@@ -48,7 +48,7 @@ static void fixNANs(double &x)
 
 PannerNode::PannerNode(AudioContext* context, float sampleRate)
     : AudioNode(context, sampleRate)
-    , m_panningModel(Panner::PanningModelHRTF)
+    , m_panningModel(Panner::PanningModelEqualPower)
     , m_distanceModel(DistanceEffect::ModelInverse)
     , m_position(0, 0, 0)
     , m_orientation(1, 0, 0)
@@ -198,7 +198,7 @@ String PannerNode::panningModel() const
         return "HRTF";
     default:
         ASSERT_NOT_REACHED();
-        return "HRTF";
+        return "equalpower";
     }
 }
 

third_party/WebKit/Source/modules/webaudio/PannerNode.idl

@@ -37,7 +37,7 @@ enum DistanceModelType {
     NoInterfaceObject,
     Conditional=WEB_AUDIO
 ] interface PannerNode : AudioNode {
-    // Default model for stereo is HRTF
+    // Default model for stereo is equalpower.
     attribute PanningModelType panningModel;
 
     // Uses a 3D cartesian coordinate system