Use stereo AudioBuffer instead of RealtimeAnalyserNode in the layout test of...

Use stereo AudioBuffer instead of RealtimeAnalyserNode in the layout test of stereo2mono-down-mixing
https://bugs.webkit.org/show_bug.cgi?id=81881

Patch by Xingnan Wang <xingnan.wang@intel.com> on 2012-03-22
Reviewed by Chris Rogers.

* webaudio/stereo2mono-down-mixing.html:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@111728 268f45cc-cd09-0410-ab3c-d52691b4dbfc

LayoutTests/ChangeLog

+2012-03-22  Xingnan Wang  <xingnan.wang@intel.com>
+
+        Use stereo AudioBuffer instead of RealtimeAnalyserNode in the layout test of stereo2mono-down-mixing
+        https://bugs.webkit.org/show_bug.cgi?id=81881
+
+        Reviewed by Chris Rogers.
+
+        * webaudio/stereo2mono-down-mixing.html:
+
 2012-03-22  Emil A Eklund  <eae@chromium.org>
         Unreviewed test_expectations update for chromium.

LayoutTests/webaudio/stereo2mono-down-mixing.html

@@ -15,21 +15,21 @@ description("This test verifies whether down mixing from stereo to mono will cau
 
 var sampleRate = 44100.0;
 var renderLengthSeconds = 0.1;
-var fftSize = 32;
 
 var context;
 var toneBuffer;
 var bufferSource;
-var analyser;
 
 function createDataBuffer(context, lengthInSeconds) {
-    var audioBuffer = context.createBuffer(1, lengthInSeconds * sampleRate, sampleRate);
+    var audioBuffer = context.createBuffer(2, lengthInSeconds * sampleRate, sampleRate);
 
     var n = audioBuffer.length;
-    var data = audioBuffer.getChannelData(0);
+    var data0 = audioBuffer.getChannelData(0);
+    var data1 = audioBuffer.getChannelData(1);
 
     for (var i = 0; i < n; ++i) {
-        data[i] = 1.0;
+        data0[i] = 1.0;
+        data1[i] = 1.0;
     }
 
     return audioBuffer;
@@ -49,20 +49,15 @@ function runTest() {
 
     window.jsTestIsAsync = true;
 
-    // Create offline audio context.
+    // Create offline audio context, the destination is mono.
     context = new webkitAudioContext(1, sampleRate * renderLengthSeconds, sampleRate);
-    // Explicitly create a mono AudioContext so that the destination is mono.
+    // Create a stereo AudioBuffer.
     toneBuffer = createDataBuffer(context, renderLengthSeconds);
 
     bufferSource = context.createBufferSource();
     bufferSource.buffer = toneBuffer;
 
-    // We create an analyser here, because it has a hard-coded stereo output.
-    analyser = context.createAnalyser();
-    analyser.fftSize = fftSize;
-
-    bufferSource.connect(analyser);
-    analyser.connect(context.destination);
+    bufferSource.connect(context.destination);
 
     bufferSource.noteOn(0);