Sub-sample accurate start of OscillatorNode

third_party/WebKit/LayoutTests/webaudio/resources/audit-util.js

Index: third_party/WebKit/LayoutTests/webaudio/resources/audit-util.js
diff --git a/third_party/WebKit/LayoutTests/webaudio/resources/audit-util.js b/third_party/WebKit/LayoutTests/webaudio/resources/audit-util.js
index 3e261f6d7ad025eb3d21d5b3784d6959d62e6612..74c6972957a5be4e0d4c31175d7d9284d33cfde3 100644
--- a/third_party/WebKit/LayoutTests/webaudio/resources/audit-util.js
+++ b/third_party/WebKit/LayoutTests/webaudio/resources/audit-util.js
@@ -257,3 +257,21 @@ function grainLengthInSampleFrames(grainOffset, duration, sampleRate) {
 function isValidNumber(x) {
     return !isNaN(x) && (x != Infinity) && (x != -Infinity);
 }
+
+// Compute the (linear) signal-to-noise ratio between |actual| and
+// |expected|.  The result is NOT in dB!  If the |actual| and
+// |expected| have different lengths, the shorter length is used.
+function computeSNR(actual, expected) {
+    var signalPower = 0;
+    var noisePower = 0;
+
+    var length = Math.min(actual.length, expected.length);
+
+    for (var k = 0; k < length; ++k) {
+        var diff = actual[k] - expected[k];
+        signalPower += expected[k] * expected[k];
+        noisePower += diff * diff;
+    }
+
+    return signalPower / noisePower;
+}