Revert of Tighten up webrtc audio tests.

content/test/data/media/webrtc_test_audio.js

Index: content/test/data/media/webrtc_test_audio.js
diff --git a/content/test/data/media/webrtc_test_audio.js b/content/test/data/media/webrtc_test_audio.js
index 52c7d3897daf7e508c6545315e0263069ce72417..40668c6d38180c9e3b96f1de13d26f8a5ae6a41c 100644
--- a/content/test/data/media/webrtc_test_audio.js
+++ b/content/test/data/media/webrtc_test_audio.js
@@ -3,9 +3,6 @@
 // found in the LICENSE file.
 
 // Audio test utilities.
-
-// GetStats reports audio output energy in the [0, 32768] range.
-var MAX_AUDIO_OUTPUT_ENERGY = 32768;
 
 // Gathers |numSamples| samples at |frequency| number of times per second and
 // calls back |callback| with an array with numbers in the [0, 32768] range.
@@ -25,29 +22,28 @@
   }, 1000 / frequency);
 }
 
-// Tries to identify the beep-every-half-second signal generated by the fake
-// audio device in media/video/capture/fake_video_capture_device.cc. Fails the
-// test if we can't see a signal. The samples should have been gathered over at
-// least two seconds since we expect to see at least three "peaks" in there
-// (we should see either 3 or 4 depending on how things line up).
+// Tries to identify the beep-every-second signal generated by the fake audio
+// media/audio/fake_audio_input_stream.cc. Fails the test if we can't see a
+// signal.
 function verifyAudioIsPlaying(samples) {
-  var numPeaks = 0;
-  var threshold = MAX_AUDIO_OUTPUT_ENERGY * 0.7;
-  var currentlyOverThreshold = false;
+  var average = 0;
+  for (var i = 0; i < samples.length; ++i)
+    average += samples[i] / samples.length;
 
-  // Detect when we have been been over the threshold and is going back again
-  // (i.e. count peaks). We should see about one peak per second.
-  for (var i = 0; i < samples.length; ++i) {
-    if (currentlyOverThreshold && samples[i] < threshold)
-      numPeaks++;
-    currentlyOverThreshold = samples[i] >= threshold;
-  }
+  var largest = 0;
+  for (var i = 0; i < samples.length; ++i)
+    largest = Math.max(largest, samples[i]);
 
-  console.log('Number of peaks identified: ' + numPeaks);
+  console.log('Average audio level: ' + average + ', largest: ' + largest);
 
-  if (numPeaks < 2)
-    failTest('Expected to see at least two peaks in audio signal, got ' +
-        numPeaks + '. Dumping samples for analysis: "' + samples + '"');
+  // TODO(phoglund): Make a more sophisticated curve-fitting algorithm. We want
+  // to see a number of peaks with relative silence between them. The following
+  // seems to work fine on a nexus 7.
+  if (average < 3000 || average > 8000)
+    failTest('Unexpected avg audio level: got ' + average + ', expected it ' +
+             'to be 4000 < avg < 8000.');
+  if (largest < 25000)
+    failTest('Too low max audio level: got ' + largest + ', expected > 30000.');
 }
 
 // If silent (like when muted), we should get very near zero audio level.