diff --git a/dom/audiochannel/AudioChannelService.cpp b/dom/audiochannel/AudioChannelService.cpp
index a17a2b21eb6..b23423f8a14 100644
--- a/dom/audiochannel/AudioChannelService.cpp
+++ b/dom/audiochannel/AudioChannelService.cpp
@@ -113,6 +113,18 @@ AudioChannelService::RegisterAudioChannelAgent(AudioChannelAgent* aAgent,
                                 aWithVideo);
   mAgents.Put(aAgent, data);
   RegisterType(aType, CONTENT_PROCESS_ID_MAIN, aWithVideo);
+
+  // If this is the first agent for this window, we must notify the observers.
+  uint32_t count = CountWindow(aAgent->Window());
+  if (count == 1) {
+    nsCOMPtr<nsIObserverService> observerService =
+      services::GetObserverService();
+    if (observerService) {
+      observerService->NotifyObservers(ToSupports(aAgent->Window()),
+                                       "media-playback",
+                                       NS_LITERAL_STRING("active").get());
+    }
+  }
 }
 
 void
@@ -181,6 +193,18 @@ AudioChannelService::UnregisterAudioChannelAgent(AudioChannelAgent* aAgent)
     mSpeakerManager[i]->SetAudioChannelActive(active);
   }
 #endif
+
+  // If this is the last agent for this window, we must notify the observers.
+  uint32_t count = CountWindow(aAgent->Window());
+  if (count == 0) {
+    nsCOMPtr<nsIObserverService> observerService =
+      services::GetObserverService();
+    if (observerService) {
+      observerService->NotifyObservers(ToSupports(aAgent->Window()),
+                                       "media-playback",
+                                       NS_LITERAL_STRING("inactive").get());
+    }
+  }
 }
 
 void
@@ -822,3 +846,37 @@ AudioChannelService::RefreshAgentsVolume(nsPIDOMWindow* aWindow)
     data.mAgents[i]->WindowVolumeChanged();
   }
 }
+
+struct CountWindowData
+{
+  CountWindowData(nsIDOMWindow* aWindow)
+    : mWindow(aWindow)
+    , mCount(0)
+  {}
+
+  nsIDOMWindow* mWindow;
+  uint32_t mCount;
+};
+
+PLDHashOperator
+AudioChannelService::CountWindowEnumerator(AudioChannelAgent* aAgent,
+                                           AudioChannelAgentData* aUnused,
+                                           void* aPtr)
+{
+  CountWindowData* data = static_cast<CountWindowData*>(aPtr);
+  MOZ_ASSERT(aAgent);
+
+  if (aAgent->Window() == data->mWindow) {
+    ++data->mCount;
+  }
+
+  return PL_DHASH_NEXT;
+}
+
+uint32_t
+AudioChannelService::CountWindow(nsIDOMWindow* aWindow)
+{
+  CountWindowData data(aWindow);
+  mAgents.EnumerateRead(CountWindowEnumerator, &data);
+  return data.mCount;
+}
diff --git a/dom/audiochannel/AudioChannelService.h b/dom/audiochannel/AudioChannelService.h
index 7aa7d98003e..011ea54fefd 100644
--- a/dom/audiochannel/AudioChannelService.h
+++ b/dom/audiochannel/AudioChannelService.h
@@ -188,6 +188,14 @@ protected:
                                 AudioChannelAgentData* aUnused,
                                 void *aPtr);
 
+  static PLDHashOperator
+  CountWindowEnumerator(AudioChannelAgent* aAgent,
+                        AudioChannelAgentData* aUnused,
+                        void *aPtr);
+
+  // This returns the number of agents from this aWindow.
+  uint32_t CountWindow(nsIDOMWindow* aWindow);
+
   nsClassHashtable< nsPtrHashKey<AudioChannelAgent>, AudioChannelAgentData > mAgents;
 #ifdef MOZ_WIDGET_GONK
   nsTArray<SpeakerManagerService*>  mSpeakerManager;
diff --git a/dom/base/test/audio.ogg b/dom/base/test/audio.ogg
new file mode 100644
index 00000000000..d7f6a0ccf47
Binary files /dev/null and b/dom/base/test/audio.ogg differ
diff --git a/dom/base/test/mochitest.ini b/dom/base/test/mochitest.ini
index f5613e88a14..622be567d25 100644
--- a/dom/base/test/mochitest.ini
+++ b/dom/base/test/mochitest.ini
@@ -1,5 +1,6 @@
 [DEFAULT]
 support-files =
+  audio.ogg
   iframe_messageChannel_cloning.html
   iframe_messageChannel_pingpong.html
   iframe_messageChannel_post.html
@@ -9,6 +10,7 @@ support-files =
 [test_Image_constructor.html]
 [test_appname_override.html]
 [test_audioWindowUtils.html]
+[test_audioNotification.html]
 [test_bug913761.html]
 [test_bug978522.html]
 [test_bug979109.html]
diff --git a/dom/base/test/test_audioNotification.html b/dom/base/test/test_audioNotification.html
new file mode 100644
index 00000000000..b035ecd9295
--- /dev/null
+++ b/dom/base/test/test_audioNotification.html
@@ -0,0 +1,75 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Test for audio controller in windows</title>
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<pre id="test">
+</pre>
+
+<script type="application/javascript">
+
+SimpleTest.waitForExplicitFinish();
+
+var expectedNotification = null;
+
+var observer = {
+  observe: function(subject, topic, data) {
+    is(topic, "media-playback", "media-playback received");
+    is(data, expectedNotification, "This is the right notification");
+    runTest();
+  }
+};
+
+var observerService = SpecialPowers.Cc["@mozilla.org/observer-service;1"]
+                                   .getService(SpecialPowers.Ci.nsIObserverService);
+
+var audio = new Audio();
+audio.src = "audio.ogg";
+
+var tests = [
+  function() {
+    SpecialPowers.pushPrefEnv({"set": [["media.useAudioChannelService", true]]}, runTest);
+  },
+
+  function() {
+    observerService.addObserver(observer, "media-playback", false);
+    ok(true, "Observer set");
+    runTest();
+  },
+
+  function() {
+    expectedNotification = 'active';
+    audio.play();
+  },
+
+  function() {
+    expectedNotification = 'inactive';
+    audio.pause();
+  },
+
+  function() {
+    observerService.removeObserver(observer, "media-playback");
+    ok(true, "Observer removed");
+    runTest();
+  }
+];
+
+function runTest() {
+  if (!tests.length) {
+    SimpleTest.finish();
+    return;
+  }
+
+  var test = tests.shift();
+  test();
+}
+
+runTest();
+
+</script>
+</body>
+</html>
+