--- a/dom/audiochannel/AudioChannelAgent.cpp
+++ b/dom/audiochannel/AudioChannelAgent.cpp
@@ -15,16 +15,19 @@ AudioChannelAgent::AudioChannelAgent()
   , mAudioChannelType(AUDIO_AGENT_CHANNEL_ERROR)
   , mIsRegToService(false)
   , mVisible(true)
 {
 }
 
 AudioChannelAgent::~AudioChannelAgent()
 {
+  if (mIsRegToService) {
+    StopPlaying();
+  }
 }
 
 /* readonly attribute long audioChannelType; */
 NS_IMETHODIMP AudioChannelAgent::GetAudioChannelType(int32_t *aAudioChannelType)
 {
   *aAudioChannelType = mAudioChannelType;
   return NS_OK;
 }
@@ -61,32 +64,32 @@ NS_IMETHODIMP AudioChannelAgent::Init(in
   return NS_OK;
 }
 
 /* boolean startPlaying (); */
 NS_IMETHODIMP AudioChannelAgent::StartPlaying(bool *_retval)
 {
   AudioChannelService *service = AudioChannelService::GetAudioChannelService();
   if (mAudioChannelType == AUDIO_AGENT_CHANNEL_ERROR ||
-      service == nullptr) {
+      service == nullptr || mIsRegToService) {
     return NS_ERROR_FAILURE;
   }
 
   service->RegisterAudioChannelAgent(this,
     static_cast<AudioChannelType>(mAudioChannelType));
   *_retval = !service->GetMuted(this, !mVisible);
   mIsRegToService = true;
   return NS_OK;
 }
 
 /* void stopPlaying (); */
 NS_IMETHODIMP AudioChannelAgent::StopPlaying(void)
 {
   if (mAudioChannelType == AUDIO_AGENT_CHANNEL_ERROR ||
-      mIsRegToService == false) {
+      !mIsRegToService) {
     return NS_ERROR_FAILURE;
   }
 
   AudioChannelService *service = AudioChannelService::GetAudioChannelService();
   service->UnregisterAudioChannelAgent(this);
   mIsRegToService = false;
   return NS_OK;
 }