diff --git a/dom/media/MediaDecoder.cpp b/dom/media/MediaDecoder.cpp
index 868cd33eb02d..9d4172d3cd2d 100644
--- a/dom/media/MediaDecoder.cpp
+++ b/dom/media/MediaDecoder.cpp
@@ -321,6 +321,7 @@ MediaDecoder::Shutdown()
     mOnPlaybackErrorEvent.Disconnect();
     mOnDecoderDoctorEvent.Disconnect();
     mOnMediaNotSeekable.Disconnect();
+    mOnEncrypted.Disconnect();
 
     mDecoderStateMachine->BeginShutdown()
       ->Then(mAbstractMainThread, __func__, this,
@@ -484,6 +485,9 @@ MediaDecoder::SetStateMachineParameters()
     mAbstractMainThread, this, &MediaDecoder::OnDecoderDoctorEvent);
   mOnMediaNotSeekable = mDecoderStateMachine->OnMediaNotSeekable().Connect(
     mAbstractMainThread, this, &MediaDecoder::OnMediaNotSeekable);
+
+  mOnEncrypted = mReader->OnEncrypted().Connect(
+    mAbstractMainThread, GetOwner(), &MediaDecoderOwner::DispatchEncrypted);
 }
 
 nsresult
diff --git a/dom/media/MediaDecoder.h b/dom/media/MediaDecoder.h
index 39e7654809a7..fb6cf65d5a96 100644
--- a/dom/media/MediaDecoder.h
+++ b/dom/media/MediaDecoder.h
@@ -703,6 +703,7 @@ protected:
   MediaEventListener mOnPlaybackErrorEvent;
   MediaEventListener mOnDecoderDoctorEvent;
   MediaEventListener mOnMediaNotSeekable;
+  MediaEventListener mOnEncrypted;
 
 protected:
   // PlaybackRate and pitch preservation status we should start at.
diff --git a/dom/media/MediaDecoderReader.h b/dom/media/MediaDecoderReader.h
index 2b2c3f72f5f5..56a36c56412f 100644
--- a/dom/media/MediaDecoderReader.h
+++ b/dom/media/MediaDecoderReader.h
@@ -275,6 +275,11 @@ public:
     return mOnTrackWaitingForKey;
   }
 
+  MediaEventSource<nsTArray<uint8_t>, nsString>& OnEncrypted()
+  {
+    return mOnEncrypted;
+  }
+
   // Switch the video decoder to NullDecoderModule. It might takes effective
   // since a few samples later depends on how much demuxed samples are already
   // queued in the original video decoder.
@@ -337,6 +342,8 @@ protected:
   // Notify if we are waiting for a decryption key.
   MediaEventProducer<TrackInfo::TrackType> mOnTrackWaitingForKey;
 
+  MediaEventProducer<nsTArray<uint8_t>, nsString> mOnEncrypted;
+
   RefPtr<MediaResource> mResource;
 
 private:
diff --git a/dom/media/MediaFormatReader.cpp b/dom/media/MediaFormatReader.cpp
index 2efcbf1b22da..3ff51437af1d 100644
--- a/dom/media/MediaFormatReader.cpp
+++ b/dom/media/MediaFormatReader.cpp
@@ -1224,35 +1224,6 @@ MediaFormatReader::InitInternal()
   return NS_OK;
 }
 
-class DispatchKeyNeededEvent : public Runnable
-{
-public:
-  DispatchKeyNeededEvent(AbstractMediaDecoder* aDecoder,
-                         nsTArray<uint8_t>& aInitData,
-                         const nsString& aInitDataType)
-    : Runnable("DispatchKeyNeededEvent")
-    , mDecoder(aDecoder)
-    , mInitData(aInitData)
-    , mInitDataType(aInitDataType)
-  {
-  }
-  NS_IMETHOD Run() override
-  {
-    // Note: Null check the owner, as the decoder could have been shutdown
-    // since this event was dispatched.
-    MediaDecoderOwner* owner = mDecoder->GetOwner();
-    if (owner) {
-      owner->DispatchEncrypted(mInitData, mInitDataType);
-    }
-    mDecoder = nullptr;
-    return NS_OK;
-  }
-private:
-  RefPtr<AbstractMediaDecoder> mDecoder;
-  nsTArray<uint8_t> mInitData;
-  nsString mInitDataType;
-};
-
 void
 MediaFormatReader::SetCDMProxy(CDMProxy* aProxy)
 {
@@ -1380,13 +1351,11 @@ MediaFormatReader::OnDemuxerInitDone(const MediaResult& aResult)
   }
 
   UniquePtr<EncryptionInfo> crypto = mDemuxer->GetCrypto();
-  if (mDecoder && crypto && crypto->IsEncrypted()) {
+  if (crypto && crypto->IsEncrypted()) {
     // Try and dispatch 'encrypted'. Won't go if ready state still HAVE_NOTHING.
     for (uint32_t i = 0; i < crypto->mInitDatas.Length(); i++) {
-      nsCOMPtr<nsIRunnable> r =
-        new DispatchKeyNeededEvent(mDecoder, crypto->mInitDatas[i].mInitData,
-                                   crypto->mInitDatas[i].mType);
-      mDecoder->AbstractMainThread()->Dispatch(r.forget());
+      mOnEncrypted.Notify(crypto->mInitDatas[i].mInitData,
+                          crypto->mInitDatas[i].mType);
     }
     mInfo.mCrypto = *crypto;
   }