--- a/dom/html/HTMLMediaElement.cpp
+++ b/dom/html/HTMLMediaElement.cpp
@@ -1585,16 +1585,21 @@ HTMLMediaElement::Seek(double aTime,
   // TODO: The spec requires us to update the current time to reflect the
   //       actual seek target before beginning the synchronous section, but
   //       that requires changing all MediaDecoderReaders to support telling
   //       us the fastSeek target, and it's currently not possible to get
   //       this information as we don't yet control the demuxer for all
   //       MediaDecoderReaders.
 
   mPlayingBeforeSeek = IsPotentiallyPlaying();
+  // Set the Variable if the Seekstarted while active playing
+  if (mPlayingThroughTheAudioChannel) {
+    mPlayingThroughTheAudioChannelBeforeSeek = true;
+  }
+
   // The media backend is responsible for dispatching the timeupdate
   // event if it changes the playback position as a result of the seek.
   LOG(LogLevel::Debug, ("%p SetCurrentTime(%f) starting seek", this, aTime));
   nsresult rv = mDecoder->Seek(aTime, aSeekType);
   if (NS_FAILED(rv)) {
     aRv.Throw(rv);
   }
 
@@ -3540,20 +3545,16 @@ void HTMLMediaElement::PlaybackEnded()
 
   FireTimeUpdate(false);
   DispatchAsyncEvent(NS_LITERAL_STRING("ended"));
 }
 
 void HTMLMediaElement::SeekStarted()
 {
   DispatchAsyncEvent(NS_LITERAL_STRING("seeking"));
-  // Set the Variable if the Seekstarted while active playing
-  if(mPlayingThroughTheAudioChannel) {
-    mPlayingThroughTheAudioChannelBeforeSeek = true;
-  }
 }
 
 void HTMLMediaElement::SeekCompleted()
 {
   mPlayingBeforeSeek = false;
   SetPlayedOrSeeked(true);
   FireTimeUpdate(false);
   DispatchAsyncEvent(NS_LITERAL_STRING("seeked"));