--- a/dom/html/HTMLMediaElement.cpp
+++ b/dom/html/HTMLMediaElement.cpp
@@ -6564,28 +6564,39 @@ HTMLMediaElement::OnVisibilityChange(Vis
   }
 
   switch (aNewVisibility) {
     case Visibility::UNTRACKED: {
         MOZ_ASSERT_UNREACHABLE("Shouldn't notify for untracked visibility");
         break;
     }
     case Visibility::NONVISIBLE: {
+      if (mPlayTime.IsStarted()) {
+        // Not visible, play time is running -> Start hidden play time if needed.
+        HiddenVideoStart();
+      }
+
       mDecoder->NotifyOwnerActivityChanged(false);
       break;
     }
     case Visibility::MAY_BECOME_VISIBLE: {
       if (aOldVisibility == Visibility::NONVISIBLE) {
+        // Visible -> Just pause hidden play time (no-op if already paused).
+        HiddenVideoStop();
+
         mDecoder->NotifyOwnerActivityChanged(true);
       } else if (aOldVisibility == Visibility::IN_DISPLAYPORT) {
         // Do nothing.
       }
       break;
     }
     case Visibility::IN_DISPLAYPORT: {
+      // Visible -> Just pause hidden play time (no-op if already paused).
+      HiddenVideoStop();
+
       mDecoder->NotifyOwnerActivityChanged(true);
       break;
     }
   }
 
 }
 
 void