diff --git a/content/media/DecoderTraits.cpp b/content/media/DecoderTraits.cpp
index db91ea27203..78646f54384 100644
--- a/content/media/DecoderTraits.cpp
+++ b/content/media/DecoderTraits.cpp
@@ -487,6 +487,12 @@ InstantiateDecoder(const nsACString& aType, MediaDecoderOwner* aOwner)
 {
   nsRefPtr<MediaDecoder> decoder;
 
+#ifdef MOZ_FMP4
+  if (IsMP4SupportedType(aType)) {
+    decoder = new MP4Decoder();
+    return decoder.forget();
+  }
+#endif
 #ifdef MOZ_GSTREAMER
   if (IsGStreamerSupportedType(aType)) {
     decoder = new GStreamerDecoder();
@@ -557,12 +563,6 @@ InstantiateDecoder(const nsACString& aType, MediaDecoderOwner* aOwner)
     return decoder.forget();
   }
 #endif
-#ifdef MOZ_FMP4
-  if (IsMP4SupportedType(aType)) {
-    decoder = new MP4Decoder();
-    return decoder.forget();
-  }
-#endif
 #ifdef MOZ_WMF
   if (IsWMFSupportedType(aType)) {
     decoder = new WMFDecoder();
@@ -597,6 +597,11 @@ MediaDecoderReader* DecoderTraits::CreateReader(const nsACString& aType, Abstrac
 {
   MediaDecoderReader* decoderReader = nullptr;
 
+#ifdef MOZ_FMP4
+  if (IsMP4SupportedType(aType)) {
+    decoderReader = new MP4Reader(aDecoder);
+  } else
+#endif
 #ifdef MOZ_GSTREAMER
   if (IsGStreamerSupportedType(aType)) {
     decoderReader = new GStreamerReader(aDecoder);
@@ -638,11 +643,6 @@ MediaDecoderReader* DecoderTraits::CreateReader(const nsACString& aType, Abstrac
     decoderReader = new DirectShowReader(aDecoder);
   } else
 #endif
-#ifdef MOZ_FMP4
-  if (IsMP4SupportedType(aType)) {
-    decoderReader = new MP4Reader(aDecoder);
-  } else
-#endif
 #ifdef MOZ_WMF
   if (IsWMFSupportedType(aType)) {
     decoderReader = new WMFReader(aDecoder);