diff --git a/include/media/MediaExtractorPluginHelper.h b/include/media/MediaExtractorPluginHelper.h
index f4d4da6..b86f177 100644
--- a/include/media/MediaExtractorPluginHelper.h
+++ b/include/media/MediaExtractorPluginHelper.h
@@ -171,6 +171,9 @@
 };
 
 inline CMediaTrack *wrap(MediaTrackHelper *track) {
+    if (track == nullptr) {
+        return nullptr;
+    }
     CMediaTrack *wrapper = (CMediaTrack*) malloc(sizeof(CMediaTrack));
     wrapper->data = track;
     wrapper->free = [](void *data) -> void {
diff --git a/include/media/MediaTrack.h b/include/media/MediaTrack.h
index e828a7f..493eba3 100644
--- a/include/media/MediaTrack.h
+++ b/include/media/MediaTrack.h
@@ -142,7 +142,7 @@
 
 class MediaTrackCUnwrapper : public MediaTrack {
 public:
-    explicit MediaTrackCUnwrapper(CMediaTrack *wrapper);
+    static MediaTrackCUnwrapper *create(CMediaTrack *wrapper);
 
     virtual status_t start();
     virtual status_t stop();
@@ -155,6 +155,7 @@
     virtual ~MediaTrackCUnwrapper();
 
 private:
+    explicit MediaTrackCUnwrapper(CMediaTrack *wrapper);
     CMediaTrack *wrapper;
     MediaBufferGroup *bufferGroup;
 };