diff --git a/media/libmediaplayerservice/MetadataRetrieverClient.cpp b/media/libmediaplayerservice/MetadataRetrieverClient.cpp
index bec6203..b45fd4f 100644
--- a/media/libmediaplayerservice/MetadataRetrieverClient.cpp
+++ b/media/libmediaplayerservice/MetadataRetrieverClient.cpp
@@ -188,10 +188,13 @@
     return ret;
 }
 
+Mutex MetadataRetrieverClient::sLock;
+
 sp<IMemory> MetadataRetrieverClient::getFrameAtTime(int64_t timeUs, int option)
 {
     ALOGV("getFrameAtTime: time(%lld us) option(%d)", timeUs, option);
     Mutex::Autolock lock(mLock);
+    Mutex::Autolock glock(sLock);
     mThumbnail.clear();
     if (mRetriever == NULL) {
         ALOGE("retriever is not initialized");
diff --git a/media/libmediaplayerservice/MetadataRetrieverClient.h b/media/libmediaplayerservice/MetadataRetrieverClient.h
index e71a29e..fe7547c 100644
--- a/media/libmediaplayerservice/MetadataRetrieverClient.h
+++ b/media/libmediaplayerservice/MetadataRetrieverClient.h
@@ -63,6 +63,7 @@
     virtual ~MetadataRetrieverClient();
 
     mutable Mutex                          mLock;
+    static  Mutex                          sLock;
     sp<MediaMetadataRetrieverBase>         mRetriever;
     pid_t                                  mPid;