diff --git a/libFDK/include/FDK_bitstream.h b/libFDK/include/FDK_bitstream.h
index d47a750..19bc864 100644
--- a/libFDK/include/FDK_bitstream.h
+++ b/libFDK/include/FDK_bitstream.h
@@ -277,11 +277,15 @@ FDK_INLINE UINT FDKreadBit(HANDLE_FDK_BITSTREAM hBitStream)
       hBitStream->CacheWord = FDK_get32 (&hBitStream->hBitBuf);
       hBitStream->BitsInCache = CACHE_BITS;
     }
-    else
+    else if (validBits > 0)
     {
       hBitStream->CacheWord = FDK_get (&hBitStream->hBitBuf,validBits);
       hBitStream->BitsInCache = validBits;
     }
+    else
+    {
+      return 0;
+    }
   }
   hBitStream->BitsInCache--;