+#include "video_decoder.h"
+#include "audio_decoder.h"
+#include "subtitle_decoder.h"
+#include <boost/optional.hpp>
+#include <iostream>
+
+using std::cout;
+using boost::optional;
+
+/** @return Earliest time of content that the next pass() will emit */
+ContentTime
+Decoder::position () const
+{
+ optional<ContentTime> pos;