3 files changed, 35 insertions, 3 deletions

diff --git a/src/lib/shuffler.cc b/src/lib/shuffler.cc
index 07c7a1d90..a46b26da0 100644
--- a/src/lib/shuffler.cc
+++ b/src/lib/shuffler.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2018 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2018-2019 Carl Hetherington <cth@carlh.net>
 
     This file is part of DCP-o-matic.
 
@@ -21,6 +21,7 @@
 #include "shuffler.h"
 #include "content_video.h"
 #include "dcpomatic_assert.h"
+#include "dcpomatic_log.h"
 #include <boost/foreach.hpp>
 #include <iostream>
 
@@ -29,6 +30,8 @@ using boost::weak_ptr;
 using boost::shared_ptr;
 using boost::optional;
 
+int const Shuffler::_max_size = 64;
+
 struct Comparator
 {
 	bool operator()(Shuffler::Store const & a, Shuffler::Store const & b) {
@@ -68,10 +71,10 @@ Shuffler::video (weak_ptr<Piece> weak_piece, ContentVideo video)
 			_last &&
 			(
 				(_store.front().second.frame == _last->frame       && _store.front().second.eyes == EYES_RIGHT && _last->eyes == EYES_LEFT) ||
-				(_store.front().second.frame == (_last->frame + 1) && _store.front().second.eyes == EYES_LEFT  && _last->eyes == EYES_RIGHT)
+				(_store.front().second.frame >= (_last->frame + 1) && _store.front().second.eyes == EYES_LEFT  && _last->eyes == EYES_RIGHT)
 				);
 
-		if (!store_front_in_sequence && _store.size() <= 8) {
+		if (!store_front_in_sequence && _store.size() <= _max_size) {
 			/* store_front_in_sequence means everything is ok; otherwise if the store is getting too big just
 			   start emitting things as best we can.  This can easily happen if, for example, there is only content
 			   for one eye in some part of the timeline.
@@ -79,6 +82,10 @@ Shuffler::video (weak_ptr<Piece> weak_piece, ContentVideo video)
 			break;
 		}
 
+		if (_store.size() > _max_size) {
+			LOG_WARNING ("Shuffler is full after receiving frame %1; 3D sync may be incorrect.", video.frame);
+		}
+
 		Video (_store.front().first, _store.front().second);
 		_last = _store.front().second;
 		_store.pop_front ();
diff --git a/src/lib/shuffler.h b/src/lib/shuffler.h
index 3eed3e4f0..7ac300b47 100644
--- a/src/lib/shuffler.h
+++ b/src/lib/shuffler.h
@@ -38,4 +38,5 @@ public:
 private:
 	std::list<Store> _store;
 	boost::optional<ContentVideo> _last;
+	static int const _max_size;
 };
diff --git a/test/shuffler_test.cc b/test/shuffler_test.cc
index 440d014cf..a8b45930f 100644
--- a/test/shuffler_test.cc
+++ b/test/shuffler_test.cc
@@ -143,3 +143,27 @@ BOOST_AUTO_TEST_CASE (shuffler_test5)
 	push (s, 9, EYES_LEFT);
 	check (1, EYES_LEFT, __LINE__);
 }
+
+/** One complete frame (L+R) missing.
+    Shuffler should carry on, skipping this frame, as the player will cope with it.
+*/
+BOOST_AUTO_TEST_CASE (shuffler_test6)
+{
+	Shuffler s;
+	s.Video.connect (boost::bind (&receive, _1, _2));
+
+	push (s, 0, EYES_LEFT);
+	check (0, EYES_LEFT, __LINE__);
+	push (s, 0, EYES_RIGHT);
+	check (0, EYES_RIGHT, __LINE__);
+
+	push (s, 2, EYES_LEFT);
+	push (s, 2, EYES_RIGHT);
+	check (2, EYES_LEFT, __LINE__);
+	check (2, EYES_RIGHT, __LINE__);
+
+	push (s, 3, EYES_LEFT);
+	check (3, EYES_LEFT, __LINE__);
+	push (s, 3, EYES_RIGHT);
+	check (3, EYES_RIGHT, __LINE__);
+}