Fixes to 3D shuffler to fix #1463.

Make the shuffler longer; I've seen examples where the video and sound
are over a second apart within the muxed file.

Allow the shuffler to pass through complete missed frames;
e.g. if the input is L1 R1 L3 R3 we can pass that through without
worrying about the missing frame #2.

Add a log warning if the shuffler fills: at this point, 3D sync
may be lost.

1 files changed, 10 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 ();