In general the player assumes that it won't receive out of order video.

This clearly can happen with separate L/R sources.  A pass in L might
emit two frames which means the arrivals can't possibly be in order.

This commit fixes this by introducing a Shuffler which all alternate-3D
sources send their video to.  The Shuffler re-orders things before they
arrive at the player.

It also fixes the code which inserts video frames before one that arrives
after a gap.  This didn't cope with 3D right before.

The audio code solves a similar (perhaps the same?) problem with the
AudioMerger; perhaps we should have a similar thing for video and make
the player emit complete 3D frames.

Should help with #976.

1 files changed, 93 insertions, 0 deletions

diff --git a/src/lib/shuffler.cc b/src/lib/shuffler.cc
new file mode 100644
index 000000000..997d91fb1
--- /dev/null
+++ b/src/lib/shuffler.cc
@@ -0,0 +1,93 @@
+/*
+    Copyright (C) 2018 Carl Hetherington <cth@carlh.net>
+
+    This file is part of DCP-o-matic.
+
+    DCP-o-matic is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    DCP-o-matic is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+#include "shuffler.h"
+#include "content_video.h"
+#include "dcpomatic_assert.h"
+#include <boost/foreach.hpp>
+#include <iostream>
+
+using std::make_pair;
+using boost::weak_ptr;
+using boost::shared_ptr;
+using boost::optional;
+
+struct Comparator
+{
+	bool operator()(Shuffler::Store const & a, Shuffler::Store const & b) {
+		if (a.second.frame != b.second.frame) {
+			return a.second.frame < b.second.frame;
+		}
+		return a.second.eyes < b.second.eyes;
+	}
+};
+
+void
+Shuffler::video (weak_ptr<Piece> weak_piece, ContentVideo video)
+{
+	std::cout << "shuffler gets " << video.frame << " " << video.eyes << "\n";
+
+	/* Something has gong wrong if our store gets too big */
+	DCPOMATIC_ASSERT (_store.size() != 8);
+	/* We should only ever see 3D_LEFT / 3D_RIGHT */
+	DCPOMATIC_ASSERT (video.eyes == EYES_LEFT || video.eyes == EYES_RIGHT);
+
+	shared_ptr<Piece> piece = weak_piece.lock ();
+	DCPOMATIC_ASSERT (piece);
+
+	if (!_last) {
+		/* We haven't seen anything since the last clear() so assume everything is OK */
+		Video (weak_piece, video);
+		_last = video;
+		return;
+	}
+
+	_store.push_back (make_pair (weak_piece, video));
+	_store.sort (Comparator());
+
+	while (
+		!_store.empty() &&
+		(
+			(_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.size() > 8
+			)
+		) {
+
+		std::cout << "shuffler emits " << _store.front().second.frame << " " << _store.front().second.eyes << "\n";
+		Video (_store.front().first, _store.front().second);
+		_last = _store.front().second;
+		_store.pop_front ();
+	}
+}
+
+void
+Shuffler::clear ()
+{
+	_last = optional<ContentVideo>();
+}
+
+void
+Shuffler::flush ()
+{
+	BOOST_FOREACH (Store i, _store) {
+		Video (i.first, i.second);
+	}
+}