1 files changed, 99 insertions, 0 deletions
diff --git a/src/lib/subtitle_sync_packet_queue.cc b/src/lib/subtitle_sync_packet_queue.cc
new file mode 100644
index 000000000..6a96924df
--- /dev/null
+++ b/src/lib/subtitle_sync_packet_queue.cc
@@ -0,0 +1,99 @@
+/*
+    Copyright (C) 2026 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 "dcpomatic_log.h"
+#include "subtitle_sync_packet_queue.h"
+extern "C" {
+#include <libavcodec/packet.h>
+#include <libavutil/avutil.h>
+}
+#include <iostream>
+
+
+using boost::optional;
+
+
+void
+SubtitleSyncPacketQueue::add(AVPacket* packet, Type type)
+{
+	switch (type) {
+	case Type::VIDEO:
+		++_num_video;
+		_other.push_back({packet, type});
+		break;
+	case Type::AUDIO:
+		_other.push_back({packet, type});
+		break;
+	case Type::DROP:
+		_other.push_back({PacketInfo(packet), type});
+		av_packet_free(&packet);
+		break;
+	case Type::SUBTITLE:
+		_subtitle.push_back(packet);
+		break;
+	}
+}
+
+
+optional<std::pair<PacketQueue::Packet, PacketQueue::Type>>
+SubtitleSyncPacketQueue::get(bool flushing)
+{
+	if (!_subtitle.empty()) {
+		/* Any subtitle packets we have get returned first */
+		auto packet = _subtitle.front();
+		_subtitle.pop_front();
+		return std::make_pair(Packet(packet), Type::SUBTITLE);
+	}
+
+	if (_other.size() > 4096) {
+		LOG_WARNING("SubtitleSyncPacketQueue is getting large: {} (_num_video={})", _other.size(), _num_video);
+	}
+
+	if ((!flushing && _num_video < 48 && _other.size() < 8192) || _other.empty()) {
+		/* We haven't queued up enough video yet, or we don't have anything */
+		return boost::none;
+	}
+
+	auto packet = _other.front();
+	if (packet.second == Type::VIDEO) {
+		--_num_video;
+	}
+	_other.pop_front();
+	return packet;
+}
+
+
+void
+SubtitleSyncPacketQueue::clear()
+{
+	for (auto i: _other) {
+		if (auto packet = boost::get<AVPacket*>(&i.first)) {
+			av_packet_free(packet);
+		}
+	}
+	for (auto i: _subtitle) {
+		av_packet_free(&i);
+	}
+	_other.clear();
+	_subtitle.clear();
+	_num_video = 0;
+}
+