Support FCP XML files containing subtitles (#2909).

1 files changed, 105 insertions, 0 deletions

diff --git a/src/lib/fcpxml_decoder.cc b/src/lib/fcpxml_decoder.cc
new file mode 100644
index 000000000..edb19e639
--- /dev/null
+++ b/src/lib/fcpxml_decoder.cc
@@ -0,0 +1,105 @@
+/*
+    Copyright (C) 2024 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 "fcpxml_content.h"
+#include "fcpxml_decoder.h"
+#include "ffmpeg_image_proxy.h"
+#include "guess_crop.h"
+#include "image.h"
+#include "rect.h"
+#include "text_decoder.h"
+#include <dcp/array_data.h>
+
+
+
+using std::make_shared;
+using std::shared_ptr;
+using std::weak_ptr;
+
+
+FCPXMLDecoder::FCPXMLDecoder(weak_ptr<const Film> film, shared_ptr<const FCPXMLContent> content)
+	: Decoder(film)
+	, _fcpxml_content(content)
+	, _sequence(dcpomatic::fcpxml::load(content->path(0)))
+{
+	text.push_back(make_shared<TextDecoder>(this, content->only_text()));
+	update_position();
+}
+
+
+bool
+FCPXMLDecoder::pass()
+{
+	if (_next >= static_cast<int>(_sequence.video.size())) {
+		return true;
+	}
+
+	auto const png_data = dcp::ArrayData(_sequence.parent / _sequence.video[_next].source);
+	auto const full_image = FFmpegImageProxy(png_data).image(Image::Alignment::PADDED).image;
+	auto const crop = guess_crop_by_alpha(full_image);
+	auto const cropped_image = full_image->crop(crop);
+
+	auto rectangle = dcpomatic::Rect<double>{
+		static_cast<double>(crop.left) / full_image->size().width,
+		static_cast<double>(crop.top) / full_image->size().height,
+		static_cast<double>(cropped_image->size().width) / full_image->size().width,
+		static_cast<double>(cropped_image->size().height) / full_image->size().height
+	};
+
+	only_text()->emit_bitmap(_sequence.video[_next].period, cropped_image, rectangle);
+
+	++_next;
+
+	update_position();
+	return false;
+}
+
+
+void
+FCPXMLDecoder::seek(dcpomatic::ContentTime time, bool accurate)
+{
+	/* It's worth back-tracking a little here as decoding is cheap and it's nice if we don't miss
+	   too many subtitles when seeking.
+	*/
+	time -= dcpomatic::ContentTime::from_seconds(5);
+	if (time < dcpomatic::ContentTime()) {
+		time = {};
+	}
+
+	Decoder::seek(time, accurate);
+
+	_next = 0;
+	while (_next < static_cast<int>(_sequence.video.size()) && _sequence.video[_next].period.from < time) {
+		++_next;
+	}
+
+	update_position();
+}
+
+
+void
+FCPXMLDecoder::update_position()
+{
+	if (_next < static_cast<int>(_sequence.video.size())) {
+		only_text()->maybe_set_position(_sequence.video[_next].period.from);
+	}
+}
+