1 files changed, 127 insertions, 0 deletions
diff --git a/src/lib/level_calculator.cc b/src/lib/level_calculator.cc
new file mode 100644
index 000000000..0563d4ed8
--- /dev/null
+++ b/src/lib/level_calculator.cc
@@ -0,0 +1,127 @@
+/*
+    Copyright (C) 2025 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 "audio_buffers.h"
+#include "level_calculator.h"
+
+
+using std::make_pair;
+using std::shared_ptr;
+using boost::optional;
+
+
+constexpr int frames_per_measurement = 48000 / 30;
+
+
+LevelCalculator::LevelCalculator()
+	: _enabled(false)
+{
+
+}
+
+
+void
+LevelCalculator::put(shared_ptr<const AudioBuffers> audio, dcpomatic::DCPTime time, int frame_rate)
+{
+	if (!_enabled) {
+		std::cout << "no calcs for me.\n";
+		return;
+	}
+
+	boost::mutex::scoped_lock lm(_current_mutex);
+
+	auto const channels = audio->channels();
+
+	if (static_cast<int>(_current_peaks.size()) != channels) {
+		_current_peaks.resize(channels);
+	}
+
+	auto const data = audio->data();
+	auto const frames = audio->frames();
+	for (auto frame = 0; frame < frames; ++frame) {
+		for (auto channel = 0; channel < channels; ++channel) {
+			_current_peaks[channel] = std::max(std::abs(data[channel][frame]), _current_peaks[channel]);
+		}
+
+		++_current_frames;
+		if (_current_frames == frames_per_measurement) {
+			{
+				boost::mutex::scoped_lock lm(_store_mutex);
+				_peaks.emplace_back(time + dcpomatic::DCPTime::from_frames(frame, frame_rate), _current_peaks);
+			}
+			std::fill(_current_peaks.begin(), _current_peaks.end(), 0.0f);
+			_current_frames = 0;
+		}
+	}
+
+}
+
+
+void
+LevelCalculator::clear()
+{
+	boost::mutex::scoped_lock slm(_store_mutex);
+	_peaks.clear();
+
+	boost::mutex::scoped_lock clm(_current_mutex);
+	std::fill(_current_peaks.begin(), _current_peaks.end(), 0.0f);
+	_current_frames = 0;
+}
+
+
+std::vector<float>
+LevelCalculator::get(dcpomatic::DCPTime time)
+{
+	boost::mutex::scoped_lock slm(_store_mutex);
+
+	auto iter = _peaks.begin();
+	optional<dcpomatic::DCPTime> last_delta;
+	std::list<Measurement>::iterator last_iter;
+	while (iter != _peaks.end()) {
+		auto const delta = dcpomatic::DCPTime(time - iter->time).abs();
+		if (last_delta) {
+			if (delta > *last_delta) {
+				/* This is worse than the last - use the last one */
+				return last_iter->value;
+			} else {
+				/* This is better - keep looking */
+				_peaks.erase(last_iter);
+			}
+		}
+		last_delta = delta;
+		last_iter = iter;
+		++iter;
+	}
+
+	if (iter == _peaks.end()) {
+		return {};
+	}
+
+	return iter->value;
+}
+
+
+void
+LevelCalculator::enable(bool e)
+{
+	_enabled = e;
+}
+