New way of checking for 2D content mislabelled as 3D (#1565).

[dcpomatic.git] / src / lib / frame_interval_checker.cc

diff --git a/src/lib/frame_interval_checker.cc b/src/lib/frame_interval_checker.cc
new file mode 100644 (file)
index 0000000..0569730
--- /dev/null
+++ b/src/lib/frame_interval_checker.cc
@@ -0,0 +1,65 @@
+/*
+    Copyright (C) 2020 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 "frame_interval_checker.h"
+#include <iostream>
+
+int const FrameIntervalChecker::_frames = 16;
+
+void
+FrameIntervalChecker::feed (ContentTime time, double frame_rate)
+{
+       /* The caller isn't meant to feed too much data before
+          calling guess() and destroying the FrameIntervalChecker.
+        */
+       DCPOMATIC_ASSERT (_intervals.size() < _frames);
+
+       if (_last) {
+               _intervals.push_back ((time - *_last).seconds() * frame_rate);
+       }
+
+       _last = time;
+}
+
+FrameIntervalChecker::Guess
+FrameIntervalChecker::guess () const
+{
+       if (_intervals.size() < _frames) {
+               /* How soon can you land?
+                * I can't tell.
+                * You can tell me, I'm a doctor.
+                * Nom I mean I'm just not sure.
+                * Can't you take a guess?
+                * Well, not for another two hours.
+                * You can't take a guess for another two hours?
+                */
+               return AGAIN;
+       }
+
+       int near_1 = 0;
+       BOOST_FOREACH (double i, _intervals) {
+               if (i > 0.5) {
+                       ++near_1;
+               }
+       }
+
+       return (near_1 < 3 * _frames / 4) ? PROBABLY_3D : PROBABLY_NOT_3D;
+}
+