implemented core subtitle support

app/node/block/subtitle/subtitle.cpp

@@ -0,0 +1,62 @@
+/***
+
+  Olive - Non-Linear Video Editor
+  Copyright (C) 2021 Olive Team
+
+  This program 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 3 of the License, or
+  (at your option) any later version.
+
+  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+***/
+
+#include "subtitle.h"
+
+namespace olive {
+
+#define super ClipBlock
+
+const QString SubtitleBlock::kTextIn = QStringLiteral("text_in");
+
+SubtitleBlock::SubtitleBlock() :
+  super(false)
+{
+  AddInput(kTextIn, NodeValue::kText, InputFlags(kInputFlagNotConnectable | kInputFlagNotKeyframable));
+}
+
+Node *SubtitleBlock::copy() const
+{
+  return new SubtitleBlock();
+}
+
+QString SubtitleBlock::Name() const
+{
+  return tr("Subtitle");
+}
+
+QString SubtitleBlock::id() const
+{
+  return QStringLiteral("org.olivevideoeditor.Olive.subtitle");
+}
+
+QString SubtitleBlock::Description() const
+{
+  return tr("A time-based node representing a single subtitle element for a certain period of time.");
+}
+
+void SubtitleBlock::Retranslate()
+{
+  super::Retranslate();
+
+  SetInputName(kTextIn, tr("Text"));
+}
+
+}