oak-editor/engine/task/project/saveotio/saveotio.cpp

/***

  Olive - Non-Linear Video Editor
  Copyright (C) 2022 Olive Team
  Modifications Copyright (C) 2025 mikesolar

  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 "saveotio.h"

#ifdef USE_OTIO

#include <opentimelineio/clip.h>
#include <opentimelineio/externalReference.h>
#include <opentimelineio/gap.h>
#include <opentimelineio/serializableCollection.h>
#include <opentimelineio/serializableObject.h>
#include <opentimelineio/transition.h>

#include "node/block/clip/clip.h"
#include "node/block/gap/gap.h"
#include "node/block/transition/transition.h"
#include "node/project/footage/footage.h"

namespace olive
{

SaveOTIOTask::SaveOTIOTask(Project *project)
	: project_(project)
{
	set_title(tr("Exporting project to OpenTimelineIO"));
}

bool SaveOTIOTask::run()
{
	QVector<Sequence *> sequences =
		project_->root()->list_children_of_type<Sequence>();

	if (sequences.isEmpty()) {
		set_error(tr("Project contains no sequences to export."));
		return false;
	}

	std::vector<OTIO::SerializableObject *> serialized;

	foreach (Sequence *seq, sequences) {
		auto otio_timeline = SerializeTimeline(seq);

		if (otio_timeline) {
			// Append to list
			serialized.push_back(otio_timeline);
		} else {
			// Delete all existing timelines
			foreach (auto s, serialized) {
				s->possibly_delete();
			}

			// Error out of function
			set_error(
				tr("Failed to serialize sequence \"%1\"").arg(seq->get_label()));

			return false;
		}
	}

	OTIO::ErrorStatus es;

	if (serialized.size() == 1) {
		// Serialize timeline on its own
		auto t = serialized.front();
		t->to_json_file(project_->filename().toStdString(), &es);
		t->possibly_delete();
	} else {
		// Serialize all into a SerializableCollection
		auto collection =
			new OTIO::SerializableCollection("Sequences", serialized);
		collection->to_json_file(project_->filename().toStdString(), &es);
		collection->possibly_delete();

		// Delete all existing timelines
		foreach (auto s, serialized) {
			s->possibly_delete();
		}
	}

	return (es.outcome == OTIO::ErrorStatus::Outcome::OK);
}

OTIO::Timeline *SaveOTIOTask::SerializeTimeline(Sequence *sequence)
{
	auto otio_timeline = new OTIO::Timeline(sequence->get_label().toStdString());
	// Retainers clean themselves up when the final user is removed
	OTIO::Timeline::Retainer<OTIO::Timeline> *timeline_retainer =
		new OTIO::Timeline::Retainer<OTIO::Timeline>(otio_timeline);
	// Suppress unused variable warning
	Q_UNUSED(timeline_retainer);

	double rate = sequence->get_video_params().frame_rate().to_double();
	if (qIsNaN(rate)) {
		return nullptr;
	}

	if (!SerializeTrackList(sequence->track_list(Track::k_video), otio_timeline,
							rate) ||
		!SerializeTrackList(sequence->track_list(Track::k_audio), otio_timeline,
							rate)) {
		otio_timeline->possibly_delete();
		return nullptr;
	}

	return otio_timeline;
}

OTIO::Track *SaveOTIOTask::SerializeTrack(Track *track, double sequence_rate,
										  Rational max_track_length)
{
	auto otio_track = new OTIO::Track();

	OTIO::ErrorStatus es;

	switch (track->type()) {
	case Track::k_video:
		otio_track->set_kind("Video");
		break;
	case Track::k_audio:
		otio_track->set_kind("Audio");
		break;
	default:
		qWarning()
			<< "Don't know OTIO track kind for native type" << track->type();
		goto fail;
	}

	foreach (Block *block, track->blocks()) {
		OTIO::Composable *otio_block = nullptr;

		if (dynamic_cast<ClipBlock *>(block)) {
			auto otio_clip = new OTIO::Clip(block->get_label().toStdString());

			otio_clip->set_source_range(
				OTIO::TimeRange(block->in().toRationalTime(sequence_rate),
								block->length().toRationalTime(sequence_rate)));

			QVector<Footage *> media_nodes = block->find_input_nodes<Footage>();
			if (!media_nodes.isEmpty()) {
				OTIO::TimeRange available_range;
				if (otio_track->kind().compare("Video") == 0) {
					// OTIO ExternalReference uses the source clips frame rate (or sample rate) as opposed to
					// the sequences rate
					double source_frame_rate = static_cast<ClipBlock *>(block)
												   ->connected_viewer()
												   ->get_video_params()
												   .frame_rate()
												   .to_double();
					available_range = OTIO::TimeRange(
						OTIO::RationalTime(0, source_frame_rate),
						OTIO::RationalTime(
							media_nodes.first()->get_video_params().duration(),
							source_frame_rate));
				} else if (otio_track->kind().compare("Audio") == 0) {
					available_range = OTIO::TimeRange(
						OTIO::RationalTime(
							0,
							media_nodes.first()->get_audio_params().sample_rate()),
						OTIO::RationalTime(
							media_nodes.first()->get_audio_params().duration(),
							media_nodes.first()->get_audio_params().sample_rate()));
				}
				auto media_ref = new OTIO::ExternalReference(
					media_nodes.first()->filename().toStdString(),
					available_range);
				otio_clip->set_media_reference(media_ref);
			}

			otio_block = otio_clip;
		} else if (dynamic_cast<GapBlock *>(block)) {
			otio_block =
				new OTIO::Gap(OTIO::TimeRange(block->in().toRationalTime(),
											  block->length().toRationalTime()),
							  block->get_label().toStdString());
		} else if (dynamic_cast<TransitionBlock *>(block)) {
			auto otio_transition =
				new OTIO::Transition(block->get_label().toStdString());

			TransitionBlock *our_transition =
				static_cast<TransitionBlock *>(block);

			otio_transition->set_in_offset(
				our_transition->in_offset().toRationalTime());
			otio_transition->set_out_offset(
				our_transition->out_offset().toRationalTime());

			otio_block = new OTIO::Transition();
		}

		if (!otio_block) {
			// We shouldn't ever get here, but catch without crashing if we ever do
			goto fail;
		}

		otio_track->append_child(otio_block, &es);

		if (es.outcome != OTIO::ErrorStatus::Outcome::OK) {
			goto fail;
		}
	}

	// All OTIO tracks must have the same duration so we add a Gap to fill the remaining time
	if (otio_track->duration(&es).to_seconds() < max_track_length.to_double()) {
		double time_left = max_track_length.to_double() -
						   otio_track->duration(&es).to_seconds();

		OTIO::Gap *gap = new OTIO::Gap(OTIO::TimeRange(
			otio_track->duration(&es), OTIO::RationalTime(time_left, 1.0)));
		otio_track->append_child(gap, &es);

		if (es.outcome != OTIO::ErrorStatus::Outcome::OK) {
			goto fail;
		}
	}

	return otio_track;

fail:
	otio_track->possibly_delete();

	return nullptr;
}

bool SaveOTIOTask::SerializeTrackList(TrackList *list,
									  OTIO::Timeline *otio_timeline,
									  double sequence_rate)
{
	OTIO::ErrorStatus es;

	Rational max_track_length = RATIONAL_MIN;

	foreach (Track *track, list->get_tracks()) {
		if (track->track_length() > max_track_length) {
			max_track_length = track->track_length();
		}
	}

	foreach (Track *track, list->get_tracks()) {
		auto otio_track =
			SerializeTrack(track, sequence_rate, max_track_length);

		if (!otio_track) {
			return false;
		}

		otio_timeline->tracks()->append_child(otio_track, &es);

		if (es.outcome != OTIO::ErrorStatus::Outcome::OK) {
			otio_track->possibly_delete();
			return false;
		}
	}

	return true;
}

}

#endif // USE_OTIO