ardour/libs/ardour/midi_stretch.cc

/*
 * Copyright (C) 2008-2015 David Robillard <d@drobilla.net>
 * Copyright (C) 2008-2017 Paul Davis <paul@linuxaudiosystems.com>
 * Copyright (C) 2010 Carl Hetherington <carl@carlh.net>
 *
 * 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 2 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, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "pbd/error.h"

#include "ardour/midi_model.h"
#include "ardour/midi_region.h"
#include "ardour/midi_source.h"
#include "ardour/midi_stretch.h"
#include "ardour/session.h"
#include "ardour/tempo.h"
#include "ardour/types.h"

#include "pbd/i18n.h"

using namespace std;
using namespace ARDOUR;
using namespace PBD;

MidiStretch::MidiStretch (Session& s, const TimeFXRequest& req)
	: Filter (s)
	, _request (req)
{
}

MidiStretch::~MidiStretch ()
{
}

int
MidiStretch::run (boost::shared_ptr<Region> r, Progress*)
{
	SourceList nsrcs;
	char suffix[32];

	boost::shared_ptr<MidiRegion> region = boost::dynamic_pointer_cast<MidiRegion>(r);
	if (!region) {
		return -1;
	}

	const TempoMap& tmap (session.tempo_map ());

	/* Fraction is based on sample-time, while MIDI source
	 * is always using music-time. This matters in case there is
	 * a tempo-ramp. So we need to scale the ratio to music-time */
	const double mtfrac =
		tmap.framewalk_to_qn (region->position (), region->length () * _request.time_fraction).to_double ()
		/
		tmap.framewalk_to_qn (region->position (), region->length ()).to_double ();

	/* the name doesn't need to be super-precise, but allow for 2 fractional
	 * digits just to disambiguate close but not identical stretches.
	 */

	snprintf (suffix, sizeof (suffix), "@%d", (int) floor (mtfrac * 100.0f));

	string new_name = region->name();
	string::size_type at = new_name.find ('@');

	// remove any existing stretch indicator

	if (at != string::npos && at > 2) {
		new_name = new_name.substr (0, at - 1);
	}

	new_name += suffix;

	/* create new sources */

	if (make_new_sources (region, nsrcs, suffix))
		return -1;

	boost::shared_ptr<MidiSource> src = region->midi_source(0);
	{
		Source::Lock lock(src->mutex());
		src->load_model(lock);
	}

	boost::shared_ptr<MidiModel> old_model = src->model();

	boost::shared_ptr<MidiSource> new_src = boost::dynamic_pointer_cast<MidiSource>(nsrcs[0]);
	if (!new_src) {
		error << _("MIDI stretch created non-MIDI source") << endmsg;
		return -1;
	}

	Glib::Threads::Mutex::Lock sl (new_src->mutex ());

	new_src->load_model(sl, true);
	boost::shared_ptr<MidiModel> new_model = new_src->model();
	new_model->start_write();

	const double r_start = tmap.quarter_notes_between_samples (region->position () - region->start (), region->position ());
	const double r_end = r_start + tmap.quarter_notes_between_samples (region->position (), region->position () + region->length ());

#ifdef DEBUG_MIDI_STRETCH
	printf ("stretch start: %f end: %f  [* %f] * %f\n", r_start, r_end, _request.time_fraction, mtfrac);
#endif

	/* Note: pass true into force_discrete for the begin() iterator so that the model doesn't
	 * do interpolation of controller data when we stretch.
	 */
	for (Evoral::Sequence<MidiModel::TimeType>::const_iterator i = old_model->begin (MidiModel::TimeType(), true); i != old_model->end(); ++i) {

		if (i->time() < r_start) {
#ifdef DEBUG_MIDI_STRETCH
			cout << "SKIP EARLY EVENT " << i->time() << "\n";
#endif
			continue;
		}
		if (i->time() > r_end) {
#ifdef DEBUG_MIDI_STRETCH
			cout << "SKIP LATE EVENT " << i->time() << "\n";
			continue;
#else
			break;
#endif
		}

#ifdef DEBUG_MIDI_STRETCH
		cout << "STRETCH " << i->time() << " OFFSET FROM START @ " << r_start << " = " << (i->time() - r_start) << " TO " << (i->time() - r_start) * mtfrac << "\n";
#endif

		const MidiModel::TimeType new_time = (i->time() - r_start) * mtfrac;

		// FIXME: double copy
		Evoral::Event<MidiModel::TimeType> ev(*i, true);
		ev.set_time(new_time);
		new_model->append(ev, Evoral::next_event_id());
	}

	new_model->end_write (Evoral::Sequence<Temporal::Beats>::ResolveStuckNotes);
	new_model->set_edited (true);

	new_src->copy_interpolation_from (src);

	const int ret = finish (region, nsrcs, new_name);

	/* non-musical */
	results[0]->set_start(0);
	results[0]->set_position (r->position ()); // force updates the region's quarter-note position
	results[0]->set_length((samplecnt_t) floor (r->length() * _request.time_fraction), 0);

	return ret;
}