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Fix MIDI Timestretch

* skip notes outside of region-range (source-start, region-length)
* handle tempo-ramps properly, apply map to stretch-fraction
* fix region properties after stretching
  (position needs to be re-set first, to set a midi-region's
   quarter-note position, which is used by the length calc)
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x42 committed Nov 1, 2019
1 parent fe880d9 commit eca27d82189c7509f7d010adad9ed3d83bccbf21
Showing with 48 additions and 7 deletions.
  1. +48 −7 libs/ardour/midi_stretch.cc
@@ -24,6 +24,8 @@
#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"
@@ -53,11 +55,21 @@ MidiStretch::run (boost::shared_ptr<Region> r, Progress*)
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.
*/
* digits just to disambiguate close but not identical stretches.
*/

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

string new_name = region->name();
string::size_type at = new_name.find ('@');
@@ -95,26 +107,55 @@ MidiStretch::run (boost::shared_ptr<Region> r, Progress*)
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) {
const MidiModel::TimeType new_time = i->time() * (double)_request.time_fraction;
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() << " 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>::DeleteStuckNotes);
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;

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