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fix linked midi-regions on different tracks #6541

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A somewhat hacky solution to address missing note-off events when a
linked midi-region is used on separate tracks at the same time.
see the source-code comment for further info.
This commit is contained in:
Robin Gareus 2015-08-25 03:48:54 +02:00
parent 53d51ac406
commit 1387e756de
1 changed files with 38 additions and 0 deletions
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38
libs/ardour/midi_source.cc
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@ -205,6 +205,7 @@ MidiSource::midi_read (const Lock& lm,
Evoral::Sequence<Evoral::Beats>::const_iterator& i = _model_iter;
const bool linear_read = _last_read_end != 0 && start == _last_read_end;
if (!linear_read || !_model_iter_valid) {
#if 0
// Cached iterator is invalid, search for the first event past start
i = _model->begin(converter.from(start), false, filtered,
linear_read ? &_model->active_notes() : NULL);
@ -212,6 +213,43 @@ MidiSource::midi_read (const Lock& lm,
if (!linear_read) {
_model->active_notes().clear();
}
#else
/* hot-fix http://tracker.ardour.org/view.php?id=6541
* "parallel playback of linked midi regions -> no note-offs"
*
* A midi source can be used by multiple tracks simultaneously,
* in which case midi_read() can called from different tracks for
* overlapping time-ranges.
*
* However there is only a single iterator for a given midi-source.
* this results in every midi_read() performing a seek.
*
* if seeking is performed with
* _model->begin(converter.from(start),...)
* the model is used for seeking. That method seeks to the first
* *note-on* event after 'start'.
*
* _model->begin(conveter.from( ) ,..) eventually calls
* Sequence<Time>::const_iterator() in libs/evoral/src/Sequence.cpp
* which looks up the note-event via seq.note_lower_bound(t);
* but the sequence 'seq' only contains note-on events(!).
* note-off events are implicit in Sequence<Time>::operator++()
* via _active_notes.pop(); and not part of seq.
*
* see also http://tracker.ardour.org/view.php?id=6287#c16671
* and call 1-900-ardour-midi ($4.99/min)
*
* The linear search below assures that reading starts at the first
* event for the given time, regardless of its event-type.
*/
for (i = _model->begin(); i != _model->end(); ++i) {
const framecnt_t time_frames = converter.to(i->time());
if (time_frames >= start) {
break;
}
}
_model_iter_valid = true;
#endif
}
_last_read_end = start + cnt;