Move all beats <-> frames time conversion into a single object that can be passed around.

This has 3 main benefits:
 - All conversion code is in one place (less duplication, potential bugs)
 - The conversion method can be passed to things that are ignorant
   of the actual time units involved, information required, etc.
   (In the future it would be nice to have user selectable tempo/frame time)
 - It should be relatively simple now to support tempo changes part-way
   through a MIDI region (at least architecturally speaking)


git-svn-id: svn://localhost/ardour2/branches/3.0@4594 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 8 insertions, 21 deletions

diff --git a/libs/ardour/smf_source.cc b/libs/ardour/smf_source.cc
index 5fd09ef1bb..ab0c290191 100644
--- a/libs/ardour/smf_source.cc
+++ b/libs/ardour/smf_source.cc
@@ -41,7 +41,6 @@
 #include <ardour/midi_ring_buffer.h>
 #include <ardour/session.h>
 #include <ardour/smf_source.h>
-#include <ardour/tempo.h>
 
 #include "i18n.h"
 
@@ -145,13 +144,7 @@ SMFSource::read_unlocked (MidiRingBuffer<nframes_t>& dst, nframes_t start, nfram
 
 	size_t scratch_size = 0; // keep track of scratch to minimize reallocs
 
-	// FIXME: assumes tempo never changes after start
-	const Tempo& tempo = _session.tempo_map().tempo_at(_timeline_position);
-	const double frames_per_beat = tempo.frames_per_beat(
-			_session.engine().frame_rate(),
-			_session.tempo_map().meter_at(_timeline_position));
-	
-	const uint64_t start_ticks = (uint64_t)((start / frames_per_beat) * ppqn());
+	const uint64_t start_ticks = (uint64_t)(_converter.from(start) * ppqn());
 
 	if (_last_read_end == 0 || start != _last_read_end) {
 		cerr << "SMFSource::read_unlocked seeking to " << start << endl;
@@ -183,8 +176,7 @@ SMFSource::read_unlocked (MidiRingBuffer<nframes_t>& dst, nframes_t start, nfram
 		ev_type = EventTypeMap::instance().midi_event_type(ev_buffer[0]);
 
 		assert(time >= start_ticks);
-		const nframes_t ev_frame_time = (nframes_t)(
-				((time / (double)ppqn()) * frames_per_beat)) + stamp_offset;
+		const nframes_t ev_frame_time = _converter.to(time / (double)ppqn()) + stamp_offset;
 
 		if (ev_frame_time < start + dur) {
 			dst.write(ev_frame_time - negative_stamp_offset, ev_type, ev_size, ev_buffer);
@@ -323,24 +315,19 @@ SMFSource::append_event_unlocked_frames(const Evoral::Event<nframes_t>& ev)
 		return;
 	}
 	
-	// FIXME: assumes tempo never changes after start
-	const Tempo& tempo = _session.tempo_map().tempo_at(_timeline_position);
-	const double frames_per_beat = tempo.frames_per_beat(
-			_session.engine().frame_rate(),
-			_session.tempo_map().meter_at(_timeline_position));
-
-	uint32_t delta_time = (uint32_t)((ev.time() - _last_ev_time_frames)
-			/ frames_per_beat * (double)ppqn());
+	const nframes_t delta_time_frames = ev.time() - _last_ev_time_frames;
+	const double    delta_time_beats  = _converter.from(delta_time_frames);
+	const uint32_t  delta_time_ticks  = (uint32_t)(lrint(delta_time_beats * (double)ppqn()));
 
-	Evoral::SMF::append_event_delta(delta_time, ev.size(), ev.buffer());
+	Evoral::SMF::append_event_delta(delta_time_ticks, ev.size(), ev.buffer());
 	_last_ev_time_frames = ev.time();
 
 	_write_data_count += ev.size();
 
 	if (_model) {
-		double beat_time = ev.time() / frames_per_beat;
+		const double ev_time_beats = _converter.from(ev.time());
 		const Evoral::Event<double> beat_ev(
-				ev.event_type(), beat_time, ev.size(), (uint8_t*)ev.buffer());
+				ev.event_type(), ev_time_beats, ev.size(), (uint8_t*)ev.buffer());
 		_model->append(beat_ev);
 	}
 }