Immediate-event/out-of-band injection update & tweak clearing buffers

Immediate events are used for MIDI-Panic and to inject GUI generated
events e.g. patch-changes, note-events from the track-header
(scroomer-keyboard) and patch-change audition.

Current behavior:

- snapshot copy immediate events from ringbuffer into a buffer at
  the beginning of each the cycle.
- Inject immediate events into input-buffer directly after reading the input
- process "normally"
- pass immediate event-buffer to disk-writer, so it can skip them
  (don't write immediate events to disk)
- if the Route is not monitoring input: clear buffer before disk-reader
  and re-inject (original) immediate events after the disk-reader
- immediate events process normally and are also sent to outputs.

4 files changed, 79 insertions, 34 deletions

diff --git a/libs/ardour/ardour/midi_track.h b/libs/ardour/ardour/midi_track.h
index dfd5a42d13..93856282c4 100644
--- a/libs/ardour/ardour/midi_track.h
+++ b/libs/ardour/ardour/midi_track.h
@@ -126,6 +126,8 @@ public:
 
 	MonitorState monitoring_state () const;
 
+	MidiBuffer const& immediate_event_buffer () const { return _immediate_event_buffer; }
+
 	void set_input_active (bool);
 	bool input_active () const;
 	PBD::Signal0<void> InputActiveChanged;
@@ -136,16 +138,19 @@ protected:
 	void act_on_mute ();
 	void monitoring_changed (bool, PBD::Controllable::GroupControlDisposition);
 
+	void snapshot_out_of_band_data (samplecnt_t nframes);
+	void write_out_of_band_data (BufferSet& bufs, samplecnt_t /* nframes */) const;
+
+
 private:
 	MidiRingBuffer<samplepos_t> _immediate_events;
+	MidiBuffer                  _immediate_event_buffer;
 	MidiRingBuffer<samplepos_t> _step_edit_ring_buffer;
-	NoteMode                   _note_mode;
-	bool                       _step_editing;
-	bool                       _input_active;
-	MidiChannelFilter          _playback_filter;
-	MidiChannelFilter          _capture_filter;
-
-	void write_out_of_band_data (BufferSet& bufs, samplepos_t start_sample, samplepos_t end_sample, samplecnt_t nframes);
+	NoteMode                    _note_mode;
+	bool                        _step_editing;
+	bool                        _input_active;
+	MidiChannelFilter           _playback_filter;
+	MidiChannelFilter           _capture_filter;
 
 	void set_state_part_two ();
 	void set_state_part_three ();
@@ -157,7 +162,7 @@ private:
 	void map_input_active (bool);
 
 	/** Update automation controls to reflect any changes in buffers. */
-	void update_controls (const BufferSet& bufs);
+	void update_controls (BufferSet const& bufs);
 	void restore_controls ();
 };
 
diff --git a/libs/ardour/ardour/route.h b/libs/ardour/ardour/route.h
index 1437fd79ed..830ef4bab3 100644
--- a/libs/ardour/ardour/route.h
+++ b/libs/ardour/ardour/route.h
@@ -597,7 +597,9 @@ protected:
 
 	virtual int no_roll_unlocked (pframes_t nframes, samplepos_t start_sample, samplepos_t end_sample, bool session_state_changing);
 
-	virtual void write_out_of_band_data (BufferSet& /* bufs */, samplepos_t /* start_sample */, samplepos_t /* end_sample */, samplecnt_t /* nframes */) {}
+	virtual void snapshot_out_of_band_data (samplecnt_t /* nframes */) {}
+	virtual void write_out_of_band_data (BufferSet&, samplecnt_t /* nframes */) const {}
+	virtual void update_controls (BufferSet const&) {}
 
 	void process_output_buffers (BufferSet& bufs,
 	                             samplepos_t start_sample, samplepos_t end_sample,
diff --git a/libs/ardour/midi_track.cc b/libs/ardour/midi_track.cc
index 2e5fd2a0b4..20faa80bc8 100644
--- a/libs/ardour/midi_track.cc
+++ b/libs/ardour/midi_track.cc
@@ -73,6 +73,7 @@ using namespace PBD;
 MidiTrack::MidiTrack (Session& sess, string name, TrackMode mode)
 	: Track (sess, name, PresentationInfo::MidiTrack, mode, DataType::MIDI)
 	, _immediate_events(6096) // FIXME: size?
+	, _immediate_event_buffer(6096)
 	, _step_edit_ring_buffer(64) // FIXME: size?
 	, _note_mode (Sustained)
 	, _step_editing (false)
@@ -303,16 +304,19 @@ MidiTrack::restore_controls ()
 }
 
 void
-MidiTrack::update_controls(const BufferSet& bufs)
+MidiTrack::update_controls (BufferSet const& bufs)
 {
 	const MidiBuffer& buf = bufs.get_midi(0);
 	for (MidiBuffer::const_iterator e = buf.begin(); e != buf.end(); ++e) {
-		const Evoral::Event<samplepos_t>&         ev      = *e;
+		const Evoral::Event<samplepos_t>&         ev     = *e;
 		const Evoral::Parameter                  param   = midi_parameter(ev.buffer(), ev.size());
 		const boost::shared_ptr<AutomationControl> control = automation_control (param);
 		if (control) {
-			control->set_double(ev.value(), _session.transport_sample(), false);
-			control->Changed (false, Controllable::NoGroup);
+			double old = control->get_double (false, 0);
+			control->set_double (ev.value(), 0, false);
+			if (old != ev.value()) {
+				control->Changed (false, Controllable::NoGroup);
+			}
 		}
 	}
 }
@@ -416,30 +420,35 @@ MidiTrack::push_midi_input_to_step_edit_ringbuffer (samplecnt_t nframes)
 }
 
 void
-MidiTrack::write_out_of_band_data (BufferSet& bufs, samplepos_t /*start*/, samplepos_t /*end*/, samplecnt_t nframes)
+MidiTrack::snapshot_out_of_band_data (samplecnt_t nframes)
 {
-	MidiBuffer& buf (bufs.get_midi (0));
-
-	update_controls (bufs);
+	_immediate_event_buffer.clear ();
+	if (0 == _immediate_events.read_space()) {
+		return;
+	}
 
-	// Append immediate events
+	assert (nframes > 0);
 
-	if (_immediate_events.read_space()) {
+	DEBUG_TRACE (DEBUG::MidiIO, string_compose ("%1 has %2 of immediate events to deliver\n",
+				name(), _immediate_events.read_space()));
 
-		DEBUG_TRACE (DEBUG::MidiIO, string_compose ("%1 has %2 of immediate events to deliver\n",
-		                                            name(), _immediate_events.read_space()));
+	/* write as many of the immediate events as we can, but give "true" as
+	 * the last argument ("stop on overflow in destination") so that we'll
+	 * ship the rest out next time.
+	 *
+	 * the Port::port_offset() + (nframes-1) argument puts all these events at the last
+	 * possible position of the output buffer, so that we do not
+	 * violate monotonicity when writing. Port::port_offset() will
+	 * be non-zero if we're in a split process cycle.
+	 */
+	_immediate_events.read (_immediate_event_buffer, 0, 1, Port::port_offset() + nframes - 1, true);
+}
 
-		/* write as many of the immediate events as we can, but give "true" as
-		 * the last argument ("stop on overflow in destination") so that we'll
-		 * ship the rest out next time.
-		 *
-		 * the Port::port_offset() + (nframes-1) argument puts all these events at the last
-		 * possible position of the output buffer, so that we do not
-		 * violate monotonicity when writing. Port::port_offset() will
-		 * be non-zero if we're in a split process cycle.
-		 */
-		_immediate_events.read (buf, 0, 1, Port::port_offset() + nframes - 1, true);
-	}
+void
+MidiTrack::write_out_of_band_data (BufferSet& bufs, samplecnt_t nframes) const
+{
+	MidiBuffer& buf (bufs.get_midi (0));
+	buf.merge_from (_immediate_event_buffer, nframes);
 }
 
 int
diff --git a/libs/ardour/route.cc b/libs/ardour/route.cc
index 0f8c892b24..236f2d7c0c 100644
--- a/libs/ardour/route.cc
+++ b/libs/ardour/route.cc
@@ -402,7 +402,8 @@ Route::process_output_buffers (BufferSet& bufs,
 	 * Also during remaining_latency_preroll, transport_rolling () is false, but
 	 * we may need to monitor disk instead.
 	 */
-	bool silence = _have_internal_generator ? false : (monitoring_state () == MonitoringSilence);
+	MonitorState ms = monitoring_state ();
+	bool silence = _have_internal_generator ? false : (ms == MonitoringSilence);
 
 	_main_outs->no_outs_cuz_we_no_monitor (silence);
 
@@ -524,6 +525,24 @@ Route::process_output_buffers (BufferSet& bufs,
 					/* input->latency() + */ latency, /* output->latency() + */ playback_latency);
 		}
 
+		bool re_inject_oob_data = false;
+		if ((*i) == _disk_reader) {
+			/* Well now, we've made it past the disk-writer and to the disk-reader.
+			 * Time to decide what to do about monitoring.
+			 *
+			 * Even when not doing MonitoringDisk, we need to run the processors,
+			 * so that it advances its internal buffers (IFF run_disk_reader is true).
+			 *
+			 */
+			if (ms == MonitoringDisk || ms == MonitoringSilence) {
+				/* this will clear out-of-band data, too (e.g. MIDI-PC, Panic etc.
+				 * OOB data is written at the end of the cycle (nframes - 1),
+				 * and jack does not re-order events, so we push them back later */
+				re_inject_oob_data = true;
+				bufs.silence (nframes, 0);
+			}
+		}
+
 		double pspeed = speed;
 		if ((!run_disk_reader && (*i) == _disk_reader) || (!run_disk_writer && (*i) == _disk_writer)) {
 			/* run with speed 0, no-roll */
@@ -531,6 +550,7 @@ Route::process_output_buffers (BufferSet& bufs,
 		}
 
 		(*i)->run (bufs, start_sample - latency, end_sample - latency, pspeed, nframes, *i != _processors.back());
+
 		bufs.set_count ((*i)->output_streams());
 
 		/* Note: plugin latency may change. While the plugin does inform the session via
@@ -542,6 +562,11 @@ Route::process_output_buffers (BufferSet& bufs,
 		if ((*i)->active ()) {
 			latency += (*i)->signal_latency ();
 		}
+
+		if (re_inject_oob_data) {
+			write_out_of_band_data (bufs, nframes);
+		}
+
 #if 0
 		if ((*i) == _delayline) {
 			latency += _delayline->get_delay ();
@@ -701,14 +726,18 @@ Route::run_route (samplepos_t start_sample, samplepos_t end_sample, pframes_t nf
 		bufs.silence (nframes, 0);
 	}
 
+	snapshot_out_of_band_data (nframes);
 	/* append immediate messages to the first MIDI buffer (thus sending it to the first output port) */
 
-	write_out_of_band_data (bufs, start_sample, end_sample, nframes);
+	write_out_of_band_data (bufs, nframes);
 
 	/* run processor chain */
 
 	process_output_buffers (bufs, start_sample, end_sample, nframes, declick, gain_automation_ok, run_disk_reader);
 
+	/* map events (e.g. MIDI-CC) back to control-parameters */
+	update_controls (bufs);
+
 	flush_processor_buffers_locked (nframes);
 }