Bootstrap MIDI export writer

This leans on the AudioGrapher API for IdentityVertex.

libs/ardour/ardour/export_smf_writer.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2022 Robin Gareus <robin@gareus.org>
+ *
+ * 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.
+ */
+
+#ifndef _libardour_export_smf_writer_h_
+#define _libardour_export_smf_writer_h_
+
+#include <boost/shared_ptr.hpp>
+
+#include "evoral/SMF.h"
+
+#include "ardour/libardour_visibility.h"
+#include "ardour/midi_state_tracker.h"
+#include "ardour/types.h"
+
+namespace ARDOUR
+{
+class MidiBuffer;
+
+class LIBARDOUR_API ExportSMFWriter : Evoral::SMF
+{
+public:
+	ExportSMFWriter ();
+	~ExportSMFWriter ();
+
+	int init (std::string const& path, samplepos_t);
+
+	void process (MidiBuffer const&, sampleoffset_t, samplecnt_t, bool);
+
+private:
+	std::string      _path;
+	samplepos_t      _pos;
+	samplepos_t      _last_ev_time_samples;
+	samplepos_t      _timespan_start;
+	MidiStateTracker _tracker;
+};
+
+} // namespace ARDOUR
+
+#endif

libs/ardour/export_smf_writer.cc

@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2022 Robin Gareus <robin@gareus.org>
+ *
+ * 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 <glib/gstdio.h>
+
+#include "ardour/export_smf_writer.h"
+#include "ardour/midi_buffer.h"
+#include "temporal/tempo.h"
+
+using namespace ARDOUR;
+using namespace Evoral;
+
+ExportSMFWriter::ExportSMFWriter ()
+	: _pos (0)
+	, _last_ev_time_samples (0)
+{
+}
+
+ExportSMFWriter::~ExportSMFWriter ()
+{
+	if (!_path.empty ()) {
+		end_write (_path);
+		SMF::close ();
+	}
+}
+
+int
+ExportSMFWriter::init (std::string const& path, samplepos_t timespan_start)
+{
+	::g_unlink (path.c_str ());
+	if (SMF::create (path)) {
+		return -1;
+	}
+	_path                 = path;
+	_pos                  = 0;
+	_last_ev_time_samples = 0;
+	_timespan_start       = timespan_start;
+	_tracker.reset ();
+	SMF::begin_write ();
+	return 0;
+}
+
+void
+ExportSMFWriter::process (MidiBuffer const& buf, sampleoffset_t off, samplecnt_t n_samples, bool last_cycle)
+{
+	if (_path.empty ()) {
+		return;
+	}
+	for (MidiBuffer::const_iterator i = buf.begin (); i != buf.end (); ++i) {
+		Evoral::Event<samplepos_t> ev (*i, false);
+		if (ev.time () < off) {
+			continue;
+		}
+
+		samplepos_t pos = _pos + ev.time () - off;
+		assert (pos >= _last_ev_time_samples);
+
+		const timepos_t       t1 (pos + _timespan_start);
+		const timepos_t       t0 (_last_ev_time_samples + _timespan_start);
+		const Temporal::Beats delta_time_beats = t1.beats () - t0.beats ();
+		const uint32_t        delta_time_ticks = delta_time_beats.to_ticks (ppqn ());
+		//std::cout << "Timespan off: " << _timespan_start << " export pos: " << _pos << " event at" << pos << " beat: " << delta_time_beats << " ticks: " << delta_time_ticks << "\n";
+
+		_tracker.track (ev.buffer ());
+
+		SMF::append_event_delta (delta_time_ticks, ev.size (), ev.buffer (), 0);
+		_last_ev_time_samples = pos;
+	}
+
+	if (last_cycle) {
+		MidiBuffer mb (8192);
+		_tracker.resolve_notes (mb, n_samples);
+		process (mb, 0, n_samples, false);
+		end_write (_path);
+		SMF::close ();
+		_path.clear ();
+	} else {
+		_pos += n_samples;
+	}
+}

libs/ardour/wscript

@@ -91,6 +91,7 @@ libardour_sources = [
         'export_handler.cc',
         'export_preset.cc',
         'export_profile_manager.cc',
+        'export_smf_writer.cc',
         'export_status.cc',
         'export_timespan.cc',
         'ffmpegfileimportable.cc',