2 Copyright (C) 2008 Paul Davis
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 #include <sys/types.h>
25 #include "pbd/error.h"
26 #include "pbd/failed_constructor.h"
27 #include "pbd/pthread_utils.h"
28 #include "pbd/convert.h"
30 #include "midi++/port.h"
32 #include "ardour/audioengine.h"
33 #include "ardour/debug.h"
34 #include "ardour/midi_buffer.h"
35 #include "ardour/midi_port.h"
36 #include "ardour/session.h"
37 #include "ardour/tempo.h"
38 #include "ardour/transport_master.h"
43 using namespace ARDOUR;
47 #define ENGINE AudioEngine::instance()
49 MIDIClock_TransportMaster::MIDIClock_TransportMaster (std::string const & name, int ppqn)
50 : TransportMaster (MIDIClock, name)
52 , midi_clock_count (0)
56 if ((_port = create_midi_port (string_compose ("%1 in", name))) == 0) {
57 throw failed_constructor();
61 MIDIClock_TransportMaster::~MIDIClock_TransportMaster()
63 port_connections.drop_connections ();
67 MIDIClock_TransportMaster::init ()
74 MIDIClock_TransportMaster::set_session (Session *session)
76 port_connections.drop_connections();
79 /* only connect to signals if we have a proxy, because otherwise we
80 * cannot interpet incoming data (no tempo map etc.)
84 parser.timing.connect_same_thread (port_connections, boost::bind (&MIDIClock_TransportMaster::update_midi_clock, this, _1, _2));
85 parser.start.connect_same_thread (port_connections, boost::bind (&MIDIClock_TransportMaster::start, this, _1, _2));
86 parser.contineu.connect_same_thread (port_connections, boost::bind (&MIDIClock_TransportMaster::contineu, this, _1, _2));
87 parser.stop.connect_same_thread (port_connections, boost::bind (&MIDIClock_TransportMaster::stop, this, _1, _2));
88 parser.position.connect_same_thread (port_connections, boost::bind (&MIDIClock_TransportMaster::position, this, _1, _2, _3, _4));
95 MIDIClock_TransportMaster::pre_process (MIDI::pframes_t nframes, samplepos_t now, boost::optional<samplepos_t> session_pos)
97 /* Read and parse incoming MIDI */
99 DEBUG_TRACE (DEBUG::MidiClock, string_compose ("preprocess with lt = %1 @ %2, running ? %3\n", current.timestamp, now, _running));
101 _midi_port->read_and_parse_entire_midi_buffer_with_no_speed_adjustment (nframes, parser, now);
103 /* no clock messages ever, or no clock messages for 1/4 second ? conclude that its stopped */
105 if (!last_timestamp || (now > last_timestamp && ((now - last_timestamp) > (ENGINE->sample_rate() / 4)))) {
106 current.update (current.position, 0, 0);
110 midi_clock_count = 0;
112 DEBUG_TRACE (DEBUG::MidiClock, "No MIDI Clock messages received for some time, stopping!\n");
116 if (!_running && midi_clock_count == 0 && session_pos) {
117 current.update (*session_pos, now, current.speed);
118 DEBUG_TRACE (DEBUG::MidiClock, string_compose ("set sbp to %1\n", current.position));
122 const samplepos_t current_pos = current.position + ((now - current.timestamp) * current.speed);
123 _current_delta = current_pos - *session_pos;
128 DEBUG_TRACE (DEBUG::MidiClock, string_compose ("speed_and_position: speed %1 should-be %2 transport %3 \n", current.speed, current.position, _session->transport_sample()));
132 MIDIClock_TransportMaster::calculate_one_ppqn_in_samples_at(samplepos_t time)
134 const double samples_per_quarter_note = _session->tempo_map().samples_per_quarter_note_at (time, ENGINE->sample_rate());
136 one_ppqn_in_samples = samples_per_quarter_note / double (ppqn);
137 // DEBUG_TRACE (DEBUG::MidiClock, string_compose ("at %1, one ppqn = %2\n", time, one_ppqn_in_samples));
141 MIDIClock_TransportMaster::calculate_song_position(uint16_t song_position_in_sixteenth_notes)
143 samplepos_t song_position_samples = 0;
144 for (uint16_t i = 1; i <= song_position_in_sixteenth_notes; ++i) {
145 // one quarter note contains ppqn pulses, so a sixteenth note is ppqn / 4 pulses
146 calculate_one_ppqn_in_samples_at(song_position_samples);
147 song_position_samples += one_ppqn_in_samples * (samplepos_t)(ppqn / 4);
150 return song_position_samples;
154 MIDIClock_TransportMaster::calculate_filter_coefficients (double qpm)
156 /* Paul says: I don't understand this computation of bandwidth
159 const double bandwidth = 2.0 / qpm;
161 /* Frequency of the clock messages is ENGINE->sample_rate() / * one_ppqn_in_samples, per second or in Hz */
162 const double freq = (double) ENGINE->sample_rate() / one_ppqn_in_samples;
164 const double omega = 2.0 * M_PI * bandwidth / freq;
165 b = 1.4142135623730950488 * omega; // sqrt (2.0) * omega
168 DEBUG_TRACE (DEBUG::MidiClock, string_compose ("DLL coefficients: bw:%1 omega:%2 b:%3 c:%4\n", bandwidth, omega, b, c));
172 MIDIClock_TransportMaster::update_midi_clock (Parser& /*parser*/, samplepos_t timestamp)
174 samplepos_t elapsed_since_start = timestamp - first_timestamp;
177 calculate_one_ppqn_in_samples_at (current.position);
179 DEBUG_TRACE (DEBUG::MidiClock, string_compose ("clock count %1, sbp %2\n", midi_clock_count, current.position));
181 if (midi_clock_count == 0) {
182 /* second 0xf8 message after start/reset has arrived */
184 first_timestamp = timestamp;
185 current.update (0, timestamp, 0);
187 DEBUG_TRACE (DEBUG::MidiClock, string_compose ("first clock message after start received @ %1\n", timestamp));
191 current.position += one_ppqn_in_samples;
193 } else if (midi_clock_count == 1) {
195 /* second 0xf8 message has arrived. we can now estimate QPM
196 * (quarters per minute, and fully initialize the DLL
199 e = timestamp - last_timestamp;
201 const samplecnt_t samples_per_quarter = e * 24;
202 _bpm = (ENGINE->sample_rate() * 60.0) / samples_per_quarter;
204 calculate_filter_coefficients (_bpm);
206 /* finish DLL initialization */
210 t1 = t0 + e2; /* timestamp we predict for the next 0xf8 clock message */
213 current.update (one_ppqn_in_samples, timestamp, 0);
217 /* 3rd or later MIDI clock message. We can now compute actual
218 * speed (and tempo) with the DLL
221 e = timestamp - t1; // error between actual time of arrival of clock message and our predicted time
226 const double samples_per_quarter = (timestamp - last_timestamp) * 24.0;
227 const double instantaneous_bpm = (ENGINE->sample_rate() * 60.0) / samples_per_quarter;
228 const double lpf_coeff = 0.05;
230 const double predicted_clock_interval_in_samples = (t1 - t0);
232 /* _speed is relative to session tempo map */
234 double speed = predicted_clock_interval_in_samples / one_ppqn_in_samples;
236 /* _bpm (really, _qpm) is absolute */
238 /* detect substantial changes in apparent tempo (defined as a
239 * change of more than 20% of the current tempo.
242 if (fabs (instantaneous_bpm - _bpm) > (0.20 * _bpm)) {
243 _bpm = instantaneous_bpm;
245 _bpm += lpf_coeff * (instantaneous_bpm - _bpm);
248 calculate_filter_coefficients (_bpm);
250 // need at least two clock events to compute speed
253 DEBUG_TRACE (DEBUG::MidiClock, string_compose ("start mclock running with speed = %1\n", (t1 - t0) / one_ppqn_in_samples));
258 current.update (current.position + one_ppqn_in_samples, timestamp, speed);
261 DEBUG_TRACE (DEBUG::MidiClock, string_compose ("clock #%1 @ %2 should-be %3 transport %4 error %5 appspeed %6 "
262 "read-delta %7 should-be delta %8 t1-t0 %9 t0 %10 t1 %11 framerate %12 engine %13 running %14\n",
263 midi_clock_count, // #
264 elapsed_since_start, // @
265 current.position, // should-be
266 _session->transport_sample(), // transport
268 (t1 - t0) / one_ppqn_in_samples, // appspeed
269 timestamp - last_timestamp, // read delta
270 one_ppqn_in_samples, // should-be delta
274 ENGINE->sample_rate(), // framerate
275 ENGINE->sample_time(),
280 last_timestamp = timestamp;
284 MIDIClock_TransportMaster::start (Parser& /*parser*/, samplepos_t timestamp)
286 DEBUG_TRACE (DEBUG::MidiClock, string_compose ("MIDIClock_TransportMaster got start message at time %1 engine time %2 transport_sample %3\n", timestamp, ENGINE->sample_time(), _session->transport_sample()));
291 current.update (_session->transport_sample(), timestamp, 0);
296 MIDIClock_TransportMaster::reset ()
298 DEBUG_TRACE (DEBUG::MidiClock, string_compose ("MidiClock Master reset(): calculated filter for period size %2\n", ENGINE->samples_per_cycle()));
300 current.update (_session->transport_sample(), 0, 0);
307 MIDIClock_TransportMaster::contineu (Parser& /*parser*/, samplepos_t /*timestamp*/)
309 DEBUG_TRACE (DEBUG::MidiClock, "MIDIClock_TransportMaster got continue message\n");
315 MIDIClock_TransportMaster::stop (Parser& /*parser*/, samplepos_t timestamp)
317 DEBUG_TRACE (DEBUG::MidiClock, "MIDIClock_TransportMaster got stop message\n");
324 // we need to go back to the last MIDI beat (6 ppqn)
325 // and lets hope the tempo didnt change in the meantime :)
327 // begin at the should be position, because
328 // that is the position of the last MIDI Clock
329 // message and that is probably what the master
330 // expects where we are right now
332 // find out the last MIDI beat: go back #midi_clocks mod 6
333 // and lets hope the tempo didnt change in those last 6 beats :)
334 current.update (current.position - (midi_clock_count % 6) * one_ppqn_in_samples, timestamp, current.speed);
339 MIDIClock_TransportMaster::position (Parser& /*parser*/, MIDI::byte* message, size_t size, samplepos_t timestamp)
341 // we are not supposed to get position messages while we are running
342 // so lets be robust and ignore those
348 MIDI::byte lsb = message[1];
349 MIDI::byte msb = message[2];
350 assert((lsb <= 0x7f) && (msb <= 0x7f));
352 uint16_t position_in_sixteenth_notes = (uint16_t(msb) << 7) | uint16_t(lsb);
353 samplepos_t position_in_samples = calculate_song_position(position_in_sixteenth_notes);
355 DEBUG_TRACE (DEBUG::MidiClock, string_compose ("Song Position: %1 samples: %2\n", position_in_sixteenth_notes, position_in_samples));
357 current.update (position_in_samples, timestamp, current.speed);
361 MIDIClock_TransportMaster::locked () const
367 MIDIClock_TransportMaster::ok() const
373 MIDIClock_TransportMaster::starting() const
379 MIDIClock_TransportMaster::resolution() const
382 return (samplecnt_t) one_ppqn_in_samples * ppqn;
386 MIDIClock_TransportMaster::position_string () const
388 return std::string();
392 MIDIClock_TransportMaster::delta_string() const
395 if (last_timestamp == 0 || starting()) {
396 snprintf(delta, sizeof(delta), "\u2012\u2012\u2012\u2012");
398 snprintf(delta, sizeof(delta), "\u0394<span foreground=\"green\" face=\"monospace\" >%s%s%" PRIi64 "</span>sm",
399 LEADINGZERO(abs(_current_delta)), PLUSMINUS(-_current_delta), abs(_current_delta));
401 return std::string(delta);