libs/ardour/midi_clock_slave.cc

   1 /*
   2     Copyright (C) 2008 Paul Davis
   3     Author: Hans Baier
   4
   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.
   9
  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.
  14
  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.
  18
  19 */
  20
  21 #include <errno.h>
  22 #include <poll.h>
  23 #include <sys/types.h>
  24 #include <unistd.h>
  25 #include "pbd/error.h"
  26 #include "pbd/failed_constructor.h"
  27 #include "pbd/pthread_utils.h"
  28
  29 #include "midi++/port.h"
  30 #include "midi++/jack.h"
  31 #include "ardour/slave.h"
  32 #include "ardour/session.h"
  33 #include "ardour/audioengine.h"
  34 #include "ardour/cycles.h"
  35 #include "ardour/tempo.h"
  36
  37
  38 #include "i18n.h"
  39
  40 using namespace std;
  41 using namespace ARDOUR;
  42 using namespace sigc;
  43 using namespace MIDI;
  44 using namespace PBD;
  45
  46 MIDIClock_Slave::MIDIClock_Slave (Session& s, MIDI::Port& p, int ppqn)
  47         : ppqn (ppqn)
  48         , bandwidth (30.0 / 60.0) // 1 BpM = 1 / 60 Hz
  49 {
  50         session = (ISlaveSessionProxy *) new SlaveSessionProxy(s);
  51         rebind (p);
  52         reset ();
  53 }
  54
  55 MIDIClock_Slave::MIDIClock_Slave (ISlaveSessionProxy* session_proxy, int ppqn)
  56         : session(session_proxy)
  57         , ppqn (ppqn)
  58         , bandwidth (30.0 / 60.0) // 1 BpM = 1 / 60 Hz
  59 {
  60         session = session_proxy;
  61         reset ();
  62 }
  63
  64 MIDIClock_Slave::~MIDIClock_Slave()
  65 {
  66   delete session;
  67 }
  68
  69 void
  70 MIDIClock_Slave::rebind (MIDI::Port& p)
  71 {
  72         for (vector<sigc::connection>::iterator i = connections.begin(); i != connections.end(); ++i) {
  73                 (*i).disconnect ();
  74         }
  75
  76         port = &p;
  77
  78         #ifdef DEBUG_MIDI_CLOCK
  79                 std::cerr << "MIDIClock_Slave: connecting to port " << port->name() << std::endl;
  80         #endif
  81
  82         connections.push_back (port->input()->timing.connect   (mem_fun (*this, &MIDIClock_Slave::update_midi_clock)));
  83         connections.push_back (port->input()->start.connect    (mem_fun (*this, &MIDIClock_Slave::start)));
  84         connections.push_back (port->input()->contineu.connect (mem_fun (*this, &MIDIClock_Slave::contineu)));
  85         connections.push_back (port->input()->stop.connect     (mem_fun (*this, &MIDIClock_Slave::stop)));
  86         connections.push_back (port->input()->position.connect (mem_fun (*this, &MIDIClock_Slave::position)));
  87 }
  88
  89 void
  90 MIDIClock_Slave::calculate_one_ppqn_in_frames_at(nframes_t time)
  91 {
  92         const Tempo& current_tempo = session->tempo_map().tempo_at(time);
  93         const Meter& current_meter = session->tempo_map().meter_at(time);
  94         double frames_per_beat =
  95                 current_tempo.frames_per_beat(session->frame_rate(),
  96                                               current_meter);
  97
  98         double quarter_notes_per_beat = 4.0 / current_tempo.note_type();
  99         double frames_per_quarter_note = frames_per_beat / quarter_notes_per_beat;
 100
 101         one_ppqn_in_frames = frames_per_quarter_note / double (ppqn);
 102 }
 103
 104 ARDOUR::nframes_t
 105 MIDIClock_Slave::calculate_song_position(uint16_t song_position_in_sixteenth_notes)
 106 {
 107         nframes_t song_position_frames = 0;
 108         for (uint16_t i = 1; i <= song_position_in_sixteenth_notes; ++i) {
 109                 // one quarter note contains ppqn pulses, so a sixteenth note is ppqn / 4 pulses
 110                 calculate_one_ppqn_in_frames_at(song_position_frames);
 111                 song_position_frames += one_ppqn_in_frames * nframes_t(ppqn / 4);
 112         }
 113
 114         return song_position_frames;
 115 }
 116
 117 void
 118 MIDIClock_Slave::calculate_filter_coefficients()
 119 {
 120         // omega = 2 * PI * Bandwidth / MIDI clock frame frequency in Hz
 121         omega = 2.0 * 3.14159265358979323846 * bandwidth * one_ppqn_in_frames / session->frame_rate();
 122         b = 1.4142135623730950488 * omega;
 123         c = omega * omega;
 124 }
 125
 126 void
 127 MIDIClock_Slave::update_midi_clock (Parser& /*parser*/, nframes_t timestamp)
 128 {
 129         // some pieces of hardware send MIDI Clock all the time
 130         if ( (!_starting) && (!_started) ) {
 131                 return;
 132         }
 133
 134         calculate_one_ppqn_in_frames_at(should_be_position);
 135
 136         nframes_t elapsed_since_start = timestamp - first_timestamp;
 137         double error = 0;
 138
 139         if (_starting || last_timestamp == 0) {
 140                 midi_clock_count = 0;
 141
 142                 first_timestamp = timestamp;
 143                 elapsed_since_start = should_be_position;
 144
 145                 // calculate filter coefficients
 146                 calculate_filter_coefficients();
 147
 148                 // initialize DLL
 149                 e2 = double(one_ppqn_in_frames) / double(session->frame_rate());
 150                 t0 = double(elapsed_since_start) / double(session->frame_rate());
 151                 t1 = t0 + e2;
 152
 153                 // let ardour go after first MIDI Clock Event
 154                 _starting = false;
 155         } else {
 156                 midi_clock_count++;
 157                 should_be_position  += one_ppqn_in_frames;
 158                 calculate_filter_coefficients();
 159
 160                 // calculate loop error
 161                 // we use session->transport_frame() instead of t1 here
 162                 // because t1 is used to calculate the transport speed,
 163                 // so the loop will compensate for accumulating rounding errors
 164                 error = (double(should_be_position) - double(session->audible_frame()));
 165                 e = error / double(session->frame_rate());
 166
 167                 // update DLL
 168                 t0 = t1;
 169                 t1 += b * e + e2;
 170                 e2 += c * e;
 171         }
 172
 173         #ifdef DEBUG_MIDI_CLOCK
 174                 cerr
 175                                   << "MIDI Clock #" << midi_clock_count
 176                                   //<< "@" << timestamp
 177                                   << " arrived at: " << elapsed_since_start << " (elapsed time) "
 178                                   << " should-be transport: " << should_be_position
 179                                   << " audible: " << session->audible_frame()
 180                                   << " real transport: " << session->transport_frame()
 181                                   << " error: " << error
 182                                   //<< " engine: " << session->frame_time()
 183                                   << " real delta: " << timestamp - last_timestamp
 184                                   << " should-be delta: " << one_ppqn_in_frames
 185                                   << " t1-t0: " << (t1 -t0) * session->frame_rate()
 186                                   << " t0: " << t0 * session->frame_rate()
 187                                   << " t1: " << t1 * session->frame_rate()
 188                                   << " frame-rate: " << session->frame_rate()
 189                                   << endl;
 190
 191                 cerr      << "frames since cycle start: " << session->frames_since_cycle_start() << endl;
 192         #endif // DEBUG_MIDI_CLOCK
 193
 194         last_timestamp = timestamp;
 195 }
 196
 197 void
 198 MIDIClock_Slave::start (Parser& /*parser*/, nframes_t /*timestamp*/)
 199 {
 200         #ifdef DEBUG_MIDI_CLOCK
 201                 cerr << "MIDIClock_Slave got start message at time "  <<  timestamp << " engine time: " << session->frame_time() << endl;
 202         #endif
 203
 204         if (!_started) {
 205                 reset();
 206
 207                 _started = true;
 208                 _starting = true;
 209         }
 210 }
 211
 212 void
 213 MIDIClock_Slave::reset ()
 214 {
 215
 216         should_be_position = 0;
 217         last_timestamp = 0;
 218
 219         _starting = false;
 220         _started  = false;
 221
 222         session->request_locate(0, false);
 223 }
 224
 225 void
 226 MIDIClock_Slave::contineu (Parser& /*parser*/, nframes_t /*timestamp*/)
 227 {
 228         #ifdef DEBUG_MIDI_CLOCK
 229                 std::cerr << "MIDIClock_Slave got continue message" << endl;
 230         #endif
 231         if (!_started) {
 232                 _starting = true;
 233                 _started  = true;
 234         }
 235 }
 236
 237
 238 void
 239 MIDIClock_Slave::stop (Parser& /*parser*/, nframes_t /*timestamp*/)
 240 {
 241         #ifdef DEBUG_MIDI_CLOCK
 242                 std::cerr << "MIDIClock_Slave got stop message" << endl;
 243         #endif
 244
 245         if (_started || _starting) {
 246                 _starting = false;
 247                 _started  = false;
 248                 // locate to last MIDI clock position
 249                 session->request_transport_speed(0.0);
 250
 251                 // we need to go back to the last MIDI beat (6 ppqn)
 252                 // and lets hope the tempo didnt change in the meantime :)
 253
 254                 // begin at the should be position, because
 255                 // that is the position of the last MIDI Clock
 256                 // message and that is probably what the master
 257                 // expects where we are right now
 258                 nframes_t stop_position = should_be_position;
 259
 260                 // find out the last MIDI beat: go back #midi_clocks mod 6
 261                 // and lets hope the tempo didnt change in those last 6 beats :)
 262                 stop_position -= (midi_clock_count % 6) * one_ppqn_in_frames;
 263
 264                 session->request_locate(stop_position, false);
 265                 should_be_position = stop_position;
 266                 last_timestamp = 0;
 267         }
 268 }
 269
 270 void
 271 MIDIClock_Slave::position (Parser& /*parser*/, byte* message, size_t size)
 272 {
 273         // we are note supposed to get position messages while we are running
 274         // so lets be robust and ignore those
 275         if (_started || _starting) {
 276                 return;
 277         }
 278
 279         assert(size == 3);
 280         byte lsb = message[1];
 281         byte msb = message[2];
 282         assert((lsb <= 0x7f) && (msb <= 0x7f));
 283
 284         uint16_t position_in_sixteenth_notes = (uint16_t(msb) << 7) | uint16_t(lsb);
 285         nframes_t position_in_frames = calculate_song_position(position_in_sixteenth_notes);
 286
 287         #ifdef DEBUG_MIDI_CLOCK
 288         cerr << "Song Position: " << position_in_sixteenth_notes << " frames: " << position_in_frames << endl;
 289         #endif
 290
 291         session->request_locate(position_in_frames, false);
 292         should_be_position  = position_in_frames;
 293         last_timestamp = 0;
 294
 295 }
 296
 297 bool
 298 MIDIClock_Slave::locked () const
 299 {
 300         return true;
 301 }
 302
 303 bool
 304 MIDIClock_Slave::ok() const
 305 {
 306         return true;
 307 }
 308
 309 bool
 310 MIDIClock_Slave::starting() const
 311 {
 312         return false;
 313 }
 314
 315 bool
 316 MIDIClock_Slave::stop_if_no_more_clock_events(nframes_t& pos, nframes_t now)
 317 {
 318         /* no timecode for 1/4 second ? conclude that its stopped */
 319         if (last_timestamp &&
 320             now > last_timestamp &&
 321             now - last_timestamp > session->frame_rate() / 4) {
 322         #ifdef DEBUG_MIDI_CLOCK
 323                         cerr << "No MIDI Clock frames received for some time, stopping!" << endl;
 324         #endif
 325                 pos = should_be_position;
 326                 session->request_transport_speed (0);
 327                 session->request_locate (should_be_position, false);
 328                 return true;
 329         } else {
 330                 return false;
 331         }
 332 }
 333
 334 bool
 335 MIDIClock_Slave::speed_and_position (double& speed, nframes_t& pos)
 336 {
 337         if (!_started || _starting) {
 338                 speed = 0.0;
 339                 pos   = should_be_position;
 340                 return true;
 341         }
 342
 343         nframes_t engine_now = session->frame_time();
 344
 345         if (stop_if_no_more_clock_events(pos, engine_now)) {
 346                 return false;
 347         }
 348
 349         // calculate speed
 350         speed = ((t1 - t0) * session->frame_rate()) / one_ppqn_in_frames;
 351
 352         // calculate position
 353         if (engine_now > last_timestamp) {
 354                 // we are in between MIDI clock messages
 355                 // so we interpolate position according to speed
 356                 nframes_t elapsed = engine_now - last_timestamp;
 357                 pos = nframes_t (should_be_position + double(elapsed) * speed);
 358         } else {
 359                 // A new MIDI clock message has arrived this cycle
 360                 pos = should_be_position;
 361         }
 362
 363         #ifdef DEBUG_MIDI_CLOCK
 364         cerr << "speed_and_position: " << speed << " & " << pos << " <-> " << session->transport_frame() << " (transport)" << endl;
 365         #endif
 366
 367         return true;
 368 }
 369
 370 ARDOUR::nframes_t
 371 MIDIClock_Slave::resolution() const
 372 {
 373         // one beat
 374         return (nframes_t) one_ppqn_in_frames * ppqn;
 375 }
 376