libs/ardour/session_process.cc

   1 /*
   2     Copyright (C) 1999-2002 Paul Davis
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18 */
  19
  20 #include <cmath>
  21 #include <cerrno>
  22 #include <algorithm>
  23 #include <unistd.h>
  24
  25 #include "pbd/error.h"
  26 #include "pbd/enumwriter.h"
  27
  28 #include <glibmm/threads.h>
  29
  30 #include "ardour/audioengine.h"
  31 #include "ardour/auditioner.h"
  32 #include "ardour/butler.h"
  33 #include "ardour/cycle_timer.h"
  34 #include "ardour/debug.h"
  35 #include "ardour/graph.h"
  36 #include "ardour/port.h"
  37 #include "ardour/process_thread.h"
  38 #include "ardour/scene_changer.h"
  39 #include "ardour/session.h"
  40 #include "ardour/slave.h"
  41 #include "ardour/ticker.h"
  42 #include "ardour/types.h"
  43
  44 #include "midi++/mmc.h"
  45
  46 #include "i18n.h"
  47
  48 using namespace ARDOUR;
  49 using namespace PBD;
  50 using namespace std;
  51
  52 /** Called by the audio engine when there is work to be done with JACK.
  53  * @param nframes Number of frames to process.
  54  */
  55
  56 void
  57 Session::process (pframes_t nframes)
  58 {
  59         framepos_t transport_at_start = _transport_frame;
  60
  61         _silent = false;
  62
  63         if (processing_blocked()) {
  64                 _silent = true;
  65                 return;
  66         }
  67
  68         if (non_realtime_work_pending()) {
  69                 if (!_butler->transport_work_requested ()) {
  70                         post_transport ();
  71                 }
  72         }
  73
  74         _engine.main_thread()->get_buffers ();
  75
  76         (this->*process_function) (nframes);
  77
  78         /* realtime-safe meter-position and processor-order changes
  79          *
  80          * ideally this would be done in
  81          * Route::process_output_buffers() but various functions
  82          * callig it hold a _processor_lock reader-lock
  83          */
  84         boost::shared_ptr<RouteList> r = routes.reader ();
  85         for (RouteList::const_iterator i = r->begin(); i != r->end(); ++i) {
  86                 if ((*i)->apply_processor_changes_rt()) {
  87                         _rt_emit_pending = true;
  88                 }
  89         }
  90         if (_rt_emit_pending) {
  91                 if (!_rt_thread_active) {
  92                         emit_route_signals ();
  93                 }
  94                 if (pthread_mutex_trylock (&_rt_emit_mutex) == 0) {
  95                         pthread_cond_signal (&_rt_emit_cond);
  96                         pthread_mutex_unlock (&_rt_emit_mutex);
  97                         _rt_emit_pending = false;
  98                 }
  99         }
 100
 101         _engine.main_thread()->drop_buffers ();
 102
 103         /* deliver MIDI clock. Note that we need to use the transport frame
 104          * position at the start of process(), not the value at the end of
 105          * it. We may already have ticked() because of a transport state
 106          * change, for example.
 107          */
 108
 109         try {
 110                 if (!_silent && !_engine.freewheeling() && Config->get_send_midi_clock() && (transport_speed() == 1.0f || transport_speed() == 0.0f) && midi_clock->has_midi_port()) {
 111                         midi_clock->tick (transport_at_start, nframes);
 112                 }
 113
 114                 _scene_changer->run (transport_at_start, transport_at_start + nframes);
 115
 116         } catch (...) {
 117                 /* don't bother with a message */
 118         }
 119
 120         SendFeedback (); /* EMIT SIGNAL */
 121 }
 122
 123 int
 124 Session::fail_roll (pframes_t nframes)
 125 {
 126         return no_roll (nframes);
 127 }
 128
 129 int
 130 Session::no_roll (pframes_t nframes)
 131 {
 132         PT_TIMING_CHECK (4);
 133
 134         framepos_t end_frame = _transport_frame + nframes; // FIXME: varispeed + no_roll ??
 135         int ret = 0;
 136         int declick = get_transport_declick_required();
 137         boost::shared_ptr<RouteList> r = routes.reader ();
 138
 139         if (_click_io) {
 140                 _click_io->silence (nframes);
 141         }
 142
 143         ltc_tx_send_time_code_for_cycle (_transport_frame, end_frame, _target_transport_speed, _transport_speed, nframes);
 144
 145         if (_process_graph) {
 146                 DEBUG_TRACE(DEBUG::ProcessThreads,"calling graph/no-roll\n");
 147                 _process_graph->routes_no_roll( nframes, _transport_frame, end_frame, non_realtime_work_pending(), declick);
 148         } else {
 149                 PT_TIMING_CHECK (10);
 150                 for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 151
 152                         if ((*i)->is_auditioner()) {
 153                                 continue;
 154                         }
 155
 156                         (*i)->set_pending_declick (declick);
 157
 158                         if ((*i)->no_roll (nframes, _transport_frame, end_frame, non_realtime_work_pending())) {
 159                                 error << string_compose(_("Session: error in no roll for %1"), (*i)->name()) << endmsg;
 160                                 ret = -1;
 161                                 break;
 162                         }
 163                 }
 164                 PT_TIMING_CHECK (11);
 165         }
 166
 167         PT_TIMING_CHECK (5);
 168         return ret;
 169 }
 170
 171 /** @param need_butler to be set to true by this method if it needs the butler,
 172  *  otherwise it must be left alone.
 173  */
 174 int
 175 Session::process_routes (pframes_t nframes, bool& need_butler)
 176 {
 177         int  declick = get_transport_declick_required();
 178         boost::shared_ptr<RouteList> r = routes.reader ();
 179
 180         const framepos_t start_frame = _transport_frame;
 181         const framepos_t end_frame = _transport_frame + floor (nframes * _transport_speed);
 182
 183         if (_process_graph) {
 184                 DEBUG_TRACE(DEBUG::ProcessThreads,"calling graph/process-routes\n");
 185                 if (_process_graph->process_routes (nframes, start_frame, end_frame, declick, need_butler) < 0) {
 186                         stop_transport ();
 187                         return -1;
 188                 }
 189         } else {
 190
 191                 for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 192
 193                         int ret;
 194
 195                         if ((*i)->is_auditioner()) {
 196                                 continue;
 197                         }
 198
 199                         (*i)->set_pending_declick (declick);
 200
 201                         bool b = false;
 202
 203                         if ((ret = (*i)->roll (nframes, start_frame, end_frame, declick, b)) < 0) {
 204                                 stop_transport ();
 205                                 return -1;
 206                         }
 207
 208                         if (b) {
 209                                 need_butler = true;
 210                         }
 211                 }
 212         }
 213
 214         return 0;
 215 }
 216
 217 /** @param need_butler to be set to true by this method if it needs the butler,
 218  *  otherwise it must be left alone.
 219  */
 220 int
 221 Session::silent_process_routes (pframes_t nframes, bool& need_butler)
 222 {
 223         boost::shared_ptr<RouteList> r = routes.reader ();
 224
 225         const framepos_t start_frame = _transport_frame;
 226         const framepos_t end_frame = _transport_frame + lrintf(nframes * _transport_speed);
 227
 228         if (_process_graph) {
 229                 _process_graph->silent_process_routes (nframes, start_frame, end_frame, need_butler);
 230         } else {
 231                 for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 232
 233                         int ret;
 234
 235                         if ((*i)->is_auditioner()) {
 236                                 continue;
 237                         }
 238
 239                         bool b = false;
 240
 241                         if ((ret = (*i)->silent_roll (nframes, start_frame, end_frame, b)) < 0) {
 242                                 stop_transport ();
 243                                 return -1;
 244                         }
 245
 246                         if (b) {
 247                                 need_butler = true;
 248                         }
 249                 }
 250         }
 251
 252         return 0;
 253 }
 254
 255 void
 256 Session::get_track_statistics ()
 257 {
 258         float pworst = 1.0f;
 259         float cworst = 1.0f;
 260
 261         boost::shared_ptr<RouteList> rl = routes.reader();
 262         for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
 263
 264                 boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
 265
 266                 if (!tr || tr->hidden()) {
 267                         continue;
 268                 }
 269
 270                 pworst = min (pworst, tr->playback_buffer_load());
 271                 cworst = min (cworst, tr->capture_buffer_load());
 272         }
 273
 274         g_atomic_int_set (&_playback_load, (uint32_t) floor (pworst * 100.0f));
 275         g_atomic_int_set (&_capture_load, (uint32_t) floor (cworst * 100.0f));
 276
 277         if (actively_recording()) {
 278                 set_dirty();
 279         }
 280 }
 281
 282 /** Process callback used when the auditioner is not active */
 283 void
 284 Session::process_with_events (pframes_t nframes)
 285 {
 286         PT_TIMING_CHECK (3);
 287
 288         SessionEvent*  ev;
 289         pframes_t      this_nframes;
 290         framepos_t     end_frame;
 291         bool           session_needs_butler = false;
 292         framecnt_t     frames_moved;
 293
 294         /* make sure the auditioner is silent */
 295
 296         if (auditioner) {
 297                 auditioner->silence (nframes);
 298         }
 299
 300         /* handle any pending events */
 301
 302         while (pending_events.read (&ev, 1) == 1) {
 303                 merge_event (ev);
 304         }
 305
 306         /* if we are not in the middle of a state change,
 307            and there are immediate events queued up,
 308            process them.
 309         */
 310
 311         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 312                 SessionEvent *ev = immediate_events.front ();
 313                 immediate_events.pop_front ();
 314                 process_event (ev);
 315         }
 316
 317         /* Decide on what to do with quarter-frame MTC during this cycle */
 318
 319         bool const was_sending_qf_mtc = _send_qf_mtc;
 320         double const tolerance = Config->get_mtc_qf_speed_tolerance() / 100.0;
 321
 322         if (_transport_speed != 0) {
 323                 _send_qf_mtc = (
 324                         Config->get_send_mtc () &&
 325                         _transport_speed >= (1 - tolerance) &&
 326                         _transport_speed <= (1 + tolerance)
 327                         );
 328
 329                 if (_send_qf_mtc && !was_sending_qf_mtc) {
 330                         /* we will re-start quarter-frame MTC this cycle, so send a full update to set things up */
 331                         _send_timecode_update = true;
 332                 }
 333
 334                 if (Config->get_send_mtc() && !_send_qf_mtc && _pframes_since_last_mtc > (frame_rate () / 4)) {
 335                         /* we're sending MTC, but we're not sending QF MTC at the moment, and it's been
 336                            a quarter of a second since we sent anything at all, so send a full MTC update
 337                            this cycle.
 338                         */
 339                         _send_timecode_update = true;
 340                 }
 341
 342                 _pframes_since_last_mtc += nframes;
 343         }
 344
 345         /* Events caused a transport change (or we re-started sending
 346          * MTC), so send an MTC Full Frame (Timecode) message.  This
 347          * is sent whether rolling or not, to give slaves an idea of
 348          * ardour time on locates (and allow slow slaves to position
 349          * and prepare for rolling)
 350          */
 351         if (_send_timecode_update) {
 352                 send_full_time_code (_transport_frame, nframes);
 353         }
 354
 355         if (!process_can_proceed()) {
 356                 _silent = true;
 357                 return;
 358         }
 359
 360         if (events.empty() || next_event == events.end()) {
 361                 process_without_events (nframes);
 362                 return;
 363         }
 364
 365         if (_transport_speed == 1.0) {
 366                 frames_moved = (framecnt_t) nframes;
 367         } else {
 368                 interpolation.set_target_speed (_target_transport_speed);
 369                 interpolation.set_speed (_transport_speed);
 370                 frames_moved = (framecnt_t) interpolation.interpolate (0, nframes, 0, 0);
 371         }
 372
 373         end_frame = _transport_frame + frames_moved;
 374
 375         {
 376                 SessionEvent* this_event;
 377                 Events::iterator the_next_one;
 378
 379                 if (!process_can_proceed()) {
 380                         _silent = true;
 381                         return;
 382                 }
 383
 384                 if (!_exporting && _slave) {
 385                         if (!follow_slave (nframes)) {
 386                                 return;
 387                         }
 388                 }
 389
 390                 if (_transport_speed == 0) {
 391                         no_roll (nframes);
 392                         return;
 393                 }
 394
 395                 if (!_exporting && !timecode_transmission_suspended()) {
 396                         send_midi_time_code_for_cycle (_transport_frame, end_frame, nframes);
 397                 }
 398
 399                 ltc_tx_send_time_code_for_cycle (_transport_frame, end_frame, _target_transport_speed, _transport_speed, nframes);
 400
 401                 framepos_t stop_limit = compute_stop_limit ();
 402
 403                 if (maybe_stop (stop_limit)) {
 404                         no_roll (nframes);
 405                         return;
 406                 }
 407
 408                 this_event = *next_event;
 409                 the_next_one = next_event;
 410                 ++the_next_one;
 411
 412                 /* yes folks, here it is, the actual loop where we really truly
 413                    process some audio
 414                 */
 415
 416                 while (nframes) {
 417
 418                         this_nframes = nframes; /* real (jack) time relative */
 419                         frames_moved = (framecnt_t) floor (_transport_speed * nframes); /* transport relative */
 420
 421                         /* running an event, position transport precisely to its time */
 422                         if (this_event && this_event->action_frame <= end_frame && this_event->action_frame >= _transport_frame) {
 423                                 /* this isn't quite right for reverse play */
 424                                 frames_moved = (framecnt_t) (this_event->action_frame - _transport_frame);
 425                                 this_nframes = abs (floor(frames_moved / _transport_speed));
 426                         }
 427
 428                         if (this_nframes) {
 429
 430                                 click (_transport_frame, this_nframes);
 431
 432                                 if (process_routes (this_nframes, session_needs_butler)) {
 433                                         fail_roll (nframes);
 434                                         return;
 435                                 }
 436
 437                                 get_track_statistics ();
 438
 439                                 nframes -= this_nframes;
 440
 441                                 if (frames_moved < 0) {
 442                                         decrement_transport_position (-frames_moved);
 443                                 } else {
 444                                         increment_transport_position (frames_moved);
 445                                 }
 446
 447                                 maybe_stop (stop_limit);
 448                                 check_declick_out ();
 449                         }
 450
 451                         if (nframes > 0) {
 452                                 _engine.split_cycle (this_nframes);
 453                         }
 454
 455                         /* now handle this event and all others scheduled for the same time */
 456
 457                         while (this_event && this_event->action_frame == _transport_frame) {
 458                                 process_event (this_event);
 459
 460                                 if (the_next_one == events.end()) {
 461                                         this_event = 0;
 462                                 } else {
 463                                         this_event = *the_next_one;
 464                                         ++the_next_one;
 465                                 }
 466                         }
 467
 468                         /* if an event left our state changing, do the right thing */
 469
 470                         if (nframes && non_realtime_work_pending()) {
 471                                 no_roll (nframes);
 472                                 break;
 473                         }
 474
 475                         /* this is necessary to handle the case of seamless looping */
 476                         end_frame = _transport_frame + floor (nframes * _transport_speed);
 477                 }
 478
 479                 set_next_event ();
 480
 481         } /* implicit release of route lock */
 482
 483         if (session_needs_butler) {
 484                 _butler->summon ();
 485         }
 486 }
 487
 488 void
 489 Session::reset_slave_state ()
 490 {
 491         average_slave_delta = 1800;
 492         delta_accumulator_cnt = 0;
 493         have_first_delta_accumulator = false;
 494         _slave_state = Stopped;
 495 }
 496
 497 bool
 498 Session::transport_locked () const
 499 {
 500         Slave* sl = _slave;
 501
 502         if (!locate_pending() && (!config.get_external_sync() || (sl && sl->ok() && sl->locked()))) {
 503                 return true;
 504         }
 505
 506         return false;
 507 }
 508
 509 bool
 510 Session::follow_slave (pframes_t nframes)
 511 {
 512         double slave_speed;
 513         framepos_t slave_transport_frame;
 514         framecnt_t this_delta;
 515         int dir;
 516
 517         if (!_slave->ok()) {
 518                 stop_transport ();
 519                 config.set_external_sync (false);
 520                 goto noroll;
 521         }
 522
 523         _slave->speed_and_position (slave_speed, slave_transport_frame);
 524
 525         DEBUG_TRACE (DEBUG::Slave, string_compose ("Slave position %1 speed %2\n", slave_transport_frame, slave_speed));
 526
 527         if (!_slave->locked()) {
 528                 DEBUG_TRACE (DEBUG::Slave, "slave not locked\n");
 529                 goto noroll;
 530         }
 531
 532         if (slave_transport_frame > _transport_frame) {
 533                 this_delta = slave_transport_frame - _transport_frame;
 534                 dir = 1;
 535         } else {
 536                 this_delta = _transport_frame - slave_transport_frame;
 537                 dir = -1;
 538         }
 539
 540         if (_slave->starting()) {
 541                 slave_speed = 0.0f;
 542         }
 543
 544         if (_slave->is_always_synced() ||
 545                         (Config->get_timecode_source_is_synced() && (dynamic_cast<TimecodeSlave*>(_slave)) != 0)
 546                         ) {
 547
 548                 /* if the TC source is synced, then we assume that its
 549                    speed is binary: 0.0 or 1.0
 550                 */
 551
 552                 if (slave_speed != 0.0f) {
 553                         slave_speed = 1.0f;
 554                 }
 555
 556         } else {
 557
 558                 /* if we are chasing and the average delta between us and the
 559                    master gets too big, we want to switch to silent
 560                    motion. so keep track of that here.
 561                 */
 562
 563                 if (_slave_state == Running) {
 564                         calculate_moving_average_of_slave_delta(dir, this_delta);
 565                 }
 566         }
 567
 568         track_slave_state (slave_speed, slave_transport_frame, this_delta);
 569
 570         DEBUG_TRACE (DEBUG::Slave, string_compose ("slave state %1 @ %2 speed %3 cur delta %4 avg delta %5\n",
 571                                                    _slave_state, slave_transport_frame, slave_speed, this_delta, average_slave_delta));
 572
 573
 574         if (_slave_state == Running && !_slave->is_always_synced() &&
 575                         !(Config->get_timecode_source_is_synced() && (dynamic_cast<TimecodeSlave*>(_slave)) != 0)
 576                         ) {
 577
 578                 if (_transport_speed != 0.0f) {
 579
 580                         /*
 581                            note that average_dir is +1 or -1
 582                         */
 583
 584                         float delta;
 585
 586                         if (average_slave_delta == 0) {
 587                                 delta = this_delta;
 588                                 delta *= dir;
 589                         } else {
 590                                 delta = average_slave_delta;
 591                                 delta *= average_dir;
 592                         }
 593
 594 #ifndef NDEBUG
 595                         if (slave_speed != 0.0) {
 596                                 DEBUG_TRACE (DEBUG::Slave, string_compose ("delta = %1 speed = %2 ts = %3 M@%4 S@%5 avgdelta %6\n",
 597                                                                            (int) (dir * this_delta),
 598                                                                            slave_speed,
 599                                                                            _transport_speed,
 600                                                                            _transport_frame,
 601                                                                            slave_transport_frame,
 602                                                                            average_slave_delta));
 603                         }
 604 #endif
 605
 606                         if (_slave->give_slave_full_control_over_transport_speed()) {
 607                                 set_transport_speed (slave_speed, 0, false, false);
 608                                 //std::cout << "set speed = " << slave_speed << "\n";
 609                         } else {
 610                                 float adjusted_speed = slave_speed + (1.5 * (delta /  float(_current_frame_rate)));
 611                                 request_transport_speed (adjusted_speed);
 612                                 DEBUG_TRACE (DEBUG::Slave, string_compose ("adjust using %1 towards %2 ratio %3 current %4 slave @ %5\n",
 613                                                                            delta, adjusted_speed, adjusted_speed/slave_speed, _transport_speed,
 614                                                                            slave_speed));
 615                         }
 616
 617 #if 1
 618                         if (!actively_recording() && (framecnt_t) abs(average_slave_delta) > _slave->resolution()) {
 619                                 cerr << "average slave delta greater than slave resolution (" << _slave->resolution() << "), going to silent motion\n";
 620                                 goto silent_motion;
 621                         }
 622 #endif
 623                 }
 624         }
 625
 626
 627         if (_slave_state == Running && !non_realtime_work_pending()) {
 628                 /* speed is set, we're locked, and good to go */
 629                 return true;
 630         }
 631
 632   silent_motion:
 633         DEBUG_TRACE (DEBUG::Slave, "silent motion\n")
 634         follow_slave_silently (nframes, slave_speed);
 635
 636   noroll:
 637         /* don't move at all */
 638         DEBUG_TRACE (DEBUG::Slave, "no roll\n")
 639         no_roll (nframes);
 640         return false;
 641 }
 642
 643 void
 644 Session::calculate_moving_average_of_slave_delta (int dir, framecnt_t this_delta)
 645 {
 646         if (delta_accumulator_cnt >= delta_accumulator_size) {
 647                 have_first_delta_accumulator = true;
 648                 delta_accumulator_cnt = 0;
 649         }
 650
 651         if (delta_accumulator_cnt != 0 || this_delta < _current_frame_rate) {
 652                 delta_accumulator[delta_accumulator_cnt++] = (framecnt_t) dir *  (framecnt_t) this_delta;
 653         }
 654
 655         if (have_first_delta_accumulator) {
 656                 average_slave_delta = 0L;
 657                 for (int i = 0; i < delta_accumulator_size; ++i) {
 658                         average_slave_delta += delta_accumulator[i];
 659                 }
 660                 average_slave_delta /= (int32_t) delta_accumulator_size;
 661                 if (average_slave_delta < 0L) {
 662                         average_dir = -1;
 663                         average_slave_delta = abs(average_slave_delta);
 664                 } else {
 665                         average_dir = 1;
 666                 }
 667         }
 668 }
 669
 670 void
 671 Session::track_slave_state (float slave_speed, framepos_t slave_transport_frame, framecnt_t /*this_delta*/)
 672 {
 673         if (slave_speed != 0.0f) {
 674
 675                 /* slave is running */
 676
 677                 switch (_slave_state) {
 678                 case Stopped:
 679                         if (_slave->requires_seekahead()) {
 680                                 slave_wait_end = slave_transport_frame + _slave->seekahead_distance ();
 681                                 DEBUG_TRACE (DEBUG::Slave, string_compose ("slave stopped, but running, requires seekahead to %1\n", slave_wait_end));
 682                                 /* we can call locate() here because we are in process context */
 683                                 locate (slave_wait_end, false, false);
 684                                 _slave_state = Waiting;
 685
 686                         } else {
 687
 688                                 DEBUG_TRACE (DEBUG::Slave, string_compose ("slave stopped -> running at %1\n", slave_transport_frame));
 689
 690                                 memset (delta_accumulator, 0, sizeof (int32_t) * delta_accumulator_size);
 691                                 average_slave_delta = 0L;
 692
 693                                 Location* al = _locations->auto_loop_location();
 694
 695                                 if (al && play_loop && (slave_transport_frame < al->start() || slave_transport_frame > al->end())) {
 696                                         // cancel looping
 697                                         request_play_loop(false);
 698                                 }
 699
 700                                 if (slave_transport_frame != _transport_frame) {
 701                                         DEBUG_TRACE (DEBUG::Slave, string_compose ("require locate to run. eng: %1 -> sl: %2\n", _transport_frame, slave_transport_frame));
 702                                         locate (slave_transport_frame, false, false);
 703                                 }
 704                                 _slave_state = Running;
 705                         }
 706                         break;
 707
 708                 case Waiting:
 709                 default:
 710                         break;
 711                 }
 712
 713                 if (_slave_state == Waiting) {
 714
 715                         DEBUG_TRACE (DEBUG::Slave, string_compose ("slave waiting at %1\n", slave_transport_frame));
 716
 717                         if (slave_transport_frame >= slave_wait_end) {
 718
 719                                 DEBUG_TRACE (DEBUG::Slave, string_compose ("slave start at %1 vs %2\n", slave_transport_frame, _transport_frame));
 720
 721                                 _slave_state = Running;
 722
 723                                 /* now perform a "micro-seek" within the disk buffers to realign ourselves
 724                                    precisely with the master.
 725                                 */
 726
 727
 728                                 bool ok = true;
 729                                 framecnt_t frame_delta = slave_transport_frame - _transport_frame;
 730
 731                                 boost::shared_ptr<RouteList> rl = routes.reader();
 732                                 for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
 733                                         boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
 734                                         if (tr && !tr->can_internal_playback_seek (frame_delta)) {
 735                                                 ok = false;
 736                                                 break;
 737                                         }
 738                                 }
 739
 740                                 if (ok) {
 741                                         for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
 742                                                 boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
 743                                                 if (tr) {
 744                                                         tr->internal_playback_seek (frame_delta);
 745                                                 }
 746                                         }
 747                                         _transport_frame += frame_delta;
 748
 749                                 } else {
 750                                         cerr << "cannot micro-seek\n";
 751                                         /* XXX what? */
 752                                 }
 753                         }
 754                 }
 755
 756                 if (_slave_state == Running && _transport_speed == 0.0f) {
 757                         DEBUG_TRACE (DEBUG::Slave, "slave starts transport\n");
 758                         start_transport ();
 759                 }
 760
 761         } else { // slave_speed is 0
 762
 763                 /* slave has stopped */
 764
 765                 if (_transport_speed != 0.0f) {
 766                         DEBUG_TRACE (DEBUG::Slave, string_compose ("slave stops transport: %1 frame %2 tf %3\n", slave_speed, slave_transport_frame, _transport_frame));
 767                         stop_transport ();
 768                 }
 769
 770                 if (slave_transport_frame != _transport_frame) {
 771                         DEBUG_TRACE (DEBUG::Slave, string_compose ("slave stopped, move to %1\n", slave_transport_frame));
 772                         force_locate (slave_transport_frame, false);
 773                 }
 774
 775                 reset_slave_state();
 776         }
 777 }
 778
 779 void
 780 Session::follow_slave_silently (pframes_t nframes, float slave_speed)
 781 {
 782         if (slave_speed && _transport_speed) {
 783
 784                 /* something isn't right, but we should move with the master
 785                    for now.
 786                 */
 787
 788                 bool need_butler = false;
 789
 790                 silent_process_routes (nframes, need_butler);
 791
 792                 get_track_statistics ();
 793
 794                 if (need_butler) {
 795                         _butler->summon ();
 796                 }
 797
 798                 int32_t frames_moved = (int32_t) floor (_transport_speed * nframes);
 799
 800                 if (frames_moved < 0) {
 801                         decrement_transport_position (-frames_moved);
 802                 } else {
 803                         increment_transport_position (frames_moved);
 804                 }
 805
 806                 framepos_t const stop_limit = compute_stop_limit ();
 807                 maybe_stop (stop_limit);
 808         }
 809 }
 810
 811 void
 812 Session::process_without_events (pframes_t nframes)
 813 {
 814         bool session_needs_butler = false;
 815         framecnt_t frames_moved;
 816
 817         if (!process_can_proceed()) {
 818                 _silent = true;
 819                 return;
 820         }
 821
 822         if (!_exporting && _slave) {
 823                 if (!follow_slave (nframes)) {
 824                         ltc_tx_send_time_code_for_cycle (_transport_frame, _transport_frame, 0, 0 , nframes);
 825                         return;
 826                 }
 827         }
 828
 829         if (_transport_speed == 0) {
 830                 fail_roll (nframes);
 831                 return;
 832         }
 833
 834         if (_transport_speed == 1.0) {
 835                 frames_moved = (framecnt_t) nframes;
 836         } else {
 837                 interpolation.set_target_speed (_target_transport_speed);
 838                 interpolation.set_speed (_transport_speed);
 839                 frames_moved = (framecnt_t) interpolation.interpolate (0, nframes, 0, 0);
 840         }
 841
 842         if (!_exporting && !timecode_transmission_suspended()) {
 843                 send_midi_time_code_for_cycle (_transport_frame, _transport_frame + frames_moved, nframes);
 844         }
 845
 846         ltc_tx_send_time_code_for_cycle (_transport_frame, _transport_frame + frames_moved, _target_transport_speed, _transport_speed, nframes);
 847
 848         framepos_t const stop_limit = compute_stop_limit ();
 849
 850         if (maybe_stop (stop_limit)) {
 851                 fail_roll (nframes);
 852                 return;
 853         }
 854
 855         if (maybe_sync_start (nframes)) {
 856                 return;
 857         }
 858
 859         click (_transport_frame, nframes);
 860
 861         if (process_routes (nframes, session_needs_butler)) {
 862                 fail_roll (nframes);
 863                 return;
 864         }
 865
 866         get_track_statistics ();
 867
 868         if (frames_moved < 0) {
 869                 decrement_transport_position (-frames_moved);
 870         } else {
 871                 increment_transport_position (frames_moved);
 872         }
 873
 874         maybe_stop (stop_limit);
 875         check_declick_out ();
 876
 877         if (session_needs_butler) {
 878                 _butler->summon ();
 879         }
 880 }
 881
 882 /** Process callback used when the auditioner is active.
 883  * @param nframes number of frames to process.
 884  */
 885 void
 886 Session::process_audition (pframes_t nframes)
 887 {
 888         SessionEvent* ev;
 889         boost::shared_ptr<RouteList> r = routes.reader ();
 890
 891         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 892                 if (!(*i)->is_auditioner()) {
 893                         (*i)->silence (nframes);
 894                 }
 895         }
 896
 897         /* run the auditioner, and if it says we need butler service, ask for it */
 898
 899         if (auditioner->play_audition (nframes) > 0) {
 900                 _butler->summon ();
 901         }
 902
 903         /* if using a monitor section, run it because otherwise we don't hear anything */
 904
 905         if (_monitor_out && auditioner->needs_monitor()) {
 906                 _monitor_out->monitor_run (_transport_frame, _transport_frame + nframes, nframes, false);
 907         }
 908
 909         /* handle pending events */
 910
 911         while (pending_events.read (&ev, 1) == 1) {
 912                 merge_event (ev);
 913         }
 914
 915         /* if we are not in the middle of a state change,
 916            and there are immediate events queued up,
 917            process them.
 918         */
 919
 920         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 921                 SessionEvent *ev = immediate_events.front ();
 922                 immediate_events.pop_front ();
 923                 process_event (ev);
 924         }
 925
 926         if (!auditioner->auditioning()) {
 927                 /* auditioner no longer active, so go back to the normal process callback */
 928                 process_function = &Session::process_with_events;
 929         }
 930 }
 931
 932 bool
 933 Session::maybe_sync_start (pframes_t & nframes)
 934 {
 935         pframes_t sync_offset;
 936
 937         if (!waiting_for_sync_offset) {
 938                 return false;
 939         }
 940
 941         if (_engine.get_sync_offset (sync_offset) && sync_offset < nframes) {
 942
 943                 /* generate silence up to the sync point, then
 944                    adjust nframes + offset to reflect whatever
 945                    is left to do.
 946                 */
 947
 948                 no_roll (sync_offset);
 949                 nframes -= sync_offset;
 950                 Port::increment_global_port_buffer_offset (sync_offset);
 951                 waiting_for_sync_offset = false;
 952
 953                 if (nframes == 0) {
 954                         return true; // done, nothing left to process
 955                 }
 956
 957         } else {
 958
 959                 /* sync offset point is not within this process()
 960                    cycle, so just generate silence. and don't bother
 961                    with any fancy stuff here, just the minimal silence.
 962                 */
 963
 964                 _silent = true;
 965
 966                 if (Config->get_locate_while_waiting_for_sync()) {
 967                         if (micro_locate (nframes)) {
 968                                 /* XXX ERROR !!! XXX */
 969                         }
 970                 }
 971
 972                 return true; // done, nothing left to process
 973         }
 974
 975         return false;
 976 }
 977
 978 void
 979 Session::queue_event (SessionEvent* ev)
 980 {
 981         if (_state_of_the_state & Deletion) {
 982                 return;
 983         } else if (_state_of_the_state & Loading) {
 984                 merge_event (ev);
 985         } else {
 986                 pending_events.write (&ev, 1);
 987         }
 988 }
 989
 990 void
 991 Session::set_next_event ()
 992 {
 993         if (events.empty()) {
 994                 next_event = events.end();
 995                 return;
 996         }
 997
 998         if (next_event == events.end()) {
 999                 next_event = events.begin();
1000         }
1001
1002         if ((*next_event)->action_frame > _transport_frame) {
1003                 next_event = events.begin();
1004         }
1005
1006         for (; next_event != events.end(); ++next_event) {
1007                 if ((*next_event)->action_frame >= _transport_frame) {
1008                         break;
1009                 }
1010         }
1011 }
1012
1013 void
1014 Session::process_event (SessionEvent* ev)
1015 {
1016         bool remove = true;
1017         bool del = true;
1018
1019         /* if we're in the middle of a state change (i.e. waiting
1020            for the butler thread to complete the non-realtime
1021            part of the change), we'll just have to queue this
1022            event for a time when the change is complete.
1023         */
1024
1025         if (non_realtime_work_pending()) {
1026
1027                 /* except locates, which we have the capability to handle */
1028
1029                 if (ev->type != SessionEvent::Locate) {
1030                         immediate_events.insert (immediate_events.end(), ev);
1031                         _remove_event (ev);
1032                         return;
1033                 }
1034         }
1035
1036         DEBUG_TRACE (DEBUG::SessionEvents, string_compose ("Processing event: %1 @ %2\n", enum_2_string (ev->type), _transport_frame));
1037
1038         switch (ev->type) {
1039         case SessionEvent::SetLoop:
1040                 set_play_loop (ev->yes_or_no, ev->speed);
1041                 break;
1042
1043         case SessionEvent::AutoLoop:
1044                 if (play_loop) {
1045                         /* roll after locate, do not flush, set "with loop"
1046                            true only if we are seamless looping
1047                         */
1048                         start_locate (ev->target_frame, true, false, Config->get_seamless_loop());
1049                 }
1050                 remove = false;
1051                 del = false;
1052                 break;
1053
1054         case SessionEvent::AutoLoopDeclick:
1055                 if (play_loop) {
1056                         /* Request a declick fade-out and a fade-in; the fade-out will happen
1057                            at the end of the loop, and the fade-in at the start.
1058                         */
1059                         transport_sub_state |= (PendingLoopDeclickOut | PendingLoopDeclickIn);
1060                 }
1061                 remove = false;
1062                 del = false;
1063                 break;
1064
1065         case SessionEvent::Locate:
1066                 if (ev->yes_or_no) {
1067                         /* args: do not roll after locate, do flush, not with loop */
1068                         locate (ev->target_frame, false, true, false);
1069                 } else {
1070                         /* args: do not roll after locate, do flush, not with loop */
1071                         start_locate (ev->target_frame, false, true, false);
1072                 }
1073                 _send_timecode_update = true;
1074                 break;
1075
1076         case SessionEvent::LocateRoll:
1077                 if (ev->yes_or_no) {
1078                         /* args: roll after locate, do flush, not with loop */
1079                         locate (ev->target_frame, true, true, false);
1080                 } else {
1081                         /* args: roll after locate, do flush, not with loop */
1082                         start_locate (ev->target_frame, true, true, false);
1083                 }
1084                 _send_timecode_update = true;
1085                 break;
1086
1087         case SessionEvent::Skip:
1088                 if (Config->get_skip_playback()) {
1089                         start_locate (ev->target_frame, true, true, false);
1090                         _send_timecode_update = true;
1091                 }
1092                 remove = false;
1093                 del = false;
1094                 break;
1095
1096         case SessionEvent::LocateRollLocate:
1097                 // locate is handled by ::request_roll_at_and_return()
1098                 _requested_return_frame = ev->target_frame;
1099                 request_locate (ev->target2_frame, true);
1100                 break;
1101
1102
1103         case SessionEvent::SetTransportSpeed:
1104                 set_transport_speed (ev->speed, ev->target_frame, ev->yes_or_no, ev->second_yes_or_no, ev->third_yes_or_no);
1105                 break;
1106
1107         case SessionEvent::PunchIn:
1108                 // cerr << "PunchIN at " << transport_frame() << endl;
1109                 if (config.get_punch_in() && record_status() == Enabled) {
1110                         enable_record ();
1111                 }
1112                 remove = false;
1113                 del = false;
1114                 break;
1115
1116         case SessionEvent::PunchOut:
1117                 // cerr << "PunchOUT at " << transport_frame() << endl;
1118                 if (config.get_punch_out()) {
1119                         step_back_from_record ();
1120                 }
1121                 remove = false;
1122                 del = false;
1123                 break;
1124
1125         case SessionEvent::StopOnce:
1126                 if (!non_realtime_work_pending()) {
1127                         _clear_event_type (SessionEvent::StopOnce);
1128                         stop_transport (ev->yes_or_no);
1129                 }
1130                 remove = false;
1131                 del = false;
1132                 break;
1133
1134         case SessionEvent::RangeStop:
1135                 if (!non_realtime_work_pending()) {
1136                         stop_transport (ev->yes_or_no);
1137                 }
1138                 remove = false;
1139                 del = false;
1140                 break;
1141
1142         case SessionEvent::RangeLocate:
1143                 /* args: roll after locate, do flush, not with loop */
1144                 start_locate (ev->target_frame, true, true, false);
1145                 remove = false;
1146                 del = false;
1147                 break;
1148
1149         case SessionEvent::Overwrite:
1150                 overwrite_some_buffers (static_cast<Track*>(ev->ptr));
1151                 break;
1152
1153         case SessionEvent::SetTrackSpeed:
1154                 set_track_speed (static_cast<Track*> (ev->ptr), ev->speed);
1155                 break;
1156
1157         case SessionEvent::SetSyncSource:
1158                 DEBUG_TRACE (DEBUG::Slave, "seen request for new slave\n");
1159                 use_sync_source (ev->slave);
1160                 break;
1161
1162         case SessionEvent::Audition:
1163                 set_audition (ev->region);
1164                 // drop reference to region
1165                 ev->region.reset ();
1166                 break;
1167
1168         case SessionEvent::InputConfigurationChange:
1169                 add_post_transport_work (PostTransportInputChange);
1170                 _butler->schedule_transport_work ();
1171                 break;
1172
1173         case SessionEvent::SetPlayAudioRange:
1174                 set_play_range (ev->audio_range, (ev->speed == 1.0f));
1175                 break;
1176
1177         case SessionEvent::CancelPlayAudioRange:
1178                 unset_play_range();
1179                 break;
1180
1181         case SessionEvent::RealTimeOperation:
1182                 process_rtop (ev);
1183                 del = false; // other side of RT request needs to clean up
1184                 break;
1185
1186         case SessionEvent::AdjustPlaybackBuffering:
1187                 schedule_playback_buffering_adjustment ();
1188                 break;
1189
1190         case SessionEvent::AdjustCaptureBuffering:
1191                 schedule_capture_buffering_adjustment ();
1192                 break;
1193
1194         case SessionEvent::SetTimecodeTransmission:
1195                 g_atomic_int_set (&_suspend_timecode_transmission, ev->yes_or_no ? 0 : 1);
1196                 break;
1197
1198         default:
1199           fatal << string_compose(_("Programming error: illegal event type in process_event (%1)"), ev->type) << endmsg;
1200                 abort(); /*NOTREACHED*/
1201                 break;
1202         };
1203
1204         if (remove) {
1205                 del = del && !_remove_event (ev);
1206         }
1207
1208         if (del) {
1209                 delete ev;
1210         }
1211 }
1212
1213 framepos_t
1214 Session::compute_stop_limit () const
1215 {
1216         if (!Config->get_stop_at_session_end ()) {
1217                 return max_framepos;
1218         }
1219
1220         if (_slave) {
1221                 return max_framepos;
1222         }
1223
1224
1225         bool const punching_in = (config.get_punch_in () && _locations->auto_punch_location());
1226         bool const punching_out = (config.get_punch_out () && _locations->auto_punch_location());
1227
1228         if (actively_recording ()) {
1229                 /* permanently recording */
1230                 return max_framepos;
1231         } else if (punching_in && !punching_out) {
1232                 /* punching in but never out */
1233                 return max_framepos;
1234         } else if (punching_in && punching_out && _locations->auto_punch_location()->end() > current_end_frame()) {
1235                 /* punching in and punching out after session end */
1236                 return max_framepos;
1237         }
1238
1239         return current_end_frame ();
1240 }
1241
1242
1243
1244 /* dedicated thread for signal emission.
1245  *
1246  * while sending cross-thread signals from the process thread
1247  * is fine in general, PBD::Signal's use of boost::function and
1248  * boost:bind can produce a vast overhead which is not
1249  * acceptable for low latency.
1250  *
1251  * This works around the issue by moving the boost overhead
1252  * out of the RT thread. The overall load is probably higher but
1253  * the realtime thread remains unaffected.
1254  */
1255
1256 void
1257 Session::emit_route_signals ()
1258 {
1259         // TODO use RAII to allow using these signals in other places
1260         BatchUpdateStart(); /* EMIT SIGNAL */
1261         boost::shared_ptr<RouteList> r = routes.reader ();
1262         for (RouteList::const_iterator ci = r->begin(); ci != r->end(); ++ci) {
1263                 (*ci)->emit_pending_signals ();
1264         }
1265         BatchUpdateEnd(); /* EMIT SIGNAL */
1266 }
1267
1268 void
1269 Session::emit_thread_start ()
1270 {
1271         if (_rt_thread_active) {
1272                 return;
1273         }
1274         _rt_thread_active = true;
1275
1276         if (pthread_create (&_rt_emit_thread, NULL, emit_thread, this)) {
1277                 _rt_thread_active = false;
1278         }
1279 }
1280
1281 void
1282 Session::emit_thread_terminate ()
1283 {
1284         if (!_rt_thread_active) {
1285                 return;
1286         }
1287         _rt_thread_active = false;
1288
1289         if (pthread_mutex_lock (&_rt_emit_mutex) == 0) {
1290                 pthread_cond_signal (&_rt_emit_cond);
1291                 pthread_mutex_unlock (&_rt_emit_mutex);
1292         }
1293
1294         void *status;
1295         pthread_join (_rt_emit_thread, &status);
1296 }
1297
1298 void *
1299 Session::emit_thread (void *arg)
1300 {
1301         Session *s = static_cast<Session *>(arg);
1302         s->emit_thread_run ();
1303         pthread_exit (0);
1304         return 0;
1305 }
1306
1307 void
1308 Session::emit_thread_run ()
1309 {
1310         pthread_mutex_lock (&_rt_emit_mutex);
1311         while (_rt_thread_active) {
1312                 emit_route_signals();
1313                 pthread_cond_wait (&_rt_emit_cond, &_rt_emit_mutex);
1314         }
1315         pthread_mutex_unlock (&_rt_emit_mutex);
1316 }