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 #include "ardour/vca.h"
  44 #include "ardour/vca_manager.h"
  45
  46 #include "midi++/mmc.h"
  47
  48 #include "pbd/i18n.h"
  49
  50 using namespace ARDOUR;
  51 using namespace PBD;
  52 using namespace std;
  53
  54 /** Called by the audio engine when there is work to be done with JACK.
  55  * @param nframes Number of frames to process.
  56  */
  57
  58 void
  59 Session::process (pframes_t nframes)
  60 {
  61         framepos_t transport_at_start = _transport_frame;
  62
  63         _silent = false;
  64
  65         if (processing_blocked()) {
  66                 _silent = true;
  67                 return;
  68         }
  69
  70         if (non_realtime_work_pending()) {
  71                 if (!_butler->transport_work_requested ()) {
  72                         post_transport ();
  73                 }
  74         }
  75
  76         _engine.main_thread()->get_buffers ();
  77
  78         (this->*process_function) (nframes);
  79
  80         /* realtime-safe meter-position and processor-order changes
  81          *
  82          * ideally this would be done in
  83          * Route::process_output_buffers() but various functions
  84          * callig it hold a _processor_lock reader-lock
  85          */
  86         boost::shared_ptr<RouteList> r = routes.reader ();
  87         for (RouteList::const_iterator i = r->begin(); i != r->end(); ++i) {
  88                 if ((*i)->apply_processor_changes_rt()) {
  89                         _rt_emit_pending = true;
  90                 }
  91         }
  92         if (_rt_emit_pending) {
  93                 if (!_rt_thread_active) {
  94                         emit_route_signals ();
  95                 }
  96                 if (pthread_mutex_trylock (&_rt_emit_mutex) == 0) {
  97                         pthread_cond_signal (&_rt_emit_cond);
  98                         pthread_mutex_unlock (&_rt_emit_mutex);
  99                         _rt_emit_pending = false;
 100                 }
 101         }
 102
 103         _engine.main_thread()->drop_buffers ();
 104
 105         /* deliver MIDI clock. Note that we need to use the transport frame
 106          * position at the start of process(), not the value at the end of
 107          * it. We may already have ticked() because of a transport state
 108          * change, for example.
 109          */
 110
 111         try {
 112                 if (!_silent && !_engine.freewheeling() && Config->get_send_midi_clock() && (transport_speed() == 1.0f || transport_speed() == 0.0f) && midi_clock->has_midi_port()) {
 113                         midi_clock->tick (transport_at_start, nframes);
 114                 }
 115
 116                 _scene_changer->run (transport_at_start, transport_at_start + nframes);
 117
 118         } catch (...) {
 119                 /* don't bother with a message */
 120         }
 121
 122         SendFeedback (); /* EMIT SIGNAL */
 123 }
 124
 125 int
 126 Session::fail_roll (pframes_t nframes)
 127 {
 128         return no_roll (nframes);
 129 }
 130
 131 int
 132 Session::no_roll (pframes_t nframes)
 133 {
 134         PT_TIMING_CHECK (4);
 135
 136         framepos_t end_frame = _transport_frame + nframes; // FIXME: varispeed + no_roll ??
 137         int ret = 0;
 138         int declick = (config.get_use_transport_fades() ? get_transport_declick_required() : false);
 139         boost::shared_ptr<RouteList> r = routes.reader ();
 140
 141         if (_click_io) {
 142                 _click_io->silence (nframes);
 143         }
 144
 145         ltc_tx_send_time_code_for_cycle (_transport_frame, end_frame, _target_transport_speed, _transport_speed, nframes);
 146
 147         VCAList v = _vca_manager->vcas ();
 148         for (VCAList::const_iterator i = v.begin(); i != v.end(); ++i) {
 149                 (*i)->automation_run (_transport_frame, nframes);
 150         }
 151
 152         if (_process_graph) {
 153                 DEBUG_TRACE(DEBUG::ProcessThreads,"calling graph/no-roll\n");
 154                 _process_graph->routes_no_roll( nframes, _transport_frame, end_frame, non_realtime_work_pending(), declick);
 155         } else {
 156                 PT_TIMING_CHECK (10);
 157                 for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 158
 159                         if ((*i)->is_auditioner()) {
 160                                 continue;
 161                         }
 162
 163                         (*i)->set_pending_declick (declick);
 164
 165                         if ((*i)->no_roll (nframes, _transport_frame, end_frame, non_realtime_work_pending())) {
 166                                 error << string_compose(_("Session: error in no roll for %1"), (*i)->name()) << endmsg;
 167                                 ret = -1;
 168                                 break;
 169                         }
 170                 }
 171                 PT_TIMING_CHECK (11);
 172         }
 173
 174         PT_TIMING_CHECK (5);
 175         return ret;
 176 }
 177
 178 /** @param need_butler to be set to true by this method if it needs the butler,
 179  *  otherwise it must be left alone.
 180  */
 181 int
 182 Session::process_routes (pframes_t nframes, bool& need_butler)
 183 {
 184         int declick = (config.get_use_transport_fades() ? get_transport_declick_required() : false);
 185         boost::shared_ptr<RouteList> r = routes.reader ();
 186
 187         const framepos_t start_frame = _transport_frame;
 188         const framepos_t end_frame = _transport_frame + floor (nframes * _transport_speed);
 189
 190         VCAList v = _vca_manager->vcas ();
 191         for (VCAList::const_iterator i = v.begin(); i != v.end(); ++i) {
 192                 (*i)->automation_run (start_frame, nframes);
 193         }
 194
 195         if (_process_graph) {
 196                 DEBUG_TRACE(DEBUG::ProcessThreads,"calling graph/process-routes\n");
 197                 if (_process_graph->process_routes (nframes, start_frame, end_frame, declick, need_butler) < 0) {
 198                         stop_transport ();
 199                         return -1;
 200                 }
 201         } else {
 202
 203                 for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 204
 205                         int ret;
 206
 207                         if ((*i)->is_auditioner()) {
 208                                 continue;
 209                         }
 210
 211                         (*i)->set_pending_declick (declick);
 212
 213                         bool b = false;
 214
 215                         if ((ret = (*i)->roll (nframes, start_frame, end_frame, declick, b)) < 0) {
 216                                 stop_transport ();
 217                                 return -1;
 218                         }
 219
 220                         if (b) {
 221                                 need_butler = true;
 222                         }
 223                 }
 224         }
 225
 226         return 0;
 227 }
 228
 229 /** @param need_butler to be set to true by this method if it needs the butler,
 230  *  otherwise it must be left alone.
 231  */
 232 int
 233 Session::silent_process_routes (pframes_t nframes, bool& need_butler)
 234 {
 235         boost::shared_ptr<RouteList> r = routes.reader ();
 236
 237         const framepos_t start_frame = _transport_frame;
 238         const framepos_t end_frame = _transport_frame + lrintf(nframes * _transport_speed);
 239
 240         VCAList v = _vca_manager->vcas ();
 241         for (VCAList::const_iterator i = v.begin(); i != v.end(); ++i) {
 242                 (*i)->automation_run (start_frame, nframes);
 243         }
 244
 245         if (_process_graph) {
 246                 _process_graph->silent_process_routes (nframes, start_frame, end_frame, need_butler);
 247         } else {
 248                 for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 249
 250                         int ret;
 251
 252                         if ((*i)->is_auditioner()) {
 253                                 continue;
 254                         }
 255
 256                         bool b = false;
 257
 258                         if ((ret = (*i)->silent_roll (nframes, start_frame, end_frame, b)) < 0) {
 259                                 stop_transport ();
 260                                 return -1;
 261                         }
 262
 263                         if (b) {
 264                                 need_butler = true;
 265                         }
 266                 }
 267         }
 268
 269         return 0;
 270 }
 271
 272 void
 273 Session::get_track_statistics ()
 274 {
 275         float pworst = 1.0f;
 276         float cworst = 1.0f;
 277
 278         boost::shared_ptr<RouteList> rl = routes.reader();
 279         for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
 280
 281                 boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
 282
 283                 if (!tr || tr->hidden()) {
 284                         continue;
 285                 }
 286
 287                 pworst = min (pworst, tr->playback_buffer_load());
 288                 cworst = min (cworst, tr->capture_buffer_load());
 289         }
 290
 291         g_atomic_int_set (&_playback_load, (uint32_t) floor (pworst * 100.0f));
 292         g_atomic_int_set (&_capture_load, (uint32_t) floor (cworst * 100.0f));
 293
 294         if (actively_recording()) {
 295                 set_dirty();
 296         }
 297 }
 298
 299 /** Process callback used when the auditioner is not active */
 300 void
 301 Session::process_with_events (pframes_t nframes)
 302 {
 303         PT_TIMING_CHECK (3);
 304
 305         SessionEvent*  ev;
 306         pframes_t      this_nframes;
 307         framepos_t     end_frame;
 308         bool           session_needs_butler = false;
 309         framecnt_t     frames_moved;
 310
 311         /* make sure the auditioner is silent */
 312
 313         if (auditioner) {
 314                 auditioner->silence (nframes);
 315         }
 316
 317         /* handle any pending events */
 318
 319         while (pending_events.read (&ev, 1) == 1) {
 320                 merge_event (ev);
 321         }
 322
 323         /* if we are not in the middle of a state change,
 324            and there are immediate events queued up,
 325            process them.
 326         */
 327
 328         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 329                 SessionEvent *ev = immediate_events.front ();
 330                 immediate_events.pop_front ();
 331                 process_event (ev);
 332         }
 333
 334         /* count in */
 335         if (_transport_speed != 1.0 && _count_in_samples > 0) {
 336                 _count_in_samples = 0;
 337         }
 338
 339         if (_count_in_samples > 0) {
 340                 framecnt_t ns = std::min ((framecnt_t)nframes, _count_in_samples);
 341
 342                 no_roll (ns);
 343                 run_click (_transport_frame - _count_in_samples, ns);
 344
 345                 _count_in_samples -= ns;
 346                 nframes -= ns;
 347
 348                 /* process events.. */
 349                 if (!events.empty() && next_event != events.end()) {
 350                         SessionEvent* this_event = *next_event;
 351                         Events::iterator the_next_one = next_event;
 352                         ++the_next_one;
 353
 354                         while (this_event && this_event->action_frame == _transport_frame) {
 355                                 process_event (this_event);
 356                                 if (the_next_one == events.end()) {
 357                                         this_event = 0;
 358                                 } else {
 359                                         this_event = *the_next_one;
 360                                         ++the_next_one;
 361                                 }
 362                         }
 363                         set_next_event ();
 364                 }
 365
 366                 check_declick_out ();
 367
 368                 if (nframes == 0) {
 369                         return;
 370                 } else {
 371                         _engine.split_cycle (ns);
 372                 }
 373         }
 374
 375         /* Decide on what to do with quarter-frame MTC during this cycle */
 376
 377         bool const was_sending_qf_mtc = _send_qf_mtc;
 378         double const tolerance = Config->get_mtc_qf_speed_tolerance() / 100.0;
 379
 380         if (_transport_speed != 0) {
 381                 _send_qf_mtc = (
 382                         Config->get_send_mtc () &&
 383                         _transport_speed >= (1 - tolerance) &&
 384                         _transport_speed <= (1 + tolerance)
 385                         );
 386
 387                 if (_send_qf_mtc && !was_sending_qf_mtc) {
 388                         /* we will re-start quarter-frame MTC this cycle, so send a full update to set things up */
 389                         _send_timecode_update = true;
 390                 }
 391
 392                 if (Config->get_send_mtc() && !_send_qf_mtc && _pframes_since_last_mtc > (frame_rate () / 4)) {
 393                         /* we're sending MTC, but we're not sending QF MTC at the moment, and it's been
 394                            a quarter of a second since we sent anything at all, so send a full MTC update
 395                            this cycle.
 396                         */
 397                         _send_timecode_update = true;
 398                 }
 399
 400                 _pframes_since_last_mtc += nframes;
 401         }
 402
 403         /* Events caused a transport change (or we re-started sending
 404          * MTC), so send an MTC Full Frame (Timecode) message.  This
 405          * is sent whether rolling or not, to give slaves an idea of
 406          * ardour time on locates (and allow slow slaves to position
 407          * and prepare for rolling)
 408          */
 409         if (_send_timecode_update) {
 410                 send_full_time_code (_transport_frame, nframes);
 411         }
 412
 413         if (!process_can_proceed()) {
 414                 _silent = true;
 415                 return;
 416         }
 417
 418         if (events.empty() || next_event == events.end()) {
 419                 try_run_lua (nframes); // also during export ?? ->move to process_without_events()
 420                 /* lua scripts may inject events */
 421                 while (_n_lua_scripts > 0 && pending_events.read (&ev, 1) == 1) {
 422                         merge_event (ev);
 423                 }
 424                 if (events.empty() || next_event == events.end()) {
 425                         process_without_events (nframes);
 426                         return;
 427                 }
 428         }
 429
 430         if (_transport_speed == 1.0) {
 431                 frames_moved = (framecnt_t) nframes;
 432         } else {
 433                 interpolation.set_target_speed (_target_transport_speed);
 434                 interpolation.set_speed (_transport_speed);
 435                 frames_moved = (framecnt_t) interpolation.interpolate (0, nframes, 0, 0);
 436         }
 437
 438         end_frame = _transport_frame + frames_moved;
 439
 440         {
 441                 SessionEvent* this_event;
 442                 Events::iterator the_next_one;
 443
 444                 if (!process_can_proceed()) {
 445                         _silent = true;
 446                         return;
 447                 }
 448
 449                 if (!_exporting && _slave) {
 450                         if (!follow_slave (nframes)) {
 451                                 return;
 452                         }
 453                 }
 454
 455                 if (_transport_speed == 0) {
 456                         no_roll (nframes);
 457                         return;
 458                 }
 459
 460                 if (!_exporting && !timecode_transmission_suspended()) {
 461                         send_midi_time_code_for_cycle (_transport_frame, end_frame, nframes);
 462                 }
 463
 464                 ltc_tx_send_time_code_for_cycle (_transport_frame, end_frame, _target_transport_speed, _transport_speed, nframes);
 465
 466                 framepos_t stop_limit = compute_stop_limit ();
 467
 468                 if (maybe_stop (stop_limit)) {
 469                         no_roll (nframes);
 470                         return;
 471                 }
 472
 473                 this_event = *next_event;
 474                 the_next_one = next_event;
 475                 ++the_next_one;
 476
 477                 /* yes folks, here it is, the actual loop where we really truly
 478                    process some audio
 479                 */
 480
 481                 while (nframes) {
 482
 483                         this_nframes = nframes; /* real (jack) time relative */
 484                         frames_moved = (framecnt_t) floor (_transport_speed * nframes); /* transport relative */
 485
 486                         /* running an event, position transport precisely to its time */
 487                         if (this_event && this_event->action_frame <= end_frame && this_event->action_frame >= _transport_frame) {
 488                                 /* this isn't quite right for reverse play */
 489                                 frames_moved = (framecnt_t) (this_event->action_frame - _transport_frame);
 490                                 this_nframes = abs (floor(frames_moved / _transport_speed));
 491                         }
 492
 493                         try_run_lua (this_nframes);
 494
 495                         if (this_nframes) {
 496
 497                                 click (_transport_frame, this_nframes);
 498
 499                                 if (process_routes (this_nframes, session_needs_butler)) {
 500                                         fail_roll (nframes);
 501                                         return;
 502                                 }
 503
 504                                 get_track_statistics ();
 505
 506                                 nframes -= this_nframes;
 507
 508                                 if (frames_moved < 0) {
 509                                         decrement_transport_position (-frames_moved);
 510                                 } else {
 511                                         increment_transport_position (frames_moved);
 512                                 }
 513
 514                                 maybe_stop (stop_limit);
 515                                 check_declick_out ();
 516                         }
 517
 518                         if (nframes > 0) {
 519                                 _engine.split_cycle (this_nframes);
 520                         }
 521
 522                         /* now handle this event and all others scheduled for the same time */
 523
 524                         while (this_event && this_event->action_frame == _transport_frame) {
 525                                 process_event (this_event);
 526
 527                                 if (the_next_one == events.end()) {
 528                                         this_event = 0;
 529                                 } else {
 530                                         this_event = *the_next_one;
 531                                         ++the_next_one;
 532                                 }
 533                         }
 534
 535                         /* if an event left our state changing, do the right thing */
 536
 537                         if (nframes && non_realtime_work_pending()) {
 538                                 no_roll (nframes);
 539                                 break;
 540                         }
 541
 542                         /* this is necessary to handle the case of seamless looping */
 543                         end_frame = _transport_frame + floor (nframes * _transport_speed);
 544                 }
 545
 546                 set_next_event ();
 547
 548         } /* implicit release of route lock */
 549
 550         if (session_needs_butler) {
 551                 _butler->summon ();
 552         }
 553 }
 554
 555 void
 556 Session::reset_slave_state ()
 557 {
 558         average_slave_delta = 1800;
 559         delta_accumulator_cnt = 0;
 560         have_first_delta_accumulator = false;
 561         _slave_state = Stopped;
 562 }
 563
 564 bool
 565 Session::transport_locked () const
 566 {
 567         Slave* sl = _slave;
 568
 569         if (!locate_pending() && (!config.get_external_sync() || (sl && sl->ok() && sl->locked()))) {
 570                 return true;
 571         }
 572
 573         return false;
 574 }
 575
 576 bool
 577 Session::follow_slave (pframes_t nframes)
 578 {
 579         double slave_speed;
 580         framepos_t slave_transport_frame;
 581         framecnt_t this_delta;
 582         int dir;
 583
 584         if (!_slave->ok()) {
 585                 stop_transport ();
 586                 config.set_external_sync (false);
 587                 goto noroll;
 588         }
 589
 590         _slave->speed_and_position (slave_speed, slave_transport_frame);
 591
 592         DEBUG_TRACE (DEBUG::Slave, string_compose ("Slave position %1 speed %2\n", slave_transport_frame, slave_speed));
 593
 594         if (!_slave->locked()) {
 595                 DEBUG_TRACE (DEBUG::Slave, "slave not locked\n");
 596                 goto noroll;
 597         }
 598
 599         if (slave_transport_frame > _transport_frame) {
 600                 this_delta = slave_transport_frame - _transport_frame;
 601                 dir = 1;
 602         } else {
 603                 this_delta = _transport_frame - slave_transport_frame;
 604                 dir = -1;
 605         }
 606
 607         if (_slave->starting()) {
 608                 slave_speed = 0.0f;
 609         }
 610
 611         if (_slave->is_always_synced() ||
 612                         (Config->get_timecode_source_is_synced() && (dynamic_cast<TimecodeSlave*>(_slave)) != 0)
 613                         ) {
 614
 615                 /* if the TC source is synced, then we assume that its
 616                    speed is binary: 0.0 or 1.0
 617                 */
 618
 619                 if (slave_speed != 0.0f) {
 620                         slave_speed = 1.0f;
 621                 }
 622
 623         } else {
 624
 625                 /* if we are chasing and the average delta between us and the
 626                    master gets too big, we want to switch to silent
 627                    motion. so keep track of that here.
 628                 */
 629
 630                 if (_slave_state == Running) {
 631                         calculate_moving_average_of_slave_delta(dir, this_delta);
 632                 }
 633         }
 634
 635         track_slave_state (slave_speed, slave_transport_frame, this_delta);
 636
 637         DEBUG_TRACE (DEBUG::Slave, string_compose ("slave state %1 @ %2 speed %3 cur delta %4 avg delta %5\n",
 638                                                    _slave_state, slave_transport_frame, slave_speed, this_delta, average_slave_delta));
 639
 640
 641         if (_slave_state == Running && !_slave->is_always_synced() &&
 642                         !(Config->get_timecode_source_is_synced() && (dynamic_cast<TimecodeSlave*>(_slave)) != 0)
 643                         ) {
 644
 645                 if (_transport_speed != 0.0f) {
 646
 647                         /*
 648                            note that average_dir is +1 or -1
 649                         */
 650
 651                         float delta;
 652
 653                         if (average_slave_delta == 0) {
 654                                 delta = this_delta;
 655                                 delta *= dir;
 656                         } else {
 657                                 delta = average_slave_delta;
 658                                 delta *= average_dir;
 659                         }
 660
 661 #ifndef NDEBUG
 662                         if (slave_speed != 0.0) {
 663                                 DEBUG_TRACE (DEBUG::Slave, string_compose ("delta = %1 speed = %2 ts = %3 M@%4 S@%5 avgdelta %6\n",
 664                                                                            (int) (dir * this_delta),
 665                                                                            slave_speed,
 666                                                                            _transport_speed,
 667                                                                            _transport_frame,
 668                                                                            slave_transport_frame,
 669                                                                            average_slave_delta));
 670                         }
 671 #endif
 672
 673                         if (_slave->give_slave_full_control_over_transport_speed()) {
 674                                 set_transport_speed (slave_speed, 0, false, false);
 675                                 //std::cout << "set speed = " << slave_speed << "\n";
 676                         } else {
 677                                 float adjusted_speed = slave_speed + (1.5 * (delta /  float(_current_frame_rate)));
 678                                 request_transport_speed (adjusted_speed);
 679                                 DEBUG_TRACE (DEBUG::Slave, string_compose ("adjust using %1 towards %2 ratio %3 current %4 slave @ %5\n",
 680                                                                            delta, adjusted_speed, adjusted_speed/slave_speed, _transport_speed,
 681                                                                            slave_speed));
 682                         }
 683
 684 #if 1
 685                         if (!actively_recording() && (framecnt_t) abs(average_slave_delta) > _slave->resolution()) {
 686                                 cerr << "average slave delta greater than slave resolution (" << _slave->resolution() << "), going to silent motion\n";
 687                                 goto silent_motion;
 688                         }
 689 #endif
 690                 }
 691         }
 692
 693
 694         if (_slave_state == Running && 0 == (post_transport_work () & ~PostTransportSpeed)) {
 695                 /* speed is set, we're locked, and good to go */
 696                 return true;
 697         }
 698
 699   silent_motion:
 700         DEBUG_TRACE (DEBUG::Slave, "silent motion\n")
 701         follow_slave_silently (nframes, slave_speed);
 702
 703   noroll:
 704         /* don't move at all */
 705         DEBUG_TRACE (DEBUG::Slave, "no roll\n")
 706         no_roll (nframes);
 707         return false;
 708 }
 709
 710 void
 711 Session::calculate_moving_average_of_slave_delta (int dir, framecnt_t this_delta)
 712 {
 713         if (delta_accumulator_cnt >= delta_accumulator_size) {
 714                 have_first_delta_accumulator = true;
 715                 delta_accumulator_cnt = 0;
 716         }
 717
 718         if (delta_accumulator_cnt != 0 || this_delta < _current_frame_rate) {
 719                 delta_accumulator[delta_accumulator_cnt++] = (framecnt_t) dir *  (framecnt_t) this_delta;
 720         }
 721
 722         if (have_first_delta_accumulator) {
 723                 average_slave_delta = 0L;
 724                 for (int i = 0; i < delta_accumulator_size; ++i) {
 725                         average_slave_delta += delta_accumulator[i];
 726                 }
 727                 average_slave_delta /= (int32_t) delta_accumulator_size;
 728                 if (average_slave_delta < 0L) {
 729                         average_dir = -1;
 730                         average_slave_delta = abs(average_slave_delta);
 731                 } else {
 732                         average_dir = 1;
 733                 }
 734         }
 735 }
 736
 737 void
 738 Session::track_slave_state (float slave_speed, framepos_t slave_transport_frame, framecnt_t /*this_delta*/)
 739 {
 740         if (slave_speed != 0.0f) {
 741
 742                 /* slave is running */
 743
 744                 switch (_slave_state) {
 745                 case Stopped:
 746                         if (_slave->requires_seekahead()) {
 747                                 slave_wait_end = slave_transport_frame + _slave->seekahead_distance ();
 748                                 DEBUG_TRACE (DEBUG::Slave, string_compose ("slave stopped, but running, requires seekahead to %1\n", slave_wait_end));
 749                                 /* we can call locate() here because we are in process context */
 750                                 locate (slave_wait_end, false, false);
 751                                 _slave_state = Waiting;
 752
 753                         } else {
 754
 755                                 DEBUG_TRACE (DEBUG::Slave, string_compose ("slave stopped -> running at %1\n", slave_transport_frame));
 756
 757                                 memset (delta_accumulator, 0, sizeof (int32_t) * delta_accumulator_size);
 758                                 average_slave_delta = 0L;
 759
 760                                 Location* al = _locations->auto_loop_location();
 761
 762                                 if (al && play_loop && (slave_transport_frame < al->start() || slave_transport_frame > al->end())) {
 763                                         // cancel looping
 764                                         request_play_loop(false);
 765                                 }
 766
 767                                 if (slave_transport_frame != _transport_frame) {
 768                                         DEBUG_TRACE (DEBUG::Slave, string_compose ("require locate to run. eng: %1 -> sl: %2\n", _transport_frame, slave_transport_frame));
 769                                         locate (slave_transport_frame, false, false);
 770                                 }
 771                                 _slave_state = Running;
 772                         }
 773                         break;
 774
 775                 case Waiting:
 776                 default:
 777                         break;
 778                 }
 779
 780                 if (_slave_state == Waiting) {
 781
 782                         DEBUG_TRACE (DEBUG::Slave, string_compose ("slave waiting at %1\n", slave_transport_frame));
 783
 784                         if (slave_transport_frame >= slave_wait_end) {
 785
 786                                 DEBUG_TRACE (DEBUG::Slave, string_compose ("slave start at %1 vs %2\n", slave_transport_frame, _transport_frame));
 787
 788                                 _slave_state = Running;
 789
 790                                 /* now perform a "micro-seek" within the disk buffers to realign ourselves
 791                                    precisely with the master.
 792                                 */
 793
 794
 795                                 bool ok = true;
 796                                 framecnt_t frame_delta = slave_transport_frame - _transport_frame;
 797
 798                                 boost::shared_ptr<RouteList> rl = routes.reader();
 799                                 for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
 800                                         boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
 801                                         if (tr && !tr->can_internal_playback_seek (frame_delta)) {
 802                                                 ok = false;
 803                                                 break;
 804                                         }
 805                                 }
 806
 807                                 if (ok) {
 808                                         for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
 809                                                 boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
 810                                                 if (tr) {
 811                                                         tr->internal_playback_seek (frame_delta);
 812                                                 }
 813                                         }
 814                                         _transport_frame += frame_delta;
 815
 816                                 } else {
 817                                         cerr << "cannot micro-seek\n";
 818                                         /* XXX what? */
 819                                 }
 820                         }
 821                 }
 822
 823                 if (_slave_state == Running && _transport_speed == 0.0f) {
 824                         DEBUG_TRACE (DEBUG::Slave, "slave starts transport\n");
 825                         start_transport ();
 826                 }
 827
 828         } else { // slave_speed is 0
 829
 830                 /* slave has stopped */
 831
 832                 if (_transport_speed != 0.0f) {
 833                         DEBUG_TRACE (DEBUG::Slave, string_compose ("slave stops transport: %1 frame %2 tf %3\n", slave_speed, slave_transport_frame, _transport_frame));
 834                         stop_transport ();
 835                 }
 836
 837                 if (slave_transport_frame != _transport_frame) {
 838                         DEBUG_TRACE (DEBUG::Slave, string_compose ("slave stopped, move to %1\n", slave_transport_frame));
 839                         force_locate (slave_transport_frame, false);
 840                 }
 841
 842                 reset_slave_state();
 843         }
 844 }
 845
 846 void
 847 Session::follow_slave_silently (pframes_t nframes, float slave_speed)
 848 {
 849         if (slave_speed && _transport_speed) {
 850
 851                 /* something isn't right, but we should move with the master
 852                    for now.
 853                 */
 854
 855                 bool need_butler = false;
 856
 857                 silent_process_routes (nframes, need_butler);
 858
 859                 get_track_statistics ();
 860
 861                 if (need_butler) {
 862                         _butler->summon ();
 863                 }
 864
 865                 int32_t frames_moved = (int32_t) floor (_transport_speed * nframes);
 866
 867                 if (frames_moved < 0) {
 868                         decrement_transport_position (-frames_moved);
 869                 } else {
 870                         increment_transport_position (frames_moved);
 871                 }
 872
 873                 framepos_t const stop_limit = compute_stop_limit ();
 874                 maybe_stop (stop_limit);
 875         }
 876 }
 877
 878 void
 879 Session::process_without_events (pframes_t nframes)
 880 {
 881         bool session_needs_butler = false;
 882         framecnt_t frames_moved;
 883
 884         if (!process_can_proceed()) {
 885                 _silent = true;
 886                 return;
 887         }
 888
 889         if (!_exporting && _slave) {
 890                 if (!follow_slave (nframes)) {
 891                         ltc_tx_send_time_code_for_cycle (_transport_frame, _transport_frame, 0, 0 , nframes);
 892                         return;
 893                 }
 894         }
 895
 896         if (_transport_speed == 0) {
 897                 fail_roll (nframes);
 898                 return;
 899         }
 900
 901         if (_transport_speed == 1.0) {
 902                 frames_moved = (framecnt_t) nframes;
 903         } else {
 904                 interpolation.set_target_speed (_target_transport_speed);
 905                 interpolation.set_speed (_transport_speed);
 906                 frames_moved = (framecnt_t) interpolation.interpolate (0, nframes, 0, 0);
 907         }
 908
 909         if (!_exporting && !timecode_transmission_suspended()) {
 910                 send_midi_time_code_for_cycle (_transport_frame, _transport_frame + frames_moved, nframes);
 911         }
 912
 913         ltc_tx_send_time_code_for_cycle (_transport_frame, _transport_frame + frames_moved, _target_transport_speed, _transport_speed, nframes);
 914
 915         framepos_t const stop_limit = compute_stop_limit ();
 916
 917         if (maybe_stop (stop_limit)) {
 918                 fail_roll (nframes);
 919                 return;
 920         }
 921
 922         if (maybe_sync_start (nframes)) {
 923                 return;
 924         }
 925
 926         click (_transport_frame, nframes);
 927
 928         if (process_routes (nframes, session_needs_butler)) {
 929                 fail_roll (nframes);
 930                 return;
 931         }
 932
 933         get_track_statistics ();
 934
 935         if (frames_moved < 0) {
 936                 decrement_transport_position (-frames_moved);
 937         } else {
 938                 increment_transport_position (frames_moved);
 939         }
 940
 941         maybe_stop (stop_limit);
 942         check_declick_out ();
 943
 944         if (session_needs_butler) {
 945                 _butler->summon ();
 946         }
 947 }
 948
 949 /** Process callback used when the auditioner is active.
 950  * @param nframes number of frames to process.
 951  */
 952 void
 953 Session::process_audition (pframes_t nframes)
 954 {
 955         SessionEvent* ev;
 956         boost::shared_ptr<RouteList> r = routes.reader ();
 957
 958         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 959                 if (!(*i)->is_auditioner()) {
 960                         (*i)->silence (nframes);
 961                 }
 962         }
 963
 964         /* run the auditioner, and if it says we need butler service, ask for it */
 965
 966         if (auditioner->play_audition (nframes) > 0) {
 967                 _butler->summon ();
 968         }
 969
 970         /* if using a monitor section, run it because otherwise we don't hear anything */
 971
 972         if (_monitor_out && auditioner->needs_monitor()) {
 973                 _monitor_out->monitor_run (_transport_frame, _transport_frame + nframes, nframes, false);
 974         }
 975
 976         /* handle pending events */
 977
 978         while (pending_events.read (&ev, 1) == 1) {
 979                 merge_event (ev);
 980         }
 981
 982         /* if we are not in the middle of a state change,
 983            and there are immediate events queued up,
 984            process them.
 985         */
 986
 987         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 988                 SessionEvent *ev = immediate_events.front ();
 989                 immediate_events.pop_front ();
 990                 process_event (ev);
 991         }
 992
 993         if (!auditioner->auditioning()) {
 994                 /* auditioner no longer active, so go back to the normal process callback */
 995                 process_function = &Session::process_with_events;
 996         }
 997 }
 998
 999 bool
1000 Session::maybe_sync_start (pframes_t & nframes)
1001 {
1002         pframes_t sync_offset;
1003
1004         if (!waiting_for_sync_offset) {
1005                 return false;
1006         }
1007
1008         if (_engine.get_sync_offset (sync_offset) && sync_offset < nframes) {
1009
1010                 /* generate silence up to the sync point, then
1011                    adjust nframes + offset to reflect whatever
1012                    is left to do.
1013                 */
1014
1015                 no_roll (sync_offset);
1016                 nframes -= sync_offset;
1017                 Port::increment_global_port_buffer_offset (sync_offset);
1018                 waiting_for_sync_offset = false;
1019
1020                 if (nframes == 0) {
1021                         return true; // done, nothing left to process
1022                 }
1023
1024         } else {
1025
1026                 /* sync offset point is not within this process()
1027                    cycle, so just generate silence. and don't bother
1028                    with any fancy stuff here, just the minimal silence.
1029                 */
1030
1031                 _silent = true;
1032
1033                 if (Config->get_locate_while_waiting_for_sync()) {
1034                         if (micro_locate (nframes)) {
1035                                 /* XXX ERROR !!! XXX */
1036                         }
1037                 }
1038
1039                 return true; // done, nothing left to process
1040         }
1041
1042         return false;
1043 }
1044
1045 void
1046 Session::queue_event (SessionEvent* ev)
1047 {
1048         if (_state_of_the_state & Deletion) {
1049                 return;
1050         } else if (_state_of_the_state & Loading) {
1051                 merge_event (ev);
1052         } else {
1053                 Glib::Threads::Mutex::Lock lm (rb_write_lock);
1054                 pending_events.write (&ev, 1);
1055         }
1056 }
1057
1058 void
1059 Session::set_next_event ()
1060 {
1061         if (events.empty()) {
1062                 next_event = events.end();
1063                 return;
1064         }
1065
1066         if (next_event == events.end()) {
1067                 next_event = events.begin();
1068         }
1069
1070         if ((*next_event)->action_frame > _transport_frame) {
1071                 next_event = events.begin();
1072         }
1073
1074         for (; next_event != events.end(); ++next_event) {
1075                 if ((*next_event)->action_frame >= _transport_frame) {
1076                         break;
1077                 }
1078         }
1079 }
1080
1081 void
1082 Session::process_event (SessionEvent* ev)
1083 {
1084         bool remove = true;
1085         bool del = true;
1086
1087         /* if we're in the middle of a state change (i.e. waiting
1088            for the butler thread to complete the non-realtime
1089            part of the change), we'll just have to queue this
1090            event for a time when the change is complete.
1091         */
1092
1093         if (non_realtime_work_pending()) {
1094
1095                 /* except locates, which we have the capability to handle */
1096
1097                 if (ev->type != SessionEvent::Locate) {
1098                         immediate_events.insert (immediate_events.end(), ev);
1099                         _remove_event (ev);
1100                         return;
1101                 }
1102         }
1103
1104         DEBUG_TRACE (DEBUG::SessionEvents, string_compose ("Processing event: %1 @ %2\n", enum_2_string (ev->type), _transport_frame));
1105
1106         switch (ev->type) {
1107         case SessionEvent::SetLoop:
1108                 set_play_loop (ev->yes_or_no, ev->speed);
1109                 break;
1110
1111         case SessionEvent::AutoLoop:
1112                 if (play_loop) {
1113                         /* roll after locate, do not flush, set "with loop"
1114                            true only if we are seamless looping
1115                         */
1116                         start_locate (ev->target_frame, true, false, Config->get_seamless_loop());
1117                 }
1118                 remove = false;
1119                 del = false;
1120                 break;
1121
1122         case SessionEvent::AutoLoopDeclick:
1123                 if (play_loop) {
1124                         /* Request a declick fade-out and a fade-in; the fade-out will happen
1125                            at the end of the loop, and the fade-in at the start.
1126                         */
1127                         transport_sub_state |= (PendingLoopDeclickOut | PendingLoopDeclickIn);
1128                 }
1129                 remove = false;
1130                 del = false;
1131                 break;
1132
1133         case SessionEvent::Locate:
1134                 if (ev->yes_or_no) {
1135                         /* args: do not roll after locate, do flush, not with loop */
1136                         locate (ev->target_frame, false, true, false);
1137                 } else {
1138                         /* args: do not roll after locate, do flush, not with loop */
1139                         start_locate (ev->target_frame, false, true, false);
1140                 }
1141                 _send_timecode_update = true;
1142                 break;
1143
1144         case SessionEvent::LocateRoll:
1145                 if (ev->yes_or_no) {
1146                         /* args: roll after locate, do flush, not with loop */
1147                         locate (ev->target_frame, true, true, false);
1148                 } else {
1149                         /* args: roll after locate, do flush, not with loop */
1150                         start_locate (ev->target_frame, true, true, false);
1151                 }
1152                 _send_timecode_update = true;
1153                 break;
1154
1155         case SessionEvent::Skip:
1156                 if (Config->get_skip_playback()) {
1157                         start_locate (ev->target_frame, true, true, false);
1158                         _send_timecode_update = true;
1159                 }
1160                 remove = false;
1161                 del = false;
1162                 break;
1163
1164         case SessionEvent::LocateRollLocate:
1165                 // locate is handled by ::request_roll_at_and_return()
1166                 _requested_return_frame = ev->target_frame;
1167                 request_locate (ev->target2_frame, true);
1168                 break;
1169
1170
1171         case SessionEvent::SetTransportSpeed:
1172                 set_transport_speed (ev->speed, ev->target_frame, ev->yes_or_no, ev->second_yes_or_no, ev->third_yes_or_no);
1173                 break;
1174
1175         case SessionEvent::PunchIn:
1176                 // cerr << "PunchIN at " << transport_frame() << endl;
1177                 if (config.get_punch_in() && record_status() == Enabled && !preroll_record_punch_enabled()) {
1178                         enable_record ();
1179                 }
1180                 remove = false;
1181                 del = false;
1182                 break;
1183
1184         case SessionEvent::PunchOut:
1185                 // cerr << "PunchOUT at " << transport_frame() << endl;
1186                 if (config.get_punch_out() && !preroll_record_punch_enabled()) {
1187                         step_back_from_record ();
1188                 }
1189                 remove = false;
1190                 del = false;
1191                 break;
1192
1193         case SessionEvent::RecordStart:
1194                 if (preroll_record_punch_enabled() && record_status() == Enabled) {
1195                         enable_record ();
1196                 }
1197                 remove = false;
1198                 del = false;
1199                 break;
1200
1201         case SessionEvent::StopOnce:
1202                 if (!non_realtime_work_pending()) {
1203                         _clear_event_type (SessionEvent::StopOnce);
1204                         stop_transport (ev->yes_or_no);
1205                 }
1206                 remove = false;
1207                 del = false;
1208                 break;
1209
1210         case SessionEvent::RangeStop:
1211                 if (!non_realtime_work_pending()) {
1212                         stop_transport (ev->yes_or_no);
1213                 }
1214                 remove = false;
1215                 del = false;
1216                 break;
1217
1218         case SessionEvent::RangeLocate:
1219                 /* args: roll after locate, do flush, not with loop */
1220                 start_locate (ev->target_frame, true, true, false);
1221                 remove = false;
1222                 del = false;
1223                 break;
1224
1225         case SessionEvent::Overwrite:
1226                 overwrite_some_buffers (static_cast<Track*>(ev->ptr));
1227                 break;
1228
1229         case SessionEvent::SetTrackSpeed:
1230                 set_track_speed (static_cast<Track*> (ev->ptr), ev->speed);
1231                 break;
1232
1233         case SessionEvent::SetSyncSource:
1234                 DEBUG_TRACE (DEBUG::Slave, "seen request for new slave\n");
1235                 use_sync_source (ev->slave);
1236                 break;
1237
1238         case SessionEvent::Audition:
1239                 set_audition (ev->region);
1240                 // drop reference to region
1241                 ev->region.reset ();
1242                 break;
1243
1244         case SessionEvent::InputConfigurationChange:
1245                 add_post_transport_work (PostTransportInputChange);
1246                 _butler->schedule_transport_work ();
1247                 break;
1248
1249         case SessionEvent::SetPlayAudioRange:
1250                 set_play_range (ev->audio_range, (ev->speed == 1.0f));
1251                 break;
1252
1253         case SessionEvent::CancelPlayAudioRange:
1254                 unset_play_range();
1255                 break;
1256
1257         case SessionEvent::RealTimeOperation:
1258                 process_rtop (ev);
1259                 del = false; // other side of RT request needs to clean up
1260                 break;
1261
1262         case SessionEvent::AdjustPlaybackBuffering:
1263                 schedule_playback_buffering_adjustment ();
1264                 break;
1265
1266         case SessionEvent::AdjustCaptureBuffering:
1267                 schedule_capture_buffering_adjustment ();
1268                 break;
1269
1270         case SessionEvent::SetTimecodeTransmission:
1271                 g_atomic_int_set (&_suspend_timecode_transmission, ev->yes_or_no ? 0 : 1);
1272                 break;
1273
1274         default:
1275           fatal << string_compose(_("Programming error: illegal event type in process_event (%1)"), ev->type) << endmsg;
1276                 abort(); /*NOTREACHED*/
1277                 break;
1278         };
1279
1280         if (remove) {
1281                 del = del && !_remove_event (ev);
1282         }
1283
1284         if (del) {
1285                 delete ev;
1286         }
1287 }
1288
1289 framepos_t
1290 Session::compute_stop_limit () const
1291 {
1292         if (!Config->get_stop_at_session_end ()) {
1293                 return max_framepos;
1294         }
1295
1296         if (_slave) {
1297                 return max_framepos;
1298         }
1299
1300         if (preroll_record_punch_enabled ()) {
1301                 return max_framepos;
1302         }
1303
1304         bool const punching_in = (config.get_punch_in () && _locations->auto_punch_location());
1305         bool const punching_out = (config.get_punch_out () && _locations->auto_punch_location());
1306
1307         if (actively_recording ()) {
1308                 /* permanently recording */
1309                 return max_framepos;
1310         } else if (punching_in && !punching_out) {
1311                 /* punching in but never out */
1312                 return max_framepos;
1313         } else if (punching_in && punching_out && _locations->auto_punch_location()->end() > current_end_frame()) {
1314                 /* punching in and punching out after session end */
1315                 return max_framepos;
1316         }
1317
1318         return current_end_frame ();
1319 }
1320
1321
1322
1323 /* dedicated thread for signal emission.
1324  *
1325  * while sending cross-thread signals from the process thread
1326  * is fine in general, PBD::Signal's use of boost::function and
1327  * boost:bind can produce a vast overhead which is not
1328  * acceptable for low latency.
1329  *
1330  * This works around the issue by moving the boost overhead
1331  * out of the RT thread. The overall load is probably higher but
1332  * the realtime thread remains unaffected.
1333  */
1334
1335 void
1336 Session::emit_route_signals ()
1337 {
1338         // TODO use RAII to allow using these signals in other places
1339         BatchUpdateStart(); /* EMIT SIGNAL */
1340         boost::shared_ptr<RouteList> r = routes.reader ();
1341         for (RouteList::const_iterator ci = r->begin(); ci != r->end(); ++ci) {
1342                 (*ci)->emit_pending_signals ();
1343         }
1344         BatchUpdateEnd(); /* EMIT SIGNAL */
1345 }
1346
1347 void
1348 Session::emit_thread_start ()
1349 {
1350         if (_rt_thread_active) {
1351                 return;
1352         }
1353         _rt_thread_active = true;
1354
1355         if (pthread_create (&_rt_emit_thread, NULL, emit_thread, this)) {
1356                 _rt_thread_active = false;
1357         }
1358 }
1359
1360 void
1361 Session::emit_thread_terminate ()
1362 {
1363         if (!_rt_thread_active) {
1364                 return;
1365         }
1366         _rt_thread_active = false;
1367
1368         if (pthread_mutex_lock (&_rt_emit_mutex) == 0) {
1369                 pthread_cond_signal (&_rt_emit_cond);
1370                 pthread_mutex_unlock (&_rt_emit_mutex);
1371         }
1372
1373         void *status;
1374         pthread_join (_rt_emit_thread, &status);
1375 }
1376
1377 void *
1378 Session::emit_thread (void *arg)
1379 {
1380         Session *s = static_cast<Session *>(arg);
1381         s->emit_thread_run ();
1382         pthread_exit (0);
1383         return 0;
1384 }
1385
1386 void
1387 Session::emit_thread_run ()
1388 {
1389         pthread_mutex_lock (&_rt_emit_mutex);
1390         while (_rt_thread_active) {
1391                 emit_route_signals();
1392                 pthread_cond_wait (&_rt_emit_cond, &_rt_emit_mutex);
1393         }
1394         pthread_mutex_unlock (&_rt_emit_mutex);
1395 }