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