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     $Id$
  19 */
  20
  21 #include <cmath>
  22 #include <cerrno>
  23 #include <algorithm>
  24 #include <unistd.h>
  25
  26 #include <ardour/timestamps.h>
  27
  28 #include <pbd/error.h>
  29 #include <pbd/atomic.h>
  30 #include <pbd/lockmonitor.h>
  31
  32 #include <ardour/ardour.h>
  33 #include <ardour/session.h>
  34 #include <ardour/diskstream.h>
  35 #include <ardour/audioengine.h>
  36 #include <ardour/slave.h>
  37 #include <ardour/auditioner.h>
  38 #include <ardour/cycles.h>
  39 #include <ardour/cycle_timer.h>
  40
  41 #include "i18n.h"
  42
  43 using namespace ARDOUR;
  44 //using namespace sigc;
  45 using namespace std;
  46
  47 void
  48 Session::process (jack_nframes_t nframes)
  49 {
  50         if (synced_to_jack() && waiting_to_start) {
  51                 if ( _engine.transport_state() == AudioEngine::TransportRolling) {
  52                         actually_start_transport ();
  53                 }
  54         }
  55
  56         if (non_realtime_work_pending()) {
  57                 if (atomic_read (&butler_should_do_transport_work) == 0) {
  58                         post_transport ();
  59                 }
  60         }
  61
  62         (this->*process_function) (nframes);
  63 }
  64
  65 void
  66 Session::prepare_diskstreams ()
  67 {
  68         for (DiskStreamList::iterator i = diskstreams.begin(); i != diskstreams.end(); ++i) {
  69                 (*i)->prepare ();
  70         }
  71 }
  72
  73 int
  74 Session::no_roll (jack_nframes_t nframes, jack_nframes_t offset)
  75 {
  76         jack_nframes_t end_frame = _transport_frame + nframes;
  77         int ret = 0;
  78         bool declick = get_transport_declick_required();
  79
  80         if (_click_io) {
  81                 _click_io->silence (nframes, offset);
  82         }
  83
  84         /* XXX we're supposed to have the route_lock while doing this.
  85            this is really bad ...
  86         */
  87
  88         if (atomic_read (&processing_prohibited)) {
  89                 for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
  90                         (*i)->silence (nframes, offset);
  91                 }
  92                 return 0;
  93         }
  94
  95         for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
  96
  97                 if ((*i)->hidden()) {
  98                         continue;
  99                 }
 100
 101                 (*i)->set_pending_declick (declick);
 102
 103                 if ((*i)->no_roll (nframes, _transport_frame, end_frame, offset, non_realtime_work_pending(),
 104                                    actively_recording(), declick)) {
 105                         error << string_compose(_("Session: error in no roll for %1"), (*i)->name()) << endmsg;
 106                         ret = -1;
 107                         break;
 108                 }
 109         }
 110
 111         return ret;
 112 }
 113
 114 int
 115 Session::process_routes (jack_nframes_t nframes, jack_nframes_t offset)
 116 {
 117         bool record_active;
 118         int  declick = get_transport_declick_required();
 119         bool rec_monitors = get_rec_monitors_input();
 120
 121         if (transport_sub_state & StopPendingCapture) {
 122                 /* force a declick out */
 123                 declick = -1;
 124         }
 125
 126         record_active = actively_recording(); // || (get_record_enabled() && get_punch_in());
 127
 128         for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
 129
 130                 int ret;
 131
 132                 if ((*i)->hidden()) {
 133                         continue;
 134                 }
 135
 136                 (*i)->set_pending_declick (declick);
 137
 138                 if ((ret = (*i)->roll (nframes, _transport_frame, _transport_frame + nframes, offset, declick, record_active, rec_monitors)) < 0) {
 139
 140                         /* we have to do this here. Route::roll() for an AudioTrack will have called DiskStream::process(),
 141                            and the DS will expect DiskStream::commit() to be called. but we're aborting from that
 142                            call path, so make sure we release any outstanding locks here before we return failure.
 143                         */
 144
 145                         for (DiskStreamList::iterator ids = diskstreams.begin(); ids != diskstreams.end(); ++ids) {
 146                                 (*ids)->recover ();
 147                         }
 148
 149                         stop_transport ();
 150                         return -1;
 151                 }
 152         }
 153
 154         return 0;
 155 }
 156
 157 int
 158 Session::silent_process_routes (jack_nframes_t nframes, jack_nframes_t offset)
 159 {
 160         bool record_active = actively_recording();
 161         int  declick = get_transport_declick_required();
 162         bool rec_monitors = get_rec_monitors_input();
 163
 164         if (transport_sub_state & StopPendingCapture) {
 165                 /* force a declick out */
 166                 declick = -1;
 167         }
 168
 169         for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
 170
 171                 int ret;
 172
 173                 if ((*i)->hidden()) {
 174                         continue;
 175                 }
 176
 177                 if ((ret = (*i)->silent_roll (nframes, _transport_frame, _transport_frame + nframes, offset, record_active, rec_monitors)) < 0) {
 178
 179                         /* we have to do this here. Route::roll() for an AudioTrack will have called DiskStream::process(),
 180                            and the DS will expect DiskStream::commit() to be called. but we're aborting from that
 181                            call path, so make sure we release any outstanding locks here before we return failure.
 182                         */
 183
 184                         for (DiskStreamList::iterator ids = diskstreams.begin(); ids != diskstreams.end(); ++ids) {
 185                                 (*ids)->recover ();
 186                         }
 187
 188                         stop_transport ();
 189                         return -1;
 190                 }
 191         }
 192
 193         return 0;
 194 }
 195
 196 void
 197 Session::commit_diskstreams (jack_nframes_t nframes, bool &needs_butler)
 198 {
 199         int dret;
 200         float pworst = 1.0f;
 201         float cworst = 1.0f;
 202
 203         for (DiskStreamList::iterator i = diskstreams.begin(); i != diskstreams.end(); ++i) {
 204
 205                 if ((*i)->hidden()) {
 206                         continue;
 207                 }
 208
 209                 /* force all diskstreams not handled by a Route to call do their stuff.
 210                  */
 211
 212                 if ((dret = (*i)->process (_transport_frame, nframes, 0, actively_recording(), get_rec_monitors_input())) == 0) {
 213                         if ((*i)->commit (nframes)) {
 214                                 needs_butler = true;
 215                         }
 216
 217                 } else if (dret < 0) {
 218                         (*i)->recover();
 219                 }
 220
 221                 pworst = min (pworst, (*i)->playback_buffer_load());
 222                 cworst = min (cworst, (*i)->capture_buffer_load());
 223         }
 224
 225         uint32_t pmin = atomic_read (&_playback_load);
 226         uint32_t pminold = atomic_read (&_playback_load_min);
 227         uint32_t cmin = atomic_read (&_capture_load);
 228         uint32_t cminold = atomic_read (&_capture_load_min);
 229
 230         atomic_set (&_playback_load, (uint32_t) floor (pworst * 100.0f));
 231         atomic_set (&_capture_load, (uint32_t) floor (cworst * 100.0f));
 232         atomic_set (&_playback_load_min, min (pmin, pminold));
 233         atomic_set (&_capture_load_min, min (cmin, cminold));
 234
 235         if (actively_recording()) {
 236                 set_dirty();
 237         }
 238 }
 239
 240 void
 241 Session::process_with_events (jack_nframes_t nframes)
 242 {
 243         Event* ev;
 244         jack_nframes_t this_nframes;
 245         jack_nframes_t end_frame;
 246         jack_nframes_t offset;
 247         bool session_needs_butler = false;
 248         jack_nframes_t stop_limit;
 249         long           frames_moved;
 250
 251         if (auditioner) {
 252                 auditioner->silence (nframes, 0);
 253         }
 254
 255         while (pending_events.read (&ev, 1) == 1) {
 256                 merge_event (ev);
 257         }
 258
 259         /* if we are not in the middle of a state change,
 260            and there are immediate events queued up,
 261            process them.
 262         */
 263
 264         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 265                 Event *ev = immediate_events.front ();
 266                 immediate_events.pop_front ();
 267                 process_event (ev);
 268         }
 269
 270         if (!process_can_proceed()) {
 271                 no_roll (nframes, 0);
 272                 return;
 273         }
 274
 275         if (events.empty() || next_event == events.end()) {
 276                 process_without_events (nframes);
 277                 return;
 278         }
 279
 280         end_frame = _transport_frame + nframes;
 281
 282         {
 283                 TentativeRWLockMonitor rm (route_lock, false, __LINE__, __FILE__);
 284                 TentativeRWLockMonitor dsm (diskstream_lock, false, __LINE__, __FILE__);
 285
 286                 Event* this_event;
 287                 Events::iterator the_next_one;
 288
 289                 if (!rm.locked() || !dsm.locked() || (post_transport_work & (PostTransportLocate|PostTransportStop))) {
 290                         no_roll (nframes, 0);
 291                         return;
 292                 }
 293
 294                 if (!_exporting && _slave) {
 295                         if (!follow_slave (nframes, 0)) {
 296                                 return;
 297                         }
 298                 }
 299
 300                 if (_transport_speed == 0) {
 301                         no_roll (nframes, 0);
 302                         return;
 303                 }
 304
 305                 if (actively_recording()) {
 306                         stop_limit = max_frames;
 307                 } else {
 308
 309                         if (Config->get_stop_at_session_end()) {
 310                                 stop_limit = current_end_frame();
 311                         } else {
 312                                 stop_limit = max_frames;
 313                         }
 314                 }
 315
 316                 if (maybe_stop (stop_limit)) {
 317                         no_roll (nframes, 0);
 318                         return;
 319                 }
 320
 321                 this_event = *next_event;
 322                 the_next_one = next_event;
 323                 ++the_next_one;
 324
 325                 offset = 0;
 326
 327                 while (nframes) {
 328
 329                         if (this_event == 0 || this_event->action_frame > end_frame || this_event->action_frame < _transport_frame) {
 330
 331                                 this_nframes = nframes;
 332
 333                         } else {
 334
 335                                 /* compute nframes to next event */
 336
 337                                 if (this_event->action_frame < end_frame) {
 338                                         this_nframes = nframes - (end_frame - this_event->action_frame);
 339                                 } else {
 340                                         this_nframes = nframes;
 341                                 }
 342                         }
 343
 344                         if (this_nframes) {
 345
 346                                 click (_transport_frame, nframes, offset);
 347
 348                                 /* now process frames between now and the first event in this block */
 349                                 prepare_diskstreams ();
 350
 351                                 if (process_routes (this_nframes, offset)) {
 352                                         no_roll (nframes, 0);
 353                                         return;
 354                                 }
 355
 356                                 commit_diskstreams (this_nframes, session_needs_butler);
 357
 358                                 nframes -= this_nframes;
 359                                 offset += this_nframes;
 360
 361                                 frames_moved = (jack_nframes_t) floor (_transport_speed * this_nframes);
 362
 363                                 if (frames_moved < 0) {
 364                                         decrement_transport_position (-frames_moved);
 365                                 } else {
 366                                         increment_transport_position (frames_moved);
 367                                 }
 368
 369                                 maybe_stop (stop_limit);
 370                                 check_declick_out ();
 371                         }
 372
 373                         /* now handle this event and all others scheduled for the same time */
 374
 375                         while (this_event && this_event->action_frame == _transport_frame) {
 376                                 process_event (this_event);
 377
 378                                 if (the_next_one == events.end()) {
 379                                         this_event = 0;
 380                                 } else {
 381                                         this_event = *the_next_one;
 382                                         ++the_next_one;
 383                                 }
 384                         }
 385
 386                         /* if an event left our state changing, do the right thing */
 387
 388                         if (non_realtime_work_pending()) {
 389                                 no_roll (nframes, offset);
 390                                 break;
 391                         }
 392
 393                         /* this is necessary to handle the case of seamless looping */
 394                         /* not sure if it will work in conjuction with varispeed */
 395                         end_frame = _transport_frame + nframes;
 396
 397                 }
 398
 399                 set_next_event ();
 400
 401         } /* implicit release of route lock */
 402
 403
 404         if (session_needs_butler) {
 405                 summon_butler ();
 406         }
 407
 408         if (!_engine.freewheeling() && send_mtc) {
 409                 send_midi_time_code_in_another_thread ();
 410         }
 411
 412         return;
 413 }
 414
 415 void
 416 Session::reset_slave_state ()
 417 {
 418         average_slave_delta = 1800;
 419         delta_accumulator_cnt = 0;
 420         have_first_delta_accumulator = false;
 421         slave_state = Stopped;
 422 }
 423
 424 bool
 425 Session::transport_locked () const
 426 {
 427         Slave* sl = _slave;
 428
 429         if (!locate_pending() && ((_slave_type == None) || (sl && sl->ok() && sl->locked()))) {
 430                 return true;
 431         }
 432
 433         return false;
 434 }
 435
 436 bool
 437 Session::follow_slave (jack_nframes_t nframes, jack_nframes_t offset)
 438 {
 439         float slave_speed;
 440         jack_nframes_t slave_transport_frame;
 441         jack_nframes_t this_delta;
 442         int dir;
 443         bool starting;
 444
 445         if (!_slave->ok()) {
 446                 stop_transport ();
 447                 set_slave_source (None, 0);
 448                 goto noroll;
 449         }
 450
 451         _slave->speed_and_position (slave_speed, slave_transport_frame);
 452
 453         if (!_slave->locked()) {
 454                 goto noroll;
 455         }
 456
 457         if (slave_transport_frame > _transport_frame) {
 458                 this_delta = slave_transport_frame - _transport_frame;
 459                 dir = 1;
 460         } else {
 461                 this_delta = _transport_frame - slave_transport_frame;
 462                 dir = -1;
 463         }
 464
 465         if ((starting = _slave->starting())) {
 466                 slave_speed = 0.0f;
 467         }
 468
 469 #if 0
 470         cerr << "delta = " << (int) (dir * this_delta)
 471              << " speed = " << slave_speed
 472              << " ts = " << _transport_speed
 473              << " M@"<< slave_transport_frame << " S@" << _transport_frame
 474              << " avgdelta = " << average_slave_delta
 475              << endl;
 476 #endif
 477
 478         if (Config->get_timecode_source_is_synced()) {
 479
 480                 /* if the TC source is synced, then we assume that its
 481                    speed is binary: 0.0 or 1.0
 482                 */
 483
 484                 if (slave_speed != 0.0f) {
 485                         slave_speed = 1.0f;
 486                 }
 487
 488         } else {
 489
 490                 /* TC source is able to drift relative to us (slave)
 491                    so we need to keep track of the drift and adjust
 492                    our speed to remain locked.
 493                 */
 494
 495                 if (delta_accumulator_cnt >= delta_accumulator_size) {
 496                         have_first_delta_accumulator = true;
 497                         delta_accumulator_cnt = 0;
 498                 }
 499
 500                 if (delta_accumulator_cnt != 0 || this_delta < _current_frame_rate) {
 501                         delta_accumulator[delta_accumulator_cnt++] = dir*this_delta;
 502                 }
 503
 504                 if (have_first_delta_accumulator) {
 505                         average_slave_delta = 0;
 506                         for (int i = 0; i < delta_accumulator_size; ++i) {
 507                                 average_slave_delta += delta_accumulator[i];
 508                         }
 509                         average_slave_delta /= delta_accumulator_size;
 510                         if (average_slave_delta < 0) {
 511                                 average_dir = -1;
 512                                 average_slave_delta = -average_slave_delta;
 513                         } else {
 514                                 average_dir = 1;
 515                         }
 516                         // cerr << "avgdelta = " << average_slave_delta*average_dir << endl;
 517                 }
 518         }
 519
 520         if (slave_speed != 0.0f) {
 521
 522                 /* slave is running */
 523
 524                 switch (slave_state) {
 525                 case Stopped:
 526                         if (_slave->requires_seekahead()) {
 527                                 slave_wait_end = slave_transport_frame + _current_frame_rate;
 528                                 locate (slave_wait_end, false, false);
 529                                 slave_state = Waiting;
 530                                 starting = true;
 531
 532                         } else {
 533
 534                                 slave_state = Running;
 535
 536                                 Location* al = _locations.auto_loop_location();
 537
 538                                 if (al && auto_loop && (slave_transport_frame < al->start() || slave_transport_frame > al->end())) {
 539                                         // cancel looping
 540                                         request_auto_loop(false);
 541                                 }
 542
 543                                 if (slave_transport_frame != _transport_frame) {
 544                                         locate (slave_transport_frame, false, false);
 545                                 }
 546                         }
 547                         break;
 548
 549                 case Waiting:
 550                         break;
 551
 552                 default:
 553                         break;
 554
 555                 }
 556
 557                 if (slave_state == Waiting) {
 558
 559                         // cerr << "waiting at " << slave_transport_frame << endl;
 560                         TentativeRWLockMonitor dsm (diskstream_lock, false, __LINE__, __FILE__);
 561
 562                         if (dsm.locked() && slave_transport_frame >= slave_wait_end) {
 563                                 // cerr << "\tstart at " << _transport_frame << endl;
 564
 565                                 slave_state = Running;
 566
 567                                 bool ok = true;
 568                                 jack_nframes_t frame_delta = slave_transport_frame - _transport_frame;
 569
 570                                 for (DiskStreamList::iterator i = diskstreams.begin(); i != diskstreams.end(); ++i) {
 571                                         if (!(*i)->can_internal_playback_seek (frame_delta)) {
 572                                                 ok = false;
 573                                                 break;
 574                                         }
 575                                 }
 576
 577                                 if (ok) {
 578                                         for (DiskStreamList::iterator i = diskstreams.begin(); i != diskstreams.end(); ++i) {
 579                                                 (*i)->internal_playback_seek (frame_delta);
 580                                         }
 581                                         _transport_frame += frame_delta;
 582
 583                                 } else {
 584                                         // cerr << "cannot micro-seek\n";
 585                                         /* XXX what? */
 586                                 }
 587
 588                                 memset (delta_accumulator, 0, sizeof (jack_nframes_t) * delta_accumulator_size);
 589                                 average_slave_delta = 0;
 590                                 this_delta = 0;
 591                         }
 592                 }
 593
 594                 if (slave_state == Running && _transport_speed == 0.0f) {
 595
 596                         // cerr << "slave starts transport\n";
 597
 598                         start_transport ();
 599                 }
 600
 601         } else {
 602
 603                 /* slave has stopped */
 604
 605                 if (_transport_speed != 0.0f) {
 606
 607                         // cerr << "slave stops transport: " << slave_speed << " frame: " << slave_transport_frame
 608                         // << " tf = " << _transport_frame
 609                         // << endl;
 610
 611                         if (_slave_type == JACK) {
 612                                 last_stop_frame = _transport_frame;
 613                         }
 614
 615                         stop_transport();
 616                 }
 617
 618                 if (slave_transport_frame != _transport_frame) {
 619                         // cerr << "slave stopped, move to " << slave_transport_frame << endl;
 620                         force_locate (slave_transport_frame, false);
 621                 }
 622
 623                 slave_state = Stopped;
 624         }
 625
 626         if (slave_state == Running && !Config->get_timecode_source_is_synced()) {
 627
 628
 629                 if (_transport_speed != 0.0f) {
 630
 631                         /*
 632                            note that average_dir is +1 or -1
 633                         */
 634
 635                         const float adjust_seconds = 1.0f;
 636                         float delta;
 637
 638                         //if (average_slave_delta == 0) {
 639                                 delta = this_delta;
 640                                 delta *= dir;
 641 //                      } else {
 642 //                              delta = average_slave_delta;
 643 //                              delta *= average_dir;
 644 //                      }
 645
 646                         float adjusted_speed = slave_speed +
 647                                 (delta / (adjust_seconds * _current_frame_rate));
 648
 649                         // cerr << "adjust using " << delta
 650                         // << " towards " << adjusted_speed
 651                         // << " ratio = " << adjusted_speed / slave_speed
 652                         // << " current = " << _transport_speed
 653                         // << " slave @ " << slave_speed
 654                         // << endl;
 655
 656                         request_transport_speed (adjusted_speed);
 657
 658 #if 1
 659                         if ((jack_nframes_t) average_slave_delta > _slave->resolution()) {
 660                                 // cerr << "not locked\n";
 661                                 goto silent_motion;
 662                         }
 663 #endif
 664                 }
 665         }
 666
 667         if (!starting && !non_realtime_work_pending()) {
 668                 /* speed is set, we're locked, and good to go */
 669                 return true;
 670         }
 671
 672   silent_motion:
 673
 674         if (slave_speed && _transport_speed) {
 675
 676                 /* something isn't right, but we should move with the master
 677                    for now.
 678                 */
 679
 680                 bool need_butler;
 681
 682                 TentativeRWLockMonitor dsm (diskstream_lock, false, __LINE__, __FILE__);
 683                 if (!dsm.locked()) {
 684                         goto noroll;
 685                 }
 686
 687
 688                 prepare_diskstreams ();
 689                 silent_process_routes (nframes, offset);
 690                 commit_diskstreams (nframes, need_butler);
 691
 692                 if (need_butler) {
 693                         summon_butler ();
 694                 }
 695
 696                 jack_nframes_t frames_moved = (long) floor (_transport_speed * nframes);
 697
 698                 if (frames_moved < 0) {
 699                         decrement_transport_position (-frames_moved);
 700                 } else {
 701                         increment_transport_position (frames_moved);
 702                 }
 703
 704                 jack_nframes_t stop_limit;
 705
 706                 if (actively_recording()) {
 707                         stop_limit = max_frames;
 708                 } else {
 709                         if (Config->get_stop_at_session_end()) {
 710                                 stop_limit = current_end_frame();
 711                         } else {
 712                                 stop_limit = max_frames;
 713                         }
 714                 }
 715
 716                 maybe_stop (stop_limit);
 717         }
 718
 719   noroll:
 720         /* don't move at all */
 721         no_roll (nframes, 0);
 722         return false;
 723 }
 724
 725 void
 726 Session::process_without_events (jack_nframes_t nframes)
 727 {
 728         bool session_needs_butler = false;
 729         jack_nframes_t stop_limit;
 730         long frames_moved;
 731
 732         {
 733                 TentativeRWLockMonitor rm (route_lock, false, __LINE__, __FILE__);
 734                 TentativeRWLockMonitor dsm (diskstream_lock, false, __LINE__, __FILE__);
 735
 736                 if (!rm.locked() || !dsm.locked() || (post_transport_work & (PostTransportLocate|PostTransportStop))) {
 737                         no_roll (nframes, 0);
 738                         return;
 739                 }
 740
 741                 if (!_exporting && _slave) {
 742                         if (!follow_slave (nframes, 0)) {
 743                                 return;
 744                         }
 745                 }
 746
 747                 if (_transport_speed == 0) {
 748                         no_roll (nframes, 0);
 749                         return;
 750                 }
 751
 752                 if (actively_recording()) {
 753                         stop_limit = max_frames;
 754                 } else {
 755                         if (Config->get_stop_at_session_end()) {
 756                                 stop_limit = current_end_frame();
 757                         } else {
 758                                 stop_limit = max_frames;
 759                         }
 760                 }
 761
 762                 if (maybe_stop (stop_limit)) {
 763                         no_roll (nframes, 0);
 764                         return;
 765                 }
 766
 767                 click (_transport_frame, nframes, 0);
 768
 769                 prepare_diskstreams ();
 770
 771                 frames_moved = (long) floor (_transport_speed * nframes);
 772
 773                 if (process_routes (nframes, 0)) {
 774                         no_roll (nframes, 0);
 775                         return;
 776                 }
 777
 778                 commit_diskstreams (nframes, session_needs_butler);
 779
 780                 if (frames_moved < 0) {
 781                         decrement_transport_position (-frames_moved);
 782                 } else {
 783                         increment_transport_position (frames_moved);
 784                 }
 785
 786                 maybe_stop (stop_limit);
 787                 check_declick_out ();
 788
 789         } /* implicit release of route lock */
 790
 791         if (session_needs_butler) {
 792                 summon_butler ();
 793         }
 794
 795         if (!_engine.freewheeling() && send_mtc) {
 796                 send_midi_time_code_in_another_thread ();
 797         }
 798
 799         return;
 800 }
 801
 802 void
 803 Session::process_audition (jack_nframes_t nframes)
 804 {
 805         TentativeRWLockMonitor rm (route_lock, false, __LINE__, __FILE__);
 806         Event* ev;
 807
 808         if (rm.locked()) {
 809                 for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
 810                         if (!(*i)->hidden()) {
 811                                 (*i)->silence (nframes, 0);
 812                         }
 813                 }
 814         }
 815
 816         if (auditioner->play_audition (nframes) > 0) {
 817                 summon_butler ();
 818         }
 819
 820         while (pending_events.read (&ev, 1) == 1) {
 821                 merge_event (ev);
 822         }
 823
 824         /* if we are not in the middle of a state change,
 825            and there are immediate events queued up,
 826            process them.
 827         */
 828
 829         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 830                 Event *ev = immediate_events.front ();
 831                 immediate_events.pop_front ();
 832                 process_event (ev);
 833         }
 834
 835         if (!auditioner->active()) {
 836                 process_function = &Session::process_with_events;
 837         }
 838 }
 839