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 <midi++/manager.h>
  42
  43 #include "i18n.h"
  44
  45 using namespace ARDOUR;
  46 //using namespace sigc;
  47 using namespace std;
  48
  49 void
  50 Session::process (jack_nframes_t nframes)
  51 {
  52         cerr << "CYCLE START " << _transport_frame << "-------------------" << endl;
  53
  54         MIDI::Manager::instance()->cycle_start(nframes);
  55
  56         if (synced_to_jack() && waiting_to_start) {
  57                 if ( _engine.transport_state() == AudioEngine::TransportRolling) {
  58                         actually_start_transport ();
  59                 }
  60         }
  61
  62         if (non_realtime_work_pending()) {
  63                 if (atomic_read (&butler_should_do_transport_work) == 0) {
  64                         post_transport ();
  65                 }
  66         }
  67
  68         (this->*process_function) (nframes);
  69
  70         MIDI::Manager::instance()->cycle_end();
  71
  72         cerr << "CYCLE END " << _transport_frame << "-----------------------" << endl;
  73 }
  74
  75 void
  76 Session::prepare_diskstreams ()
  77 {
  78         for (DiskStreamList::iterator i = diskstreams.begin(); i != diskstreams.end(); ++i) {
  79                 (*i)->prepare ();
  80         }
  81 }
  82
  83 int
  84 Session::no_roll (jack_nframes_t nframes, jack_nframes_t offset)
  85 {
  86         jack_nframes_t end_frame = _transport_frame + nframes;
  87         int ret = 0;
  88         bool declick = get_transport_declick_required();
  89
  90         cerr << "[DR] no_roll\n";
  91
  92         if (_click_io) {
  93                 _click_io->silence (nframes, offset);
  94         }
  95
  96         /* XXX we're supposed to have the route_lock while doing this.
  97            this is really bad ...
  98         */
  99
 100         if (atomic_read (&processing_prohibited)) {
 101                 for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
 102                         (*i)->silence (nframes, offset);
 103                 }
 104                 return 0;
 105         }
 106
 107         for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
 108
 109                 if ((*i)->hidden()) {
 110                         continue;
 111                 }
 112
 113                 (*i)->set_pending_declick (declick);
 114
 115                 if ((*i)->no_roll (nframes, _transport_frame, end_frame, offset, non_realtime_work_pending(),
 116                                    actively_recording(), declick)) {
 117                         error << string_compose(_("Session: error in no roll for %1"), (*i)->name()) << endmsg;
 118                         ret = -1;
 119                         break;
 120                 }
 121         }
 122
 123         return ret;
 124 }
 125
 126 int
 127 Session::process_routes (jack_nframes_t nframes, jack_nframes_t offset)
 128 {
 129         bool record_active;
 130         int  declick = get_transport_declick_required();
 131         bool rec_monitors = get_rec_monitors_input();
 132
 133         if (transport_sub_state & StopPendingCapture) {
 134                 /* force a declick out */
 135                 declick = -1;
 136         }
 137
 138         record_active = actively_recording(); // || (get_record_enabled() && get_punch_in());
 139
 140         for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
 141
 142                 int ret;
 143
 144                 if ((*i)->hidden()) {
 145                         continue;
 146                 }
 147
 148                 (*i)->set_pending_declick (declick);
 149
 150                 if ((ret = (*i)->roll (nframes, _transport_frame, _transport_frame + nframes, offset, declick, record_active, rec_monitors)) < 0) {
 151
 152                         /* we have to do this here. Route::roll() for an AudioTrack will have called DiskStream::process(),
 153                            and the DS will expect DiskStream::commit() to be called. but we're aborting from that
 154                            call path, so make sure we release any outstanding locks here before we return failure.
 155                         */
 156
 157                         for (DiskStreamList::iterator ids = diskstreams.begin(); ids != diskstreams.end(); ++ids) {
 158                                 (*ids)->recover ();
 159                         }
 160
 161                         stop_transport ();
 162                         return -1;
 163                 }
 164         }
 165
 166         return 0;
 167 }
 168
 169 int
 170 Session::silent_process_routes (jack_nframes_t nframes, jack_nframes_t offset)
 171 {
 172         bool record_active = actively_recording();
 173         int  declick = get_transport_declick_required();
 174         bool rec_monitors = get_rec_monitors_input();
 175
 176         if (transport_sub_state & StopPendingCapture) {
 177                 /* force a declick out */
 178                 declick = -1;
 179         }
 180
 181         for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
 182
 183                 int ret;
 184
 185                 if ((*i)->hidden()) {
 186                         continue;
 187                 }
 188
 189                 if ((ret = (*i)->silent_roll (nframes, _transport_frame, _transport_frame + nframes, offset, record_active, rec_monitors)) < 0) {
 190
 191                         /* we have to do this here. Route::roll() for an AudioTrack will have called DiskStream::process(),
 192                            and the DS will expect DiskStream::commit() to be called. but we're aborting from that
 193                            call path, so make sure we release any outstanding locks here before we return failure.
 194                         */
 195
 196                         for (DiskStreamList::iterator ids = diskstreams.begin(); ids != diskstreams.end(); ++ids) {
 197                                 (*ids)->recover ();
 198                         }
 199
 200                         stop_transport ();
 201                         return -1;
 202                 }
 203         }
 204
 205         return 0;
 206 }
 207
 208 void
 209 Session::commit_diskstreams (jack_nframes_t nframes, bool &needs_butler)
 210 {
 211         int dret;
 212         float pworst = 1.0f;
 213         float cworst = 1.0f;
 214
 215         for (DiskStreamList::iterator i = diskstreams.begin(); i != diskstreams.end(); ++i) {
 216
 217                 if ((*i)->hidden()) {
 218                         continue;
 219                 }
 220
 221                 /* force all diskstreams not handled by a Route to call do their stuff.
 222                  */
 223
 224                 if ((dret = (*i)->process (_transport_frame, nframes, 0, actively_recording(), get_rec_monitors_input())) == 0) {
 225                         if ((*i)->commit (nframes)) {
 226                                 needs_butler = true;
 227                         }
 228
 229                 } else if (dret < 0) {
 230                         (*i)->recover();
 231                 }
 232
 233                 pworst = min (pworst, (*i)->playback_buffer_load());
 234                 cworst = min (cworst, (*i)->capture_buffer_load());
 235         }
 236
 237         uint32_t pmin = atomic_read (&_playback_load);
 238         uint32_t pminold = atomic_read (&_playback_load_min);
 239         uint32_t cmin = atomic_read (&_capture_load);
 240         uint32_t cminold = atomic_read (&_capture_load_min);
 241
 242         atomic_set (&_playback_load, (uint32_t) floor (pworst * 100.0f));
 243         atomic_set (&_capture_load, (uint32_t) floor (cworst * 100.0f));
 244         atomic_set (&_playback_load_min, min (pmin, pminold));
 245         atomic_set (&_capture_load_min, min (cmin, cminold));
 246
 247         if (actively_recording()) {
 248                 set_dirty();
 249         }
 250 }
 251
 252
 253 void
 254 Session::process_with_events (jack_nframes_t nframes)
 255 {
 256         Event*         ev;
 257         jack_nframes_t this_nframes;
 258         jack_nframes_t end_frame;
 259         jack_nframes_t offset;
 260         jack_nframes_t stop_limit;
 261         long           frames_moved;
 262         bool           session_needs_butler = false;
 263
 264         cerr << "[DR] with events" << endl;
 265
 266         if (auditioner) {
 267                 auditioner->silence (nframes, 0);
 268         }
 269
 270         while (pending_events.read (&ev, 1) == 1) {
 271                 merge_event (ev);
 272         }
 273
 274         /* if we are not in the middle of a state change,
 275            and there are immediate events queued up,
 276            process them.
 277         */
 278
 279         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 280                 Event *ev = immediate_events.front ();
 281                 immediate_events.pop_front ();
 282                 process_event (ev);
 283         }
 284
 285         /* Events caused a transport change and we need to send MTC
 286          * [DR] FIXME: best place for this? */
 287         if (_send_smpte_update) {
 288                 cerr << "[DR] TIME CHANGE\n" << endl;
 289                 send_full_time_code(nframes);
 290         }
 291
 292         if (!process_can_proceed()) {
 293                 no_roll (nframes, 0);
 294                 return;
 295         }
 296
 297         if (events.empty() || next_event == events.end()) {
 298                 process_without_events (nframes);
 299                 return;
 300         }
 301
 302         end_frame = _transport_frame + nframes;
 303
 304         {
 305                 TentativeRWLockMonitor rm (route_lock, false, __LINE__, __FILE__);
 306                 TentativeRWLockMonitor dsm (diskstream_lock, false, __LINE__, __FILE__);
 307
 308                 Event* this_event;
 309                 Events::iterator the_next_one;
 310
 311                 if (!rm.locked() || !dsm.locked() || (post_transport_work & (PostTransportLocate|PostTransportStop))) {
 312                         no_roll (nframes, 0);
 313                         return;
 314                 }
 315
 316                 if (!_exporting && _slave) {
 317                         if (!follow_slave (nframes, 0)) {
 318                                 return;
 319                         }
 320                 }
 321
 322                 if (_transport_speed == 0) {
 323                         no_roll (nframes, 0);
 324                         return;
 325                 }
 326
 327                 if (actively_recording()) {
 328                         stop_limit = max_frames;
 329                 } else {
 330
 331                         if (Config->get_stop_at_session_end()) {
 332                                 stop_limit = current_end_frame();
 333                         } else {
 334                                 stop_limit = max_frames;
 335                         }
 336                 }
 337
 338                 if (maybe_stop (stop_limit)) {
 339                         no_roll (nframes, 0);
 340                         return;
 341                 }
 342
 343                 this_event = *next_event;
 344                 the_next_one = next_event;
 345                 ++the_next_one;
 346
 347                 offset = 0;
 348
 349                 while (nframes) {
 350
 351                         if (this_event == 0 || this_event->action_frame > end_frame || this_event->action_frame < _transport_frame) {
 352
 353                                 this_nframes = nframes;
 354
 355                         } else {
 356
 357                                 /* compute nframes to next event */
 358
 359                                 if (this_event->action_frame < end_frame) {
 360                                         this_nframes = nframes - (end_frame - this_event->action_frame);
 361                                 } else {
 362                                         this_nframes = nframes;
 363                                 }
 364                         }
 365
 366                         if (this_nframes) {
 367
 368                                 click (_transport_frame, nframes, offset);
 369
 370                                 /* now process frames between now and the first event in this block */
 371                                 prepare_diskstreams ();
 372
 373                                 if (process_routes (this_nframes, offset)) {
 374                                         no_roll (nframes, 0);
 375                                         return;
 376                                 }
 377
 378                                 commit_diskstreams (this_nframes, session_needs_butler);
 379
 380                                 nframes -= this_nframes;
 381                                 offset += this_nframes;
 382
 383                                 frames_moved = (jack_nframes_t) floor (_transport_speed * this_nframes);
 384
 385                                 if (frames_moved < 0) {
 386                                         decrement_transport_position (-frames_moved);
 387                                 } else {
 388                                         increment_transport_position (frames_moved);
 389                                 }
 390
 391                                 maybe_stop (stop_limit);
 392                                 check_declick_out ();
 393                         }
 394
 395                         /* now handle this event and all others scheduled for the same time */
 396
 397                         while (this_event && this_event->action_frame == _transport_frame) {
 398                                 process_event (this_event);
 399
 400                                 if (the_next_one == events.end()) {
 401                                         this_event = 0;
 402                                 } else {
 403                                         this_event = *the_next_one;
 404                                         ++the_next_one;
 405                                 }
 406                         }
 407
 408                         /* if an event left our state changing, do the right thing */
 409
 410                         if (non_realtime_work_pending()) {
 411                                 no_roll (nframes, offset);
 412                                 break;
 413                         }
 414
 415                         /* this is necessary to handle the case of seamless looping */
 416                         /* not sure if it will work in conjuction with varispeed */
 417                         end_frame = _transport_frame + nframes;
 418
 419                 }
 420
 421                 set_next_event ();
 422
 423         } /* implicit release of route lock */
 424
 425         if (session_needs_butler)
 426                 summon_butler ();
 427
 428         send_midi_time_code_for_cycle(nframes);
 429 }
 430
 431 void
 432 Session::reset_slave_state ()
 433 {
 434         average_slave_delta = 1800;
 435         delta_accumulator_cnt = 0;
 436         have_first_delta_accumulator = false;
 437         slave_state = Stopped;
 438 }
 439
 440 bool
 441 Session::transport_locked () const
 442 {
 443         Slave* sl = _slave;
 444
 445         if (!locate_pending() && ((_slave_type == None) || (sl && sl->ok() && sl->locked()))) {
 446                 return true;
 447         }
 448
 449         return false;
 450 }
 451
 452 bool
 453 Session::follow_slave (jack_nframes_t nframes, jack_nframes_t offset)
 454 {
 455         float slave_speed;
 456         jack_nframes_t slave_transport_frame;
 457         jack_nframes_t this_delta;
 458         int dir;
 459         bool starting;
 460
 461         if (!_slave->ok()) {
 462                 stop_transport ();
 463                 set_slave_source (None, 0);
 464                 goto noroll;
 465         }
 466
 467         _slave->speed_and_position (slave_speed, slave_transport_frame);
 468
 469         if (!_slave->locked()) {
 470                 goto noroll;
 471         }
 472
 473         if (slave_transport_frame > _transport_frame) {
 474                 this_delta = slave_transport_frame - _transport_frame;
 475                 dir = 1;
 476         } else {
 477                 this_delta = _transport_frame - slave_transport_frame;
 478                 dir = -1;
 479         }
 480
 481         if ((starting = _slave->starting())) {
 482                 slave_speed = 0.0f;
 483         }
 484
 485 #if 0
 486         cerr << "delta = " << (int) (dir * this_delta)
 487              << " speed = " << slave_speed
 488              << " ts = " << _transport_speed
 489              << " M@"<< slave_transport_frame << " S@" << _transport_frame
 490              << " avgdelta = " << average_slave_delta
 491              << endl;
 492 #endif
 493
 494         if (Config->get_timecode_source_is_synced()) {
 495
 496                 /* if the TC source is synced, then we assume that its
 497                    speed is binary: 0.0 or 1.0
 498                 */
 499
 500                 if (slave_speed != 0.0f) {
 501                         slave_speed = 1.0f;
 502                 }
 503
 504         } else {
 505
 506                 /* TC source is able to drift relative to us (slave)
 507                    so we need to keep track of the drift and adjust
 508                    our speed to remain locked.
 509                 */
 510
 511                 if (delta_accumulator_cnt >= delta_accumulator_size) {
 512                         have_first_delta_accumulator = true;
 513                         delta_accumulator_cnt = 0;
 514                 }
 515
 516                 if (delta_accumulator_cnt != 0 || this_delta < _current_frame_rate) {
 517                         delta_accumulator[delta_accumulator_cnt++] = dir*this_delta;
 518                 }
 519
 520                 if (have_first_delta_accumulator) {
 521                         average_slave_delta = 0;
 522                         for (int i = 0; i < delta_accumulator_size; ++i) {
 523                                 average_slave_delta += delta_accumulator[i];
 524                         }
 525                         average_slave_delta /= delta_accumulator_size;
 526                         if (average_slave_delta < 0) {
 527                                 average_dir = -1;
 528                                 average_slave_delta = -average_slave_delta;
 529                         } else {
 530                                 average_dir = 1;
 531                         }
 532                         // cerr << "avgdelta = " << average_slave_delta*average_dir << endl;
 533                 }
 534         }
 535
 536         if (slave_speed != 0.0f) {
 537
 538                 /* slave is running */
 539
 540                 switch (slave_state) {
 541                 case Stopped:
 542                         if (_slave->requires_seekahead()) {
 543                                 slave_wait_end = slave_transport_frame + _current_frame_rate;
 544                                 locate (slave_wait_end, false, false);
 545                                 slave_state = Waiting;
 546                                 starting = true;
 547
 548                         } else {
 549
 550                                 slave_state = Running;
 551
 552                                 Location* al = _locations.auto_loop_location();
 553
 554                                 if (al && auto_loop && (slave_transport_frame < al->start() || slave_transport_frame > al->end())) {
 555                                         // cancel looping
 556                                         request_auto_loop(false);
 557                                 }
 558
 559                                 if (slave_transport_frame != _transport_frame) {
 560                                         locate (slave_transport_frame, false, false);
 561                                 }
 562                         }
 563                         break;
 564
 565                 case Waiting:
 566                         break;
 567
 568                 default:
 569                         break;
 570
 571                 }
 572
 573                 if (slave_state == Waiting) {
 574
 575                         // cerr << "waiting at " << slave_transport_frame << endl;
 576                         TentativeRWLockMonitor dsm (diskstream_lock, false, __LINE__, __FILE__);
 577
 578                         if (dsm.locked() && slave_transport_frame >= slave_wait_end) {
 579                                 // cerr << "\tstart at " << _transport_frame << endl;
 580
 581                                 slave_state = Running;
 582
 583                                 bool ok = true;
 584                                 jack_nframes_t frame_delta = slave_transport_frame - _transport_frame;
 585
 586                                 for (DiskStreamList::iterator i = diskstreams.begin(); i != diskstreams.end(); ++i) {
 587                                         if (!(*i)->can_internal_playback_seek (frame_delta)) {
 588                                                 ok = false;
 589                                                 break;
 590                                         }
 591                                 }
 592
 593                                 if (ok) {
 594                                         for (DiskStreamList::iterator i = diskstreams.begin(); i != diskstreams.end(); ++i) {
 595                                                 (*i)->internal_playback_seek (frame_delta);
 596                                         }
 597                                         _transport_frame += frame_delta;
 598
 599                                 } else {
 600                                         // cerr << "cannot micro-seek\n";
 601                                         /* XXX what? */
 602                                 }
 603
 604                                 memset (delta_accumulator, 0, sizeof (jack_nframes_t) * delta_accumulator_size);
 605                                 average_slave_delta = 0;
 606                                 this_delta = 0;
 607                         }
 608                 }
 609
 610                 if (slave_state == Running && _transport_speed == 0.0f) {
 611
 612                         // cerr << "slave starts transport\n";
 613
 614                         start_transport ();
 615                 }
 616
 617         } else {
 618
 619                 /* slave has stopped */
 620
 621                 if (_transport_speed != 0.0f) {
 622
 623                         // cerr << "slave stops transport: " << slave_speed << " frame: " << slave_transport_frame
 624                         // << " tf = " << _transport_frame
 625                         // << endl;
 626
 627                         if (_slave_type == JACK) {
 628                                 last_stop_frame = _transport_frame;
 629                         }
 630
 631                         stop_transport();
 632                 }
 633
 634                 if (slave_transport_frame != _transport_frame) {
 635                         // cerr << "slave stopped, move to " << slave_transport_frame << endl;
 636                         force_locate (slave_transport_frame, false);
 637                 }
 638
 639                 slave_state = Stopped;
 640         }
 641
 642         if (slave_state == Running && !Config->get_timecode_source_is_synced()) {
 643
 644
 645                 if (_transport_speed != 0.0f) {
 646
 647                         /*
 648                            note that average_dir is +1 or -1
 649                         */
 650
 651                         const float adjust_seconds = 1.0f;
 652                         float delta;
 653
 654                         //if (average_slave_delta == 0) {
 655                                 delta = this_delta;
 656                                 delta *= dir;
 657 //                      } else {
 658 //                              delta = average_slave_delta;
 659 //                              delta *= average_dir;
 660 //                      }
 661
 662                         float adjusted_speed = slave_speed +
 663                                 (delta / (adjust_seconds * _current_frame_rate));
 664
 665                         // cerr << "adjust using " << delta
 666                         // << " towards " << adjusted_speed
 667                         // << " ratio = " << adjusted_speed / slave_speed
 668                         // << " current = " << _transport_speed
 669                         // << " slave @ " << slave_speed
 670                         // << endl;
 671
 672                         request_transport_speed (adjusted_speed);
 673
 674 #if 1
 675                         if ((jack_nframes_t) average_slave_delta > _slave->resolution()) {
 676                                 // cerr << "not locked\n";
 677                                 goto silent_motion;
 678                         }
 679 #endif
 680                 }
 681         }
 682
 683         if (!starting && !non_realtime_work_pending()) {
 684                 /* speed is set, we're locked, and good to go */
 685                 return true;
 686         }
 687
 688   silent_motion:
 689
 690         if (slave_speed && _transport_speed) {
 691
 692                 /* something isn't right, but we should move with the master
 693                    for now.
 694                 */
 695
 696                 bool need_butler;
 697
 698                 TentativeRWLockMonitor dsm (diskstream_lock, false, __LINE__, __FILE__);
 699                 if (!dsm.locked()) {
 700                         goto noroll;
 701                 }
 702
 703
 704                 prepare_diskstreams ();
 705                 silent_process_routes (nframes, offset);
 706                 commit_diskstreams (nframes, need_butler);
 707
 708                 if (need_butler) {
 709                         summon_butler ();
 710                 }
 711
 712                 jack_nframes_t frames_moved = (long) floor (_transport_speed * nframes);
 713
 714                 if (frames_moved < 0) {
 715                         decrement_transport_position (-frames_moved);
 716                 } else {
 717                         increment_transport_position (frames_moved);
 718                 }
 719
 720                 jack_nframes_t stop_limit;
 721
 722                 if (actively_recording()) {
 723                         stop_limit = max_frames;
 724                 } else {
 725                         if (Config->get_stop_at_session_end()) {
 726                                 stop_limit = current_end_frame();
 727                         } else {
 728                                 stop_limit = max_frames;
 729                         }
 730                 }
 731
 732                 maybe_stop (stop_limit);
 733         }
 734
 735   noroll:
 736         /* don't move at all */
 737         no_roll (nframes, 0);
 738         return false;
 739 }
 740
 741 void
 742 Session::process_without_events (jack_nframes_t nframes)
 743 {
 744         cerr << "[DR] without events" << endl;
 745
 746         bool session_needs_butler = false;
 747         jack_nframes_t stop_limit;
 748         long frames_moved;
 749
 750         {
 751                 TentativeRWLockMonitor rm (route_lock, false, __LINE__, __FILE__);
 752                 TentativeRWLockMonitor dsm (diskstream_lock, false, __LINE__, __FILE__);
 753
 754                 if (!rm.locked() || !dsm.locked() || (post_transport_work & (PostTransportLocate|PostTransportStop))) {
 755                         no_roll (nframes, 0);
 756                         return;
 757                 }
 758
 759                 if (!_exporting && _slave) {
 760                         if (!follow_slave (nframes, 0)) {
 761                                 return;
 762                         }
 763                 }
 764
 765                 if (_transport_speed == 0) {
 766                         no_roll (nframes, 0);
 767                         return;
 768                 }
 769
 770                 if (actively_recording()) {
 771                         stop_limit = max_frames;
 772                 } else {
 773                         if (Config->get_stop_at_session_end()) {
 774                                 stop_limit = current_end_frame();
 775                         } else {
 776                                 stop_limit = max_frames;
 777                         }
 778                 }
 779
 780                 if (maybe_stop (stop_limit)) {
 781                         no_roll (nframes, 0);
 782                         return;
 783                 }
 784
 785                 click (_transport_frame, nframes, 0);
 786
 787                 prepare_diskstreams ();
 788
 789                 frames_moved = (long) floor (_transport_speed * nframes);
 790
 791                 if (process_routes (nframes, 0)) {
 792                         no_roll (nframes, 0);
 793                         return;
 794                 }
 795
 796                 commit_diskstreams (nframes, session_needs_butler);
 797
 798                 if (frames_moved < 0) {
 799                         decrement_transport_position (-frames_moved);
 800                 } else {
 801                         increment_transport_position (frames_moved);
 802                 }
 803
 804                 maybe_stop (stop_limit);
 805                 check_declick_out ();
 806
 807         } /* implicit release of route lock */
 808
 809         send_midi_time_code_for_cycle(nframes);
 810
 811         if (session_needs_butler)
 812                 summon_butler ();
 813 }
 814
 815 void
 816 Session::process_audition (jack_nframes_t nframes)
 817 {
 818         TentativeRWLockMonitor rm (route_lock, false, __LINE__, __FILE__);
 819         Event* ev;
 820
 821         if (rm.locked()) {
 822                 for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
 823                         if (!(*i)->hidden()) {
 824                                 (*i)->silence (nframes, 0);
 825                         }
 826                 }
 827         }
 828
 829         if (auditioner->play_audition (nframes) > 0) {
 830                 summon_butler ();
 831         }
 832
 833         while (pending_events.read (&ev, 1) == 1) {
 834                 merge_event (ev);
 835         }
 836
 837         /* if we are not in the middle of a state change,
 838            and there are immediate events queued up,
 839            process them.
 840         */
 841
 842         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 843                 Event *ev = immediate_events.front ();
 844                 immediate_events.pop_front ();
 845                 process_event (ev);
 846         }
 847
 848         if (!auditioner->active()) {
 849                 process_function = &Session::process_with_events;
 850         }
 851 }
 852