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 <pbd/error.h>
  27
  28 #include <glibmm/thread.h>
  29
  30 #include <ardour/ardour.h>
  31 #include <ardour/session.h>
  32 #include <ardour/timestamps.h>
  33 #include <ardour/audio_diskstream.h>
  34 #include <ardour/audioengine.h>
  35 #include <ardour/slave.h>
  36 #include <ardour/auditioner.h>
  37 #include <ardour/cycles.h>
  38 #include <ardour/cycle_timer.h>
  39
  40 #include "i18n.h"
  41
  42 using namespace ARDOUR;
  43 using namespace PBD;
  44 using namespace std;
  45
  46 void
  47 Session::process (jack_nframes_t nframes)
  48 {
  49         if (synced_to_jack() && waiting_to_start) {
  50                 if ( _engine.transport_state() == AudioEngine::TransportRolling) {
  51                         actually_start_transport ();
  52                 }
  53         }
  54
  55         if (non_realtime_work_pending()) {
  56                 if (g_atomic_int_get (&butler_should_do_transport_work) == 0) {
  57                         post_transport ();
  58                 }
  59         }
  60
  61         (this->*process_function) (nframes);
  62
  63         SendFeedback (); /* EMIT SIGNAL */
  64 }
  65
  66 void
  67 Session::prepare_diskstreams ()
  68 {
  69         for (AudioDiskstreamList::iterator i = audio_diskstreams.begin(); i != audio_diskstreams.end(); ++i) {
  70                 (*i)->prepare ();
  71         }
  72 }
  73
  74 int
  75 Session::no_roll (jack_nframes_t nframes, jack_nframes_t offset)
  76 {
  77         jack_nframes_t end_frame = _transport_frame + nframes;
  78         int ret = 0;
  79         bool declick = get_transport_declick_required();
  80         boost::shared_ptr<RouteList> r = routes.reader ();
  81
  82         if (_click_io) {
  83                 _click_io->silence (nframes, offset);
  84         }
  85
  86         if (g_atomic_int_get (&processing_prohibited)) {
  87                 for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
  88                         (*i)->silence (nframes, offset);
  89                 }
  90                 return 0;
  91         }
  92
  93         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
  94
  95                 if ((*i)->hidden()) {
  96                         continue;
  97                 }
  98
  99                 (*i)->set_pending_declick (declick);
 100
 101                 if ((*i)->no_roll (nframes, _transport_frame, end_frame, offset, non_realtime_work_pending(),
 102                                    actively_recording(), declick)) {
 103                         error << string_compose(_("Session: error in no roll for %1"), (*i)->name()) << endmsg;
 104                         ret = -1;
 105                         break;
 106                 }
 107         }
 108
 109         return ret;
 110 }
 111
 112 int
 113 Session::process_routes (jack_nframes_t nframes, jack_nframes_t offset)
 114 {
 115         bool record_active;
 116         int  declick = get_transport_declick_required();
 117         bool rec_monitors = get_rec_monitors_input();
 118         boost::shared_ptr<RouteList> r = routes.reader ();
 119
 120         if (transport_sub_state & StopPendingCapture) {
 121                 /* force a declick out */
 122                 declick = -1;
 123         }
 124
 125         record_active = actively_recording(); // || (get_record_enabled() && get_punch_in());
 126
 127         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 128
 129                 int ret;
 130
 131                 if ((*i)->hidden()) {
 132                         continue;
 133                 }
 134
 135                 (*i)->set_pending_declick (declick);
 136
 137                 if ((ret = (*i)->roll (nframes, _transport_frame, _transport_frame + nframes, offset, declick, record_active, rec_monitors)) < 0) {
 138
 139                         /* we have to do this here. Route::roll() for an AudioTrack will have called AudioDiskstream::process(),
 140                            and the DS will expect AudioDiskstream::commit() to be called. but we're aborting from that
 141                            call path, so make sure we release any outstanding locks here before we return failure.
 142                         */
 143
 144                         for (AudioDiskstreamList::iterator ids = audio_diskstreams.begin(); ids != audio_diskstreams.end(); ++ids) {
 145                                 (*ids)->recover ();
 146                         }
 147
 148                         stop_transport ();
 149                         return -1;
 150                 }
 151         }
 152
 153         return 0;
 154 }
 155
 156 int
 157 Session::silent_process_routes (jack_nframes_t nframes, jack_nframes_t offset)
 158 {
 159         bool record_active = actively_recording();
 160         int  declick = get_transport_declick_required();
 161         bool rec_monitors = get_rec_monitors_input();
 162         boost::shared_ptr<RouteList> r = routes.reader ();
 163
 164         if (transport_sub_state & StopPendingCapture) {
 165                 /* force a declick out */
 166                 declick = -1;
 167         }
 168
 169         for (RouteList::iterator i = r->begin(); i != r->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 AudioDiskstream::process(),
 180                            and the DS will expect AudioDiskstream::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 (AudioDiskstreamList::iterator ids = audio_diskstreams.begin(); ids != audio_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 (AudioDiskstreamList::iterator i = audio_diskstreams.begin(); i != audio_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 = g_atomic_int_get (&_playback_load);
 226         uint32_t pminold = g_atomic_int_get (&_playback_load_min);
 227         uint32_t cmin = g_atomic_int_get (&_capture_load);
 228         uint32_t cminold = g_atomic_int_get (&_capture_load_min);
 229
 230         g_atomic_int_set (&_playback_load, (uint32_t) floor (pworst * 100.0f));
 231         g_atomic_int_set (&_capture_load, (uint32_t) floor (cworst * 100.0f));
 232         g_atomic_int_set (&_playback_load_min, min (pmin, pminold));
 233         g_atomic_int_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         /* make sure the auditioner is silent */
 252
 253         if (auditioner) {
 254                 auditioner->silence (nframes, 0);
 255         }
 256
 257         /* handle any pending events */
 258
 259         while (pending_events.read (&ev, 1) == 1) {
 260                 merge_event (ev);
 261         }
 262
 263         /* if we are not in the middle of a state change,
 264            and there are immediate events queued up,
 265            process them.
 266         */
 267
 268         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 269                 Event *ev = immediate_events.front ();
 270                 immediate_events.pop_front ();
 271                 process_event (ev);
 272         }
 273
 274         if (!process_can_proceed()) {
 275                 no_roll (nframes, 0);
 276                 return;
 277         }
 278
 279         if (events.empty() || next_event == events.end()) {
 280                 process_without_events (nframes);
 281                 return;
 282         }
 283
 284         end_frame = _transport_frame + nframes;
 285
 286         {
 287                 Glib::RWLock::ReaderLock dsm (diskstream_lock, Glib::TRY_LOCK);
 288
 289                 Event* this_event;
 290                 Events::iterator the_next_one;
 291
 292                 if (!dsm.locked() || (post_transport_work & (PostTransportLocate|PostTransportStop))) {
 293                         no_roll (nframes, 0);
 294                         return;
 295                 }
 296
 297                 if (!_exporting && _slave) {
 298                         if (!follow_slave (nframes, 0)) {
 299                                 return;
 300                         }
 301                 }
 302
 303                 if (_transport_speed == 0) {
 304                         no_roll (nframes, 0);
 305                         return;
 306                 }
 307
 308                 if (actively_recording()) {
 309                         stop_limit = max_frames;
 310                 } else {
 311
 312                         if (Config->get_stop_at_session_end()) {
 313                                 stop_limit = current_end_frame();
 314                         } else {
 315                                 stop_limit = max_frames;
 316                         }
 317                 }
 318
 319                 if (maybe_stop (stop_limit)) {
 320                         no_roll (nframes, 0);
 321                         return;
 322                 }
 323
 324                 this_event = *next_event;
 325                 the_next_one = next_event;
 326                 ++the_next_one;
 327
 328                 offset = 0;
 329
 330                 while (nframes) {
 331
 332                         if (this_event == 0 || this_event->action_frame > end_frame || this_event->action_frame < _transport_frame) {
 333
 334                                 this_nframes = nframes;
 335
 336                         } else {
 337
 338                                 /* compute nframes to next event */
 339
 340                                 if (this_event->action_frame < end_frame) {
 341                                         this_nframes = nframes - (end_frame - this_event->action_frame);
 342                                 } else {
 343                                         this_nframes = nframes;
 344                                 }
 345                         }
 346
 347                         if (this_nframes) {
 348
 349                                 click (_transport_frame, nframes, offset);
 350
 351                                 /* now process frames between now and the first event in this block */
 352                                 prepare_diskstreams ();
 353
 354                                 if (process_routes (this_nframes, offset)) {
 355                                         no_roll (nframes, 0);
 356                                         return;
 357                                 }
 358
 359                                 commit_diskstreams (this_nframes, session_needs_butler);
 360
 361                                 nframes -= this_nframes;
 362                                 offset += this_nframes;
 363
 364                                 frames_moved = (jack_nframes_t) floor (_transport_speed * this_nframes);
 365
 366                                 if (frames_moved < 0) {
 367                                         decrement_transport_position (-frames_moved);
 368                                 } else {
 369                                         increment_transport_position (frames_moved);
 370                                 }
 371
 372                                 maybe_stop (stop_limit);
 373                                 check_declick_out ();
 374                         }
 375
 376                         /* now handle this event and all others scheduled for the same time */
 377
 378                         while (this_event && this_event->action_frame == _transport_frame) {
 379                                 process_event (this_event);
 380
 381                                 if (the_next_one == events.end()) {
 382                                         this_event = 0;
 383                                 } else {
 384                                         this_event = *the_next_one;
 385                                         ++the_next_one;
 386                                 }
 387                         }
 388
 389                         /* if an event left our state changing, do the right thing */
 390
 391                         if (non_realtime_work_pending()) {
 392                                 no_roll (nframes, offset);
 393                                 break;
 394                         }
 395
 396                         /* this is necessary to handle the case of seamless looping */
 397                         /* not sure if it will work in conjuction with varispeed */
 398                         end_frame = _transport_frame + nframes;
 399
 400                 }
 401
 402                 set_next_event ();
 403
 404         } /* implicit release of route lock */
 405
 406
 407         if (session_needs_butler) {
 408                 summon_butler ();
 409         }
 410
 411         if (!_engine.freewheeling() && send_mtc) {
 412                 send_midi_time_code_in_another_thread ();
 413         }
 414
 415         return;
 416 }
 417
 418 void
 419 Session::reset_slave_state ()
 420 {
 421         average_slave_delta = 1800;
 422         delta_accumulator_cnt = 0;
 423         have_first_delta_accumulator = false;
 424         slave_state = Stopped;
 425 }
 426
 427 bool
 428 Session::transport_locked () const
 429 {
 430         Slave* sl = _slave;
 431
 432         if (!locate_pending() && ((_slave_type == None) || (sl && sl->ok() && sl->locked()))) {
 433                 return true;
 434         }
 435
 436         return false;
 437 }
 438
 439 bool
 440 Session::follow_slave (jack_nframes_t nframes, jack_nframes_t offset)
 441 {
 442         float slave_speed;
 443         jack_nframes_t slave_transport_frame;
 444         jack_nframes_t this_delta;
 445         int dir;
 446         bool starting;
 447
 448         if (!_slave->ok()) {
 449                 stop_transport ();
 450                 set_slave_source (None, 0);
 451                 goto noroll;
 452         }
 453
 454         _slave->speed_and_position (slave_speed, slave_transport_frame);
 455
 456         if (!_slave->locked()) {
 457                 goto noroll;
 458         }
 459
 460         if (slave_transport_frame > _transport_frame) {
 461                 this_delta = slave_transport_frame - _transport_frame;
 462                 dir = 1;
 463         } else {
 464                 this_delta = _transport_frame - slave_transport_frame;
 465                 dir = -1;
 466         }
 467
 468         if ((starting = _slave->starting())) {
 469                 slave_speed = 0.0f;
 470         }
 471
 472 #if 0
 473         cerr << "delta = " << (int) (dir * this_delta)
 474              << " speed = " << slave_speed
 475              << " ts = " << _transport_speed
 476              << " M@"<< slave_transport_frame << " S@" << _transport_frame
 477              << " avgdelta = " << average_slave_delta
 478              << endl;
 479 #endif
 480
 481         if (Config->get_timecode_source_is_synced()) {
 482
 483                 /* if the TC source is synced, then we assume that its
 484                    speed is binary: 0.0 or 1.0
 485                 */
 486
 487                 if (slave_speed != 0.0f) {
 488                         slave_speed = 1.0f;
 489                 }
 490
 491         } else {
 492
 493                 /* TC source is able to drift relative to us (slave)
 494                    so we need to keep track of the drift and adjust
 495                    our speed to remain locked.
 496                 */
 497
 498                 if (delta_accumulator_cnt >= delta_accumulator_size) {
 499                         have_first_delta_accumulator = true;
 500                         delta_accumulator_cnt = 0;
 501                 }
 502
 503                 if (delta_accumulator_cnt != 0 || this_delta < _current_frame_rate) {
 504                         delta_accumulator[delta_accumulator_cnt++] = dir*this_delta;
 505                 }
 506
 507                 if (have_first_delta_accumulator) {
 508                         average_slave_delta = 0;
 509                         for (int i = 0; i < delta_accumulator_size; ++i) {
 510                                 average_slave_delta += delta_accumulator[i];
 511                         }
 512                         average_slave_delta /= delta_accumulator_size;
 513                         if (average_slave_delta < 0) {
 514                                 average_dir = -1;
 515                                 average_slave_delta = -average_slave_delta;
 516                         } else {
 517                                 average_dir = 1;
 518                         }
 519                         // cerr << "avgdelta = " << average_slave_delta*average_dir << endl;
 520                 }
 521         }
 522
 523         if (slave_speed != 0.0f) {
 524
 525                 /* slave is running */
 526
 527                 switch (slave_state) {
 528                 case Stopped:
 529                         if (_slave->requires_seekahead()) {
 530                                 slave_wait_end = slave_transport_frame + _current_frame_rate;
 531                                 locate (slave_wait_end, false, false);
 532                                 slave_state = Waiting;
 533                                 starting = true;
 534
 535                         } else {
 536
 537                                 slave_state = Running;
 538
 539                                 Location* al = _locations.auto_loop_location();
 540
 541                                 if (al && auto_loop && (slave_transport_frame < al->start() || slave_transport_frame > al->end())) {
 542                                         // cancel looping
 543                                         request_auto_loop(false);
 544                                 }
 545
 546                                 if (slave_transport_frame != _transport_frame) {
 547                                         locate (slave_transport_frame, false, false);
 548                                 }
 549                         }
 550                         break;
 551
 552                 case Waiting:
 553                         break;
 554
 555                 default:
 556                         break;
 557
 558                 }
 559
 560                 if (slave_state == Waiting) {
 561
 562                         // cerr << "waiting at " << slave_transport_frame << endl;
 563                         Glib::RWLock::ReaderLock dsm (diskstream_lock, Glib::TRY_LOCK);
 564
 565                         if (dsm.locked() && slave_transport_frame >= slave_wait_end) {
 566                                 // cerr << "\tstart at " << _transport_frame << endl;
 567
 568                                 slave_state = Running;
 569
 570                                 bool ok = true;
 571                                 jack_nframes_t frame_delta = slave_transport_frame - _transport_frame;
 572
 573                                 for (AudioDiskstreamList::iterator i = audio_diskstreams.begin(); i != audio_diskstreams.end(); ++i) {
 574                                         if (!(*i)->can_internal_playback_seek (frame_delta)) {
 575                                                 ok = false;
 576                                                 break;
 577                                         }
 578                                 }
 579
 580                                 if (ok) {
 581                                         for (AudioDiskstreamList::iterator i = audio_diskstreams.begin(); i != audio_diskstreams.end(); ++i) {
 582                                                 (*i)->internal_playback_seek (frame_delta);
 583                                         }
 584                                         _transport_frame += frame_delta;
 585
 586                                 } else {
 587                                         // cerr << "cannot micro-seek\n";
 588                                         /* XXX what? */
 589                                 }
 590
 591                                 memset (delta_accumulator, 0, sizeof (jack_nframes_t) * delta_accumulator_size);
 592                                 average_slave_delta = 0;
 593                                 this_delta = 0;
 594                         }
 595                 }
 596
 597                 if (slave_state == Running && _transport_speed == 0.0f) {
 598
 599                         // cerr << "slave starts transport\n";
 600
 601                         start_transport ();
 602                 }
 603
 604         } else {
 605
 606                 /* slave has stopped */
 607
 608                 if (_transport_speed != 0.0f) {
 609
 610                         // cerr << "slave stops transport: " << slave_speed << " frame: " << slave_transport_frame
 611                         // << " tf = " << _transport_frame
 612                         // << endl;
 613
 614                         if (_slave_type == JACK) {
 615                                 last_stop_frame = _transport_frame;
 616                         }
 617
 618                         stop_transport();
 619                 }
 620
 621                 if (slave_transport_frame != _transport_frame) {
 622                         // cerr << "slave stopped, move to " << slave_transport_frame << endl;
 623                         force_locate (slave_transport_frame, false);
 624                 }
 625
 626                 slave_state = Stopped;
 627         }
 628
 629         if (slave_state == Running && !Config->get_timecode_source_is_synced()) {
 630
 631
 632                 if (_transport_speed != 0.0f) {
 633
 634                         /*
 635                            note that average_dir is +1 or -1
 636                         */
 637
 638                         const float adjust_seconds = 1.0f;
 639                         float delta;
 640
 641                         //if (average_slave_delta == 0) {
 642                                 delta = this_delta;
 643                                 delta *= dir;
 644 //                      } else {
 645 //                              delta = average_slave_delta;
 646 //                              delta *= average_dir;
 647 //                      }
 648
 649                         float adjusted_speed = slave_speed +
 650                                 (delta / (adjust_seconds * _current_frame_rate));
 651
 652                         // cerr << "adjust using " << delta
 653                         // << " towards " << adjusted_speed
 654                         // << " ratio = " << adjusted_speed / slave_speed
 655                         // << " current = " << _transport_speed
 656                         // << " slave @ " << slave_speed
 657                         // << endl;
 658
 659                         request_transport_speed (adjusted_speed);
 660
 661 #if 1
 662                         if ((jack_nframes_t) average_slave_delta > _slave->resolution()) {
 663                                 // cerr << "not locked\n";
 664                                 goto silent_motion;
 665                         }
 666 #endif
 667                 }
 668         }
 669
 670         if (!starting && !non_realtime_work_pending()) {
 671                 /* speed is set, we're locked, and good to go */
 672                 return true;
 673         }
 674
 675   silent_motion:
 676
 677         if (slave_speed && _transport_speed) {
 678
 679                 /* something isn't right, but we should move with the master
 680                    for now.
 681                 */
 682
 683                 bool need_butler;
 684
 685                 Glib::RWLock::ReaderLock dsm (diskstream_lock, Glib::TRY_LOCK);
 686                 if (!dsm.locked()) {
 687                         goto noroll;
 688                 }
 689
 690
 691                 prepare_diskstreams ();
 692                 silent_process_routes (nframes, offset);
 693                 commit_diskstreams (nframes, need_butler);
 694
 695                 if (need_butler) {
 696                         summon_butler ();
 697                 }
 698
 699                 int32_t frames_moved = (int32_t) floor (_transport_speed * nframes);
 700
 701                 if (frames_moved < 0) {
 702                         decrement_transport_position (-frames_moved);
 703                 } else {
 704                         increment_transport_position (frames_moved);
 705                 }
 706
 707                 jack_nframes_t stop_limit;
 708
 709                 if (actively_recording()) {
 710                         stop_limit = max_frames;
 711                 } else {
 712                         if (Config->get_stop_at_session_end()) {
 713                                 stop_limit = current_end_frame();
 714                         } else {
 715                                 stop_limit = max_frames;
 716                         }
 717                 }
 718
 719                 maybe_stop (stop_limit);
 720         }
 721
 722   noroll:
 723         /* don't move at all */
 724         no_roll (nframes, 0);
 725         return false;
 726 }
 727
 728 void
 729 Session::process_without_events (jack_nframes_t nframes)
 730 {
 731         bool session_needs_butler = false;
 732         jack_nframes_t stop_limit;
 733         long frames_moved;
 734
 735         {
 736                 Glib::RWLock::ReaderLock dsm (diskstream_lock, Glib::TRY_LOCK);
 737
 738                 if (!dsm.locked() || (post_transport_work & (PostTransportLocate|PostTransportStop))) {
 739                         no_roll (nframes, 0);
 740                         return;
 741                 }
 742
 743                 if (!_exporting && _slave) {
 744                         if (!follow_slave (nframes, 0)) {
 745                                 return;
 746                         }
 747                 }
 748
 749                 if (_transport_speed == 0) {
 750                         no_roll (nframes, 0);
 751                         return;
 752                 }
 753
 754                 if (actively_recording()) {
 755                         stop_limit = max_frames;
 756                 } else {
 757                         if (Config->get_stop_at_session_end()) {
 758                                 stop_limit = current_end_frame();
 759                         } else {
 760                                 stop_limit = max_frames;
 761                         }
 762                 }
 763
 764                 if (maybe_stop (stop_limit)) {
 765                         no_roll (nframes, 0);
 766                         return;
 767                 }
 768
 769                 click (_transport_frame, nframes, 0);
 770
 771                 prepare_diskstreams ();
 772
 773                 frames_moved = (long) floor (_transport_speed * nframes);
 774
 775                 if (process_routes (nframes, 0)) {
 776                         no_roll (nframes, 0);
 777                         return;
 778                 }
 779
 780                 commit_diskstreams (nframes, session_needs_butler);
 781
 782                 if (frames_moved < 0) {
 783                         decrement_transport_position (-frames_moved);
 784                 } else {
 785                         increment_transport_position (frames_moved);
 786                 }
 787
 788                 maybe_stop (stop_limit);
 789                 check_declick_out ();
 790
 791         } /* implicit release of route lock */
 792
 793         if (session_needs_butler) {
 794                 summon_butler ();
 795         }
 796
 797         if (!_engine.freewheeling() && send_mtc) {
 798                 send_midi_time_code_in_another_thread ();
 799         }
 800
 801         return;
 802 }
 803
 804 void
 805 Session::process_audition (jack_nframes_t nframes)
 806 {
 807         Event* ev;
 808         boost::shared_ptr<RouteList> r = routes.reader ();
 809
 810         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 811                 if (!(*i)->hidden()) {
 812                         (*i)->silence (nframes, 0);
 813                 }
 814         }
 815
 816         /* run the auditioner, and if it says we need butler service, ask for it */
 817
 818         if (auditioner->play_audition (nframes) > 0) {
 819                 summon_butler ();
 820         }
 821
 822         /* handle pending events */
 823
 824         while (pending_events.read (&ev, 1) == 1) {
 825                 merge_event (ev);
 826         }
 827
 828         /* if we are not in the middle of a state change,
 829            and there are immediate events queued up,
 830            process them.
 831         */
 832
 833         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 834                 Event *ev = immediate_events.front ();
 835                 immediate_events.pop_front ();
 836                 process_event (ev);
 837         }
 838
 839         if (!auditioner->active()) {
 840                 process_function = &Session::process_with_events;
 841         }
 842 }
 843