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