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