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 <midi++/manager.h>
  41
  42 #include "i18n.h"
  43
  44 using namespace ARDOUR;
  45 using namespace PBD;
  46 using namespace std;
  47
  48 void
  49 Session::process (jack_nframes_t nframes)
  50 {
  51         MIDI::Manager::instance()->cycle_start(nframes);
  52
  53         if (synced_to_jack() && waiting_to_start) {
  54                 if ( _engine.transport_state() == AudioEngine::TransportRolling) {
  55                         actually_start_transport ();
  56                 }
  57         }
  58
  59         if (non_realtime_work_pending()) {
  60                 if (g_atomic_int_get (&butler_should_do_transport_work) == 0) {
  61                         post_transport ();
  62                 }
  63         }
  64
  65         (this->*process_function) (nframes);
  66
  67         MIDI::Manager::instance()->cycle_end();
  68
  69         SendFeedback (); /* EMIT SIGNAL */
  70 }
  71
  72 void
  73 Session::prepare_diskstreams ()
  74 {
  75         for (DiskstreamList::iterator i = diskstreams.begin(); i != diskstreams.end(); ++i) {
  76                 (*i)->prepare ();
  77         }
  78 }
  79
  80 int
  81 Session::no_roll (jack_nframes_t nframes, jack_nframes_t offset)
  82 {
  83         jack_nframes_t end_frame = _transport_frame + nframes;
  84         int ret = 0;
  85         bool declick = get_transport_declick_required();
  86
  87         if (_click_io) {
  88                 _click_io->silence (nframes, offset);
  89         }
  90
  91         /* XXX we're supposed to have the route_lock while doing this.
  92            this is really bad ...
  93         */
  94
  95         if (g_atomic_int_get (&processing_prohibited)) {
  96                 for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
  97                         (*i)->silence (nframes, offset);
  98                 }
  99                 return 0;
 100         }
 101
 102         for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
 103
 104                 if ((*i)->hidden()) {
 105                         continue;
 106                 }
 107
 108                 (*i)->set_pending_declick (declick);
 109
 110                 if ((*i)->no_roll (nframes, _transport_frame, end_frame, offset, non_realtime_work_pending(),
 111                                    actively_recording(), declick)) {
 112                         error << string_compose(_("Session: error in no roll for %1"), (*i)->name()) << endmsg;
 113                         ret = -1;
 114                         break;
 115                 }
 116         }
 117
 118         return ret;
 119 }
 120
 121 int
 122 Session::process_routes (jack_nframes_t nframes, jack_nframes_t offset)
 123 {
 124         bool record_active;
 125         int  declick = get_transport_declick_required();
 126         bool rec_monitors = get_rec_monitors_input();
 127
 128         if (transport_sub_state & StopPendingCapture) {
 129                 /* force a declick out */
 130                 declick = -1;
 131         }
 132
 133         record_active = actively_recording(); // || (get_record_enabled() && get_punch_in());
 134
 135         for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
 136
 137                 int ret;
 138
 139                 if ((*i)->hidden()) {
 140                         continue;
 141                 }
 142
 143                 (*i)->set_pending_declick (declick);
 144
 145                 if ((ret = (*i)->roll (nframes, _transport_frame, _transport_frame + nframes, offset, declick, record_active, rec_monitors)) < 0) {
 146
 147                         /* we have to do this here. Route::roll() for an AudioTrack will have called AudioDiskstream::process(),
 148                            and the DS will expect AudioDiskstream::commit() to be called. but we're aborting from that
 149                            call path, so make sure we release any outstanding locks here before we return failure.
 150                         */
 151
 152                         for (DiskstreamList::iterator ids = diskstreams.begin(); ids != diskstreams.end(); ++ids) {
 153                                 (*ids)->recover ();
 154                         }
 155
 156                         stop_transport ();
 157                         return -1;
 158                 }
 159         }
 160
 161         return 0;
 162 }
 163
 164 int
 165 Session::silent_process_routes (jack_nframes_t nframes, jack_nframes_t offset)
 166 {
 167         bool record_active = actively_recording();
 168         int  declick = get_transport_declick_required();
 169         bool rec_monitors = get_rec_monitors_input();
 170
 171         if (transport_sub_state & StopPendingCapture) {
 172                 /* force a declick out */
 173                 declick = -1;
 174         }
 175
 176         for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
 177
 178                 int ret;
 179
 180                 if ((*i)->hidden()) {
 181                         continue;
 182                 }
 183
 184                 if ((ret = (*i)->silent_roll (nframes, _transport_frame, _transport_frame + nframes, offset, record_active, rec_monitors)) < 0) {
 185
 186                         /* we have to do this here. Route::roll() for an AudioTrack will have called AudioDiskstream::process(),
 187                            and the DS will expect AudioDiskstream::commit() to be called. but we're aborting from that
 188                            call path, so make sure we release any outstanding locks here before we return failure.
 189                         */
 190
 191                         for (DiskstreamList::iterator ids = diskstreams.begin(); ids != diskstreams.end(); ++ids) {
 192                                 (*ids)->recover ();
 193                         }
 194
 195                         stop_transport ();
 196                         return -1;
 197                 }
 198         }
 199
 200         return 0;
 201 }
 202
 203 void
 204 Session::commit_diskstreams (jack_nframes_t nframes, bool &needs_butler)
 205 {
 206         int dret;
 207         float pworst = 1.0f;
 208         float cworst = 1.0f;
 209
 210         for (DiskstreamList::iterator i = diskstreams.begin(); i != diskstreams.end(); ++i) {
 211
 212                 if ((*i)->hidden()) {
 213                         continue;
 214                 }
 215
 216                 /* force all diskstreams not handled by a Route to call do their stuff.
 217                  */
 218
 219                 if ((dret = (*i)->process (_transport_frame, nframes, 0, actively_recording(), get_rec_monitors_input())) == 0) {
 220                         if ((*i)->commit (nframes)) {
 221                                 needs_butler = true;
 222                         }
 223
 224                 } else if (dret < 0) {
 225                         (*i)->recover();
 226                 }
 227
 228                 pworst = min (pworst, (*i)->playback_buffer_load());
 229                 cworst = min (cworst, (*i)->capture_buffer_load());
 230         }
 231
 232         uint32_t pmin = g_atomic_int_get (&_playback_load);
 233         uint32_t pminold = g_atomic_int_get (&_playback_load_min);
 234         uint32_t cmin = g_atomic_int_get (&_capture_load);
 235         uint32_t cminold = g_atomic_int_get (&_capture_load_min);
 236
 237         g_atomic_int_set (&_playback_load, (uint32_t) floor (pworst * 100.0f));
 238         g_atomic_int_set (&_capture_load, (uint32_t) floor (cworst * 100.0f));
 239         g_atomic_int_set (&_playback_load_min, min (pmin, pminold));
 240         g_atomic_int_set (&_capture_load_min, min (cmin, cminold));
 241
 242         if (actively_recording()) {
 243                 set_dirty();
 244         }
 245 }
 246
 247
 248 void
 249 Session::process_with_events (jack_nframes_t nframes)
 250 {
 251         Event*         ev;
 252         jack_nframes_t this_nframes;
 253         jack_nframes_t end_frame;
 254         jack_nframes_t offset;
 255         jack_nframes_t stop_limit;
 256         long           frames_moved;
 257         bool           session_needs_butler = false;
 258
 259         if (auditioner) {
 260                 auditioner->silence (nframes, 0);
 261         }
 262
 263         while (pending_events.read (&ev, 1) == 1) {
 264                 merge_event (ev);
 265         }
 266
 267         /* if we are not in the middle of a state change,
 268            and there are immediate events queued up,
 269            process them.
 270         */
 271
 272         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 273                 Event *ev = immediate_events.front ();
 274                 immediate_events.pop_front ();
 275                 process_event (ev);
 276         }
 277
 278         /* Events caused a transport change, send an MTC Full Frame (SMPTE) message.
 279          * This is sent whether rolling or not, to give slaves an idea of ardour time
 280          * on locates (and allow slow slaves to position and prepare for rolling)
 281          */
 282         if (_send_smpte_update) {
 283                 send_full_time_code(nframes);
 284         }
 285
 286         if (!process_can_proceed()) {
 287                 no_roll (nframes, 0);
 288                 return;
 289         }
 290
 291         if (events.empty() || next_event == events.end()) {
 292                 process_without_events (nframes);
 293                 return;
 294         }
 295
 296         end_frame = _transport_frame + nframes;
 297
 298         {
 299                 Glib::RWLock::ReaderLock rm (route_lock, Glib::TRY_LOCK);
 300                 Glib::RWLock::ReaderLock dsm (diskstream_lock, Glib::TRY_LOCK);
 301
 302                 Event* this_event;
 303                 Events::iterator the_next_one;
 304
 305                 if (!rm.locked() || !dsm.locked() || (post_transport_work & (PostTransportLocate|PostTransportStop))) {
 306                         no_roll (nframes, 0);
 307                         return;
 308                 }
 309
 310                 if (!_exporting && _slave) {
 311                         if (!follow_slave (nframes, 0)) {
 312                                 return;
 313                         }
 314                 }
 315
 316                 if (_transport_speed == 0) {
 317                         no_roll (nframes, 0);
 318                         return;
 319                 }
 320
 321                 send_midi_time_code_for_cycle(nframes);
 322
 323                 if (actively_recording()) {
 324                         stop_limit = max_frames;
 325                 } else {
 326
 327                         if (Config->get_stop_at_session_end()) {
 328                                 stop_limit = current_end_frame();
 329                         } else {
 330                                 stop_limit = max_frames;
 331                         }
 332                 }
 333
 334                 if (maybe_stop (stop_limit)) {
 335                         no_roll (nframes, 0);
 336                         return;
 337                 }
 338
 339                 this_event = *next_event;
 340                 the_next_one = next_event;
 341                 ++the_next_one;
 342
 343                 offset = 0;
 344
 345                 while (nframes) {
 346
 347                         if (this_event == 0 || this_event->action_frame > end_frame || this_event->action_frame < _transport_frame) {
 348
 349                                 this_nframes = nframes;
 350
 351                         } else {
 352
 353                                 /* compute nframes to next event */
 354
 355                                 if (this_event->action_frame < end_frame) {
 356                                         this_nframes = nframes - (end_frame - this_event->action_frame);
 357                                 } else {
 358                                         this_nframes = nframes;
 359                                 }
 360                         }
 361
 362                         if (this_nframes) {
 363
 364                                 click (_transport_frame, nframes, offset);
 365
 366                                 /* now process frames between now and the first event in this block */
 367                                 prepare_diskstreams ();
 368
 369                                 if (process_routes (this_nframes, offset)) {
 370                                         no_roll (nframes, 0);
 371                                         return;
 372                                 }
 373
 374                                 commit_diskstreams (this_nframes, session_needs_butler);
 375
 376                                 nframes -= this_nframes;
 377                                 offset += this_nframes;
 378
 379                                 frames_moved = (jack_nframes_t) floor (_transport_speed * this_nframes);
 380
 381                                 if (frames_moved < 0) {
 382                                         decrement_transport_position (-frames_moved);
 383                                 } else {
 384                                         increment_transport_position (frames_moved);
 385                                 }
 386
 387                                 maybe_stop (stop_limit);
 388                                 check_declick_out ();
 389                         }
 390
 391                         /* now handle this event and all others scheduled for the same time */
 392
 393                         while (this_event && this_event->action_frame == _transport_frame) {
 394                                 process_event (this_event);
 395
 396                                 if (the_next_one == events.end()) {
 397                                         this_event = 0;
 398                                 } else {
 399                                         this_event = *the_next_one;
 400                                         ++the_next_one;
 401                                 }
 402                         }
 403
 404                         /* if an event left our state changing, do the right thing */
 405
 406                         if (non_realtime_work_pending()) {
 407                                 no_roll (nframes, offset);
 408                                 break;
 409                         }
 410
 411                         /* this is necessary to handle the case of seamless looping */
 412                         /* not sure if it will work in conjuction with varispeed */
 413                         end_frame = _transport_frame + nframes;
 414
 415                 }
 416
 417                 set_next_event ();
 418
 419         } /* implicit release of route lock */
 420
 421         if (session_needs_butler)
 422                 summon_butler ();
 423 }
 424
 425 void
 426 Session::reset_slave_state ()
 427 {
 428         average_slave_delta = 1800;
 429         delta_accumulator_cnt = 0;
 430         have_first_delta_accumulator = false;
 431         slave_state = Stopped;
 432 }
 433
 434 bool
 435 Session::transport_locked () const
 436 {
 437         Slave* sl = _slave;
 438
 439         if (!locate_pending() && ((_slave_type == None) || (sl && sl->ok() && sl->locked()))) {
 440                 return true;
 441         }
 442
 443         return false;
 444 }
 445
 446 bool
 447 Session::follow_slave (jack_nframes_t nframes, jack_nframes_t offset)
 448 {
 449         float slave_speed;
 450         jack_nframes_t slave_transport_frame;
 451         jack_nframes_t this_delta;
 452         int dir;
 453         bool starting;
 454
 455         if (!_slave->ok()) {
 456                 stop_transport ();
 457                 set_slave_source (None, 0);
 458                 goto noroll;
 459         }
 460
 461         _slave->speed_and_position (slave_speed, slave_transport_frame);
 462
 463         if (!_slave->locked()) {
 464                 goto noroll;
 465         }
 466
 467         if (slave_transport_frame > _transport_frame) {
 468                 this_delta = slave_transport_frame - _transport_frame;
 469                 dir = 1;
 470         } else {
 471                 this_delta = _transport_frame - slave_transport_frame;
 472                 dir = -1;
 473         }
 474
 475         if ((starting = _slave->starting())) {
 476                 slave_speed = 0.0f;
 477         }
 478
 479 #if 0
 480         cerr << "delta = " << (int) (dir * this_delta)
 481              << " speed = " << slave_speed
 482              << " ts = " << _transport_speed
 483              << " M@"<< slave_transport_frame << " S@" << _transport_frame
 484              << " avgdelta = " << average_slave_delta
 485              << endl;
 486 #endif
 487
 488         if (Config->get_timecode_source_is_synced()) {
 489
 490                 /* if the TC source is synced, then we assume that its
 491                    speed is binary: 0.0 or 1.0
 492                 */
 493
 494                 if (slave_speed != 0.0f) {
 495                         slave_speed = 1.0f;
 496                 }
 497
 498         } else {
 499
 500                 /* TC source is able to drift relative to us (slave)
 501                    so we need to keep track of the drift and adjust
 502                    our speed to remain locked.
 503                 */
 504
 505                 if (delta_accumulator_cnt >= delta_accumulator_size) {
 506                         have_first_delta_accumulator = true;
 507                         delta_accumulator_cnt = 0;
 508                 }
 509
 510                 if (delta_accumulator_cnt != 0 || this_delta < _current_frame_rate) {
 511                         delta_accumulator[delta_accumulator_cnt++] = dir*this_delta;
 512                 }
 513
 514                 if (have_first_delta_accumulator) {
 515                         average_slave_delta = 0;
 516                         for (int i = 0; i < delta_accumulator_size; ++i) {
 517                                 average_slave_delta += delta_accumulator[i];
 518                         }
 519                         average_slave_delta /= delta_accumulator_size;
 520                         if (average_slave_delta < 0) {
 521                                 average_dir = -1;
 522                                 average_slave_delta = -average_slave_delta;
 523                         } else {
 524                                 average_dir = 1;
 525                         }
 526                         // cerr << "avgdelta = " << average_slave_delta*average_dir << endl;
 527                 }
 528         }
 529
 530         if (slave_speed != 0.0f) {
 531
 532                 /* slave is running */
 533
 534                 switch (slave_state) {
 535                 case Stopped:
 536                         if (_slave->requires_seekahead()) {
 537                                 slave_wait_end = slave_transport_frame + _current_frame_rate;
 538                                 locate (slave_wait_end, false, false);
 539                                 slave_state = Waiting;
 540                                 starting = true;
 541
 542                         } else {
 543
 544                                 slave_state = Running;
 545
 546                                 Location* al = _locations.auto_loop_location();
 547
 548                                 if (al && auto_loop && (slave_transport_frame < al->start() || slave_transport_frame > al->end())) {
 549                                         // cancel looping
 550                                         request_auto_loop(false);
 551                                 }
 552
 553                                 if (slave_transport_frame != _transport_frame) {
 554                                         locate (slave_transport_frame, false, false);
 555                                 }
 556                         }
 557                         break;
 558
 559                 case Waiting:
 560                         break;
 561
 562                 default:
 563                         break;
 564
 565                 }
 566
 567                 if (slave_state == Waiting) {
 568
 569                         // cerr << "waiting at " << slave_transport_frame << endl;
 570                         Glib::RWLock::ReaderLock dsm (diskstream_lock, Glib::TRY_LOCK);
 571
 572                         if (dsm.locked() && slave_transport_frame >= slave_wait_end) {
 573                                 // cerr << "\tstart at " << _transport_frame << endl;
 574
 575                                 slave_state = Running;
 576
 577                                 bool ok = true;
 578                                 jack_nframes_t frame_delta = slave_transport_frame - _transport_frame;
 579
 580                                 for (DiskstreamList::iterator i = diskstreams.begin(); i != diskstreams.end(); ++i) {
 581                                         if (!(*i)->can_internal_playback_seek (frame_delta)) {
 582                                                 ok = false;
 583                                                 break;
 584                                         }
 585                                 }
 586
 587                                 if (ok) {
 588                                         for (DiskstreamList::iterator i = diskstreams.begin(); i != diskstreams.end(); ++i) {
 589                                                 (*i)->internal_playback_seek (frame_delta);
 590                                         }
 591                                         _transport_frame += frame_delta;
 592
 593                                 } else {
 594                                         // cerr << "cannot micro-seek\n";
 595                                         /* XXX what? */
 596                                 }
 597
 598                                 memset (delta_accumulator, 0, sizeof (jack_nframes_t) * delta_accumulator_size);
 599                                 average_slave_delta = 0;
 600                                 this_delta = 0;
 601                         }
 602                 }
 603
 604                 if (slave_state == Running && _transport_speed == 0.0f) {
 605
 606                         // cerr << "slave starts transport\n";
 607
 608                         start_transport ();
 609                 }
 610
 611         } else {
 612
 613                 /* slave has stopped */
 614
 615                 if (_transport_speed != 0.0f) {
 616
 617                         // cerr << "slave stops transport: " << slave_speed << " frame: " << slave_transport_frame
 618                         // << " tf = " << _transport_frame
 619                         // << endl;
 620
 621                         if (_slave_type == JACK) {
 622                                 last_stop_frame = _transport_frame;
 623                         }
 624
 625                         stop_transport();
 626                 }
 627
 628                 if (slave_transport_frame != _transport_frame) {
 629                         // cerr << "slave stopped, move to " << slave_transport_frame << endl;
 630                         force_locate (slave_transport_frame, false);
 631                 }
 632
 633                 slave_state = Stopped;
 634         }
 635
 636         if (slave_state == Running && !Config->get_timecode_source_is_synced()) {
 637
 638
 639                 if (_transport_speed != 0.0f) {
 640
 641                         /*
 642                            note that average_dir is +1 or -1
 643                         */
 644
 645                         const float adjust_seconds = 1.0f;
 646                         float delta;
 647
 648                         //if (average_slave_delta == 0) {
 649                                 delta = this_delta;
 650                                 delta *= dir;
 651 //                      } else {
 652 //                              delta = average_slave_delta;
 653 //                              delta *= average_dir;
 654 //                      }
 655
 656                         float adjusted_speed = slave_speed +
 657                                 (delta / (adjust_seconds * _current_frame_rate));
 658
 659                         // cerr << "adjust using " << delta
 660                         // << " towards " << adjusted_speed
 661                         // << " ratio = " << adjusted_speed / slave_speed
 662                         // << " current = " << _transport_speed
 663                         // << " slave @ " << slave_speed
 664                         // << endl;
 665
 666                         request_transport_speed (adjusted_speed);
 667
 668 #if 1
 669                         if ((jack_nframes_t) average_slave_delta > _slave->resolution()) {
 670                                 // cerr << "not locked\n";
 671                                 goto silent_motion;
 672                         }
 673 #endif
 674                 }
 675         }
 676
 677         if (!starting && !non_realtime_work_pending()) {
 678                 /* speed is set, we're locked, and good to go */
 679                 return true;
 680         }
 681
 682   silent_motion:
 683
 684         if (slave_speed && _transport_speed) {
 685
 686                 /* something isn't right, but we should move with the master
 687                    for now.
 688                 */
 689
 690                 bool need_butler;
 691
 692                 Glib::RWLock::ReaderLock dsm (diskstream_lock, Glib::TRY_LOCK);
 693                 if (!dsm.locked()) {
 694                         goto noroll;
 695                 }
 696
 697
 698                 prepare_diskstreams ();
 699                 silent_process_routes (nframes, offset);
 700                 commit_diskstreams (nframes, need_butler);
 701
 702                 if (need_butler) {
 703                         summon_butler ();
 704                 }
 705
 706                 jack_nframes_t frames_moved = (long) floor (_transport_speed * nframes);
 707
 708                 if (frames_moved < 0) {
 709                         decrement_transport_position (-frames_moved);
 710                 } else {
 711                         increment_transport_position (frames_moved);
 712                 }
 713
 714                 jack_nframes_t stop_limit;
 715
 716                 if (actively_recording()) {
 717                         stop_limit = max_frames;
 718                 } else {
 719                         if (Config->get_stop_at_session_end()) {
 720                                 stop_limit = current_end_frame();
 721                         } else {
 722                                 stop_limit = max_frames;
 723                         }
 724                 }
 725
 726                 maybe_stop (stop_limit);
 727         }
 728
 729   noroll:
 730         /* don't move at all */
 731         no_roll (nframes, 0);
 732         return false;
 733 }
 734
 735 void
 736 Session::process_without_events (jack_nframes_t nframes)
 737 {
 738         bool session_needs_butler = false;
 739         jack_nframes_t stop_limit;
 740         long frames_moved;
 741
 742         {
 743                 Glib::RWLock::ReaderLock rm (route_lock, Glib::TRY_LOCK);
 744                 Glib::RWLock::ReaderLock dsm (diskstream_lock, Glib::TRY_LOCK);
 745
 746                 if (!rm.locked() || !dsm.locked() || (post_transport_work & (PostTransportLocate|PostTransportStop))) {
 747                         no_roll (nframes, 0);
 748                         return;
 749                 }
 750
 751                 if (!_exporting && _slave) {
 752                         if (!follow_slave (nframes, 0)) {
 753                                 return;
 754                         }
 755                 }
 756
 757                 if (_transport_speed == 0) {
 758                         no_roll (nframes, 0);
 759                         return;
 760                 }
 761
 762                 send_midi_time_code_for_cycle(nframes);
 763
 764                 if (actively_recording()) {
 765                         stop_limit = max_frames;
 766                 } else {
 767                         if (Config->get_stop_at_session_end()) {
 768                                 stop_limit = current_end_frame();
 769                         } else {
 770                                 stop_limit = max_frames;
 771                         }
 772                 }
 773
 774                 if (maybe_stop (stop_limit)) {
 775                         no_roll (nframes, 0);
 776                         return;
 777                 }
 778
 779                 click (_transport_frame, nframes, 0);
 780
 781                 prepare_diskstreams ();
 782
 783                 frames_moved = (long) floor (_transport_speed * nframes);
 784
 785                 if (process_routes (nframes, 0)) {
 786                         no_roll (nframes, 0);
 787                         return;
 788                 }
 789
 790                 commit_diskstreams (nframes, session_needs_butler);
 791
 792                 if (frames_moved < 0) {
 793                         decrement_transport_position (-frames_moved);
 794                 } else {
 795                         increment_transport_position (frames_moved);
 796                 }
 797
 798                 maybe_stop (stop_limit);
 799                 check_declick_out ();
 800
 801         } /* implicit release of route lock */
 802
 803         if (session_needs_butler)
 804                 summon_butler ();
 805 }
 806
 807 void
 808 Session::process_audition (jack_nframes_t nframes)
 809 {
 810         Glib::RWLock::ReaderLock rm (route_lock, Glib::TRY_LOCK);
 811         Event* ev;
 812
 813         if (rm.locked()) {
 814                 for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
 815                         if (!(*i)->hidden()) {
 816                                 (*i)->silence (nframes, 0);
 817                         }
 818                 }
 819         }
 820
 821         if (auditioner->play_audition (nframes) > 0) {
 822                 summon_butler ();
 823         }
 824
 825         while (pending_events.read (&ev, 1) == 1) {
 826                 merge_event (ev);
 827         }
 828
 829         /* if we are not in the middle of a state change,
 830            and there are immediate events queued up,
 831            process them.
 832         */
 833
 834         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 835                 Event *ev = immediate_events.front ();
 836                 immediate_events.pop_front ();
 837                 process_event (ev);
 838         }
 839
 840         if (!auditioner->active()) {
 841                 process_function = &Session::process_with_events;
 842         }
 843 }
 844