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; // FIXME: varispeed + no_roll ??
  84         int ret = 0;
  85         bool declick = get_transport_declick_required();
  86         boost::shared_ptr<RouteList> r = routes.reader ();
  87
  88         if (_click_io) {
  89                 _click_io->silence (nframes, offset);
  90         }
  91
  92         if (g_atomic_int_get (&processing_prohibited)) {
  93                 for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
  94                         (*i)->silence (nframes, offset);
  95                 }
  96                 return 0;
  97         }
  98
  99         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 100
 101                 if ((*i)->hidden()) {
 102                         continue;
 103                 }
 104
 105                 (*i)->set_pending_declick (declick);
 106
 107                 if ((*i)->no_roll (nframes, _transport_frame, end_frame, offset, non_realtime_work_pending(),
 108                                    actively_recording(), declick)) {
 109                         error << string_compose(_("Session: error in no roll for %1"), (*i)->name()) << endmsg;
 110                         ret = -1;
 111                         break;
 112                 }
 113         }
 114
 115         return ret;
 116 }
 117
 118 int
 119 Session::process_routes (jack_nframes_t nframes, jack_nframes_t offset)
 120 {
 121         bool record_active;
 122         int  declick = get_transport_declick_required();
 123         bool rec_monitors = get_rec_monitors_input();
 124         boost::shared_ptr<RouteList> r = routes.reader ();
 125
 126         if (transport_sub_state & StopPendingCapture) {
 127                 /* force a declick out */
 128                 declick = -1;
 129         }
 130
 131         record_active = actively_recording(); // || (get_record_enabled() && get_punch_in());
 132
 133         const jack_nframes_t start_frame = _transport_frame;
 134         const jack_nframes_t end_frame = _transport_frame + lrintf(nframes * _transport_speed);
 135
 136         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 137
 138                 int ret;
 139
 140                 if ((*i)->hidden()) {
 141                         continue;
 142                 }
 143
 144                 (*i)->set_pending_declick (declick);
 145
 146                 if ((ret = (*i)->roll (nframes, start_frame, end_frame, offset, declick, record_active, rec_monitors)) < 0) {
 147
 148                         /* we have to do this here. Route::roll() for an AudioTrack will have called AudioDiskstream::process(),
 149                            and the DS will expect AudioDiskstream::commit() to be called. but we're aborting from that
 150                            call path, so make sure we release any outstanding locks here before we return failure.
 151                         */
 152
 153                         for (DiskstreamList::iterator ids = diskstreams.begin(); ids != diskstreams.end(); ++ids) {
 154                                 (*ids)->recover ();
 155                         }
 156
 157                         stop_transport ();
 158                         return -1;
 159                 }
 160         }
 161
 162         return 0;
 163 }
 164
 165 int
 166 Session::silent_process_routes (jack_nframes_t nframes, jack_nframes_t offset)
 167 {
 168         bool record_active = actively_recording();
 169         int  declick = get_transport_declick_required();
 170         bool rec_monitors = get_rec_monitors_input();
 171         boost::shared_ptr<RouteList> r = routes.reader ();
 172
 173         if (transport_sub_state & StopPendingCapture) {
 174                 /* force a declick out */
 175                 declick = -1;
 176         }
 177
 178         const jack_nframes_t start_frame = _transport_frame;
 179         const jack_nframes_t end_frame = _transport_frame + lrintf(nframes * _transport_speed);
 180
 181         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 182
 183                 int ret;
 184
 185                 if ((*i)->hidden()) {
 186                         continue;
 187                 }
 188
 189                 if ((ret = (*i)->silent_roll (nframes, start_frame, end_frame, offset, record_active, rec_monitors)) < 0) {
 190
 191                         /* we have to do this here. Route::roll() for an AudioTrack will have called AudioDiskstream::process(),
 192                            and the DS will expect AudioDiskstream::commit() to be called. but we're aborting from that
 193                            call path, so make sure we release any outstanding locks here before we return failure.
 194                         */
 195
 196                         for (DiskstreamList::iterator ids = diskstreams.begin(); ids != diskstreams.end(); ++ids) {
 197                                 (*ids)->recover ();
 198                         }
 199
 200                         stop_transport ();
 201                         return -1;
 202                 }
 203         }
 204
 205         return 0;
 206 }
 207
 208 void
 209 Session::commit_diskstreams (jack_nframes_t nframes, bool &needs_butler)
 210 {
 211         int dret;
 212         float pworst = 1.0f;
 213         float cworst = 1.0f;
 214
 215         for (DiskstreamList::iterator i = diskstreams.begin(); i != diskstreams.end(); ++i) {
 216
 217                 if ((*i)->hidden()) {
 218                         continue;
 219                 }
 220
 221                 /* force all diskstreams not handled by a Route to call do their stuff.
 222                  */
 223
 224                 if ((dret = (*i)->process (_transport_frame, nframes, 0, actively_recording(), get_rec_monitors_input())) == 0) {
 225                         if ((*i)->commit (nframes)) {
 226                                 needs_butler = true;
 227                         }
 228
 229                 } else if (dret < 0) {
 230                         (*i)->recover();
 231                 }
 232
 233                 pworst = min (pworst, (*i)->playback_buffer_load());
 234                 cworst = min (cworst, (*i)->capture_buffer_load());
 235         }
 236
 237         uint32_t pmin = g_atomic_int_get (&_playback_load);
 238         uint32_t pminold = g_atomic_int_get (&_playback_load_min);
 239         uint32_t cmin = g_atomic_int_get (&_capture_load);
 240         uint32_t cminold = g_atomic_int_get (&_capture_load_min);
 241
 242         g_atomic_int_set (&_playback_load, (uint32_t) floor (pworst * 100.0f));
 243         g_atomic_int_set (&_capture_load, (uint32_t) floor (cworst * 100.0f));
 244         g_atomic_int_set (&_playback_load_min, min (pmin, pminold));
 245         g_atomic_int_set (&_capture_load_min, min (cmin, cminold));
 246
 247         if (actively_recording()) {
 248                 set_dirty();
 249         }
 250 }
 251
 252
 253 void
 254 Session::process_with_events (jack_nframes_t nframes)
 255 {
 256         Event*         ev;
 257         jack_nframes_t this_nframes;
 258         jack_nframes_t end_frame;
 259         jack_nframes_t offset;
 260         jack_nframes_t stop_limit;
 261         long           frames_moved;
 262         bool           session_needs_butler = false;
 263
 264         /* make sure the auditioner is silent */
 265
 266         if (auditioner) {
 267                 auditioner->silence (nframes, 0);
 268         }
 269
 270         /* handle any pending events */
 271
 272         while (pending_events.read (&ev, 1) == 1) {
 273                 merge_event (ev);
 274         }
 275
 276         /* if we are not in the middle of a state change,
 277            and there are immediate events queued up,
 278            process them.
 279         */
 280
 281         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 282                 Event *ev = immediate_events.front ();
 283                 immediate_events.pop_front ();
 284                 process_event (ev);
 285         }
 286
 287         /* Events caused a transport change, send an MTC Full Frame (SMPTE) message.
 288          * This is sent whether rolling or not, to give slaves an idea of ardour time
 289          * on locates (and allow slow slaves to position and prepare for rolling)
 290          */
 291         if (_send_smpte_update) {
 292                 send_full_time_code(nframes);
 293         }
 294
 295         if (!process_can_proceed()) {
 296                 no_roll (nframes, 0);
 297                 return;
 298         }
 299
 300         if (events.empty() || next_event == events.end()) {
 301                 process_without_events (nframes);
 302                 return;
 303         }
 304
 305         end_frame = _transport_frame + nframes;
 306
 307         {
 308                 Glib::RWLock::ReaderLock dsm (diskstream_lock, Glib::TRY_LOCK);
 309
 310                 Event* this_event;
 311                 Events::iterator the_next_one;
 312
 313                 if (!dsm.locked() || (post_transport_work & (PostTransportLocate|PostTransportStop))) {
 314                         no_roll (nframes, 0);
 315                         return;
 316                 }
 317
 318                 if (!_exporting && _slave) {
 319                         if (!follow_slave (nframes, 0)) {
 320                                 return;
 321                         }
 322                 }
 323
 324                 if (_transport_speed == 0) {
 325                         no_roll (nframes, 0);
 326                         return;
 327                 }
 328
 329                 send_midi_time_code_for_cycle(nframes);
 330
 331                 if (actively_recording()) {
 332                         stop_limit = max_frames;
 333                 } else {
 334
 335                         if (Config->get_stop_at_session_end()) {
 336                                 stop_limit = current_end_frame();
 337                         } else {
 338                                 stop_limit = max_frames;
 339                         }
 340                 }
 341
 342                 if (maybe_stop (stop_limit)) {
 343                         no_roll (nframes, 0);
 344                         return;
 345                 }
 346
 347                 this_event = *next_event;
 348                 the_next_one = next_event;
 349                 ++the_next_one;
 350
 351                 offset = 0;
 352
 353                 while (nframes) {
 354
 355                         if (this_event == 0 || this_event->action_frame > end_frame || this_event->action_frame < _transport_frame) {
 356
 357                                 this_nframes = nframes;
 358
 359                         } else {
 360
 361                                 /* compute nframes to next event */
 362
 363                                 if (this_event->action_frame < end_frame) {
 364                                         this_nframes = nframes - (end_frame - this_event->action_frame);
 365                                 } else {
 366                                         this_nframes = nframes;
 367                                 }
 368                         }
 369
 370                         if (this_nframes) {
 371
 372                                 click (_transport_frame, nframes, offset);
 373
 374                                 /* now process frames between now and the first event in this block */
 375                                 prepare_diskstreams ();
 376
 377                                 if (process_routes (this_nframes, offset)) {
 378                                         no_roll (nframes, 0);
 379                                         return;
 380                                 }
 381
 382                                 commit_diskstreams (this_nframes, session_needs_butler);
 383
 384                                 nframes -= this_nframes;
 385                                 offset += this_nframes;
 386
 387                                 frames_moved = (jack_nframes_t) floor (_transport_speed * this_nframes);
 388
 389                                 if (frames_moved < 0) {
 390                                         decrement_transport_position (-frames_moved);
 391                                 } else {
 392                                         increment_transport_position (frames_moved);
 393                                 }
 394
 395                                 maybe_stop (stop_limit);
 396                                 check_declick_out ();
 397                         }
 398
 399                         /* now handle this event and all others scheduled for the same time */
 400
 401                         while (this_event && this_event->action_frame == _transport_frame) {
 402                                 process_event (this_event);
 403
 404                                 if (the_next_one == events.end()) {
 405                                         this_event = 0;
 406                                 } else {
 407                                         this_event = *the_next_one;
 408                                         ++the_next_one;
 409                                 }
 410                         }
 411
 412                         /* if an event left our state changing, do the right thing */
 413
 414                         if (non_realtime_work_pending()) {
 415                                 no_roll (nframes, offset);
 416                                 break;
 417                         }
 418
 419                         /* this is necessary to handle the case of seamless looping */
 420                         /* not sure if it will work in conjuction with varispeed */
 421                         end_frame = _transport_frame + nframes;
 422
 423                 }
 424
 425                 set_next_event ();
 426
 427         } /* implicit release of route lock */
 428
 429         if (session_needs_butler)
 430                 summon_butler ();
 431 }
 432
 433 void
 434 Session::reset_slave_state ()
 435 {
 436         average_slave_delta = 1800;
 437         delta_accumulator_cnt = 0;
 438         have_first_delta_accumulator = false;
 439         slave_state = Stopped;
 440 }
 441
 442 bool
 443 Session::transport_locked () const
 444 {
 445         Slave* sl = _slave;
 446
 447         if (!locate_pending() && ((_slave_type == None) || (sl && sl->ok() && sl->locked()))) {
 448                 return true;
 449         }
 450
 451         return false;
 452 }
 453
 454 bool
 455 Session::follow_slave (jack_nframes_t nframes, jack_nframes_t offset)
 456 {
 457         float slave_speed;
 458         jack_nframes_t slave_transport_frame;
 459         jack_nframes_t this_delta;
 460         int dir;
 461         bool starting;
 462
 463         if (!_slave->ok()) {
 464                 stop_transport ();
 465                 set_slave_source (None, 0);
 466                 goto noroll;
 467         }
 468
 469         _slave->speed_and_position (slave_speed, slave_transport_frame);
 470
 471         if (!_slave->locked()) {
 472                 goto noroll;
 473         }
 474
 475         if (slave_transport_frame > _transport_frame) {
 476                 this_delta = slave_transport_frame - _transport_frame;
 477                 dir = 1;
 478         } else {
 479                 this_delta = _transport_frame - slave_transport_frame;
 480                 dir = -1;
 481         }
 482
 483         if ((starting = _slave->starting())) {
 484                 slave_speed = 0.0f;
 485         }
 486
 487 #if 0
 488         cerr << "delta = " << (int) (dir * this_delta)
 489              << " speed = " << slave_speed
 490              << " ts = " << _transport_speed
 491              << " M@"<< slave_transport_frame << " S@" << _transport_frame
 492              << " avgdelta = " << average_slave_delta
 493              << endl;
 494 #endif
 495
 496         if (Config->get_timecode_source_is_synced()) {
 497
 498                 /* if the TC source is synced, then we assume that its
 499                    speed is binary: 0.0 or 1.0
 500                 */
 501
 502                 if (slave_speed != 0.0f) {
 503                         slave_speed = 1.0f;
 504                 }
 505
 506         } else {
 507
 508                 /* TC source is able to drift relative to us (slave)
 509                    so we need to keep track of the drift and adjust
 510                    our speed to remain locked.
 511                 */
 512
 513                 if (delta_accumulator_cnt >= delta_accumulator_size) {
 514                         have_first_delta_accumulator = true;
 515                         delta_accumulator_cnt = 0;
 516                 }
 517
 518                 if (delta_accumulator_cnt != 0 || this_delta < _current_frame_rate) {
 519                         delta_accumulator[delta_accumulator_cnt++] = dir*this_delta;
 520                 }
 521
 522                 if (have_first_delta_accumulator) {
 523                         average_slave_delta = 0;
 524                         for (int i = 0; i < delta_accumulator_size; ++i) {
 525                                 average_slave_delta += delta_accumulator[i];
 526                         }
 527                         average_slave_delta /= delta_accumulator_size;
 528                         if (average_slave_delta < 0) {
 529                                 average_dir = -1;
 530                                 average_slave_delta = -average_slave_delta;
 531                         } else {
 532                                 average_dir = 1;
 533                         }
 534                         // cerr << "avgdelta = " << average_slave_delta*average_dir << endl;
 535                 }
 536         }
 537
 538         if (slave_speed != 0.0f) {
 539
 540                 /* slave is running */
 541
 542                 switch (slave_state) {
 543                 case Stopped:
 544                         if (_slave->requires_seekahead()) {
 545                                 slave_wait_end = slave_transport_frame + _current_frame_rate;
 546                                 locate (slave_wait_end, false, false);
 547                                 slave_state = Waiting;
 548                                 starting = true;
 549
 550                         } else {
 551
 552                                 slave_state = Running;
 553
 554                                 Location* al = _locations.auto_loop_location();
 555
 556                                 if (al && auto_loop && (slave_transport_frame < al->start() || slave_transport_frame > al->end())) {
 557                                         // cancel looping
 558                                         request_auto_loop(false);
 559                                 }
 560
 561                                 if (slave_transport_frame != _transport_frame) {
 562                                         locate (slave_transport_frame, false, false);
 563                                 }
 564                         }
 565                         break;
 566
 567                 case Waiting:
 568                         break;
 569
 570                 default:
 571                         break;
 572
 573                 }
 574
 575                 if (slave_state == Waiting) {
 576
 577                         // cerr << "waiting at " << slave_transport_frame << endl;
 578                         Glib::RWLock::ReaderLock dsm (diskstream_lock, Glib::TRY_LOCK);
 579
 580                         if (dsm.locked() && slave_transport_frame >= slave_wait_end) {
 581                                 // cerr << "\tstart at " << _transport_frame << endl;
 582
 583                                 slave_state = Running;
 584
 585                                 bool ok = true;
 586                                 jack_nframes_t frame_delta = slave_transport_frame - _transport_frame;
 587
 588                                 for (DiskstreamList::iterator i = diskstreams.begin(); i != diskstreams.end(); ++i) {
 589                                         if (!(*i)->can_internal_playback_seek (frame_delta)) {
 590                                                 ok = false;
 591                                                 break;
 592                                         }
 593                                 }
 594
 595                                 if (ok) {
 596                                         for (DiskstreamList::iterator i = diskstreams.begin(); i != diskstreams.end(); ++i) {
 597                                                 (*i)->internal_playback_seek (frame_delta);
 598                                         }
 599                                         _transport_frame += frame_delta;
 600
 601                                 } else {
 602                                         // cerr << "cannot micro-seek\n";
 603                                         /* XXX what? */
 604                                 }
 605
 606                                 memset (delta_accumulator, 0, sizeof (jack_nframes_t) * delta_accumulator_size);
 607                                 average_slave_delta = 0;
 608                                 this_delta = 0;
 609                         }
 610                 }
 611
 612                 if (slave_state == Running && _transport_speed == 0.0f) {
 613
 614                         // cerr << "slave starts transport\n";
 615
 616                         start_transport ();
 617                 }
 618
 619         } else {
 620
 621                 /* slave has stopped */
 622
 623                 if (_transport_speed != 0.0f) {
 624
 625                         // cerr << "slave stops transport: " << slave_speed << " frame: " << slave_transport_frame
 626                         // << " tf = " << _transport_frame
 627                         // << endl;
 628
 629                         if (_slave_type == JACK) {
 630                                 last_stop_frame = _transport_frame;
 631                         }
 632
 633                         stop_transport();
 634                 }
 635
 636                 if (slave_transport_frame != _transport_frame) {
 637                         // cerr << "slave stopped, move to " << slave_transport_frame << endl;
 638                         force_locate (slave_transport_frame, false);
 639                 }
 640
 641                 slave_state = Stopped;
 642         }
 643
 644         if (slave_state == Running && !Config->get_timecode_source_is_synced()) {
 645
 646
 647                 if (_transport_speed != 0.0f) {
 648
 649                         /*
 650                            note that average_dir is +1 or -1
 651                         */
 652
 653                         const float adjust_seconds = 1.0f;
 654                         float delta;
 655
 656                         //if (average_slave_delta == 0) {
 657                                 delta = this_delta;
 658                                 delta *= dir;
 659 //                      } else {
 660 //                              delta = average_slave_delta;
 661 //                              delta *= average_dir;
 662 //                      }
 663
 664                         float adjusted_speed = slave_speed +
 665                                 (delta / (adjust_seconds * _current_frame_rate));
 666
 667                         // cerr << "adjust using " << delta
 668                         // << " towards " << adjusted_speed
 669                         // << " ratio = " << adjusted_speed / slave_speed
 670                         // << " current = " << _transport_speed
 671                         // << " slave @ " << slave_speed
 672                         // << endl;
 673
 674                         request_transport_speed (adjusted_speed);
 675
 676 #if 1
 677                         if ((jack_nframes_t) average_slave_delta > _slave->resolution()) {
 678                                 // cerr << "not locked\n";
 679                                 goto silent_motion;
 680                         }
 681 #endif
 682                 }
 683         }
 684
 685         if (!starting && !non_realtime_work_pending()) {
 686                 /* speed is set, we're locked, and good to go */
 687                 return true;
 688         }
 689
 690   silent_motion:
 691
 692         if (slave_speed && _transport_speed) {
 693
 694                 /* something isn't right, but we should move with the master
 695                    for now.
 696                 */
 697
 698                 bool need_butler;
 699
 700                 Glib::RWLock::ReaderLock dsm (diskstream_lock, Glib::TRY_LOCK);
 701                 if (!dsm.locked()) {
 702                         goto noroll;
 703                 }
 704
 705
 706                 prepare_diskstreams ();
 707                 silent_process_routes (nframes, offset);
 708                 commit_diskstreams (nframes, need_butler);
 709
 710                 if (need_butler) {
 711                         summon_butler ();
 712                 }
 713
 714                 int32_t frames_moved = (int32_t) floor (_transport_speed * nframes);
 715
 716                 if (frames_moved < 0) {
 717                         decrement_transport_position (-frames_moved);
 718                 } else {
 719                         increment_transport_position (frames_moved);
 720                 }
 721
 722                 jack_nframes_t stop_limit;
 723
 724                 if (actively_recording()) {
 725                         stop_limit = max_frames;
 726                 } else {
 727                         if (Config->get_stop_at_session_end()) {
 728                                 stop_limit = current_end_frame();
 729                         } else {
 730                                 stop_limit = max_frames;
 731                         }
 732                 }
 733
 734                 maybe_stop (stop_limit);
 735         }
 736
 737   noroll:
 738         /* don't move at all */
 739         no_roll (nframes, 0);
 740         return false;
 741 }
 742
 743 void
 744 Session::process_without_events (jack_nframes_t nframes)
 745 {
 746         bool session_needs_butler = false;
 747         jack_nframes_t stop_limit;
 748         long frames_moved;
 749
 750         {
 751                 Glib::RWLock::ReaderLock dsm (diskstream_lock, Glib::TRY_LOCK);
 752
 753                 if (!dsm.locked() || (post_transport_work & (PostTransportLocate|PostTransportStop))) {
 754                         no_roll (nframes, 0);
 755                         return;
 756                 }
 757
 758                 if (!_exporting && _slave) {
 759                         if (!follow_slave (nframes, 0)) {
 760                                 return;
 761                         }
 762                 }
 763
 764                 if (_transport_speed == 0) {
 765                         no_roll (nframes, 0);
 766                         return;
 767                 }
 768
 769                 send_midi_time_code_for_cycle(nframes);
 770
 771                 if (actively_recording()) {
 772                         stop_limit = max_frames;
 773                 } else {
 774                         if (Config->get_stop_at_session_end()) {
 775                                 stop_limit = current_end_frame();
 776                         } else {
 777                                 stop_limit = max_frames;
 778                         }
 779                 }
 780
 781                 if (maybe_stop (stop_limit)) {
 782                         no_roll (nframes, 0);
 783                         return;
 784                 }
 785
 786                 click (_transport_frame, nframes, 0);
 787
 788                 prepare_diskstreams ();
 789
 790                 frames_moved = (long) floor (_transport_speed * nframes);
 791
 792                 if (process_routes (nframes, 0)) {
 793                         no_roll (nframes, 0);
 794                         return;
 795                 }
 796
 797                 commit_diskstreams (nframes, session_needs_butler);
 798
 799                 if (frames_moved < 0) {
 800                         decrement_transport_position (-frames_moved);
 801                 } else {
 802                         increment_transport_position (frames_moved);
 803                 }
 804
 805                 maybe_stop (stop_limit);
 806                 check_declick_out ();
 807
 808         } /* implicit release of route lock */
 809
 810         if (session_needs_butler)
 811                 summon_butler ();
 812 }
 813
 814 void
 815 Session::process_audition (jack_nframes_t nframes)
 816 {
 817         Event* ev;
 818         boost::shared_ptr<RouteList> r = routes.reader ();
 819
 820         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 821                 if (!(*i)->hidden()) {
 822                         (*i)->silence (nframes, 0);
 823                 }
 824         }
 825
 826         /* run the auditioner, and if it says we need butler service, ask for it */
 827
 828         if (auditioner->play_audition (nframes) > 0) {
 829                 summon_butler ();
 830         }
 831
 832         /* handle pending events */
 833
 834         while (pending_events.read (&ev, 1) == 1) {
 835                 merge_event (ev);
 836         }
 837
 838         /* if we are not in the middle of a state change,
 839            and there are immediate events queued up,
 840            process them.
 841         */
 842
 843         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 844                 Event *ev = immediate_events.front ();
 845                 immediate_events.pop_front ();
 846                 process_event (ev);
 847         }
 848
 849         if (!auditioner->active()) {
 850                 process_function = &Session::process_with_events;
 851         }
 852 }
 853