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 */
  19
  20 #include <cmath>
  21 #include <cerrno>
  22 #include <algorithm>
  23 #include <unistd.h>
  24
  25 #include <pbd/error.h>
  26
  27 #include <glibmm/thread.h>
  28
  29 #include <ardour/ardour.h>
  30 #include <ardour/session.h>
  31 #include <ardour/timestamps.h>
  32 #include <ardour/audio_diskstream.h>
  33 #include <ardour/audioengine.h>
  34 #include <ardour/slave.h>
  35 #include <ardour/auditioner.h>
  36 #include <ardour/cycles.h>
  37 #include <ardour/cycle_timer.h>
  38
  39 #include <midi++/manager.h>
  40
  41 #include "i18n.h"
  42
  43 using namespace ARDOUR;
  44 using namespace PBD;
  45 using namespace std;
  46
  47 void
  48 Session::process (nframes_t nframes)
  49 {
  50         MIDI::Manager::instance()->cycle_start(nframes);
  51
  52         if (synced_to_jack() && waiting_to_start) {
  53                 if ( _engine.transport_state() == AudioEngine::TransportRolling) {
  54                         actually_start_transport ();
  55                 }
  56         }
  57
  58         if (non_realtime_work_pending()) {
  59                 if (!transport_work_requested ()) {
  60                         post_transport ();
  61                 }
  62         }
  63
  64         (this->*process_function) (nframes);
  65
  66         MIDI::Manager::instance()->cycle_end();
  67
  68         SendFeedback (); /* EMIT SIGNAL */
  69 }
  70
  71 void
  72 Session::prepare_diskstreams ()
  73 {
  74         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
  75         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
  76                 (*i)->prepare ();
  77         }
  78 }
  79
  80 int
  81 Session::no_roll (nframes_t nframes, nframes_t offset)
  82 {
  83         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 (nframes_t nframes, 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 + (jack_nframes_t)floor(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                         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 154                         for (DiskstreamList::iterator ids = dsl->begin(); ids != dsl->end(); ++ids) {
 155                                 (*ids)->recover ();
 156                         }
 157
 158                         stop_transport ();
 159                         return -1;
 160                 }
 161         }
 162
 163         return 0;
 164 }
 165
 166 int
 167 Session::silent_process_routes (nframes_t nframes, nframes_t offset)
 168 {
 169         bool record_active = actively_recording();
 170         int  declick = get_transport_declick_required();
 171         bool rec_monitors = get_rec_monitors_input();
 172         boost::shared_ptr<RouteList> r = routes.reader ();
 173
 174         if (transport_sub_state & StopPendingCapture) {
 175                 /* force a declick out */
 176                 declick = -1;
 177         }
 178
 179         const jack_nframes_t start_frame = _transport_frame;
 180         const jack_nframes_t end_frame = _transport_frame + lrintf(nframes * _transport_speed);
 181
 182         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 183
 184                 int ret;
 185
 186                 if ((*i)->hidden()) {
 187                         continue;
 188                 }
 189
 190                 if ((ret = (*i)->silent_roll (nframes, start_frame, end_frame, offset, record_active, rec_monitors)) < 0) {
 191
 192                         /* we have to do this here. Route::roll() for an AudioTrack will have called AudioDiskstream::process(),
 193                            and the DS will expect AudioDiskstream::commit() to be called. but we're aborting from that
 194                            call path, so make sure we release any outstanding locks here before we return failure.
 195                         */
 196
 197                         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 198                         for (DiskstreamList::iterator ids = dsl->begin(); ids != dsl->end(); ++ids) {
 199                                 (*ids)->recover ();
 200                         }
 201
 202                         stop_transport ();
 203                         return -1;
 204                 }
 205         }
 206
 207         return 0;
 208 }
 209
 210 void
 211 Session::commit_diskstreams (nframes_t nframes, bool &needs_butler)
 212 {
 213         int dret;
 214         float pworst = 1.0f;
 215         float cworst = 1.0f;
 216
 217         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 218         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 219
 220                 if ((*i)->hidden()) {
 221                         continue;
 222                 }
 223
 224                 /* force all diskstreams not handled by a Route to call do their stuff.
 225                  */
 226
 227                 if ((dret = (*i)->process (_transport_frame, nframes, 0, actively_recording(), get_rec_monitors_input())) == 0) {
 228                         if ((*i)->commit (nframes)) {
 229                                 needs_butler = true;
 230                         }
 231
 232                 } else if (dret < 0) {
 233                         (*i)->recover();
 234                 }
 235
 236                 pworst = min (pworst, (*i)->playback_buffer_load());
 237                 cworst = min (cworst, (*i)->capture_buffer_load());
 238         }
 239
 240         uint32_t pmin = g_atomic_int_get (&_playback_load);
 241         uint32_t pminold = g_atomic_int_get (&_playback_load_min);
 242         uint32_t cmin = g_atomic_int_get (&_capture_load);
 243         uint32_t cminold = g_atomic_int_get (&_capture_load_min);
 244
 245         g_atomic_int_set (&_playback_load, (uint32_t) floor (pworst * 100.0f));
 246         g_atomic_int_set (&_capture_load, (uint32_t) floor (cworst * 100.0f));
 247         g_atomic_int_set (&_playback_load_min, min (pmin, pminold));
 248         g_atomic_int_set (&_capture_load_min, min (cmin, cminold));
 249
 250         if (actively_recording()) {
 251                 set_dirty();
 252         }
 253 }
 254
 255
 256 void
 257 Session::process_with_events (nframes_t nframes)
 258 {
 259         Event*         ev;
 260         nframes_t this_nframes;
 261         nframes_t end_frame;
 262         nframes_t offset;
 263         nframes_t stop_limit;
 264         long           frames_moved;
 265         bool           session_needs_butler = false;
 266
 267         /* make sure the auditioner is silent */
 268
 269         if (auditioner) {
 270                 auditioner->silence (nframes, 0);
 271         }
 272
 273         /* handle any pending events */
 274
 275         while (pending_events.read (&ev, 1) == 1) {
 276                 merge_event (ev);
 277         }
 278
 279         /* if we are not in the middle of a state change,
 280            and there are immediate events queued up,
 281            process them.
 282         */
 283
 284         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 285                 Event *ev = immediate_events.front ();
 286                 immediate_events.pop_front ();
 287                 process_event (ev);
 288         }
 289
 290         /* Events caused a transport change, send an MTC Full Frame (SMPTE) message.
 291          * This is sent whether rolling or not, to give slaves an idea of ardour time
 292          * on locates (and allow slow slaves to position and prepare for rolling)
 293          */
 294         if (_send_smpte_update) {
 295                 send_full_time_code(nframes);
 296         }
 297
 298         if (!process_can_proceed()) {
 299                 no_roll (nframes, 0);
 300                 return;
 301         }
 302
 303         if (events.empty() || next_event == events.end()) {
 304                 process_without_events (nframes);
 305                 return;
 306         }
 307
 308         end_frame = _transport_frame + (nframes_t)abs(floor(nframes * _transport_speed));
 309
 310         {
 311                 Event* this_event;
 312                 Events::iterator the_next_one;
 313
 314                 if (post_transport_work & (PostTransportLocate|PostTransportStop)) {
 315                         no_roll (nframes, 0);
 316                         return;
 317                 }
 318
 319                 if (!_exporting && _slave) {
 320                         if (!follow_slave (nframes, 0)) {
 321                                 return;
 322                         }
 323                 }
 324
 325                 if (_transport_speed == 0) {
 326                         no_roll (nframes, 0);
 327                         return;
 328                 }
 329
 330                 send_midi_time_code_for_cycle(nframes);
 331
 332                 if (actively_recording()) {
 333                         stop_limit = max_frames;
 334                 } else {
 335
 336                         if (Config->get_stop_at_session_end()) {
 337                                 stop_limit = current_end_frame();
 338                         } else {
 339                                 stop_limit = max_frames;
 340                         }
 341                 }
 342
 343                 if (maybe_stop (stop_limit)) {
 344                         no_roll (nframes, 0);
 345                         return;
 346                 }
 347
 348                 this_event = *next_event;
 349                 the_next_one = next_event;
 350                 ++the_next_one;
 351
 352                 offset = 0;
 353
 354                 while (nframes) {
 355
 356                         this_nframes = nframes; /* real (jack) time relative */
 357                         frames_moved = (long) floor (_transport_speed * nframes); /* transport relative */
 358
 359                         /* running an event, position transport precisely to its time */
 360                         if (this_event && this_event->action_frame <= end_frame && this_event->action_frame >= _transport_frame) {
 361                                 /* this isn't quite right for reverse play */
 362                                 frames_moved = (long) (this_event->action_frame - _transport_frame);
 363                                 this_nframes = (nframes_t) abs( floor(frames_moved / _transport_speed) );
 364                         }
 365
 366                         if (this_nframes) {
 367
 368                                 click (_transport_frame, nframes, offset);
 369
 370                                 /* now process frames between now and the first event in this block */
 371                                 prepare_diskstreams ();
 372
 373                                 if (process_routes (this_nframes, offset)) {
 374                                         no_roll (nframes, 0);
 375                                         return;
 376                                 }
 377
 378                                 commit_diskstreams (this_nframes, session_needs_butler);
 379
 380                                 nframes -= this_nframes;
 381                                 offset += this_nframes;
 382
 383                                 if (frames_moved < 0) {
 384                                         decrement_transport_position (-frames_moved);
 385                                 } else {
 386                                         increment_transport_position (frames_moved);
 387                                 }
 388
 389                                 maybe_stop (stop_limit);
 390                                 check_declick_out ();
 391                         }
 392
 393                         /* now handle this event and all others scheduled for the same time */
 394
 395                         while (this_event && this_event->action_frame == _transport_frame) {
 396                                 process_event (this_event);
 397
 398                                 if (the_next_one == events.end()) {
 399                                         this_event = 0;
 400                                 } else {
 401                                         this_event = *the_next_one;
 402                                         ++the_next_one;
 403                                 }
 404                         }
 405
 406                         /* if an event left our state changing, do the right thing */
 407
 408                         if (non_realtime_work_pending()) {
 409                                 no_roll (nframes, offset);
 410                                 break;
 411                         }
 412
 413                         /* this is necessary to handle the case of seamless looping */
 414                         end_frame = _transport_frame + (nframes_t) floor (nframes * _transport_speed);
 415
 416                 }
 417
 418                 set_next_event ();
 419
 420         } /* implicit release of route lock */
 421
 422         if (session_needs_butler)
 423                 summon_butler ();
 424 }
 425
 426 void
 427 Session::reset_slave_state ()
 428 {
 429         average_slave_delta = 1800;
 430         delta_accumulator_cnt = 0;
 431         have_first_delta_accumulator = false;
 432         slave_state = Stopped;
 433 }
 434
 435 bool
 436 Session::transport_locked () const
 437 {
 438         Slave* sl = _slave;
 439
 440         if (!locate_pending() && ((Config->get_slave_source() == None) || (sl && sl->ok() && sl->locked()))) {
 441                 return true;
 442         }
 443
 444         return false;
 445 }
 446
 447 bool
 448 Session::follow_slave (nframes_t nframes, nframes_t offset)
 449 {
 450         float slave_speed;
 451         nframes_t slave_transport_frame;
 452         nframes_t this_delta;
 453         int dir;
 454         bool starting;
 455
 456         if (!_slave->ok()) {
 457                 stop_transport ();
 458                 Config->set_slave_source (None);
 459                 goto noroll;
 460         }
 461
 462         _slave->speed_and_position (slave_speed, slave_transport_frame);
 463
 464         if (!_slave->locked()) {
 465                 goto noroll;
 466         }
 467
 468         if (slave_transport_frame > _transport_frame) {
 469                 this_delta = slave_transport_frame - _transport_frame;
 470                 dir = 1;
 471         } else {
 472                 this_delta = _transport_frame - slave_transport_frame;
 473                 dir = -1;
 474         }
 475
 476         if ((starting = _slave->starting())) {
 477                 slave_speed = 0.0f;
 478         }
 479
 480 #if 0
 481         cerr << "delta = " << (int) (dir * this_delta)
 482              << " speed = " << slave_speed
 483              << " ts = " << _transport_speed
 484              << " M@"<< slave_transport_frame << " S@" << _transport_frame
 485              << " avgdelta = " << average_slave_delta
 486              << endl;
 487 #endif
 488
 489         if (Config->get_timecode_source_is_synced()) {
 490
 491                 /* if the TC source is synced, then we assume that its
 492                    speed is binary: 0.0 or 1.0
 493                 */
 494
 495                 if (slave_speed != 0.0f) {
 496                         slave_speed = 1.0f;
 497                 }
 498
 499         } else {
 500
 501                 /* TC source is able to drift relative to us (slave)
 502                    so we need to keep track of the drift and adjust
 503                    our speed to remain locked.
 504                 */
 505
 506                 if (delta_accumulator_cnt >= delta_accumulator_size) {
 507                         have_first_delta_accumulator = true;
 508                         delta_accumulator_cnt = 0;
 509                 }
 510
 511                 if (delta_accumulator_cnt != 0 || this_delta < _current_frame_rate) {
 512                         delta_accumulator[delta_accumulator_cnt++] = dir*this_delta;
 513                 }
 514
 515                 if (have_first_delta_accumulator) {
 516                         average_slave_delta = 0;
 517                         for (int i = 0; i < delta_accumulator_size; ++i) {
 518                                 average_slave_delta += delta_accumulator[i];
 519                         }
 520                         average_slave_delta /= delta_accumulator_size;
 521                         if (average_slave_delta < 0) {
 522                                 average_dir = -1;
 523                                 average_slave_delta = -average_slave_delta;
 524                         } else {
 525                                 average_dir = 1;
 526                         }
 527                         // cerr << "avgdelta = " << average_slave_delta*average_dir << endl;
 528                 }
 529         }
 530
 531         if (slave_speed != 0.0f) {
 532
 533                 /* slave is running */
 534
 535                 switch (slave_state) {
 536                 case Stopped:
 537                         if (_slave->requires_seekahead()) {
 538                                 slave_wait_end = slave_transport_frame + _current_frame_rate;
 539                                 locate (slave_wait_end, false, false);
 540                                 slave_state = Waiting;
 541                                 starting = true;
 542
 543                         } else {
 544
 545                                 slave_state = Running;
 546
 547                                 Location* al = _locations.auto_loop_location();
 548
 549                                 if (al && play_loop && (slave_transport_frame < al->start() || slave_transport_frame > al->end())) {
 550                                         // cancel looping
 551                                         request_play_loop(false);
 552                                 }
 553
 554                                 if (slave_transport_frame != _transport_frame) {
 555                                         locate (slave_transport_frame, false, false);
 556                                 }
 557                         }
 558                         break;
 559
 560                 case Waiting:
 561                         break;
 562
 563                 default:
 564                         break;
 565
 566                 }
 567
 568                 if (slave_state == Waiting) {
 569
 570                         // cerr << "waiting at " << slave_transport_frame << endl;
 571                         if (slave_transport_frame >= slave_wait_end) {
 572                                 // cerr << "\tstart at " << _transport_frame << endl;
 573
 574                                 slave_state = Running;
 575
 576                                 bool ok = true;
 577                                 nframes_t frame_delta = slave_transport_frame - _transport_frame;
 578
 579                                 boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 580
 581                                 for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 582                                         if (!(*i)->can_internal_playback_seek (frame_delta)) {
 583                                                 ok = false;
 584                                                 break;
 585                                         }
 586                                 }
 587
 588                                 if (ok) {
 589                                         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 590                                                 (*i)->internal_playback_seek (frame_delta);
 591                                         }
 592                                         _transport_frame += frame_delta;
 593
 594                                 } else {
 595                                         // cerr << "cannot micro-seek\n";
 596                                         /* XXX what? */
 597                                 }
 598
 599                                 memset (delta_accumulator, 0, sizeof (nframes_t) * delta_accumulator_size);
 600                                 average_slave_delta = 0;
 601                                 this_delta = 0;
 602                         }
 603                 }
 604
 605                 if (slave_state == Running && _transport_speed == 0.0f) {
 606
 607                         // cerr << "slave starts transport\n";
 608
 609                         start_transport ();
 610                 }
 611
 612         } else {
 613
 614                 /* slave has stopped */
 615
 616                 if (_transport_speed != 0.0f) {
 617
 618                         // cerr << "slave stops transport: " << slave_speed << " frame: " << slave_transport_frame
 619                         // << " tf = " << _transport_frame
 620                         // << endl;
 621
 622                         if (Config->get_slave_source() == JACK) {
 623                                 last_stop_frame = _transport_frame;
 624                         }
 625
 626                         stop_transport();
 627                 }
 628
 629                 if (slave_transport_frame != _transport_frame) {
 630                         // cerr << "slave stopped, move to " << slave_transport_frame << endl;
 631                         force_locate (slave_transport_frame, false);
 632                 }
 633
 634                 slave_state = Stopped;
 635         }
 636
 637         if (slave_state == Running && !Config->get_timecode_source_is_synced()) {
 638
 639
 640                 if (_transport_speed != 0.0f) {
 641
 642                         /*
 643                            note that average_dir is +1 or -1
 644                         */
 645
 646                         const float adjust_seconds = 1.0f;
 647                         float delta;
 648
 649                         //if (average_slave_delta == 0) {
 650                                 delta = this_delta;
 651                                 delta *= dir;
 652 //                      } else {
 653 //                              delta = average_slave_delta;
 654 //                              delta *= average_dir;
 655 //                      }
 656
 657                         float adjusted_speed = slave_speed +
 658                                 (delta / (adjust_seconds * _current_frame_rate));
 659
 660                         // cerr << "adjust using " << delta
 661                         // << " towards " << adjusted_speed
 662                         // << " ratio = " << adjusted_speed / slave_speed
 663                         // << " current = " << _transport_speed
 664                         // << " slave @ " << slave_speed
 665                         // << endl;
 666
 667                         request_transport_speed (adjusted_speed);
 668
 669 #if 1
 670                         if ((nframes_t) average_slave_delta > _slave->resolution()) {
 671                                 // cerr << "not locked\n";
 672                                 goto silent_motion;
 673                         }
 674 #endif
 675                 }
 676         }
 677
 678         if (!starting && !non_realtime_work_pending()) {
 679                 /* speed is set, we're locked, and good to go */
 680                 return true;
 681         }
 682
 683   silent_motion:
 684
 685         if (slave_speed && _transport_speed) {
 686
 687                 /* something isn't right, but we should move with the master
 688                    for now.
 689                 */
 690
 691                 bool need_butler;
 692
 693                 prepare_diskstreams ();
 694                 silent_process_routes (nframes, offset);
 695                 commit_diskstreams (nframes, need_butler);
 696
 697                 if (need_butler) {
 698                         summon_butler ();
 699                 }
 700
 701                 int32_t frames_moved = (int32_t) floor (_transport_speed * nframes);
 702
 703                 if (frames_moved < 0) {
 704                         decrement_transport_position (-frames_moved);
 705                 } else {
 706                         increment_transport_position (frames_moved);
 707                 }
 708
 709                 nframes_t stop_limit;
 710
 711                 if (actively_recording()) {
 712                         stop_limit = max_frames;
 713                 } else {
 714                         if (Config->get_stop_at_session_end()) {
 715                                 stop_limit = current_end_frame();
 716                         } else {
 717                                 stop_limit = max_frames;
 718                         }
 719                 }
 720
 721                 maybe_stop (stop_limit);
 722         }
 723
 724   noroll:
 725         /* don't move at all */
 726         no_roll (nframes, 0);
 727         return false;
 728 }
 729
 730 void
 731 Session::process_without_events (nframes_t nframes)
 732 {
 733         bool session_needs_butler = false;
 734         nframes_t stop_limit;
 735         long frames_moved;
 736         nframes_t offset = 0;
 737
 738         {
 739                 if (post_transport_work & (PostTransportLocate|PostTransportStop)) {
 740                         no_roll (nframes, 0);
 741                         return;
 742                 }
 743
 744                 if (!_exporting && _slave) {
 745                         if (!follow_slave (nframes, 0)) {
 746                                 return;
 747                         }
 748                 }
 749
 750                 if (_transport_speed == 0) {
 751                         no_roll (nframes, 0);
 752                         return;
 753                 }
 754
 755                 send_midi_time_code_for_cycle(nframes);
 756
 757                 if (actively_recording()) {
 758                         stop_limit = max_frames;
 759                 } else {
 760                         if (Config->get_stop_at_session_end()) {
 761                                 stop_limit = current_end_frame();
 762                         } else {
 763                                 stop_limit = max_frames;
 764                         }
 765                 }
 766
 767                 if (maybe_stop (stop_limit)) {
 768                         no_roll (nframes, 0);
 769                         return;
 770                 }
 771
 772                 if (maybe_sync_start (nframes, offset)) {
 773                         return;
 774                 }
 775
 776                 click (_transport_frame, nframes, offset);
 777
 778                 prepare_diskstreams ();
 779
 780                 frames_moved = (long) floor (_transport_speed * nframes);
 781
 782                 if (process_routes (nframes, offset)) {
 783                         no_roll (nframes, offset);
 784                         return;
 785                 }
 786
 787                 commit_diskstreams (nframes, session_needs_butler);
 788
 789                 if (frames_moved < 0) {
 790                         decrement_transport_position (-frames_moved);
 791                 } else {
 792                         increment_transport_position (frames_moved);
 793                 }
 794
 795                 maybe_stop (stop_limit);
 796                 check_declick_out ();
 797
 798         } /* implicit release of route lock */
 799
 800         if (session_needs_butler)
 801                 summon_butler ();
 802 }
 803
 804 void
 805 Session::process_audition (nframes_t nframes)
 806 {
 807         Event* ev;
 808         boost::shared_ptr<RouteList> r = routes.reader ();
 809
 810         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 811                 if (!(*i)->hidden()) {
 812                         (*i)->silence (nframes, 0);
 813                 }
 814         }
 815
 816         /* run the auditioner, and if it says we need butler service, ask for it */
 817
 818         if (auditioner->play_audition (nframes) > 0) {
 819                 summon_butler ();
 820         }
 821
 822         /* handle pending events */
 823
 824         while (pending_events.read (&ev, 1) == 1) {
 825                 merge_event (ev);
 826         }
 827
 828         /* if we are not in the middle of a state change,
 829            and there are immediate events queued up,
 830            process them.
 831         */
 832
 833         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 834                 Event *ev = immediate_events.front ();
 835                 immediate_events.pop_front ();
 836                 process_event (ev);
 837         }
 838
 839         if (!auditioner->active()) {
 840                 process_function = &Session::process_with_events;
 841         }
 842 }
 843
 844 bool
 845 Session::maybe_sync_start (nframes_t& nframes, nframes_t& offset)
 846 {
 847         nframes_t sync_offset;
 848
 849         if (!waiting_for_sync_offset) {
 850                 return false;
 851         }
 852
 853         if (_engine.get_sync_offset (sync_offset) && sync_offset < nframes) {
 854
 855                 no_roll (sync_offset, 0);
 856                 nframes -= sync_offset;
 857                 offset += sync_offset;
 858                 waiting_for_sync_offset = false;
 859
 860                 if (nframes == 0) {
 861                         return true; // done
 862                 }
 863
 864         } else {
 865                 no_roll (nframes, 0);
 866                 return true; // done
 867         }
 868
 869         return false;
 870 }
 871