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 nframes_t start_frame = _transport_frame;
 134         const nframes_t end_frame = _transport_frame + (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 nframes_t start_frame = _transport_frame;
 180         const 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                    Note: the diskstreams that were handled by a route will just return zero
 226                    from this call, because they know they were processed. So in fact, this
 227                    also runs commit() for every diskstream.
 228                  */
 229
 230                 if ((dret = (*i)->process (_transport_frame, nframes, 0, actively_recording(), get_rec_monitors_input())) == 0) {
 231                         if ((*i)->commit (nframes)) {
 232                                 needs_butler = true;
 233                         }
 234
 235                 } else if (dret < 0) {
 236                         (*i)->recover();
 237                 }
 238
 239                 pworst = min (pworst, (*i)->playback_buffer_load());
 240                 cworst = min (cworst, (*i)->capture_buffer_load());
 241         }
 242
 243         uint32_t pmin = g_atomic_int_get (&_playback_load);
 244         uint32_t pminold = g_atomic_int_get (&_playback_load_min);
 245         uint32_t cmin = g_atomic_int_get (&_capture_load);
 246         uint32_t cminold = g_atomic_int_get (&_capture_load_min);
 247
 248         g_atomic_int_set (&_playback_load, (uint32_t) floor (pworst * 100.0f));
 249         g_atomic_int_set (&_capture_load, (uint32_t) floor (cworst * 100.0f));
 250         g_atomic_int_set (&_playback_load_min, min (pmin, pminold));
 251         g_atomic_int_set (&_capture_load_min, min (cmin, cminold));
 252
 253         if (actively_recording()) {
 254                 set_dirty();
 255         }
 256 }
 257
 258
 259 void
 260 Session::process_with_events (nframes_t nframes)
 261 {
 262         Event*         ev;
 263         nframes_t this_nframes;
 264         nframes_t end_frame;
 265         nframes_t offset;
 266         nframes_t stop_limit;
 267         long           frames_moved;
 268         bool           session_needs_butler = false;
 269
 270         /* make sure the auditioner is silent */
 271
 272         if (auditioner) {
 273                 auditioner->silence (nframes, 0);
 274         }
 275
 276         /* handle any pending events */
 277
 278         while (pending_events.read (&ev, 1) == 1) {
 279                 merge_event (ev);
 280         }
 281
 282         /* if we are not in the middle of a state change,
 283            and there are immediate events queued up,
 284            process them.
 285         */
 286
 287         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 288                 Event *ev = immediate_events.front ();
 289                 immediate_events.pop_front ();
 290                 process_event (ev);
 291         }
 292
 293         /* Events caused a transport change, send an MTC Full Frame (SMPTE) message.
 294          * This is sent whether rolling or not, to give slaves an idea of ardour time
 295          * on locates (and allow slow slaves to position and prepare for rolling)
 296          */
 297         if (_send_smpte_update) {
 298                 send_full_time_code(nframes);
 299         }
 300
 301         if (!process_can_proceed()) {
 302                 no_roll (nframes, 0);
 303                 return;
 304         }
 305
 306         if (events.empty() || next_event == events.end()) {
 307                 process_without_events (nframes);
 308                 return;
 309         }
 310
 311         end_frame = _transport_frame + (nframes_t)abs(floor(nframes * _transport_speed));
 312
 313         {
 314                 Event* this_event;
 315                 Events::iterator the_next_one;
 316
 317                 if (post_transport_work & (PostTransportLocate|PostTransportStop)) {
 318                         no_roll (nframes, 0);
 319                         return;
 320                 }
 321
 322                 if (!_exporting && _slave) {
 323                         if (!follow_slave (nframes, 0)) {
 324                                 return;
 325                         }
 326                 }
 327
 328                 if (_transport_speed == 0) {
 329                         no_roll (nframes, 0);
 330                         return;
 331                 }
 332
 333                 send_midi_time_code_for_cycle(nframes);
 334
 335                 if (actively_recording()) {
 336                         stop_limit = max_frames;
 337                 } else {
 338
 339                         if (Config->get_stop_at_session_end()) {
 340                                 stop_limit = current_end_frame();
 341                         } else {
 342                                 stop_limit = max_frames;
 343                         }
 344                 }
 345
 346                 if (maybe_stop (stop_limit)) {
 347                         no_roll (nframes, 0);
 348                         return;
 349                 }
 350
 351                 this_event = *next_event;
 352                 the_next_one = next_event;
 353                 ++the_next_one;
 354
 355                 offset = 0;
 356
 357                 while (nframes) {
 358
 359                         this_nframes = nframes; /* real (jack) time relative */
 360                         frames_moved = (long) floor (_transport_speed * nframes); /* transport relative */
 361
 362                         /* running an event, position transport precisely to its time */
 363                         if (this_event && this_event->action_frame <= end_frame && this_event->action_frame >= _transport_frame) {
 364                                 /* this isn't quite right for reverse play */
 365                                 frames_moved = (long) (this_event->action_frame - _transport_frame);
 366                                 this_nframes = (nframes_t) abs( floor(frames_moved / _transport_speed) );
 367                         }
 368
 369                         if (this_nframes) {
 370
 371                                 click (_transport_frame, nframes, offset);
 372
 373                                 /* now process frames between now and the first event in this block */
 374                                 prepare_diskstreams ();
 375
 376                                 if (process_routes (this_nframes, offset)) {
 377                                         no_roll (nframes, 0);
 378                                         return;
 379                                 }
 380
 381                                 commit_diskstreams (this_nframes, session_needs_butler);
 382
 383                                 nframes -= this_nframes;
 384                                 offset += this_nframes;
 385
 386                                 if (frames_moved < 0) {
 387                                         decrement_transport_position (-frames_moved);
 388                                 } else {
 389                                         increment_transport_position (frames_moved);
 390                                 }
 391
 392                                 maybe_stop (stop_limit);
 393                                 check_declick_out ();
 394                         }
 395
 396                         /* now handle this event and all others scheduled for the same time */
 397
 398                         while (this_event && this_event->action_frame == _transport_frame) {
 399                                 process_event (this_event);
 400
 401                                 if (the_next_one == events.end()) {
 402                                         this_event = 0;
 403                                 } else {
 404                                         this_event = *the_next_one;
 405                                         ++the_next_one;
 406                                 }
 407                         }
 408
 409                         /* if an event left our state changing, do the right thing */
 410
 411                         if (non_realtime_work_pending()) {
 412                                 no_roll (nframes, offset);
 413                                 break;
 414                         }
 415
 416                         /* this is necessary to handle the case of seamless looping */
 417                         end_frame = _transport_frame + (nframes_t) floor (nframes * _transport_speed);
 418
 419                 }
 420
 421                 set_next_event ();
 422
 423         } /* implicit release of route lock */
 424
 425         if (session_needs_butler)
 426                 summon_butler ();
 427 }
 428
 429 void
 430 Session::reset_slave_state ()
 431 {
 432         average_slave_delta = 1800;
 433         delta_accumulator_cnt = 0;
 434         have_first_delta_accumulator = false;
 435         slave_state = Stopped;
 436 }
 437
 438 bool
 439 Session::transport_locked () const
 440 {
 441         Slave* sl = _slave;
 442
 443         if (!locate_pending() && ((Config->get_slave_source() == None) || (sl && sl->ok() && sl->locked()))) {
 444                 return true;
 445         }
 446
 447         return false;
 448 }
 449
 450 bool
 451 Session::follow_slave (nframes_t nframes, nframes_t offset)
 452 {
 453         float slave_speed;
 454         nframes_t slave_transport_frame;
 455         nframes_t this_delta;
 456         int dir;
 457         bool starting;
 458
 459         if (!_slave->ok()) {
 460                 stop_transport ();
 461                 Config->set_slave_source (None);
 462                 goto noroll;
 463         }
 464
 465         _slave->speed_and_position (slave_speed, slave_transport_frame);
 466
 467         if (!_slave->locked()) {
 468                 goto noroll;
 469         }
 470
 471         if (slave_transport_frame > _transport_frame) {
 472                 this_delta = slave_transport_frame - _transport_frame;
 473                 dir = 1;
 474         } else {
 475                 this_delta = _transport_frame - slave_transport_frame;
 476                 dir = -1;
 477         }
 478
 479         if ((starting = _slave->starting())) {
 480                 slave_speed = 0.0f;
 481         }
 482
 483 #if 0
 484         cerr << "delta = " << (int) (dir * this_delta)
 485              << " speed = " << slave_speed
 486              << " ts = " << _transport_speed
 487              << " M@"<< slave_transport_frame << " S@" << _transport_frame
 488              << " avgdelta = " << average_slave_delta
 489              << endl;
 490 #endif
 491
 492         if (Config->get_timecode_source_is_synced()) {
 493
 494                 /* if the TC source is synced, then we assume that its
 495                    speed is binary: 0.0 or 1.0
 496                 */
 497
 498                 if (slave_speed != 0.0f) {
 499                         slave_speed = 1.0f;
 500                 }
 501
 502         } else {
 503
 504                 /* TC source is able to drift relative to us (slave)
 505                    so we need to keep track of the drift and adjust
 506                    our speed to remain locked.
 507                 */
 508
 509                 if (delta_accumulator_cnt >= delta_accumulator_size) {
 510                         have_first_delta_accumulator = true;
 511                         delta_accumulator_cnt = 0;
 512                 }
 513
 514                 if (delta_accumulator_cnt != 0 || this_delta < _current_frame_rate) {
 515                         delta_accumulator[delta_accumulator_cnt++] = dir*this_delta;
 516                 }
 517
 518                 if (have_first_delta_accumulator) {
 519                         average_slave_delta = 0;
 520                         for (int i = 0; i < delta_accumulator_size; ++i) {
 521                                 average_slave_delta += delta_accumulator[i];
 522                         }
 523                         average_slave_delta /= delta_accumulator_size;
 524                         if (average_slave_delta < 0) {
 525                                 average_dir = -1;
 526                                 average_slave_delta = -average_slave_delta;
 527                         } else {
 528                                 average_dir = 1;
 529                         }
 530                         // cerr << "avgdelta = " << average_slave_delta*average_dir << endl;
 531                 }
 532         }
 533
 534         if (slave_speed != 0.0f) {
 535
 536                 /* slave is running */
 537
 538                 switch (slave_state) {
 539                 case Stopped:
 540                         if (_slave->requires_seekahead()) {
 541                                 slave_wait_end = slave_transport_frame + _current_frame_rate;
 542                                 locate (slave_wait_end, false, false);
 543                                 slave_state = Waiting;
 544                                 starting = true;
 545
 546                         } else {
 547
 548                                 slave_state = Running;
 549
 550                                 Location* al = _locations.auto_loop_location();
 551
 552                                 if (al && play_loop && (slave_transport_frame < al->start() || slave_transport_frame > al->end())) {
 553                                         // cancel looping
 554                                         request_play_loop(false);
 555                                 }
 556
 557                                 if (slave_transport_frame != _transport_frame) {
 558                                         locate (slave_transport_frame, false, false);
 559                                 }
 560                         }
 561                         break;
 562
 563                 case Waiting:
 564                         break;
 565
 566                 default:
 567                         break;
 568
 569                 }
 570
 571                 if (slave_state == Waiting) {
 572
 573                         // cerr << "waiting at " << slave_transport_frame << endl;
 574                         if (slave_transport_frame >= slave_wait_end) {
 575                                 // cerr << "\tstart at " << _transport_frame << endl;
 576
 577                                 slave_state = Running;
 578
 579                                 bool ok = true;
 580                                 nframes_t frame_delta = slave_transport_frame - _transport_frame;
 581
 582                                 boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 583
 584                                 for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 585                                         if (!(*i)->can_internal_playback_seek (frame_delta)) {
 586                                                 ok = false;
 587                                                 break;
 588                                         }
 589                                 }
 590
 591                                 if (ok) {
 592                                         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 593                                                 (*i)->internal_playback_seek (frame_delta);
 594                                         }
 595                                         _transport_frame += frame_delta;
 596
 597                                 } else {
 598                                         // cerr << "cannot micro-seek\n";
 599                                         /* XXX what? */
 600                                 }
 601
 602                                 memset (delta_accumulator, 0, sizeof (nframes_t) * delta_accumulator_size);
 603                                 average_slave_delta = 0;
 604                                 this_delta = 0;
 605                         }
 606                 }
 607
 608                 if (slave_state == Running && _transport_speed == 0.0f) {
 609
 610                         // cerr << "slave starts transport\n";
 611
 612                         start_transport ();
 613                 }
 614
 615         } else {
 616
 617                 /* slave has stopped */
 618
 619                 if (_transport_speed != 0.0f) {
 620
 621                         // cerr << "slave stops transport: " << slave_speed << " frame: " << slave_transport_frame
 622                         // << " tf = " << _transport_frame
 623                         // << endl;
 624
 625                         if (Config->get_slave_source() == JACK) {
 626                                 last_stop_frame = _transport_frame;
 627                         }
 628
 629                         stop_transport();
 630                 }
 631
 632                 if (slave_transport_frame != _transport_frame) {
 633                         // cerr << "slave stopped, move to " << slave_transport_frame << endl;
 634                         force_locate (slave_transport_frame, false);
 635                 }
 636
 637                 slave_state = Stopped;
 638         }
 639
 640         if (slave_state == Running && !Config->get_timecode_source_is_synced()) {
 641
 642
 643                 if (_transport_speed != 0.0f) {
 644
 645                         /*
 646                            note that average_dir is +1 or -1
 647                         */
 648
 649                         const float adjust_seconds = 1.0f;
 650                         float delta;
 651
 652                         //if (average_slave_delta == 0) {
 653                                 delta = this_delta;
 654                                 delta *= dir;
 655 //                      } else {
 656 //                              delta = average_slave_delta;
 657 //                              delta *= average_dir;
 658 //                      }
 659
 660                         float adjusted_speed = slave_speed +
 661                                 (delta / (adjust_seconds * _current_frame_rate));
 662
 663                         // cerr << "adjust using " << delta
 664                         // << " towards " << adjusted_speed
 665                         // << " ratio = " << adjusted_speed / slave_speed
 666                         // << " current = " << _transport_speed
 667                         // << " slave @ " << slave_speed
 668                         // << endl;
 669
 670                         request_transport_speed (adjusted_speed);
 671
 672 #if 1
 673                         if ((nframes_t) average_slave_delta > _slave->resolution()) {
 674                                 // cerr << "not locked\n";
 675                                 goto silent_motion;
 676                         }
 677 #endif
 678                 }
 679         }
 680
 681         if (!starting && !non_realtime_work_pending()) {
 682                 /* speed is set, we're locked, and good to go */
 683                 return true;
 684         }
 685
 686   silent_motion:
 687
 688         if (slave_speed && _transport_speed) {
 689
 690                 /* something isn't right, but we should move with the master
 691                    for now.
 692                 */
 693
 694                 bool need_butler;
 695
 696                 prepare_diskstreams ();
 697                 silent_process_routes (nframes, offset);
 698                 commit_diskstreams (nframes, need_butler);
 699
 700                 if (need_butler) {
 701                         summon_butler ();
 702                 }
 703
 704                 int32_t frames_moved = (int32_t) floor (_transport_speed * nframes);
 705
 706                 if (frames_moved < 0) {
 707                         decrement_transport_position (-frames_moved);
 708                 } else {
 709                         increment_transport_position (frames_moved);
 710                 }
 711
 712                 nframes_t stop_limit;
 713
 714                 if (actively_recording()) {
 715                         stop_limit = max_frames;
 716                 } else {
 717                         if (Config->get_stop_at_session_end()) {
 718                                 stop_limit = current_end_frame();
 719                         } else {
 720                                 stop_limit = max_frames;
 721                         }
 722                 }
 723
 724                 maybe_stop (stop_limit);
 725         }
 726
 727   noroll:
 728         /* don't move at all */
 729         no_roll (nframes, 0);
 730         return false;
 731 }
 732
 733 void
 734 Session::process_without_events (nframes_t nframes)
 735 {
 736         bool session_needs_butler = false;
 737         nframes_t stop_limit;
 738         long frames_moved;
 739         nframes_t offset = 0;
 740
 741         {
 742                 if (post_transport_work & (PostTransportLocate|PostTransportStop)) {
 743                         no_roll (nframes, 0);
 744                         return;
 745                 }
 746
 747                 if (!_exporting && _slave) {
 748                         if (!follow_slave (nframes, 0)) {
 749                                 return;
 750                         }
 751                 }
 752
 753                 if (_transport_speed == 0) {
 754                         no_roll (nframes, 0);
 755                         return;
 756                 }
 757
 758                 send_midi_time_code_for_cycle(nframes);
 759
 760                 if (actively_recording()) {
 761                         stop_limit = max_frames;
 762                 } else {
 763                         if (Config->get_stop_at_session_end()) {
 764                                 stop_limit = current_end_frame();
 765                         } else {
 766                                 stop_limit = max_frames;
 767                         }
 768                 }
 769
 770                 if (maybe_stop (stop_limit)) {
 771                         no_roll (nframes, 0);
 772                         return;
 773                 }
 774
 775                 if (maybe_sync_start (nframes, offset)) {
 776                         return;
 777                 }
 778
 779                 click (_transport_frame, nframes, offset);
 780
 781                 prepare_diskstreams ();
 782
 783                 frames_moved = (long) floor (_transport_speed * nframes);
 784
 785                 if (process_routes (nframes, offset)) {
 786                         no_roll (nframes, offset);
 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 (nframes_t nframes)
 809 {
 810         Event* ev;
 811         boost::shared_ptr<RouteList> r = routes.reader ();
 812
 813         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 814                 if (!(*i)->hidden()) {
 815                         (*i)->silence (nframes, 0);
 816                 }
 817         }
 818
 819         /* run the auditioner, and if it says we need butler service, ask for it */
 820
 821         if (auditioner->play_audition (nframes) > 0) {
 822                 summon_butler ();
 823         }
 824
 825         /* handle pending events */
 826
 827         while (pending_events.read (&ev, 1) == 1) {
 828                 merge_event (ev);
 829         }
 830
 831         /* if we are not in the middle of a state change,
 832            and there are immediate events queued up,
 833            process them.
 834         */
 835
 836         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 837                 Event *ev = immediate_events.front ();
 838                 immediate_events.pop_front ();
 839                 process_event (ev);
 840         }
 841
 842         if (!auditioner->active()) {
 843                 process_function = &Session::process_with_events;
 844         }
 845 }
 846
 847 bool
 848 Session::maybe_sync_start (nframes_t& nframes, nframes_t& offset)
 849 {
 850         nframes_t sync_offset;
 851
 852         if (!waiting_for_sync_offset) {
 853                 return false;
 854         }
 855
 856         if (_engine.get_sync_offset (sync_offset) && sync_offset < nframes) {
 857
 858                 no_roll (sync_offset, 0);
 859                 nframes -= sync_offset;
 860                 offset += sync_offset;
 861                 waiting_for_sync_offset = false;
 862
 863                 if (nframes == 0) {
 864                         return true; // done
 865                 }
 866
 867         } else {
 868                 no_roll (nframes, 0);
 869                 return true; // done
 870         }
 871
 872         return false;
 873 }
 874