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 "i18n.h"
  40
  41 using namespace ARDOUR;
  42 using namespace PBD;
  43 using namespace std;
  44
  45 void
  46 Session::process (nframes_t nframes)
  47 {
  48         _silent = false;
  49
  50         if (non_realtime_work_pending()) {
  51                 if (!transport_work_requested ()) {
  52                         post_transport ();
  53                 }
  54         }
  55
  56         (this->*process_function) (nframes);
  57
  58         {
  59                 Glib::Mutex::Lock lm (midi_lock, Glib::TRY_LOCK);
  60                 SendFeedback (); /* EMIT SIGNAL */
  61         }
  62 }
  63
  64 void
  65 Session::prepare_diskstreams ()
  66 {
  67         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
  68         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
  69                 (*i)->prepare ();
  70         }
  71 }
  72
  73 int
  74 Session::no_roll (nframes_t nframes, nframes_t offset)
  75 {
  76         nframes_t end_frame = _transport_frame + nframes;
  77         int ret = 0;
  78         bool declick = get_transport_declick_required();
  79         boost::shared_ptr<RouteList> r = routes.reader ();
  80
  81         if (_click_io) {
  82                 _click_io->silence (nframes, offset);
  83         }
  84
  85         if (g_atomic_int_get (&processing_prohibited)) {
  86                 for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
  87                         (*i)->silence (nframes, offset);
  88                 }
  89                 return 0;
  90         }
  91
  92         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
  93
  94                 if ((*i)->hidden()) {
  95                         continue;
  96                 }
  97
  98                 (*i)->set_pending_declick (declick);
  99
 100                 if ((*i)->no_roll (nframes, _transport_frame, end_frame, offset, non_realtime_work_pending(),
 101                                    actively_recording(), declick)) {
 102                         error << string_compose(_("Session: error in no roll for %1"), (*i)->name()) << endmsg;
 103                         ret = -1;
 104                         break;
 105                 }
 106         }
 107
 108         return ret;
 109 }
 110
 111 int
 112 Session::process_routes (nframes_t nframes, nframes_t offset)
 113 {
 114         bool record_active;
 115         int  declick = get_transport_declick_required();
 116         bool rec_monitors = get_rec_monitors_input();
 117         boost::shared_ptr<RouteList> r = routes.reader ();
 118
 119         if (transport_sub_state & StopPendingCapture) {
 120                 /* force a declick out */
 121                 declick = -1;
 122         }
 123
 124         record_active = actively_recording(); // || (get_record_enabled() && get_punch_in());
 125
 126         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 127
 128                 int ret;
 129
 130                 if ((*i)->hidden()) {
 131                         continue;
 132                 }
 133
 134                 (*i)->set_pending_declick (declick);
 135
 136                 if ((ret = (*i)->roll (nframes, _transport_frame, _transport_frame + nframes, offset, declick, record_active, rec_monitors)) < 0) {
 137
 138                         /* we have to do this here. Route::roll() for an AudioTrack will have called AudioDiskstream::process(),
 139                            and the DS will expect AudioDiskstream::commit() to be called. but we're aborting from that
 140                            call path, so make sure we release any outstanding locks here before we return failure.
 141                         */
 142
 143                         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 144                         for (DiskstreamList::iterator ids = dsl->begin(); ids != dsl->end(); ++ids) {
 145                                 (*ids)->recover ();
 146                         }
 147
 148                         stop_transport ();
 149                         return -1;
 150                 }
 151         }
 152
 153         return 0;
 154 }
 155
 156 int
 157 Session::silent_process_routes (nframes_t nframes, nframes_t offset)
 158 {
 159         bool record_active = actively_recording();
 160         int  declick = get_transport_declick_required();
 161         bool rec_monitors = get_rec_monitors_input();
 162         boost::shared_ptr<RouteList> r = routes.reader ();
 163
 164         if (transport_sub_state & StopPendingCapture) {
 165                 /* force a declick out */
 166                 declick = -1;
 167         }
 168
 169         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 170
 171                 int ret;
 172
 173                 if ((*i)->hidden()) {
 174                         continue;
 175                 }
 176
 177                 if ((ret = (*i)->silent_roll (nframes, _transport_frame, _transport_frame + nframes, offset, record_active, rec_monitors)) < 0) {
 178
 179                         /* we have to do this here. Route::roll() for an AudioTrack will have called AudioDiskstream::process(),
 180                            and the DS will expect AudioDiskstream::commit() to be called. but we're aborting from that
 181                            call path, so make sure we release any outstanding locks here before we return failure.
 182                         */
 183
 184                         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 185                         for (DiskstreamList::iterator ids = dsl->begin(); ids != dsl->end(); ++ids) {
 186                                 (*ids)->recover ();
 187                         }
 188
 189                         stop_transport ();
 190                         return -1;
 191                 }
 192         }
 193
 194         return 0;
 195 }
 196
 197 void
 198 Session::commit_diskstreams (nframes_t nframes, bool &needs_butler)
 199 {
 200         int dret;
 201         float pworst = 1.0f;
 202         float cworst = 1.0f;
 203
 204         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 205         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 206
 207                 if ((*i)->hidden()) {
 208                         continue;
 209                 }
 210
 211                 /* force all diskstreams not handled by a Route to call do their stuff.
 212                    Note: the diskstreams that were handled by a route will just return zero
 213                    from this call, because they know they were processed. So in fact, this
 214                    also runs commit() for every diskstream.
 215                  */
 216
 217                 if ((dret = (*i)->process (_transport_frame, nframes, 0, actively_recording(), get_rec_monitors_input())) == 0) {
 218                         if ((*i)->commit (nframes)) {
 219                                 needs_butler = true;
 220                         }
 221
 222                 } else if (dret < 0) {
 223                         (*i)->recover();
 224                 }
 225
 226                 pworst = min (pworst, (*i)->playback_buffer_load());
 227                 cworst = min (cworst, (*i)->capture_buffer_load());
 228         }
 229
 230         uint32_t pmin = g_atomic_int_get (&_playback_load);
 231         uint32_t pminold = g_atomic_int_get (&_playback_load_min);
 232         uint32_t cmin = g_atomic_int_get (&_capture_load);
 233         uint32_t cminold = g_atomic_int_get (&_capture_load_min);
 234
 235         g_atomic_int_set (&_playback_load, (uint32_t) floor (pworst * 100.0f));
 236         g_atomic_int_set (&_capture_load, (uint32_t) floor (cworst * 100.0f));
 237         g_atomic_int_set (&_playback_load_min, min (pmin, pminold));
 238         g_atomic_int_set (&_capture_load_min, min (cmin, cminold));
 239
 240         if (actively_recording()) {
 241                 set_dirty();
 242         }
 243 }
 244
 245 void
 246 Session::process_with_events (nframes_t nframes)
 247 {
 248         Event* ev;
 249         nframes_t this_nframes;
 250         nframes_t end_frame;
 251         nframes_t offset;
 252         bool session_needs_butler = false;
 253         nframes_t stop_limit;
 254         long           frames_moved;
 255
 256         /* make sure the auditioner is silent */
 257
 258         if (auditioner) {
 259                 auditioner->silence (nframes, 0);
 260         }
 261
 262         /* handle any pending events */
 263
 264         while (pending_events.read (&ev, 1) == 1) {
 265                 merge_event (ev);
 266         }
 267
 268         /* if we are not in the middle of a state change,
 269            and there are immediate events queued up,
 270            process them.
 271         */
 272
 273         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 274                 Event *ev = immediate_events.front ();
 275                 immediate_events.pop_front ();
 276                 process_event (ev);
 277         }
 278
 279         if (!process_can_proceed()) {
 280                 _silent = true;
 281                 return;
 282         }
 283
 284         if (events.empty() || next_event == events.end()) {
 285                 process_without_events (nframes);
 286                 return;
 287         }
 288
 289         end_frame = _transport_frame + (nframes_t)abs(floor(nframes * _transport_speed));
 290
 291         {
 292                 Event* this_event;
 293                 Events::iterator the_next_one;
 294
 295                 if (!process_can_proceed()) {
 296                         _silent = true;
 297                         return;
 298                 }
 299
 300                 if (!_exporting && _slave) {
 301                         if (!follow_slave (nframes, 0)) {
 302                                 return;
 303                         }
 304                 }
 305
 306                 if (_transport_speed == 0) {
 307                         no_roll (nframes, 0);
 308                         return;
 309                 }
 310
 311                 if (actively_recording()) {
 312                         stop_limit = max_frames;
 313                 } else {
 314
 315                         if (Config->get_stop_at_session_end()) {
 316                                 stop_limit = current_end_frame();
 317                         } else {
 318                                 stop_limit = max_frames;
 319                         }
 320                 }
 321
 322                 if (maybe_stop (stop_limit)) {
 323                         no_roll (nframes, 0);
 324                         return;
 325                 }
 326
 327                 this_event = *next_event;
 328                 the_next_one = next_event;
 329                 ++the_next_one;
 330
 331                 offset = 0;
 332
 333                 while (nframes) {
 334
 335                         this_nframes = nframes; /* real (jack) time relative */
 336                         frames_moved = (long) floor (_transport_speed * nframes); /* transport relative */
 337
 338                         /* running an event, position transport precisely to its time */
 339                         if (this_event && this_event->action_frame <= end_frame && this_event->action_frame >= _transport_frame) {
 340                                 /* this isn't quite right for reverse play */
 341                                 frames_moved = (long) (this_event->action_frame - _transport_frame);
 342                                 this_nframes = (nframes_t) abs( floor(frames_moved / _transport_speed) );
 343                         }
 344
 345                         if (this_nframes) {
 346
 347                                 click (_transport_frame, nframes, offset);
 348
 349                                 /* now process frames between now and the first event in this block */
 350                                 prepare_diskstreams ();
 351
 352                                 if (process_routes (this_nframes, offset)) {
 353                                         no_roll (nframes, 0);
 354                                         return;
 355                                 }
 356
 357                                 commit_diskstreams (this_nframes, session_needs_butler);
 358
 359                                 nframes -= this_nframes;
 360                                 offset += this_nframes;
 361
 362                                 if (frames_moved < 0) {
 363                                         decrement_transport_position (-frames_moved);
 364                                 } else {
 365                                         increment_transport_position (frames_moved);
 366                                 }
 367
 368                                 maybe_stop (stop_limit);
 369                                 check_declick_out ();
 370                         }
 371
 372                         /* now handle this event and all others scheduled for the same time */
 373
 374                         while (this_event && this_event->action_frame == _transport_frame) {
 375                                 process_event (this_event);
 376
 377                                 if (the_next_one == events.end()) {
 378                                         this_event = 0;
 379                                 } else {
 380                                         this_event = *the_next_one;
 381                                         ++the_next_one;
 382                                 }
 383                         }
 384
 385                         /* if an event left our state changing, do the right thing */
 386
 387                         if (non_realtime_work_pending()) {
 388                                 no_roll (nframes, offset);
 389                                 break;
 390                         }
 391
 392                         /* this is necessary to handle the case of seamless looping */
 393                         end_frame = _transport_frame + (nframes_t) floor (nframes * _transport_speed);
 394
 395                 }
 396
 397                 set_next_event ();
 398
 399         } /* implicit release of route lock */
 400
 401
 402         if (session_needs_butler) {
 403                 summon_butler ();
 404         }
 405
 406         if (!_engine.freewheeling() && session_send_mtc) {
 407                 send_midi_time_code_in_another_thread ();
 408         }
 409
 410         return;
 411 }
 412
 413 void
 414 Session::reset_slave_state ()
 415 {
 416         average_slave_delta = 1800;
 417         delta_accumulator_cnt = 0;
 418         have_first_delta_accumulator = false;
 419         slave_state = Stopped;
 420 }
 421
 422 bool
 423 Session::transport_locked () const
 424 {
 425         Slave* sl = _slave;
 426
 427         if (!locate_pending() && ((Config->get_slave_source() == None) || (sl && sl->ok() && sl->locked()))) {
 428                 return true;
 429         }
 430
 431         return false;
 432 }
 433
 434 bool
 435 Session::follow_slave (nframes_t nframes, nframes_t offset)
 436 {
 437         float slave_speed;
 438         nframes_t slave_transport_frame;
 439         nframes_t this_delta;
 440         int dir;
 441         bool starting;
 442
 443         if (!_slave->ok()) {
 444                 stop_transport ();
 445                 Config->set_slave_source (None);
 446                 goto noroll;
 447         }
 448
 449         _slave->speed_and_position (slave_speed, slave_transport_frame);
 450
 451         if (!_slave->locked()) {
 452                 // cerr << "Slave not locked, not rolling\n";
 453                 goto noroll;
 454         }
 455
 456         if (slave_transport_frame > _transport_frame) {
 457                 this_delta = slave_transport_frame - _transport_frame;
 458                 dir = 1;
 459         } else {
 460                 this_delta = _transport_frame - slave_transport_frame;
 461                 dir = -1;
 462         }
 463
 464         if ((starting = _slave->starting())) {
 465                 slave_speed = 0.0f;
 466         }
 467
 468 #if 0
 469         cerr << "delta = " << (int) (dir * this_delta)
 470              << " speed = " << slave_speed
 471              << " ts = " << _transport_speed
 472              << " M@ "<< slave_transport_frame << " S@ " << _transport_frame
 473              << " avgdelta = " << average_slave_delta
 474              << endl;
 475 #endif
 476
 477         if (_slave->is_always_synced() || Config->get_timecode_source_is_synced()) {
 478
 479                 /* if the TC source is synced, then we assume that its
 480                    speed is binary: 0.0 or 1.0
 481                 */
 482
 483                 if (slave_speed != 0.0f) {
 484                         slave_speed = 1.0f;
 485                 }
 486
 487         } else {
 488
 489                 /* TC source is able to drift relative to us (slave)
 490                    so we need to keep track of the drift and adjust
 491                    our speed to remain locked.
 492                 */
 493
 494                 if (delta_accumulator_cnt >= delta_accumulator_size) {
 495                         have_first_delta_accumulator = true;
 496                         delta_accumulator_cnt = 0;
 497                 }
 498
 499                 if (delta_accumulator_cnt != 0 || this_delta < _current_frame_rate) {
 500                         delta_accumulator[delta_accumulator_cnt++] = dir*this_delta;
 501                 }
 502
 503                 if (have_first_delta_accumulator) {
 504                         average_slave_delta = 0;
 505                         for (int i = 0; i < delta_accumulator_size; ++i) {
 506                                 average_slave_delta += delta_accumulator[i];
 507                         }
 508                         average_slave_delta /= delta_accumulator_size;
 509                         if (average_slave_delta < 0) {
 510                                 average_dir = -1;
 511                                 average_slave_delta = -average_slave_delta;
 512                         } else {
 513                                 average_dir = 1;
 514                         }
 515                         // cerr << "avgdelta = " << average_slave_delta*average_dir << endl;
 516                 }
 517         }
 518
 519         if (slave_speed != 0.0f) {
 520
 521                 /* slave is running */
 522
 523                 switch (slave_state) {
 524                 case Stopped:
 525                         if (_slave->requires_seekahead()) {
 526                                 slave_wait_end = slave_transport_frame + _current_frame_rate;
 527                                 locate (slave_wait_end, false, false);
 528                                 slave_state = Waiting;
 529                                 starting = true;
 530
 531                         } else {
 532
 533                                 slave_state = Running;
 534
 535                                 Location* al = _locations.auto_loop_location();
 536
 537                                 if (al && play_loop && (slave_transport_frame < al->start() || slave_transport_frame > al->end())) {
 538                                         // cancel looping
 539                                         request_play_loop(false);
 540                                 }
 541
 542                                 if (slave_transport_frame != _transport_frame) {
 543                                         locate (slave_transport_frame, false, false);
 544                                 }
 545                         }
 546                         break;
 547
 548                 case Waiting:
 549                         break;
 550
 551                 default:
 552                         break;
 553
 554                 }
 555
 556                 if (slave_state == Waiting) {
 557
 558                         // cerr << "waiting at " << slave_transport_frame << endl;
 559
 560                         if (slave_transport_frame >= slave_wait_end) {
 561                                 // cerr << "\tstart at " << _transport_frame << endl;
 562
 563                                 slave_state = Running;
 564
 565                                 bool ok = true;
 566                                 nframes_t frame_delta = slave_transport_frame - _transport_frame;
 567
 568                                 boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 569
 570                                 for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 571                                         if (!(*i)->can_internal_playback_seek (frame_delta)) {
 572                                                 ok = false;
 573                                                 break;
 574                                         }
 575                                 }
 576
 577                                 if (ok) {
 578                                         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 579                                                 (*i)->internal_playback_seek (frame_delta);
 580                                         }
 581                                         _transport_frame += frame_delta;
 582
 583                                 } else {
 584                                         // cerr << "cannot micro-seek\n";
 585                                         /* XXX what? */
 586                                 }
 587
 588                                 memset (delta_accumulator, 0, sizeof (nframes_t) * delta_accumulator_size);
 589                                 average_slave_delta = 0;
 590                                 this_delta = 0;
 591                         }
 592                 }
 593
 594                 if (slave_state == Running && _transport_speed == 0.0f) {
 595
 596                         // cerr << "slave starts transport\n";
 597
 598                         start_transport ();
 599                 }
 600
 601         } else {
 602
 603                 /* slave has stopped */
 604
 605                 if (_transport_speed != 0.0f) {
 606
 607                         // cerr << "slave stops transport: " << slave_speed << " frame: " << slave_transport_frame
 608                         // << " tf = " << _transport_frame
 609                         // << endl;
 610
 611                         if (Config->get_slave_source() == JACK) {
 612                                 last_stop_frame = _transport_frame;
 613                         }
 614
 615                         stop_transport();
 616                 }
 617
 618                 if (slave_transport_frame != _transport_frame) {
 619                         // cerr << "slave stopped, move to " << slave_transport_frame << endl;
 620                         force_locate (slave_transport_frame, false);
 621                 }
 622
 623                 slave_state = Stopped;
 624         }
 625
 626         if (slave_state == Running && !_slave->is_always_synced() && !Config->get_timecode_source_is_synced()) {
 627
 628
 629                 if (_transport_speed != 0.0f) {
 630
 631                         /*
 632                            note that average_dir is +1 or -1
 633                         */
 634
 635                         const float adjust_seconds = 1.0f;
 636                         float delta;
 637
 638                         //if (average_slave_delta == 0) {
 639                                 delta = this_delta;
 640                                 delta *= dir;
 641 //                      } else {
 642 //                              delta = average_slave_delta;
 643 //                              delta *= average_dir;
 644 //                      }
 645
 646                         float adjusted_speed = slave_speed +
 647                                 (delta / (adjust_seconds * _current_frame_rate));
 648
 649 #if 0
 650                         cerr << "adjust using " << delta
 651                              << " towards " << adjusted_speed
 652                              << " ratio = " << adjusted_speed / slave_speed
 653                              << " current = " << _transport_speed
 654                              << " slave @ " << slave_speed
 655                              << endl;
 656 #endif
 657
 658                         request_transport_speed (adjusted_speed);
 659
 660 #if 1
 661                         if ((nframes_t) average_slave_delta > _slave->resolution()) {
 662                                 // cerr << "not locked\n";
 663                                 goto silent_motion;
 664                         }
 665 #endif
 666                 }
 667         }
 668
 669         if (!starting && !non_realtime_work_pending()) {
 670                 /* speed is set, we're locked, and good to go */
 671                 return true;
 672         }
 673
 674   silent_motion:
 675
 676         if (slave_speed && _transport_speed) {
 677
 678                 /* something isn't right, but we should move with the master
 679                    for now.
 680                 */
 681
 682                 bool need_butler;
 683
 684                 prepare_diskstreams ();
 685                 silent_process_routes (nframes, offset);
 686                 commit_diskstreams (nframes, need_butler);
 687
 688                 if (need_butler) {
 689                         summon_butler ();
 690                 }
 691
 692                 int32_t frames_moved = (int32_t) floor (_transport_speed * nframes);
 693
 694                 if (frames_moved < 0) {
 695                         decrement_transport_position (-frames_moved);
 696                 } else {
 697                         increment_transport_position (frames_moved);
 698                 }
 699
 700                 nframes_t stop_limit;
 701
 702                 if (actively_recording()) {
 703                         stop_limit = max_frames;
 704                 } else {
 705                         if (Config->get_stop_at_session_end()) {
 706                                 stop_limit = current_end_frame();
 707                         } else {
 708                                 stop_limit = max_frames;
 709                         }
 710                 }
 711
 712                 maybe_stop (stop_limit);
 713         }
 714
 715   noroll:
 716         /* don't move at all */
 717         no_roll (nframes, 0);
 718         return false;
 719 }
 720
 721 void
 722 Session::process_without_events (nframes_t nframes)
 723 {
 724         bool session_needs_butler = false;
 725         nframes_t stop_limit;
 726         long frames_moved;
 727         nframes_t offset = 0;
 728
 729         if (!process_can_proceed()) {
 730                 _silent = true;
 731                 return;
 732         }
 733
 734         if (!_exporting && _slave) {
 735                 if (!follow_slave (nframes, 0)) {
 736                         return;
 737                 }
 738         }
 739
 740         if (_transport_speed == 0) {
 741                 no_roll (nframes, 0);
 742                 return;
 743         }
 744
 745         if (actively_recording()) {
 746                 stop_limit = max_frames;
 747         } else {
 748                 if (Config->get_stop_at_session_end()) {
 749                         stop_limit = current_end_frame();
 750                 } else {
 751                         stop_limit = max_frames;
 752                 }
 753         }
 754
 755         if (maybe_stop (stop_limit)) {
 756                 no_roll (nframes, 0);
 757                 return;
 758         }
 759
 760         if (maybe_sync_start (nframes, offset)) {
 761                 return;
 762         }
 763
 764         click (_transport_frame, nframes, offset);
 765
 766         prepare_diskstreams ();
 767
 768         frames_moved = (long) floor (_transport_speed * nframes);
 769
 770         if (process_routes (nframes, offset)) {
 771                 no_roll (nframes, offset);
 772                 return;
 773         }
 774
 775         commit_diskstreams (nframes, session_needs_butler);
 776
 777         if (frames_moved < 0) {
 778                 decrement_transport_position (-frames_moved);
 779         } else {
 780                 increment_transport_position (frames_moved);
 781         }
 782
 783         maybe_stop (stop_limit);
 784         check_declick_out ();
 785
 786         if (session_needs_butler) {
 787                 summon_butler ();
 788         }
 789
 790         if (!_engine.freewheeling() && session_send_mtc) {
 791                 send_midi_time_code_in_another_thread ();
 792         }
 793
 794         return;
 795 }
 796
 797 void
 798 Session::process_audition (nframes_t nframes)
 799 {
 800         Event* ev;
 801         boost::shared_ptr<RouteList> r = routes.reader ();
 802
 803         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 804                 if (!(*i)->hidden()) {
 805                         (*i)->silence (nframes, 0);
 806                 }
 807         }
 808
 809         /* run the auditioner, and if it says we need butler service, ask for it */
 810
 811         if (auditioner->play_audition (nframes) > 0) {
 812                 summon_butler ();
 813         }
 814
 815         /* handle pending events */
 816
 817         while (pending_events.read (&ev, 1) == 1) {
 818                 merge_event (ev);
 819         }
 820
 821         /* if we are not in the middle of a state change,
 822            and there are immediate events queued up,
 823            process them.
 824         */
 825
 826         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 827                 Event *ev = immediate_events.front ();
 828                 immediate_events.pop_front ();
 829                 process_event (ev);
 830         }
 831
 832         if (!auditioner->active()) {
 833                 process_function = &Session::process_with_events;
 834         }
 835 }
 836
 837 bool
 838 Session::maybe_sync_start (nframes_t& nframes, nframes_t& offset)
 839 {
 840         nframes_t sync_offset;
 841
 842         if (!waiting_for_sync_offset) {
 843                 return false;
 844         }
 845
 846         if (_engine.get_sync_offset (sync_offset) && sync_offset < nframes) {
 847
 848                 /* generate silence up to the sync point, then
 849                    adjust nframes + offset to reflect whatever
 850                    is left to do.
 851                 */
 852
 853                 no_roll (sync_offset, 0);
 854                 nframes -= sync_offset;
 855                 offset += sync_offset;
 856                 waiting_for_sync_offset = false;
 857
 858                 if (nframes == 0) {
 859                         return true; // done, nothing left to process
 860                 }
 861
 862         } else {
 863
 864                 /* sync offset point is not within this process()
 865                    cycle, so just generate silence. and don't bother
 866                    with any fancy stuff here, just the minimal silence.
 867                 */
 868
 869                 g_atomic_int_inc (&processing_prohibited);
 870                 no_roll (nframes, 0);
 871                 g_atomic_int_dec_and_test (&processing_prohibited);
 872
 873                 if (Config->get_locate_while_waiting_for_sync()) {
 874                         if (micro_locate (nframes)) {
 875                                 /* XXX ERROR !!! XXX */
 876                         }
 877                 }
 878
 879                 return true; // done, nothing left to process
 880         }
 881
 882         return false;
 883 }
 884