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 /** Called by the audio engine when there is work to be done with JACK.
  48  * @param nframes Number of frames to process.
  49  */
  50 void
  51 Session::process (nframes_t nframes)
  52 {
  53         MIDI::Manager::instance()->cycle_start(nframes);
  54
  55         _silent = false;
  56
  57         if (non_realtime_work_pending()) {
  58                 if (!transport_work_requested ()) {
  59                         post_transport ();
  60                 }
  61         }
  62
  63         (this->*process_function) (nframes);
  64
  65         MIDI::Manager::instance()->cycle_end();
  66
  67         SendFeedback (); /* EMIT SIGNAL */
  68 }
  69
  70 void
  71 Session::prepare_diskstreams ()
  72 {
  73         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
  74         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
  75                 (*i)->prepare ();
  76         }
  77 }
  78
  79 int
  80 Session::no_roll (nframes_t nframes, nframes_t offset)
  81 {
  82         nframes_t end_frame = _transport_frame + nframes; // FIXME: varispeed + no_roll ??
  83         int ret = 0;
  84         bool declick = get_transport_declick_required();
  85         boost::shared_ptr<RouteList> r = routes.reader ();
  86
  87         if (_click_io) {
  88                 _click_io->silence (nframes, offset);
  89         }
  90
  91         if (g_atomic_int_get (&processing_prohibited)) {
  92                 for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
  93                         (*i)->silence (nframes, offset);
  94                 }
  95                 return 0;
  96         }
  97
  98         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
  99
 100                 if ((*i)->is_hidden()) {
 101                         continue;
 102                 }
 103
 104                 (*i)->set_pending_declick (declick);
 105
 106                 if ((*i)->no_roll (nframes, _transport_frame, end_frame, offset, non_realtime_work_pending(),
 107                                    actively_recording(), declick)) {
 108                         error << string_compose(_("Session: error in no roll for %1"), (*i)->name()) << endmsg;
 109                         ret = -1;
 110                         break;
 111                 }
 112         }
 113
 114         return ret;
 115 }
 116
 117 int
 118 Session::process_routes (nframes_t nframes, nframes_t offset)
 119 {
 120         bool record_active;
 121         int  declick = get_transport_declick_required();
 122         bool rec_monitors = get_rec_monitors_input();
 123         boost::shared_ptr<RouteList> r = routes.reader ();
 124
 125         if (transport_sub_state & StopPendingCapture) {
 126                 /* force a declick out */
 127                 declick = -1;
 128         }
 129
 130         record_active = actively_recording(); // || (get_record_enabled() && get_punch_in());
 131
 132         const nframes_t start_frame = _transport_frame;
 133         const nframes_t end_frame = _transport_frame + (nframes_t)floor(nframes * _transport_speed);
 134
 135         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 136
 137                 int ret;
 138
 139                 if ((*i)->is_hidden()) {
 140                         continue;
 141                 }
 142
 143                 (*i)->set_pending_declick (declick);
 144
 145                 if ((ret = (*i)->roll (nframes, start_frame, end_frame, offset, declick, record_active, rec_monitors)) < 0) {
 146
 147                         /* we have to do this here. Route::roll() for an AudioTrack will have called AudioDiskstream::process(),
 148                            and the DS will expect AudioDiskstream::commit() to be called. but we're aborting from that
 149                            call path, so make sure we release any outstanding locks here before we return failure.
 150                         */
 151
 152                         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 153                         for (DiskstreamList::iterator ids = dsl->begin(); ids != dsl->end(); ++ids) {
 154                                 (*ids)->recover ();
 155                         }
 156
 157                         stop_transport ();
 158                         return -1;
 159                 }
 160         }
 161
 162         return 0;
 163 }
 164
 165 int
 166 Session::silent_process_routes (nframes_t nframes, nframes_t offset)
 167 {
 168         bool record_active = actively_recording();
 169         int  declick = get_transport_declick_required();
 170         bool rec_monitors = get_rec_monitors_input();
 171         boost::shared_ptr<RouteList> r = routes.reader ();
 172
 173         if (transport_sub_state & StopPendingCapture) {
 174                 /* force a declick out */
 175                 declick = -1;
 176         }
 177
 178         const nframes_t start_frame = _transport_frame;
 179         const nframes_t end_frame = _transport_frame + lrintf(nframes * _transport_speed);
 180
 181         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 182
 183                 int ret;
 184
 185                 if ((*i)->is_hidden()) {
 186                         continue;
 187                 }
 188
 189                 if ((ret = (*i)->silent_roll (nframes, start_frame, end_frame, offset, record_active, rec_monitors)) < 0) {
 190
 191                         /* we have to do this here. Route::roll() for an AudioTrack will have called AudioDiskstream::process(),
 192                            and the DS will expect AudioDiskstream::commit() to be called. but we're aborting from that
 193                            call path, so make sure we release any outstanding locks here before we return failure.
 194                         */
 195
 196                         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 197                         for (DiskstreamList::iterator ids = dsl->begin(); ids != dsl->end(); ++ids) {
 198                                 (*ids)->recover ();
 199                         }
 200
 201                         stop_transport ();
 202                         return -1;
 203                 }
 204         }
 205
 206         return 0;
 207 }
 208
 209 void
 210 Session::commit_diskstreams (nframes_t nframes, bool &needs_butler)
 211 {
 212         int dret;
 213         float pworst = 1.0f;
 214         float cworst = 1.0f;
 215
 216         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 217         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 218
 219                 if ((*i)->hidden()) {
 220                         continue;
 221                 }
 222
 223                 /* force all diskstreams not handled by a Route to call do their stuff.
 224                    Note: the diskstreams that were handled by a route will just return zero
 225                    from this call, because they know they were processed. So in fact, this
 226                    also runs commit() for every diskstream.
 227                  */
 228
 229                 if ((dret = (*i)->process (_transport_frame, nframes, 0, actively_recording(), get_rec_monitors_input())) == 0) {
 230                         if ((*i)->commit (nframes)) {
 231                                 needs_butler = true;
 232                         }
 233
 234                 } else if (dret < 0) {
 235                         (*i)->recover();
 236                 }
 237
 238                 pworst = min (pworst, (*i)->playback_buffer_load());
 239                 cworst = min (cworst, (*i)->capture_buffer_load());
 240         }
 241
 242         uint32_t pmin = g_atomic_int_get (&_playback_load);
 243         uint32_t pminold = g_atomic_int_get (&_playback_load_min);
 244         uint32_t cmin = g_atomic_int_get (&_capture_load);
 245         uint32_t cminold = g_atomic_int_get (&_capture_load_min);
 246
 247         g_atomic_int_set (&_playback_load, (uint32_t) floor (pworst * 100.0f));
 248         g_atomic_int_set (&_capture_load, (uint32_t) floor (cworst * 100.0f));
 249         g_atomic_int_set (&_playback_load_min, min (pmin, pminold));
 250         g_atomic_int_set (&_capture_load_min, min (cmin, cminold));
 251
 252         if (actively_recording()) {
 253                 set_dirty();
 254         }
 255 }
 256
 257 /** Process callback used when the auditioner is not active */
 258 void
 259 Session::process_with_events (nframes_t nframes)
 260 {
 261         Event*         ev;
 262         nframes_t this_nframes;
 263         nframes_t end_frame;
 264         nframes_t offset;
 265         bool session_needs_butler = false;
 266         nframes_t stop_limit;
 267         long           frames_moved;
 268
 269         /* make sure the auditioner is silent */
 270
 271         if (auditioner) {
 272                 auditioner->silence (nframes, 0);
 273         }
 274
 275         /* handle any pending events */
 276
 277         while (pending_events.read (&ev, 1) == 1) {
 278                 merge_event (ev);
 279         }
 280
 281         /* if we are not in the middle of a state change,
 282            and there are immediate events queued up,
 283            process them.
 284         */
 285
 286         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 287                 Event *ev = immediate_events.front ();
 288                 immediate_events.pop_front ();
 289                 process_event (ev);
 290         }
 291
 292         /* Events caused a transport change, send an MTC Full Frame (SMPTE) message.
 293          * This is sent whether rolling or not, to give slaves an idea of ardour time
 294          * on locates (and allow slow slaves to position and prepare for rolling)
 295          */
 296         if (_send_smpte_update) {
 297                 send_full_time_code(nframes);
 298         }
 299
 300         if (!process_can_proceed()) {
 301                 _silent = true;
 302                 return;
 303         }
 304
 305         if (events.empty() || next_event == events.end()) {
 306                 process_without_events (nframes);
 307                 return;
 308         }
 309
 310         end_frame = _transport_frame + (nframes_t)abs(floor(nframes * _transport_speed));
 311
 312         {
 313                 Event* this_event;
 314                 Events::iterator the_next_one;
 315
 316                 if (!process_can_proceed()) {
 317                         _silent = true;
 318                         return;
 319                 }
 320
 321                 if (!_exporting && _slave) {
 322                         if (!follow_slave (nframes, 0)) {
 323                                 return;
 324                         }
 325                 }
 326
 327                 if (_transport_speed == 0) {
 328                         no_roll (nframes, 0);
 329                         return;
 330                 }
 331
 332                 if (!_exporting) {
 333                         send_midi_time_code_for_cycle (nframes);
 334                 }
 335
 336                 if (actively_recording()) {
 337                         stop_limit = max_frames;
 338                 } else {
 339
 340                         if (Config->get_stop_at_session_end()) {
 341                                 stop_limit = current_end_frame();
 342                         } else {
 343                                 stop_limit = max_frames;
 344                         }
 345                 }
 346
 347                 if (maybe_stop (stop_limit)) {
 348                         no_roll (nframes, 0);
 349                         return;
 350                 }
 351
 352                 this_event = *next_event;
 353                 the_next_one = next_event;
 354                 ++the_next_one;
 355
 356                 offset = 0;
 357
 358                 /* yes folks, here it is, the actual loop where we really truly
 359                    process some audio */
 360                 while (nframes) {
 361
 362                         this_nframes = nframes; /* real (jack) time relative */
 363                         frames_moved = (long) floor (_transport_speed * nframes); /* transport relative */
 364
 365                         /* running an event, position transport precisely to its time */
 366                         if (this_event && this_event->action_frame <= end_frame && this_event->action_frame >= _transport_frame) {
 367                                 /* this isn't quite right for reverse play */
 368                                 frames_moved = (long) (this_event->action_frame - _transport_frame);
 369                                 this_nframes = (nframes_t) abs( floor(frames_moved / _transport_speed) );
 370                         }
 371
 372                         if (this_nframes) {
 373
 374                                 click (_transport_frame, nframes, offset);
 375
 376                                 /* now process frames between now and the first event in this block */
 377                                 prepare_diskstreams ();
 378
 379                                 if (process_routes (this_nframes, offset)) {
 380                                         no_roll (nframes, 0);
 381                                         return;
 382                                 }
 383
 384                                 commit_diskstreams (this_nframes, session_needs_butler);
 385
 386                                 nframes -= this_nframes;
 387                                 offset += this_nframes;
 388
 389                                 if (frames_moved < 0) {
 390                                         decrement_transport_position (-frames_moved);
 391                                 } else {
 392                                         increment_transport_position (frames_moved);
 393                                 }
 394
 395                                 maybe_stop (stop_limit);
 396                                 check_declick_out ();
 397                         }
 398
 399                         /* now handle this event and all others scheduled for the same time */
 400
 401                         while (this_event && this_event->action_frame == _transport_frame) {
 402                                 process_event (this_event);
 403
 404                                 if (the_next_one == events.end()) {
 405                                         this_event = 0;
 406                                 } else {
 407                                         this_event = *the_next_one;
 408                                         ++the_next_one;
 409                                 }
 410                         }
 411
 412                         /* if an event left our state changing, do the right thing */
 413
 414                         if (non_realtime_work_pending()) {
 415                                 no_roll (nframes, offset);
 416                                 break;
 417                         }
 418
 419                         /* this is necessary to handle the case of seamless looping */
 420                         end_frame = _transport_frame + (nframes_t) floor (nframes * _transport_speed);
 421
 422                 }
 423
 424                 set_next_event ();
 425
 426         } /* implicit release of route lock */
 427
 428         if (session_needs_butler)
 429                 summon_butler ();
 430 }
 431
 432 void
 433 Session::reset_slave_state ()
 434 {
 435         average_slave_delta = 1800;
 436         delta_accumulator_cnt = 0;
 437         have_first_delta_accumulator = false;
 438         slave_state = Stopped;
 439 }
 440
 441 bool
 442 Session::transport_locked () const
 443 {
 444         Slave* sl = _slave;
 445
 446         if (!locate_pending() && ((Config->get_slave_source() == None) || (sl && sl->ok() && sl->locked()))) {
 447                 return true;
 448         }
 449
 450         return false;
 451 }
 452
 453 bool
 454 Session::follow_slave (nframes_t nframes, nframes_t offset)
 455 {
 456         float slave_speed;
 457         nframes_t slave_transport_frame;
 458         nframes_t this_delta;
 459         int dir;
 460         bool starting;
 461
 462         if (!_slave->ok()) {
 463                 stop_transport ();
 464                 Config->set_slave_source (None);
 465                 goto noroll;
 466         }
 467
 468         _slave->speed_and_position (slave_speed, slave_transport_frame);
 469
 470         if (!_slave->locked()) {
 471                 goto noroll;
 472         }
 473
 474         if (slave_transport_frame > _transport_frame) {
 475                 this_delta = slave_transport_frame - _transport_frame;
 476                 dir = 1;
 477         } else {
 478                 this_delta = _transport_frame - slave_transport_frame;
 479                 dir = -1;
 480         }
 481
 482         if ((starting = _slave->starting())) {
 483                 slave_speed = 0.0f;
 484         }
 485
 486 #if 0
 487         cerr << "delta = " << (int) (dir * this_delta)
 488              << " speed = " << slave_speed
 489              << " ts = " << _transport_speed
 490              << " M@ "<< slave_transport_frame << " S@ " << _transport_frame
 491              << " avgdelta = " << average_slave_delta
 492              << endl;
 493 #endif
 494
 495         if (_slave->is_always_synced() || Config->get_timecode_source_is_synced()) {
 496
 497                 /* if the TC source is synced, then we assume that its
 498                    speed is binary: 0.0 or 1.0
 499                 */
 500
 501                 if (slave_speed != 0.0f) {
 502                         slave_speed = 1.0f;
 503                 }
 504
 505         } else {
 506
 507                 /* TC source is able to drift relative to us (slave)
 508                    so we need to keep track of the drift and adjust
 509                    our speed to remain locked.
 510                 */
 511
 512                 if (delta_accumulator_cnt >= delta_accumulator_size) {
 513                         have_first_delta_accumulator = true;
 514                         delta_accumulator_cnt = 0;
 515                 }
 516
 517                 if (delta_accumulator_cnt != 0 || this_delta < _current_frame_rate) {
 518                         delta_accumulator[delta_accumulator_cnt++] = dir*this_delta;
 519                 }
 520
 521                 if (have_first_delta_accumulator) {
 522                         average_slave_delta = 0;
 523                         for (int i = 0; i < delta_accumulator_size; ++i) {
 524                                 average_slave_delta += delta_accumulator[i];
 525                         }
 526                         average_slave_delta /= delta_accumulator_size;
 527                         if (average_slave_delta < 0) {
 528                                 average_dir = -1;
 529                                 average_slave_delta = -average_slave_delta;
 530                         } else {
 531                                 average_dir = 1;
 532                         }
 533                         // cerr << "avgdelta = " << average_slave_delta*average_dir << endl;
 534                 }
 535         }
 536
 537         if (slave_speed != 0.0f) {
 538
 539                 /* slave is running */
 540
 541                 switch (slave_state) {
 542                 case Stopped:
 543                         if (_slave->requires_seekahead()) {
 544                                 slave_wait_end = slave_transport_frame + _current_frame_rate;
 545                                 locate (slave_wait_end, false, false);
 546                                 slave_state = Waiting;
 547                                 starting = true;
 548
 549                         } else {
 550
 551                                 slave_state = Running;
 552
 553                                 Location* al = _locations.auto_loop_location();
 554
 555                                 if (al && play_loop && (slave_transport_frame < al->start() || slave_transport_frame > al->end())) {
 556                                         // cancel looping
 557                                         request_play_loop(false);
 558                                 }
 559
 560                                 if (slave_transport_frame != _transport_frame) {
 561                                         locate (slave_transport_frame, false, false);
 562                                 }
 563                         }
 564                         break;
 565
 566                 case Waiting:
 567                         break;
 568
 569                 default:
 570                         break;
 571
 572                 }
 573
 574                 if (slave_state == Waiting) {
 575
 576                         // cerr << "waiting at " << slave_transport_frame << endl;
 577                         if (slave_transport_frame >= slave_wait_end) {
 578                                 // cerr << "\tstart at " << _transport_frame << endl;
 579
 580                                 slave_state = Running;
 581
 582                                 bool ok = true;
 583                                 nframes_t frame_delta = slave_transport_frame - _transport_frame;
 584
 585                                 boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 586
 587                                 for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 588                                         if (!(*i)->can_internal_playback_seek (frame_delta)) {
 589                                                 ok = false;
 590                                                 break;
 591                                         }
 592                                 }
 593
 594                                 if (ok) {
 595                                         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 596                                                 (*i)->internal_playback_seek (frame_delta);
 597                                         }
 598                                         _transport_frame += frame_delta;
 599
 600                                 } else {
 601                                         // cerr << "cannot micro-seek\n";
 602                                         /* XXX what? */
 603                                 }
 604
 605                                 memset (delta_accumulator, 0, sizeof (nframes_t) * delta_accumulator_size);
 606                                 average_slave_delta = 0;
 607                                 this_delta = 0;
 608                         }
 609                 }
 610
 611                 if (slave_state == Running && _transport_speed == 0.0f) {
 612
 613                         // cerr << "slave starts transport\n";
 614
 615                         start_transport ();
 616                 }
 617
 618         } else {
 619
 620                 /* slave has stopped */
 621
 622                 if (_transport_speed != 0.0f) {
 623
 624                         // cerr << "slave stops transport: " << slave_speed << " frame: " << slave_transport_frame
 625                         // << " tf = " << _transport_frame
 626                         // << endl;
 627
 628                         if (Config->get_slave_source() == JACK) {
 629                                 last_stop_frame = _transport_frame;
 630                         }
 631
 632                         stop_transport();
 633                 }
 634
 635                 if (slave_transport_frame != _transport_frame) {
 636                         // cerr << "slave stopped, move to " << slave_transport_frame << endl;
 637                         force_locate (slave_transport_frame, false);
 638                 }
 639
 640                 slave_state = Stopped;
 641         }
 642
 643         if (slave_state == Running && !_slave->is_always_synced() && !Config->get_timecode_source_is_synced()) {
 644
 645
 646                 if (_transport_speed != 0.0f) {
 647
 648                         /*
 649                            note that average_dir is +1 or -1
 650                         */
 651
 652                         const float adjust_seconds = 1.0f;
 653                         float delta;
 654
 655                         //if (average_slave_delta == 0) {
 656                                 delta = this_delta;
 657                                 delta *= dir;
 658 //                      } else {
 659 //                              delta = average_slave_delta;
 660 //                              delta *= average_dir;
 661 //                      }
 662
 663                         float adjusted_speed = slave_speed +
 664                                 (delta / (adjust_seconds * _current_frame_rate));
 665
 666                         // cerr << "adjust using " << delta
 667                         // << " towards " << adjusted_speed
 668                         // << " ratio = " << adjusted_speed / slave_speed
 669                         // << " current = " << _transport_speed
 670                         // << " slave @ " << slave_speed
 671                         // << endl;
 672
 673                         request_transport_speed (adjusted_speed);
 674
 675 #if 1
 676                         if ((nframes_t) average_slave_delta > _slave->resolution()) {
 677                                 // cerr << "not locked\n";
 678                                 goto silent_motion;
 679                         }
 680 #endif
 681                 }
 682         }
 683
 684         if (!starting && !non_realtime_work_pending()) {
 685                 /* speed is set, we're locked, and good to go */
 686                 return true;
 687         }
 688
 689   silent_motion:
 690
 691         if (slave_speed && _transport_speed) {
 692
 693                 /* something isn't right, but we should move with the master
 694                    for now.
 695                 */
 696
 697                 bool need_butler;
 698
 699                 prepare_diskstreams ();
 700                 silent_process_routes (nframes, offset);
 701                 commit_diskstreams (nframes, need_butler);
 702
 703                 if (need_butler) {
 704                         summon_butler ();
 705                 }
 706
 707                 int32_t frames_moved = (int32_t) floor (_transport_speed * nframes);
 708
 709                 if (frames_moved < 0) {
 710                         decrement_transport_position (-frames_moved);
 711                 } else {
 712                         increment_transport_position (frames_moved);
 713                 }
 714
 715                 nframes_t stop_limit;
 716
 717                 if (actively_recording()) {
 718                         stop_limit = max_frames;
 719                 } else {
 720                         if (Config->get_stop_at_session_end()) {
 721                                 stop_limit = current_end_frame();
 722                         } else {
 723                                 stop_limit = max_frames;
 724                         }
 725                 }
 726
 727                 maybe_stop (stop_limit);
 728         }
 729
 730   noroll:
 731         /* don't move at all */
 732         no_roll (nframes, 0);
 733         return false;
 734 }
 735
 736 void
 737 Session::process_without_events (nframes_t nframes)
 738 {
 739         bool session_needs_butler = false;
 740         nframes_t stop_limit;
 741         long frames_moved;
 742         nframes_t offset = 0;
 743
 744         if (!process_can_proceed()) {
 745                 _silent = true;
 746                 return;
 747         }
 748
 749         if (!_exporting && _slave) {
 750                 if (!follow_slave (nframes, 0)) {
 751                         return;
 752                 }
 753         }
 754
 755         if (_transport_speed == 0) {
 756                 no_roll (nframes, 0);
 757                 return;
 758         }
 759
 760         if (!_exporting) {
 761                 send_midi_time_code_for_cycle (nframes);
 762         }
 763
 764         if (actively_recording()) {
 765                 stop_limit = max_frames;
 766         } else {
 767                 if (Config->get_stop_at_session_end()) {
 768                         stop_limit = current_end_frame();
 769                 } else {
 770                         stop_limit = max_frames;
 771                 }
 772         }
 773
 774         if (maybe_stop (stop_limit)) {
 775                 no_roll (nframes, 0);
 776                 return;
 777         }
 778
 779         if (maybe_sync_start (nframes, offset)) {
 780                 return;
 781         }
 782
 783         click (_transport_frame, nframes, offset);
 784
 785         prepare_diskstreams ();
 786
 787         frames_moved = (long) floor (_transport_speed * nframes);
 788
 789         if (process_routes (nframes, offset)) {
 790                 no_roll (nframes, offset);
 791                 return;
 792         }
 793
 794         commit_diskstreams (nframes, session_needs_butler);
 795
 796         if (frames_moved < 0) {
 797                 decrement_transport_position (-frames_moved);
 798         } else {
 799                 increment_transport_position (frames_moved);
 800         }
 801
 802         maybe_stop (stop_limit);
 803         check_declick_out ();
 804
 805         if (session_needs_butler)
 806                 summon_butler ();
 807 }
 808
 809 /** Process callback used when the auditioner is active.
 810  * @param nframes number of frames to process.
 811  */
 812 void
 813 Session::process_audition (nframes_t nframes)
 814 {
 815         Event* ev;
 816         boost::shared_ptr<RouteList> r = routes.reader ();
 817
 818         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 819                 if (!(*i)->is_hidden()) {
 820                         (*i)->silence (nframes, 0);
 821                 }
 822         }
 823
 824         /* run the auditioner, and if it says we need butler service, ask for it */
 825
 826         if (auditioner->play_audition (nframes) > 0) {
 827                 summon_butler ();
 828         }
 829
 830         /* handle pending events */
 831
 832         while (pending_events.read (&ev, 1) == 1) {
 833                 merge_event (ev);
 834         }
 835
 836         /* if we are not in the middle of a state change,
 837            and there are immediate events queued up,
 838            process them.
 839         */
 840
 841         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 842                 Event *ev = immediate_events.front ();
 843                 immediate_events.pop_front ();
 844                 process_event (ev);
 845         }
 846
 847         if (!auditioner->active()) {
 848                 /* auditioner no longer active, so go back to the normal process callback */
 849                 process_function = &Session::process_with_events;
 850         }
 851 }
 852
 853 bool
 854 Session::maybe_sync_start (nframes_t& nframes, nframes_t& offset)
 855 {
 856         nframes_t sync_offset;
 857
 858         if (!waiting_for_sync_offset) {
 859                 return false;
 860         }
 861
 862         if (_engine.get_sync_offset (sync_offset) && sync_offset < nframes) {
 863
 864                 /* generate silence up to the sync point, then
 865                    adjust nframes + offset to reflect whatever
 866                    is left to do.
 867                 */
 868
 869                 no_roll (sync_offset, 0);
 870                 nframes -= sync_offset;
 871                 offset += sync_offset;
 872                 waiting_for_sync_offset = false;
 873
 874                 if (nframes == 0) {
 875                         return true; // done, nothing left to process
 876                 }
 877
 878         } else {
 879
 880                 /* sync offset point is not within this process()
 881                    cycle, so just generate silence. and don't bother
 882                    with any fancy stuff here, just the minimal silence.
 883                 */
 884
 885                 g_atomic_int_inc (&processing_prohibited);
 886                 no_roll (nframes, 0);
 887                 g_atomic_int_dec_and_test (&processing_prohibited);
 888
 889                 if (Config->get_locate_while_waiting_for_sync()) {
 890                         if (micro_locate (nframes)) {
 891                                 /* XXX ERROR !!! XXX */
 892                         }
 893                 }
 894
 895                 return true; // done, nothing left to process
 896         }
 897
 898         return false;
 899 }
 900