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         // This is no more the appropriate place to call cycle
  54         // start. cycle_start needs to be called at the Route::roll()
  55         // where the signals which we want to mixdown have been calculated.
  56         //
  57         MIDI::Manager::instance()->cycle_start(nframes);
  58
  59         _silent = false;
  60
  61         if (processing_blocked()) {
  62                 _silent = true;
  63                 return;
  64         }
  65
  66         if (non_realtime_work_pending()) {
  67                 if (!transport_work_requested ()) {
  68                         post_transport ();
  69                 }
  70         }
  71
  72         (this->*process_function) (nframes);
  73
  74         // the ticker is for sending time information like MidiClock
  75         nframes_t transport_frames = transport_frame();
  76         BBT_Time  transport_bbt;
  77         bbt_time(transport_frames, transport_bbt);
  78         SMPTE::Time transport_smpte;
  79         smpte_time(transport_frames, transport_smpte);
  80         tick (transport_frames, transport_bbt, transport_smpte); /* EMIT SIGNAL */
  81
  82         SendFeedback (); /* EMIT SIGNAL */
  83
  84         MIDI::Manager::instance()->cycle_end();
  85 }
  86
  87 void
  88 Session::prepare_diskstreams ()
  89 {
  90         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
  91         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
  92                 (*i)->prepare ();
  93         }
  94 }
  95
  96 int
  97 Session::fail_roll (nframes_t nframes)
  98 {
  99         return no_roll (nframes);
 100 }
 101
 102 int
 103 Session::no_roll (nframes_t nframes)
 104 {
 105         nframes_t end_frame = _transport_frame + nframes; // FIXME: varispeed + no_roll ??
 106         int ret = 0;
 107         bool declick = get_transport_declick_required();
 108         boost::shared_ptr<RouteList> r = routes.reader ();
 109
 110         if (_click_io) {
 111                 _click_io->silence (nframes);
 112         }
 113
 114         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 115
 116                 if ((*i)->is_hidden()) {
 117                         continue;
 118                 }
 119
 120                 (*i)->set_pending_declick (declick);
 121
 122                 if ((*i)->no_roll (nframes, _transport_frame, end_frame, non_realtime_work_pending(),
 123                                    actively_recording(), declick)) {
 124                         error << string_compose(_("Session: error in no roll for %1"), (*i)->name()) << endmsg;
 125                         ret = -1;
 126                         break;
 127                 }
 128         }
 129
 130         return ret;
 131 }
 132
 133 int
 134 Session::process_routes (nframes_t nframes)
 135 {
 136         bool record_active;
 137         int  declick = get_transport_declick_required();
 138         bool rec_monitors = get_rec_monitors_input();
 139         boost::shared_ptr<RouteList> r = routes.reader ();
 140
 141         if (transport_sub_state & StopPendingCapture) {
 142                 /* force a declick out */
 143                 declick = -1;
 144         }
 145
 146         record_active = actively_recording(); // || (get_record_enabled() && get_punch_in());
 147
 148         const nframes_t start_frame = _transport_frame;
 149         const nframes_t end_frame = _transport_frame + (nframes_t)floor(nframes * _transport_speed);
 150
 151         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 152
 153                 int ret;
 154
 155                 if ((*i)->is_hidden()) {
 156                         continue;
 157                 }
 158
 159                 (*i)->set_pending_declick (declick);
 160
 161                 if ((ret = (*i)->roll (nframes, start_frame, end_frame, declick, record_active, rec_monitors)) < 0) {
 162
 163                         /* we have to do this here. Route::roll() for an AudioTrack will have called AudioDiskstream::process(),
 164                            and the DS will expect AudioDiskstream::commit() to be called. but we're aborting from that
 165                            call path, so make sure we release any outstanding locks here before we return failure.
 166                         */
 167
 168                         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 169                         for (DiskstreamList::iterator ids = dsl->begin(); ids != dsl->end(); ++ids) {
 170                                 (*ids)->recover ();
 171                         }
 172
 173                         stop_transport ();
 174                         return -1;
 175                 }
 176         }
 177
 178         return 0;
 179 }
 180
 181 int
 182 Session::silent_process_routes (nframes_t nframes)
 183 {
 184         bool record_active = actively_recording();
 185         int  declick = get_transport_declick_required();
 186         bool rec_monitors = get_rec_monitors_input();
 187         boost::shared_ptr<RouteList> r = routes.reader ();
 188
 189         if (transport_sub_state & StopPendingCapture) {
 190                 /* force a declick out */
 191                 declick = -1;
 192         }
 193
 194         const nframes_t start_frame = _transport_frame;
 195         const nframes_t end_frame = _transport_frame + lrintf(nframes * _transport_speed);
 196
 197         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 198
 199                 int ret;
 200
 201                 if ((*i)->is_hidden()) {
 202                         continue;
 203                 }
 204
 205                 if ((ret = (*i)->silent_roll (nframes, start_frame, end_frame, record_active, rec_monitors)) < 0) {
 206
 207                         /* we have to do this here. Route::roll() for an AudioTrack will have called AudioDiskstream::process(),
 208                            and the DS will expect AudioDiskstream::commit() to be called. but we're aborting from that
 209                            call path, so make sure we release any outstanding locks here before we return failure.
 210                         */
 211
 212                         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 213                         for (DiskstreamList::iterator ids = dsl->begin(); ids != dsl->end(); ++ids) {
 214                                 (*ids)->recover ();
 215                         }
 216
 217                         stop_transport ();
 218                         return -1;
 219                 }
 220         }
 221
 222         return 0;
 223 }
 224
 225 void
 226 Session::commit_diskstreams (nframes_t nframes, bool &needs_butler)
 227 {
 228         int dret;
 229         float pworst = 1.0f;
 230         float cworst = 1.0f;
 231
 232         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 233         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 234
 235                 if ((*i)->hidden()) {
 236                         continue;
 237                 }
 238
 239                 /* force all diskstreams not handled by a Route to call do their stuff.
 240                    Note: the diskstreams that were handled by a route will just return zero
 241                    from this call, because they know they were processed. So in fact, this
 242                    also runs commit() for every diskstream.
 243                  */
 244
 245                 if ((dret = (*i)->process (_transport_frame, nframes, actively_recording(), get_rec_monitors_input())) == 0) {
 246                         if ((*i)->commit (nframes)) {
 247                                 needs_butler = true;
 248                         }
 249
 250                 } else if (dret < 0) {
 251                         (*i)->recover();
 252                 }
 253
 254                 pworst = min (pworst, (*i)->playback_buffer_load());
 255                 cworst = min (cworst, (*i)->capture_buffer_load());
 256         }
 257
 258         uint32_t pmin = g_atomic_int_get (&_playback_load);
 259         uint32_t pminold = g_atomic_int_get (&_playback_load_min);
 260         uint32_t cmin = g_atomic_int_get (&_capture_load);
 261         uint32_t cminold = g_atomic_int_get (&_capture_load_min);
 262
 263         g_atomic_int_set (&_playback_load, (uint32_t) floor (pworst * 100.0f));
 264         g_atomic_int_set (&_capture_load, (uint32_t) floor (cworst * 100.0f));
 265         g_atomic_int_set (&_playback_load_min, min (pmin, pminold));
 266         g_atomic_int_set (&_capture_load_min, min (cmin, cminold));
 267
 268         if (actively_recording()) {
 269                 set_dirty();
 270         }
 271 }
 272
 273 /** Process callback used when the auditioner is not active */
 274 void
 275 Session::process_with_events (nframes_t nframes)
 276 {
 277         Event*         ev;
 278         nframes_t      this_nframes;
 279         nframes_t      end_frame;
 280         bool           session_needs_butler = false;
 281         nframes_t      stop_limit;
 282         long           frames_moved;
 283
 284         /* make sure the auditioner is silent */
 285
 286         if (auditioner) {
 287                 auditioner->silence (nframes);
 288         }
 289
 290         /* handle any pending events */
 291
 292         while (pending_events.read (&ev, 1) == 1) {
 293                 merge_event (ev);
 294         }
 295
 296         /* if we are not in the middle of a state change,
 297            and there are immediate events queued up,
 298            process them.
 299         */
 300
 301         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 302                 Event *ev = immediate_events.front ();
 303                 immediate_events.pop_front ();
 304                 process_event (ev);
 305         }
 306
 307         /* Events caused a transport change, send an MTC Full Frame (SMPTE) message.
 308          * This is sent whether rolling or not, to give slaves an idea of ardour time
 309          * on locates (and allow slow slaves to position and prepare for rolling)
 310          */
 311         if (_send_smpte_update) {
 312                 send_full_time_code(nframes);
 313         }
 314
 315         if (!process_can_proceed()) {
 316                 _silent = true;
 317                 return;
 318         }
 319
 320         if (events.empty() || next_event == events.end()) {
 321                 process_without_events (nframes);
 322                 return;
 323         }
 324
 325         /// TODO: Figure out what happens to phi and phase, if transport speed momentarily becomes
 326         /// 1.0 eg. during the adjustments of a slave. If that is a bug, then AudioDiskstream::process
 327         /// is very likely broken too
 328         if (_transport_speed == 1.0) {
 329                 frames_moved = (long) nframes;
 330         } else {
 331                 frames_moved = (long) AudioDiskstream::
 332                         calculate_varispeed_playback_distance(nframes, phase, phi, target_phi);
 333         }
 334
 335         end_frame = _transport_frame + (nframes_t)frames_moved;
 336
 337         {
 338                 Event* this_event;
 339                 Events::iterator the_next_one;
 340
 341                 if (!process_can_proceed()) {
 342                         _silent = true;
 343                         return;
 344                 }
 345
 346                 if (!_exporting && _slave) {
 347                         if (!follow_slave (nframes)) {
 348                                 return;
 349                         }
 350                 }
 351
 352                 if (_transport_speed == 0) {
 353                         no_roll (nframes);
 354                         return;
 355                 }
 356
 357                 if (!_exporting) {
 358                         send_midi_time_code_for_cycle (nframes);
 359                 }
 360
 361                 if (actively_recording()) {
 362                         stop_limit = max_frames;
 363                 } else {
 364
 365                         if (Config->get_stop_at_session_end()) {
 366                                 stop_limit = current_end_frame();
 367                         } else {
 368                                 stop_limit = max_frames;
 369                         }
 370                 }
 371
 372                 if (maybe_stop (stop_limit)) {
 373                         no_roll (nframes);
 374                         return;
 375                 }
 376
 377                 this_event = *next_event;
 378                 the_next_one = next_event;
 379                 ++the_next_one;
 380
 381                 /* yes folks, here it is, the actual loop where we really truly
 382                    process some audio
 383                 */
 384
 385                 while (nframes) {
 386
 387                         this_nframes = nframes; /* real (jack) time relative */
 388
 389                         /* running an event, position transport precisely to its time */
 390                         if (this_event && this_event->action_frame <= end_frame && this_event->action_frame >= _transport_frame) {
 391                                 /* this isn't quite right for reverse play */
 392                                 frames_moved = (long) (this_event->action_frame - _transport_frame);
 393                                 this_nframes = (nframes_t) abs( floor(frames_moved / _transport_speed) );
 394                         }
 395
 396                         if (this_nframes) {
 397
 398                                 click (_transport_frame, this_nframes);
 399
 400                                 /* now process frames between now and the first event in this block */
 401                                 prepare_diskstreams ();
 402
 403                                 if (process_routes (this_nframes)) {
 404                                         fail_roll (nframes);
 405                                         return;
 406                                 }
 407
 408                                 commit_diskstreams (this_nframes, session_needs_butler);
 409
 410                                 nframes -= this_nframes;
 411
 412                                 if (frames_moved < 0) {
 413                                         decrement_transport_position (-frames_moved);
 414                                 } else {
 415                                         increment_transport_position (frames_moved);
 416                                 }
 417
 418                                 maybe_stop (stop_limit);
 419                                 check_declick_out ();
 420                         }
 421
 422                         _engine.split_cycle (this_nframes);
 423
 424                         /* now handle this event and all others scheduled for the same time */
 425
 426                         while (this_event && this_event->action_frame == _transport_frame) {
 427                                 process_event (this_event);
 428
 429                                 if (the_next_one == events.end()) {
 430                                         this_event = 0;
 431                                 } else {
 432                                         this_event = *the_next_one;
 433                                         ++the_next_one;
 434                                 }
 435                         }
 436
 437                         /* if an event left our state changing, do the right thing */
 438
 439                         if (nframes && non_realtime_work_pending()) {
 440                                 no_roll (nframes);
 441                                 break;
 442                         }
 443
 444                         /* this is necessary to handle the case of seamless looping */
 445                         end_frame = _transport_frame + (nframes_t) floor (nframes * _transport_speed);
 446
 447                 }
 448
 449                 set_next_event ();
 450
 451         } /* implicit release of route lock */
 452
 453         if (session_needs_butler)
 454                 summon_butler ();
 455 }
 456
 457 void
 458 Session::reset_slave_state ()
 459 {
 460         average_slave_delta = 1800;
 461         delta_accumulator_cnt = 0;
 462         have_first_delta_accumulator = false;
 463         slave_state = Stopped;
 464 }
 465
 466 bool
 467 Session::transport_locked () const
 468 {
 469         Slave* sl = _slave;
 470
 471         if (!locate_pending() && ((Config->get_slave_source() == None) || (sl && sl->ok() && sl->locked()))) {
 472                 return true;
 473         }
 474
 475         return false;
 476 }
 477
 478 bool
 479 Session::follow_slave (nframes_t nframes)
 480 {
 481         double slave_speed;
 482         nframes_t slave_transport_frame;
 483         nframes_t this_delta;
 484         int dir;
 485         bool starting;
 486
 487         if (!_slave->ok()) {
 488                 stop_transport ();
 489                 Config->set_slave_source (None);
 490                 goto noroll;
 491         }
 492
 493         _slave->speed_and_position (slave_speed, slave_transport_frame);
 494
 495         if (!_slave->locked()) {
 496                 goto noroll;
 497         }
 498
 499         if (slave_transport_frame > _transport_frame) {
 500                 this_delta = slave_transport_frame - _transport_frame;
 501                 dir = 1;
 502         } else {
 503                 this_delta = _transport_frame - slave_transport_frame;
 504                 dir = -1;
 505         }
 506
 507         if ((starting = _slave->starting())) {
 508                 slave_speed = 0.0f;
 509         }
 510
 511         if (_slave->is_always_synced() || config.get_timecode_source_is_synced()) {
 512
 513                 /* if the TC source is synced, then we assume that its
 514                    speed is binary: 0.0 or 1.0
 515                 */
 516
 517                 if (slave_speed != 0.0f) {
 518                         slave_speed = 1.0f;
 519                 }
 520
 521         } else {
 522
 523                 /* TC source is able to drift relative to us (slave)
 524                    so we need to keep track of the drift and adjust
 525                    our speed to remain locked.
 526                 */
 527
 528                 calculate_moving_average_of_slave_delta(dir, this_delta);
 529         }
 530
 531         track_slave_state(slave_speed, slave_transport_frame, this_delta, starting);
 532
 533         if (slave_state == Running && !_slave->is_always_synced() && !config.get_timecode_source_is_synced()) {
 534
 535                 if (_transport_speed != 0.0f) {
 536
 537                         /*
 538                            note that average_dir is +1 or -1
 539                         */
 540
 541                         float delta;
 542
 543                         #ifdef USE_MOVING_AVERAGE_OF_SLAVE
 544                                 if (average_slave_delta == 0) {
 545                                         delta = this_delta;
 546                                         delta *= dir;
 547                                 } else {
 548                                         delta = average_slave_delta;
 549                                         delta *= average_dir;
 550                                 }
 551                         #else
 552                                 delta = this_delta;
 553                                 delta *= dir;
 554                         #endif
 555
 556                         float adjusted_speed = slave_speed + (delta /  float(_current_frame_rate));
 557
 558                         if (_slave->give_slave_full_control_over_transport_speed()) {
 559                                 request_transport_speed(slave_speed);
 560                         } else {
 561                                 request_transport_speed(adjusted_speed);
 562                                 #ifdef DEBUG_SLAVES
 563                                 cerr << "adjust using " << delta
 564                                          << " towards " << adjusted_speed
 565                                          << " ratio = " << adjusted_speed / slave_speed
 566                                          << " current = " << _transport_speed
 567                                          << " slave @ " << slave_speed
 568                                          << endl;
 569                                 #endif
 570                         }
 571
 572                         if (abs(average_slave_delta) > (long) _slave->resolution()) {
 573                                 cerr << "average slave delta greater than slave resolution, going to silent motion\n";
 574                                 goto silent_motion;
 575                         }
 576                 }
 577         }
 578
 579         #ifdef DEBUG_SLAVES
 580         if (slave_speed != 0.0)
 581         cerr << "delta = " << (int) (dir * this_delta)
 582                  << " speed = " << slave_speed
 583                  << " ts = " << _transport_speed
 584                  << " M@ "<< slave_transport_frame << " S@ " << _transport_frame
 585                  << " avgdelta = " << average_slave_delta
 586                  << endl;
 587         #endif
 588
 589         if (!starting && !non_realtime_work_pending()) {
 590                 /* speed is set, we're locked, and good to go */
 591                 return true;
 592         }
 593
 594   silent_motion:
 595         #ifdef DEBUG_SLAVES
 596         cerr << "reached silent_motion:" <<endl;
 597         #endif
 598
 599         follow_slave_silently (nframes, slave_speed);
 600
 601   noroll:
 602         /* don't move at all */
 603         #ifdef DEBUG_SLAVES
 604         cerr << "reached no_roll:" <<endl;
 605         #endif
 606         no_roll (nframes);
 607         return false;
 608 }
 609
 610 void
 611 Session::calculate_moving_average_of_slave_delta(int dir, nframes_t this_delta)
 612 {
 613         if (delta_accumulator_cnt >= delta_accumulator_size) {
 614                 have_first_delta_accumulator = true;
 615                 delta_accumulator_cnt = 0;
 616         }
 617
 618         if (delta_accumulator_cnt != 0 || this_delta < _current_frame_rate) {
 619                 delta_accumulator[delta_accumulator_cnt++] = long(dir) * long(this_delta);
 620         }
 621
 622         if (have_first_delta_accumulator) {
 623                 average_slave_delta = 0L;
 624                 for (int i = 0; i < delta_accumulator_size; ++i) {
 625                         average_slave_delta += delta_accumulator[i];
 626                 }
 627                 average_slave_delta /= long(delta_accumulator_size);
 628                 if (average_slave_delta < 0L) {
 629                         average_dir = -1;
 630                         average_slave_delta = abs(average_slave_delta);
 631                 } else {
 632                         average_dir = 1;
 633                 }
 634         }
 635 }
 636
 637 void
 638 Session::track_slave_state(
 639                 float slave_speed,
 640                 nframes_t slave_transport_frame,
 641                 nframes_t this_delta,
 642                 bool starting)
 643 {
 644         if (slave_speed != 0.0f) {
 645
 646                 /* slave is running */
 647
 648                 switch (slave_state) {
 649                 case Stopped:
 650                         if (_slave->requires_seekahead()) {
 651                                 slave_wait_end = slave_transport_frame + _current_frame_rate;
 652                                 locate (slave_wait_end, false, false);
 653                                 slave_state = Waiting;
 654                                 starting = true;
 655
 656                         } else {
 657
 658                                 slave_state = Running;
 659
 660                                 Location* al = _locations.auto_loop_location();
 661
 662                                 if (al && play_loop && (slave_transport_frame < al->start() || slave_transport_frame > al->end())) {
 663                                         // cancel looping
 664                                         request_play_loop(false);
 665                                 }
 666
 667                                 if (slave_transport_frame != _transport_frame) {
 668                                         locate (slave_transport_frame, false, false);
 669                                 }
 670                         }
 671                         break;
 672
 673                 case Waiting:
 674                         break;
 675
 676                 default:
 677                         break;
 678
 679                 }
 680
 681                 if (slave_state == Waiting) {
 682
 683                 #ifdef DEBUG_SLAVES
 684                         cerr << "waiting at " << slave_transport_frame << endl;
 685                 #endif
 686                         if (slave_transport_frame >= slave_wait_end) {
 687 #ifdef DEBUG_SLAVES
 688                                 cerr << "\tstart at " << _transport_frame << endl;
 689 #endif
 690                                 slave_state = Running;
 691
 692                                 bool ok = true;
 693                                 nframes_t frame_delta = slave_transport_frame - _transport_frame;
 694
 695                                 boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 696
 697                                 for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 698                                         if (!(*i)->can_internal_playback_seek (frame_delta)) {
 699                                                 ok = false;
 700                                                 break;
 701                                         }
 702                                 }
 703
 704                                 if (ok) {
 705                                         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
 706                                                 (*i)->internal_playback_seek (frame_delta);
 707                                         }
 708                                         _transport_frame += frame_delta;
 709
 710                                 } else {
 711                                         cerr << "cannot micro-seek\n";
 712                                         /* XXX what? */
 713                                 }
 714
 715                                 memset (delta_accumulator, 0, sizeof (long) * delta_accumulator_size);
 716                                 average_slave_delta = 0L;
 717                                 this_delta = 0;
 718                         }
 719                 }
 720
 721                 if (slave_state == Running && _transport_speed == 0.0f) {
 722
 723         #ifdef DEBUG_SLAVES
 724                         cerr << "slave starts transport\n";
 725         #endif
 726                         start_transport ();
 727                 }
 728
 729         } else { // slave_speed is 0
 730
 731                 /* slave has stopped */
 732
 733                 if (_transport_speed != 0.0f) {
 734
 735          #ifdef DEBUG_SLAVES
 736                         cerr << "slave stops transport: " << slave_speed << " frame: " << slave_transport_frame
 737                              << " tf = " << _transport_frame << endl;
 738          #endif
 739
 740                         stop_transport();
 741                 }
 742
 743                 if (slave_transport_frame != _transport_frame) {
 744         #ifdef DEBUG_SLAVES
 745                         cerr << "slave stopped, move to " << slave_transport_frame << endl;
 746         #endif
 747                         force_locate (slave_transport_frame, false);
 748                 }
 749
 750                 slave_state = Stopped;
 751         }
 752 }
 753
 754 void
 755 Session::follow_slave_silently (nframes_t nframes, float slave_speed)
 756 {
 757         if (slave_speed && _transport_speed) {
 758
 759                 /* something isn't right, but we should move with the master
 760                    for now.
 761                 */
 762
 763                 bool need_butler;
 764
 765                 prepare_diskstreams ();
 766                 silent_process_routes (nframes);
 767                 commit_diskstreams (nframes, need_butler);
 768
 769                 if (need_butler) {
 770                         summon_butler ();
 771                 }
 772
 773                 int32_t frames_moved = (int32_t) floor (_transport_speed * nframes);
 774
 775                 if (frames_moved < 0) {
 776                         decrement_transport_position (-frames_moved);
 777                 } else {
 778                         increment_transport_position (frames_moved);
 779                 }
 780
 781                 nframes_t stop_limit;
 782
 783                 if (actively_recording()) {
 784                         stop_limit = max_frames;
 785                 } else {
 786                         if (Config->get_stop_at_session_end()) {
 787                                 stop_limit = current_end_frame();
 788                         } else {
 789                                 stop_limit = max_frames;
 790                         }
 791                 }
 792
 793                 maybe_stop (stop_limit);
 794         }
 795 }
 796
 797 void
 798 Session::process_without_events (nframes_t nframes)
 799 {
 800         bool session_needs_butler = false;
 801         nframes_t stop_limit;
 802         long frames_moved;
 803
 804         if (!process_can_proceed()) {
 805                 _silent = true;
 806                 return;
 807         }
 808
 809         if (!_exporting && _slave) {
 810                 if (!follow_slave (nframes)) {
 811                         return;
 812                 }
 813         }
 814
 815         if (_transport_speed == 0) {
 816                 fail_roll (nframes);
 817                 return;
 818         }
 819
 820         if (!_exporting) {
 821                 send_midi_time_code_for_cycle (nframes);
 822         }
 823
 824         if (actively_recording()) {
 825                 stop_limit = max_frames;
 826         } else {
 827                 if (Config->get_stop_at_session_end()) {
 828                         stop_limit = current_end_frame();
 829                 } else {
 830                         stop_limit = max_frames;
 831                 }
 832         }
 833
 834         if (maybe_stop (stop_limit)) {
 835                 fail_roll (nframes);
 836                 return;
 837         }
 838
 839         if (maybe_sync_start (nframes)) {
 840                 return;
 841         }
 842
 843         click (_transport_frame, nframes);
 844
 845         prepare_diskstreams ();
 846
 847         /// TODO: Figure out what happens to phi and phase, if transport speed momentarily becomes
 848         /// 1.0 eg. during the adjustments of a slave. If that is a bug, then AudioDiskstream::process
 849         /// is very likely broken too
 850         if (_transport_speed == 1.0) {
 851                 frames_moved = (long) nframes;
 852         } else {
 853                 frames_moved = (long) AudioDiskstream::
 854                         calculate_varispeed_playback_distance(nframes, phase, phi, target_phi);
 855         }
 856
 857         if (process_routes (nframes)) {
 858                 fail_roll (nframes);
 859                 return;
 860         }
 861
 862         commit_diskstreams (nframes, session_needs_butler);
 863
 864         if (frames_moved < 0) {
 865                 decrement_transport_position (-frames_moved);
 866         } else {
 867                 increment_transport_position (frames_moved);
 868         }
 869
 870         maybe_stop (stop_limit);
 871         check_declick_out ();
 872
 873         if (session_needs_butler)
 874                 summon_butler ();
 875 }
 876
 877 /** Process callback used when the auditioner is active.
 878  * @param nframes number of frames to process.
 879  */
 880 void
 881 Session::process_audition (nframes_t nframes)
 882 {
 883         Event* ev;
 884         boost::shared_ptr<RouteList> r = routes.reader ();
 885
 886         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 887                 if (!(*i)->is_hidden()) {
 888                         (*i)->silence (nframes);
 889                 }
 890         }
 891
 892         /* run the auditioner, and if it says we need butler service, ask for it */
 893
 894         if (auditioner->play_audition (nframes) > 0) {
 895                 summon_butler ();
 896         }
 897
 898         /* handle pending events */
 899
 900         while (pending_events.read (&ev, 1) == 1) {
 901                 merge_event (ev);
 902         }
 903
 904         /* if we are not in the middle of a state change,
 905            and there are immediate events queued up,
 906            process them.
 907         */
 908
 909         while (!non_realtime_work_pending() && !immediate_events.empty()) {
 910                 Event *ev = immediate_events.front ();
 911                 immediate_events.pop_front ();
 912                 process_event (ev);
 913         }
 914
 915         if (!auditioner->active()) {
 916                 /* auditioner no longer active, so go back to the normal process callback */
 917                 process_function = &Session::process_with_events;
 918         }
 919 }
 920
 921 bool
 922 Session::maybe_sync_start (nframes_t& nframes)
 923 {
 924         nframes_t sync_offset;
 925
 926         if (!waiting_for_sync_offset) {
 927                 return false;
 928         }
 929
 930         if (_engine.get_sync_offset (sync_offset) && sync_offset < nframes) {
 931
 932                 /* generate silence up to the sync point, then
 933                    adjust nframes + offset to reflect whatever
 934                    is left to do.
 935                 */
 936
 937                 no_roll (sync_offset);
 938                 nframes -= sync_offset;
 939                 Port::increment_port_offset (sync_offset);
 940                 waiting_for_sync_offset = false;
 941
 942                 if (nframes == 0) {
 943                         return true; // done, nothing left to process
 944                 }
 945
 946         } else {
 947
 948                 /* sync offset point is not within this process()
 949                    cycle, so just generate silence. and don't bother
 950                    with any fancy stuff here, just the minimal silence.
 951                 */
 952
 953                 _silent = true;
 954
 955                 if (Config->get_locate_while_waiting_for_sync()) {
 956                         if (micro_locate (nframes)) {
 957                                 /* XXX ERROR !!! XXX */
 958                         }
 959                 }
 960
 961                 return true; // done, nothing left to process
 962         }
 963
 964         return false;
 965 }
 966