Move butler methods from Session to Butler.
[ardour.git] / 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/audio_diskstream.h"
31 #include "ardour/audioengine.h"
32 #include "ardour/auditioner.h"
33 #include "ardour/butler.h"
34 #include "ardour/cycle_timer.h"
35 #include "ardour/cycles.h"
36 #include "ardour/session.h"
37 #include "ardour/slave.h"
38 #include "ardour/timestamps.h"
39
40 #include "midi++/manager.h"
41
42 #include "i18n.h"
43
44 using namespace ARDOUR;
45 using namespace PBD;
46 using namespace std;
47
48 /** Called by the audio engine when there is work to be done with JACK.
49  * @param nframes Number of frames to process.
50  */
51 void
52 Session::process (nframes_t nframes)
53 {
54         // This is no more the appropriate place to call cycle
55         // start. cycle_start needs to be called at the Route::roll()
56         // where the signals which we want to mixdown have been calculated.
57         //
58         MIDI::Manager::instance()->cycle_start(nframes);
59
60         _silent = false;
61
62         if (processing_blocked()) {
63                 _silent = true;
64                 return;
65         }
66
67         if (non_realtime_work_pending()) {
68                 if (!_butler->transport_work_requested ()) {
69                         post_transport ();
70                 }
71         }
72
73         (this->*process_function) (nframes);
74
75         // the ticker is for sending time information like MidiClock
76         nframes_t transport_frames = transport_frame();
77         BBT_Time  transport_bbt;
78         bbt_time(transport_frames, transport_bbt);
79         SMPTE::Time transport_smpte;
80         smpte_time(transport_frames, transport_smpte);
81         tick (transport_frames, transport_bbt, transport_smpte); /* EMIT SIGNAL */
82
83         SendFeedback (); /* EMIT SIGNAL */
84
85         MIDI::Manager::instance()->cycle_end();
86 }
87
88 void
89 Session::prepare_diskstreams ()
90 {
91         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
92         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
93                 (*i)->prepare ();
94         }
95 }
96
97 int
98 Session::fail_roll (nframes_t nframes)
99 {
100         return no_roll (nframes);
101 }
102
103 int
104 Session::no_roll (nframes_t nframes)
105 {
106         nframes_t end_frame = _transport_frame + nframes; // FIXME: varispeed + no_roll ??
107         int ret = 0;
108         bool declick = get_transport_declick_required();
109         boost::shared_ptr<RouteList> r = routes.reader ();
110
111         if (_click_io) {
112                 _click_io->silence (nframes);
113         }
114
115         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
116
117                 if ((*i)->is_hidden()) {
118                         continue;
119                 }
120
121                 (*i)->set_pending_declick (declick);
122
123                 if ((*i)->no_roll (nframes, _transport_frame, end_frame, non_realtime_work_pending(),
124                                    actively_recording(), declick)) {
125                         error << string_compose(_("Session: error in no roll for %1"), (*i)->name()) << endmsg;
126                         ret = -1;
127                         break;
128                 }
129         }
130
131         return ret;
132 }
133
134 int
135 Session::process_routes (nframes_t nframes)
136 {
137         bool record_active;
138         int  declick = get_transport_declick_required();
139         bool rec_monitors = get_rec_monitors_input();
140         boost::shared_ptr<RouteList> r = routes.reader ();
141
142         if (transport_sub_state & StopPendingCapture) {
143                 /* force a declick out */
144                 declick = -1;
145         }
146
147         record_active = actively_recording(); // || (get_record_enabled() && get_punch_in());
148
149         const nframes_t start_frame = _transport_frame;
150         const nframes_t end_frame = _transport_frame + (nframes_t)floor(nframes * _transport_speed);
151
152         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
153
154                 int ret;
155
156                 if ((*i)->is_hidden()) {
157                         continue;
158                 }
159
160                 (*i)->set_pending_declick (declick);
161
162                 if ((ret = (*i)->roll (nframes, start_frame, end_frame, declick, record_active, rec_monitors)) < 0) {
163
164                         /* we have to do this here. Route::roll() for an AudioTrack will have called AudioDiskstream::process(),
165                            and the DS will expect AudioDiskstream::commit() to be called. but we're aborting from that
166                            call path, so make sure we release any outstanding locks here before we return failure.
167                         */
168
169                         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
170                         for (DiskstreamList::iterator ids = dsl->begin(); ids != dsl->end(); ++ids) {
171                                 (*ids)->recover ();
172                         }
173
174                         stop_transport ();
175                         return -1;
176                 }
177         }
178
179         return 0;
180 }
181
182 int
183 Session::silent_process_routes (nframes_t nframes)
184 {
185         bool record_active = actively_recording();
186         int  declick = get_transport_declick_required();
187         bool rec_monitors = get_rec_monitors_input();
188         boost::shared_ptr<RouteList> r = routes.reader ();
189
190         if (transport_sub_state & StopPendingCapture) {
191                 /* force a declick out */
192                 declick = -1;
193         }
194
195         const nframes_t start_frame = _transport_frame;
196         const nframes_t end_frame = _transport_frame + lrintf(nframes * _transport_speed);
197
198         for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
199
200                 int ret;
201
202                 if ((*i)->is_hidden()) {
203                         continue;
204                 }
205
206                 if ((ret = (*i)->silent_roll (nframes, start_frame, end_frame, record_active, rec_monitors)) < 0) {
207
208                         /* we have to do this here. Route::roll() for an AudioTrack will have called AudioDiskstream::process(),
209                            and the DS will expect AudioDiskstream::commit() to be called. but we're aborting from that
210                            call path, so make sure we release any outstanding locks here before we return failure.
211                         */
212
213                         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
214                         for (DiskstreamList::iterator ids = dsl->begin(); ids != dsl->end(); ++ids) {
215                                 (*ids)->recover ();
216                         }
217
218                         stop_transport ();
219                         return -1;
220                 }
221         }
222
223         return 0;
224 }
225
226 void
227 Session::commit_diskstreams (nframes_t nframes, bool &needs_butler)
228 {
229         int dret;
230         float pworst = 1.0f;
231         float cworst = 1.0f;
232
233         boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
234         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
235
236                 if ((*i)->hidden()) {
237                         continue;
238                 }
239
240                 /* force all diskstreams not handled by a Route to call do their stuff.
241                    Note: the diskstreams that were handled by a route will just return zero
242                    from this call, because they know they were processed. So in fact, this
243                    also runs commit() for every diskstream.
244                  */
245
246                 if ((dret = (*i)->process (_transport_frame, nframes, actively_recording(), get_rec_monitors_input())) == 0) {
247                         if ((*i)->commit (nframes)) {
248                                 needs_butler = true;
249                         }
250
251                 } else if (dret < 0) {
252                         (*i)->recover();
253                 }
254
255                 pworst = min (pworst, (*i)->playback_buffer_load());
256                 cworst = min (cworst, (*i)->capture_buffer_load());
257         }
258
259         uint32_t pmin = g_atomic_int_get (&_playback_load);
260         uint32_t pminold = g_atomic_int_get (&_playback_load_min);
261         uint32_t cmin = g_atomic_int_get (&_capture_load);
262         uint32_t cminold = g_atomic_int_get (&_capture_load_min);
263
264         g_atomic_int_set (&_playback_load, (uint32_t) floor (pworst * 100.0f));
265         g_atomic_int_set (&_capture_load, (uint32_t) floor (cworst * 100.0f));
266         g_atomic_int_set (&_playback_load_min, min (pmin, pminold));
267         g_atomic_int_set (&_capture_load_min, min (cmin, cminold));
268
269         if (actively_recording()) {
270                 set_dirty();
271         }
272 }
273
274 /** Process callback used when the auditioner is not active */
275 void
276 Session::process_with_events (nframes_t nframes)
277 {
278         Event*         ev;
279         nframes_t      this_nframes;
280         nframes_t      end_frame;
281         bool           session_needs_butler = false;
282         nframes_t      stop_limit;
283         long           frames_moved;
284
285         /* make sure the auditioner is silent */
286
287         if (auditioner) {
288                 auditioner->silence (nframes);
289         }
290
291         /* handle any pending events */
292
293         while (pending_events.read (&ev, 1) == 1) {
294                 merge_event (ev);
295         }
296
297         /* if we are not in the middle of a state change,
298            and there are immediate events queued up,
299            process them.
300         */
301
302         while (!non_realtime_work_pending() && !immediate_events.empty()) {
303                 Event *ev = immediate_events.front ();
304                 immediate_events.pop_front ();
305                 process_event (ev);
306         }
307
308         /* Events caused a transport change, send an MTC Full Frame (SMPTE) message.
309          * This is sent whether rolling or not, to give slaves an idea of ardour time
310          * on locates (and allow slow slaves to position and prepare for rolling)
311          */
312         if (_send_smpte_update) {
313                 send_full_time_code(nframes);
314         }
315
316         if (!process_can_proceed()) {
317                 _silent = true;
318                 return;
319         }
320
321         if (events.empty() || next_event == events.end()) {
322                 process_without_events (nframes);
323                 return;
324         }
325
326         if (_transport_speed == 1.0) {
327                 frames_moved = (long) nframes;
328         } else {
329                 interpolation.set_target_speed (fabs(_target_transport_speed));
330                 interpolation.set_speed (fabs(_transport_speed));
331                 frames_moved = (long) interpolation.interpolate (0, nframes, 0, 0);
332         }
333
334         end_frame = _transport_frame + (nframes_t)frames_moved;
335
336         {
337                 Event* this_event;
338                 Events::iterator the_next_one;
339
340                 if (!process_can_proceed()) {
341                         _silent = true;
342                         return;
343                 }
344
345                 if (!_exporting && _slave) {
346                         if (!follow_slave (nframes)) {
347                                 return;
348                         }
349                 }
350
351                 if (_transport_speed == 0) {
352                         no_roll (nframes);
353                         return;
354                 }
355
356                 if (!_exporting) {
357                         send_midi_time_code_for_cycle (nframes);
358                 }
359
360                 if (actively_recording()) {
361                         stop_limit = max_frames;
362                 } else {
363
364                         if (Config->get_stop_at_session_end()) {
365                                 stop_limit = current_end_frame();
366                         } else {
367                                 stop_limit = max_frames;
368                         }
369                 }
370
371                 if (maybe_stop (stop_limit)) {
372                         no_roll (nframes);
373                         return;
374                 }
375
376                 this_event = *next_event;
377                 the_next_one = next_event;
378                 ++the_next_one;
379
380                 /* yes folks, here it is, the actual loop where we really truly
381                    process some audio
382                 */
383
384                 while (nframes) {
385
386                         this_nframes = nframes; /* real (jack) time relative */
387                         frames_moved = (long) floor (_transport_speed * nframes); /* transport 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                 _butler->summon ();
455         }
456 }
457
458 void
459 Session::reset_slave_state ()
460 {
461         average_slave_delta = 1800;
462         delta_accumulator_cnt = 0;
463         have_first_delta_accumulator = false;
464         slave_state = Stopped;
465 }
466
467 bool
468 Session::transport_locked () const
469 {
470         Slave* sl = _slave;
471
472         if (!locate_pending() && ((Config->get_slave_source() == None) || (sl && sl->ok() && sl->locked()))) {
473                 return true;
474         }
475
476         return false;
477 }
478
479 bool
480 Session::follow_slave (nframes_t nframes)
481 {
482         double slave_speed;
483         nframes_t slave_transport_frame;
484         nframes_t this_delta;
485         int dir;
486         bool starting;
487
488         if (!_slave->ok()) {
489                 stop_transport ();
490                 Config->set_slave_source (None);
491                 goto noroll;
492         }
493
494         _slave->speed_and_position (slave_speed, slave_transport_frame);
495
496         if (!_slave->locked()) {
497                 goto noroll;
498         }
499
500         if (slave_transport_frame > _transport_frame) {
501                 this_delta = slave_transport_frame - _transport_frame;
502                 dir = 1;
503         } else {
504                 this_delta = _transport_frame - slave_transport_frame;
505                 dir = -1;
506         }
507
508         if ((starting = _slave->starting())) {
509                 slave_speed = 0.0f;
510         }
511
512         if (_slave->is_always_synced() || config.get_timecode_source_is_synced()) {
513
514                 /* if the TC source is synced, then we assume that its
515                    speed is binary: 0.0 or 1.0
516                 */
517
518                 if (slave_speed != 0.0f) {
519                         slave_speed = 1.0f;
520                 }
521
522         } else {
523
524                 /* TC source is able to drift relative to us (slave)
525                    so we need to keep track of the drift and adjust
526                    our speed to remain locked.
527                 */
528
529                 calculate_moving_average_of_slave_delta(dir, this_delta);
530         }
531
532         track_slave_state(slave_speed, slave_transport_frame, this_delta, starting);
533
534         if (slave_state == Running && !_slave->is_always_synced() && !config.get_timecode_source_is_synced()) {
535
536                 if (_transport_speed != 0.0f) {
537
538                         /*
539                            note that average_dir is +1 or -1
540                         */
541
542                         float delta;
543
544                         #ifdef USE_MOVING_AVERAGE_OF_SLAVE
545                                 if (average_slave_delta == 0) {
546                                         delta = this_delta;
547                                         delta *= dir;
548                                 } else {
549                                         delta = average_slave_delta;
550                                         delta *= average_dir;
551                                 }
552                         #else
553                                 delta = this_delta;
554                                 delta *= dir;
555                         #endif
556
557                         float adjusted_speed = slave_speed + (delta /  float(_current_frame_rate));
558
559                         if (_slave->give_slave_full_control_over_transport_speed()) {
560                                 request_transport_speed(slave_speed);
561                         } else {
562                                 request_transport_speed(adjusted_speed);
563                                 #ifdef DEBUG_SLAVES
564                                 cerr << "adjust using " << delta
565                                          << " towards " << adjusted_speed
566                                          << " ratio = " << adjusted_speed / slave_speed
567                                          << " current = " << _transport_speed
568                                          << " slave @ " << slave_speed
569                                          << endl;
570                                 #endif
571                         }
572
573                         if (abs(average_slave_delta) > (long) _slave->resolution()) {
574                                 cerr << "average slave delta greater than slave resolution, going to silent motion\n";
575                                 goto silent_motion;
576                         }
577                 }
578         }
579
580         #ifdef DEBUG_SLAVES
581         if (slave_speed != 0.0)
582         cerr << "delta = " << (int) (dir * this_delta)
583                  << " speed = " << slave_speed
584                  << " ts = " << _transport_speed
585                  << " M@ "<< slave_transport_frame << " S@ " << _transport_frame
586                  << " avgdelta = " << average_slave_delta
587                  << endl;
588         #endif
589
590         if (!starting && !non_realtime_work_pending()) {
591                 /* speed is set, we're locked, and good to go */
592                 return true;
593         }
594
595   silent_motion:
596         #ifdef DEBUG_SLAVES
597         cerr << "reached silent_motion:" <<endl;
598         #endif
599
600         follow_slave_silently (nframes, slave_speed);
601
602   noroll:
603         /* don't move at all */
604         #ifdef DEBUG_SLAVES
605         cerr << "reached no_roll:" <<endl;
606         #endif
607         no_roll (nframes);
608         return false;
609 }
610
611 void
612 Session::calculate_moving_average_of_slave_delta(int dir, nframes_t this_delta)
613 {
614         if (delta_accumulator_cnt >= delta_accumulator_size) {
615                 have_first_delta_accumulator = true;
616                 delta_accumulator_cnt = 0;
617         }
618
619         if (delta_accumulator_cnt != 0 || this_delta < _current_frame_rate) {
620                 delta_accumulator[delta_accumulator_cnt++] = long(dir) * long(this_delta);
621         }
622
623         if (have_first_delta_accumulator) {
624                 average_slave_delta = 0L;
625                 for (int i = 0; i < delta_accumulator_size; ++i) {
626                         average_slave_delta += delta_accumulator[i];
627                 }
628                 average_slave_delta /= long(delta_accumulator_size);
629                 if (average_slave_delta < 0L) {
630                         average_dir = -1;
631                         average_slave_delta = abs(average_slave_delta);
632                 } else {
633                         average_dir = 1;
634                 }
635         }
636 }
637
638 void
639 Session::track_slave_state(
640                 float slave_speed,
641                 nframes_t slave_transport_frame,
642                 nframes_t this_delta,
643                 bool starting)
644 {
645         if (slave_speed != 0.0f) {
646
647                 /* slave is running */
648
649                 switch (slave_state) {
650                 case Stopped:
651                         if (_slave->requires_seekahead()) {
652                                 slave_wait_end = slave_transport_frame + _current_frame_rate;
653                                 locate (slave_wait_end, false, false);
654                                 slave_state = Waiting;
655                                 starting = true;
656
657                         } else {
658
659                                 slave_state = Running;
660
661                                 Location* al = _locations.auto_loop_location();
662
663                                 if (al && play_loop && (slave_transport_frame < al->start() || slave_transport_frame > al->end())) {
664                                         // cancel looping
665                                         request_play_loop(false);
666                                 }
667
668                                 if (slave_transport_frame != _transport_frame) {
669                                         locate (slave_transport_frame, false, false);
670                                 }
671                         }
672                         break;
673
674                 case Waiting:
675                         break;
676
677                 default:
678                         break;
679
680                 }
681
682                 if (slave_state == Waiting) {
683
684                 #ifdef DEBUG_SLAVES
685                         cerr << "waiting at " << slave_transport_frame << endl;
686                 #endif
687                         if (slave_transport_frame >= slave_wait_end) {
688 #ifdef DEBUG_SLAVES
689                                 cerr << "\tstart at " << _transport_frame << endl;
690 #endif
691                                 slave_state = Running;
692
693                                 bool ok = true;
694                                 nframes_t frame_delta = slave_transport_frame - _transport_frame;
695
696                                 boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
697
698                                 for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
699                                         if (!(*i)->can_internal_playback_seek (frame_delta)) {
700                                                 ok = false;
701                                                 break;
702                                         }
703                                 }
704
705                                 if (ok) {
706                                         for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
707                                                 (*i)->internal_playback_seek (frame_delta);
708                                         }
709                                         _transport_frame += frame_delta;
710
711                                 } else {
712                                         cerr << "cannot micro-seek\n";
713                                         /* XXX what? */
714                                 }
715
716                                 memset (delta_accumulator, 0, sizeof (long) * delta_accumulator_size);
717                                 average_slave_delta = 0L;
718                                 this_delta = 0;
719                         }
720                 }
721
722                 if (slave_state == Running && _transport_speed == 0.0f) {
723
724         #ifdef DEBUG_SLAVES
725                         cerr << "slave starts transport\n";
726         #endif
727                         start_transport ();
728                 }
729
730         } else { // slave_speed is 0
731
732                 /* slave has stopped */
733
734                 if (_transport_speed != 0.0f) {
735
736          #ifdef DEBUG_SLAVES
737                         cerr << "slave stops transport: " << slave_speed << " frame: " << slave_transport_frame
738                              << " tf = " << _transport_frame << endl;
739          #endif
740
741                         stop_transport();
742                 }
743
744                 if (slave_transport_frame != _transport_frame) {
745         #ifdef DEBUG_SLAVES
746                         cerr << "slave stopped, move to " << slave_transport_frame << endl;
747         #endif
748                         force_locate (slave_transport_frame, false);
749                 }
750
751                 slave_state = Stopped;
752         }
753 }
754
755 void
756 Session::follow_slave_silently (nframes_t nframes, float slave_speed)
757 {
758         if (slave_speed && _transport_speed) {
759
760                 /* something isn't right, but we should move with the master
761                    for now.
762                 */
763
764                 bool need_butler;
765
766                 prepare_diskstreams ();
767                 silent_process_routes (nframes);
768                 commit_diskstreams (nframes, need_butler);
769
770                 if (need_butler) {
771                         _butler->summon ();
772                 }
773
774                 int32_t frames_moved = (int32_t) floor (_transport_speed * nframes);
775
776                 if (frames_moved < 0) {
777                         decrement_transport_position (-frames_moved);
778                 } else {
779                         increment_transport_position (frames_moved);
780                 }
781
782                 nframes_t stop_limit;
783
784                 if (actively_recording()) {
785                         stop_limit = max_frames;
786                 } else {
787                         if (Config->get_stop_at_session_end()) {
788                                 stop_limit = current_end_frame();
789                         } else {
790                                 stop_limit = max_frames;
791                         }
792                 }
793
794                 maybe_stop (stop_limit);
795         }
796 }
797
798 void
799 Session::process_without_events (nframes_t nframes)
800 {
801         bool session_needs_butler = false;
802         nframes_t stop_limit;
803         long frames_moved;
804
805         if (!process_can_proceed()) {
806                 _silent = true;
807                 return;
808         }
809
810         if (!_exporting && _slave) {
811                 if (!follow_slave (nframes)) {
812                         return;
813                 }
814         }
815
816         if (_transport_speed == 0) {
817                 fail_roll (nframes);
818                 return;
819         }
820
821         if (!_exporting) {
822                 send_midi_time_code_for_cycle (nframes);
823         }
824
825         if (actively_recording()) {
826                 stop_limit = max_frames;
827         } else {
828                 if (Config->get_stop_at_session_end()) {
829                         stop_limit = current_end_frame();
830                 } else {
831                         stop_limit = max_frames;
832                 }
833         }
834
835         if (maybe_stop (stop_limit)) {
836                 fail_roll (nframes);
837                 return;
838         }
839
840         if (maybe_sync_start (nframes)) {
841                 return;
842         }
843
844         click (_transport_frame, nframes);
845
846         prepare_diskstreams ();
847
848         if (_transport_speed == 1.0) {
849                 frames_moved = (long) nframes;
850         } else {
851                 interpolation.set_target_speed (fabs(_target_transport_speed));
852                 interpolation.set_speed (fabs(_transport_speed));
853                 frames_moved = (long) interpolation.interpolate (0, nframes, 0, 0);
854         }
855
856         if (process_routes (nframes)) {
857                 fail_roll (nframes);
858                 return;
859         }
860
861         commit_diskstreams (nframes, session_needs_butler);
862
863         if (frames_moved < 0) {
864                 decrement_transport_position (-frames_moved);
865         } else {
866                 increment_transport_position (frames_moved);
867         }
868
869         maybe_stop (stop_limit);
870         check_declick_out ();
871
872         if (session_needs_butler) {
873                 _butler->summon ();
874         }
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                 _butler->summon ();
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