libs/ardour/diskstream.cc

   1 /*
   2     Copyright (C) 2000-2006 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 <fstream>
  21 #include <cassert>
  22 #include <cstdio>
  23 #include <unistd.h>
  24 #include <cmath>
  25 #include <cerrno>
  26 #include <string>
  27 #include <climits>
  28 #include <fcntl.h>
  29 #include <cstdlib>
  30 #include <ctime>
  31 #include <sys/stat.h>
  32 #include <sys/mman.h>
  33
  34
  35 #include <glibmm/thread.h>
  36
  37 #include "pbd/error.h"
  38 #include "pbd/basename.h"
  39 #include "pbd/memento_command.h"
  40 #include "pbd/xml++.h"
  41 #include "pbd/stacktrace.h"
  42
  43 #include "ardour/ardour.h"
  44 #include "ardour/audioengine.h"
  45 #include "ardour/debug.h"
  46 #include "ardour/diskstream.h"
  47 #include "ardour/utils.h"
  48 #include "ardour/configuration.h"
  49 #include "ardour/audiofilesource.h"
  50 #include "ardour/send.h"
  51 #include "ardour/pannable.h"
  52 #include "ardour/panner_shell.h"
  53 #include "ardour/playlist.h"
  54 #include "ardour/cycle_timer.h"
  55 #include "ardour/region.h"
  56 #include "ardour/panner.h"
  57 #include "ardour/session.h"
  58 #include "ardour/io.h"
  59 #include "ardour/track.h"
  60
  61 #include "i18n.h"
  62 #include <locale.h>
  63
  64 using namespace std;
  65 using namespace ARDOUR;
  66 using namespace PBD;
  67
  68 /* XXX This goes uninitialized when there is no ~/.config/ardour3 directory.
  69  * I can't figure out why, so this will do for now (just stole the
  70  * default from configuration_vars.h).  0 is not a good value for
  71  * allocating buffer sizes..
  72  */
  73 ARDOUR::framecnt_t Diskstream::disk_io_chunk_frames = 1024 * 256 / sizeof (Sample);
  74
  75 PBD::Signal0<void>                Diskstream::DiskOverrun;
  76 PBD::Signal0<void>                Diskstream::DiskUnderrun;
  77
  78 Diskstream::Diskstream (Session &sess, const string &name, Flag flag)
  79         : SessionObject(sess, name)
  80         , i_am_the_modifier (0)
  81         , _track (0)
  82         , _record_enabled (0)
  83         , _visible_speed (1.0f)
  84         , _actual_speed (1.0f)
  85         , _buffer_reallocation_required (false)
  86         , _seek_required (false)
  87         , force_refill (false)
  88         , capture_start_frame (0)
  89         , capture_captured (0)
  90         , was_recording (false)
  91         , adjust_capture_position (0)
  92         , _capture_offset (0)
  93         , _roll_delay (0)
  94         , first_recordable_frame (max_framepos)
  95         , last_recordable_frame (max_framepos)
  96         , last_possibly_recording (0)
  97         , _alignment_style (ExistingMaterial)
  98         , _alignment_choice (Automatic)
  99         , _scrubbing (false)
 100         , _slaved (false)
 101         , loop_location (0)
 102         , overwrite_frame (0)
 103         , overwrite_offset (0)
 104         , _pending_overwrite (false)
 105         , overwrite_queued (false)
 106         , wrap_buffer_size (0)
 107         , speed_buffer_size (0)
 108         , _speed (1.0)
 109         , _target_speed (_speed)
 110         , file_frame (0)
 111         , playback_sample (0)
 112         , playback_distance (0)
 113         , _read_data_count (0)
 114         , _write_data_count (0)
 115         , in_set_state (false)
 116         , _flags (flag)
 117         , deprecated_io_node (0)
 118 {
 119 }
 120
 121 Diskstream::Diskstream (Session& sess, const XMLNode& /*node*/)
 122         : SessionObject(sess, "unnamed diskstream")
 123         , i_am_the_modifier (0)
 124         , _track (0)
 125         , _record_enabled (0)
 126         , _visible_speed (1.0f)
 127         , _actual_speed (1.0f)
 128         , _buffer_reallocation_required (false)
 129         , _seek_required (false)
 130         , force_refill (false)
 131         , capture_start_frame (0)
 132         , capture_captured (0)
 133         , was_recording (false)
 134         , adjust_capture_position (0)
 135         , _capture_offset (0)
 136         , _roll_delay (0)
 137         , first_recordable_frame (max_framepos)
 138         , last_recordable_frame (max_framepos)
 139         , last_possibly_recording (0)
 140         , _alignment_style (ExistingMaterial)
 141         , _alignment_choice (Automatic)
 142         , _scrubbing (false)
 143         , _slaved (false)
 144         , loop_location (0)
 145         , overwrite_frame (0)
 146         , overwrite_offset (0)
 147         , _pending_overwrite (false)
 148         , overwrite_queued (false)
 149         , wrap_buffer_size (0)
 150         , speed_buffer_size (0)
 151         , _speed (1.0)
 152         , _target_speed (_speed)
 153         , file_frame (0)
 154         , playback_sample (0)
 155         , playback_distance (0)
 156         , _read_data_count (0)
 157         , _write_data_count (0)
 158         , in_set_state (false)
 159         , _flags (Recordable)
 160         , deprecated_io_node (0)
 161 {
 162 }
 163
 164 Diskstream::~Diskstream ()
 165 {
 166         DEBUG_TRACE (DEBUG::Destruction, string_compose ("Diskstream %1 deleted\n", _name));
 167
 168         if (_playlist) {
 169                 _playlist->release ();
 170         }
 171
 172         delete deprecated_io_node;
 173 }
 174
 175 void
 176 Diskstream::set_track (Track* t)
 177 {
 178         _track = t;
 179         _io = _track->input();
 180
 181         ic_connection.disconnect();
 182         _io->changed.connect_same_thread (ic_connection, boost::bind (&Diskstream::handle_input_change, this, _1, _2));
 183
 184         if (_io->n_ports() != ChanCount::ZERO) {
 185                 input_change_pending.type = IOChange::Type (IOChange::ConfigurationChanged|IOChange::ConnectionsChanged);
 186                 non_realtime_input_change ();
 187         }
 188
 189         _track->Destroyed.connect_same_thread (*this, boost::bind (&Diskstream::route_going_away, this));
 190 }
 191
 192 void
 193 Diskstream::handle_input_change (IOChange change, void * /*src*/)
 194 {
 195         Glib::Mutex::Lock lm (state_lock);
 196
 197         if (change.type & (IOChange::ConfigurationChanged|IOChange::ConnectionsChanged)) {
 198
 199                 /* rather than handle this here on a DS-by-DS basis we defer to the
 200                    session transport/butler thread, and let it tackle
 201                    as many diskstreams as need it in one shot. this avoids many repeated
 202                    takings of the audioengine process lock.
 203                 */
 204
 205                 if (!(input_change_pending.type & change.type)) {
 206                         input_change_pending.type = IOChange::Type (input_change_pending.type | change.type);
 207                         _session.request_input_change_handling ();
 208                 }
 209         }
 210 }
 211
 212 void
 213 Diskstream::non_realtime_set_speed ()
 214 {
 215         if (_buffer_reallocation_required)
 216         {
 217                 Glib::Mutex::Lock lm (state_lock);
 218                 allocate_temporary_buffers ();
 219
 220                 _buffer_reallocation_required = false;
 221         }
 222
 223         if (_seek_required) {
 224                 if (speed() != 1.0f || speed() != -1.0f) {
 225                         seek ((framepos_t) (_session.transport_frame() * (double) speed()), true);
 226                 }
 227                 else {
 228                         seek (_session.transport_frame(), true);
 229                 }
 230
 231                 _seek_required = false;
 232         }
 233 }
 234
 235 bool
 236 Diskstream::realtime_set_speed (double sp, bool global)
 237 {
 238         bool changed = false;
 239         double new_speed = sp * _session.transport_speed();
 240
 241         if (_visible_speed != sp) {
 242                 _visible_speed = sp;
 243                 changed = true;
 244         }
 245
 246         if (new_speed != _actual_speed) {
 247
 248                 framecnt_t required_wrap_size = (framecnt_t) floor (_session.get_block_size() *
 249                                                                   fabs (new_speed)) + 1;
 250
 251                 if (required_wrap_size > wrap_buffer_size) {
 252                         _buffer_reallocation_required = true;
 253                 }
 254
 255                 _actual_speed = new_speed;
 256                 _target_speed = fabs(_actual_speed);
 257         }
 258
 259         if (changed) {
 260                 if (!global) {
 261                         _seek_required = true;
 262                 }
 263                 SpeedChanged (); /* EMIT SIGNAL */
 264         }
 265
 266         return _buffer_reallocation_required || _seek_required;
 267 }
 268
 269 void
 270 Diskstream::set_capture_offset ()
 271 {
 272         if (_io == 0) {
 273                 /* can't capture, so forget it */
 274                 return;
 275         }
 276
 277         _capture_offset = _io->latency();
 278         DEBUG_TRACE (DEBUG::CaptureAlignment, string_compose ("%1: using IO latency, capture offset set to %2\n", name(), _capture_offset));
 279 }
 280
 281
 282 void
 283 Diskstream::set_align_style (AlignStyle a, bool force)
 284 {
 285         if (record_enabled() && _session.actively_recording()) {
 286                 return;
 287         }
 288
 289         if ((a != _alignment_style) || force) {
 290                 _alignment_style = a;
 291                 AlignmentStyleChanged ();
 292         }
 293 }
 294
 295 void
 296 Diskstream::set_align_choice (AlignChoice a, bool force)
 297 {
 298         if (record_enabled() && _session.actively_recording()) {
 299                 return;
 300         }
 301
 302         if ((a != _alignment_choice) || force) {
 303                 _alignment_choice = a;
 304
 305                 switch (_alignment_choice) {
 306                 case Automatic:
 307                         set_align_style_from_io ();
 308                         break;
 309                 case UseExistingMaterial:
 310                         set_align_style (ExistingMaterial);
 311                         break;
 312                 case UseCaptureTime:
 313                         set_align_style (CaptureTime);
 314                         break;
 315                 }
 316         }
 317 }
 318
 319 int
 320 Diskstream::set_loop (Location *location)
 321 {
 322         if (location) {
 323                 if (location->start() >= location->end()) {
 324                         error << string_compose(_("Location \"%1\" not valid for track loop (start >= end)"), location->name()) << endl;
 325                         return -1;
 326                 }
 327         }
 328
 329         loop_location = location;
 330
 331         LoopSet (location); /* EMIT SIGNAL */
 332         return 0;
 333 }
 334
 335 /** Get the start position (in session frames) of the nth capture in the current pass */
 336 ARDOUR::framepos_t
 337 Diskstream::get_capture_start_frame (uint32_t n) const
 338 {
 339         Glib::Mutex::Lock lm (capture_info_lock);
 340
 341         if (capture_info.size() > n) {
 342                 /* this is a completed capture */
 343                 return capture_info[n]->start;
 344         } else {
 345                 /* this is the currently in-progress capture */
 346                 return capture_start_frame;
 347         }
 348 }
 349
 350 ARDOUR::framecnt_t
 351 Diskstream::get_captured_frames (uint32_t n) const
 352 {
 353         Glib::Mutex::Lock lm (capture_info_lock);
 354
 355         if (capture_info.size() > n) {
 356                 /* this is a completed capture */
 357                 return capture_info[n]->frames;
 358         } else {
 359                 /* this is the currently in-progress capture */
 360                 return capture_captured;
 361         }
 362 }
 363
 364 void
 365 Diskstream::set_roll_delay (ARDOUR::framecnt_t nframes)
 366 {
 367         _roll_delay = nframes;
 368 }
 369
 370 int
 371 Diskstream::use_playlist (boost::shared_ptr<Playlist> playlist)
 372 {
 373         if (!playlist) {
 374                 return 0;
 375         }
 376
 377         bool prior_playlist = false;
 378
 379         {
 380                 Glib::Mutex::Lock lm (state_lock);
 381
 382                 if (playlist == _playlist) {
 383                         return 0;
 384                 }
 385
 386                 playlist_connections.drop_connections ();
 387
 388                 if (_playlist) {
 389                         _playlist->release();
 390                         prior_playlist = true;
 391                 }
 392
 393                 _playlist = playlist;
 394                 _playlist->use();
 395
 396                 if (!in_set_state && recordable()) {
 397                         reset_write_sources (false);
 398                 }
 399
 400                 _playlist->ContentsChanged.connect_same_thread (playlist_connections, boost::bind (&Diskstream::playlist_modified, this));
 401                 _playlist->DropReferences.connect_same_thread (playlist_connections, boost::bind (&Diskstream::playlist_deleted, this, boost::weak_ptr<Playlist>(_playlist)));
 402                 _playlist->RangesMoved.connect_same_thread (playlist_connections, boost::bind (&Diskstream::playlist_ranges_moved, this, _1, _2));
 403         }
 404
 405         /* don't do this if we've already asked for it *or* if we are setting up
 406            the diskstream for the very first time - the input changed handling will
 407            take care of the buffer refill.
 408         */
 409
 410         if (!overwrite_queued && prior_playlist) {
 411                 _session.request_overwrite_buffer (_track);
 412                 overwrite_queued = true;
 413         }
 414
 415         PlaylistChanged (); /* EMIT SIGNAL */
 416         _session.set_dirty ();
 417
 418         return 0;
 419 }
 420
 421 void
 422 Diskstream::playlist_changed (const PropertyChange&)
 423 {
 424         playlist_modified ();
 425 }
 426
 427 void
 428 Diskstream::playlist_modified ()
 429 {
 430         if (!i_am_the_modifier && !overwrite_queued) {
 431                 _session.request_overwrite_buffer (_track);
 432                 overwrite_queued = true;
 433         }
 434 }
 435
 436 void
 437 Diskstream::playlist_deleted (boost::weak_ptr<Playlist> wpl)
 438 {
 439         boost::shared_ptr<Playlist> pl (wpl.lock());
 440
 441         if (pl == _playlist) {
 442
 443                 /* this catches an ordering issue with session destruction. playlists
 444                    are destroyed before diskstreams. we have to invalidate any handles
 445                    we have to the playlist.
 446                 */
 447
 448                 if (_playlist) {
 449                         _playlist.reset ();
 450                 }
 451         }
 452 }
 453
 454 bool
 455 Diskstream::set_name (const string& str)
 456 {
 457         if (_name != str) {
 458                 assert(playlist());
 459                 playlist()->set_name (str);
 460                 SessionObject::set_name(str);
 461         }
 462         return true;
 463 }
 464
 465 XMLNode&
 466 Diskstream::get_state ()
 467 {
 468         XMLNode* node = new XMLNode ("Diskstream");
 469         char buf[64];
 470         LocaleGuard lg (X_("POSIX"));
 471
 472         node->add_property ("flags", enum_2_string (_flags));
 473         node->add_property ("playlist", _playlist->name());
 474         node->add_property("name", _name);
 475         id().print (buf, sizeof (buf));
 476         node->add_property("id", buf);
 477         snprintf (buf, sizeof(buf), "%f", _visible_speed);
 478         node->add_property ("speed", buf);
 479         node->add_property ("capture-alignment", enum_2_string (_alignment_choice));
 480
 481         if (_extra_xml) {
 482                 node->add_child_copy (*_extra_xml);
 483         }
 484
 485         return *node;
 486 }
 487
 488 int
 489 Diskstream::set_state (const XMLNode& node, int /*version*/)
 490 {
 491         const XMLProperty* prop;
 492
 493         if ((prop = node.property ("name")) != 0) {
 494                 _name = prop->value();
 495         }
 496
 497         if (deprecated_io_node) {
 498                 if ((prop = deprecated_io_node->property ("id")) != 0) {
 499                         _id = prop->value ();
 500                 }
 501         } else {
 502                 if ((prop = node.property ("id")) != 0) {
 503                         _id = prop->value ();
 504                 }
 505         }
 506
 507         if ((prop = node.property ("flags")) != 0) {
 508                 _flags = Flag (string_2_enum (prop->value(), _flags));
 509         }
 510
 511         if ((prop = node.property (X_("capture-alignment"))) != 0) {
 512                 set_align_choice (AlignChoice (string_2_enum (prop->value(), _alignment_choice)), true);
 513         } else {
 514                 set_align_choice (Automatic, true);
 515         }
 516
 517         if ((prop = node.property ("playlist")) == 0) {
 518                 return -1;
 519         }
 520
 521         {
 522                 bool had_playlist = (_playlist != 0);
 523
 524                 if (find_and_use_playlist (prop->value())) {
 525                         return -1;
 526                 }
 527
 528                 if (!had_playlist) {
 529                         _playlist->set_orig_diskstream_id (id());
 530                 }
 531         }
 532
 533         if ((prop = node.property ("speed")) != 0) {
 534                 double sp = atof (prop->value().c_str());
 535
 536                 if (realtime_set_speed (sp, false)) {
 537                         non_realtime_set_speed ();
 538                 }
 539         }
 540
 541         return 0;
 542 }
 543
 544 void
 545 Diskstream::playlist_ranges_moved (list< Evoral::RangeMove<framepos_t> > const & movements_frames, bool from_undo)
 546 {
 547         /* If we're coming from an undo, it will have handled
 548            automation undo (it must, since automation-follows-regions
 549            can lose automation data).  Hence we can do nothing here.
 550         */
 551
 552         if (from_undo) {
 553                 return;
 554         }
 555
 556         if (!_track || Config->get_automation_follows_regions () == false) {
 557                 return;
 558         }
 559
 560         list< Evoral::RangeMove<double> > movements;
 561
 562         for (list< Evoral::RangeMove<framepos_t> >::const_iterator i = movements_frames.begin();
 563              i != movements_frames.end();
 564              ++i) {
 565
 566                 movements.push_back(Evoral::RangeMove<double>(i->from, i->length, i->to));
 567         }
 568
 569         /* move panner automation */
 570         boost::shared_ptr<Pannable> pannable = _track->pannable();
 571         Evoral::ControlSet::Controls& c (pannable->controls());
 572
 573         for (Evoral::ControlSet::Controls::iterator ci = c.begin(); ci != c.end(); ++ci) {
 574                 boost::shared_ptr<AutomationControl> ac = boost::dynamic_pointer_cast<AutomationControl>(ci->second);
 575                 if (!ac) {
 576                         continue;
 577                 }
 578                 boost::shared_ptr<AutomationList> alist = ac->alist();
 579
 580                 XMLNode & before = alist->get_state ();
 581                 bool const things_moved = alist->move_ranges (movements);
 582                 if (things_moved) {
 583                         _session.add_command (new MementoCommand<AutomationList> (
 584                                                       *alist.get(), &before, &alist->get_state ()));
 585                 }
 586         }
 587
 588         /* move processor automation */
 589         _track->foreach_processor (boost::bind (&Diskstream::move_processor_automation, this, _1, movements_frames));
 590 }
 591
 592 void
 593 Diskstream::move_processor_automation (boost::weak_ptr<Processor> p, list< Evoral::RangeMove<framepos_t> > const & movements_frames)
 594 {
 595         boost::shared_ptr<Processor> processor (p.lock ());
 596         if (!processor) {
 597                 return;
 598         }
 599
 600         list< Evoral::RangeMove<double> > movements;
 601         for (list< Evoral::RangeMove<framepos_t> >::const_iterator i = movements_frames.begin(); i != movements_frames.end(); ++i) {
 602                 movements.push_back(Evoral::RangeMove<double>(i->from, i->length, i->to));
 603         }
 604
 605         set<Evoral::Parameter> const a = processor->what_can_be_automated ();
 606
 607         for (set<Evoral::Parameter>::iterator i = a.begin (); i != a.end (); ++i) {
 608                 boost::shared_ptr<AutomationList> al = processor->automation_control(*i)->alist();
 609                 XMLNode & before = al->get_state ();
 610                 bool const things_moved = al->move_ranges (movements);
 611                 if (things_moved) {
 612                         _session.add_command (
 613                                 new MementoCommand<AutomationList> (
 614                                         *al.get(), &before, &al->get_state ()
 615                                         )
 616                                 );
 617                 }
 618         }
 619 }
 620
 621 void
 622 Diskstream::check_record_status (framepos_t transport_frame, bool can_record)
 623 {
 624         int possibly_recording;
 625         int rolling;
 626         int change;
 627         const int transport_rolling = 0x4;
 628         const int track_rec_enabled = 0x2;
 629         const int global_rec_enabled = 0x1;
 630         const int fully_rec_enabled = (transport_rolling|track_rec_enabled|global_rec_enabled);
 631
 632         /* merge together the 3 factors that affect record status, and compute
 633            what has changed.
 634         */
 635
 636         rolling = _session.transport_speed() != 0.0f;
 637         possibly_recording = (rolling << 2) | (record_enabled() << 1) | can_record;
 638         change = possibly_recording ^ last_possibly_recording;
 639
 640         if (possibly_recording == last_possibly_recording) {
 641                 return;
 642         }
 643
 644         framecnt_t existing_material_offset = _session.worst_playback_latency();
 645
 646         if (possibly_recording == fully_rec_enabled) {
 647
 648                 if (last_possibly_recording == fully_rec_enabled) {
 649                         return;
 650                 }
 651
 652                 capture_start_frame = _session.transport_frame();
 653                 first_recordable_frame = capture_start_frame + _capture_offset;
 654                 last_recordable_frame = max_framepos;
 655
 656                 DEBUG_TRACE (DEBUG::CaptureAlignment, string_compose ("%1: @ %7 (%9) FRF = %2 CSF = %4 CO = %5, EMO = %6 RD = %8 WOL %10 WTL %11\n",
 657                                                                       name(), first_recordable_frame, last_recordable_frame, capture_start_frame,
 658                                                                       _capture_offset,
 659                                                                       existing_material_offset,
 660                                                                       transport_frame,
 661                                                                       _roll_delay,
 662                                                                       _session.transport_frame(),
 663                                                                       _session.worst_output_latency(),
 664                                                                       _session.worst_track_latency()));
 665
 666
 667                 if (_alignment_style == ExistingMaterial) {
 668                         first_recordable_frame += existing_material_offset;
 669                         DEBUG_TRACE (DEBUG::CaptureAlignment, string_compose ("\tshift FRF by EMO %1\n",
 670                                                                               first_recordable_frame));
 671                 }
 672
 673                 prepare_record_status (capture_start_frame);
 674
 675         } else {
 676
 677                 if (last_possibly_recording == fully_rec_enabled) {
 678
 679                         /* we were recording last time */
 680
 681                         if (change & transport_rolling) {
 682
 683                                 /* transport-change (stopped rolling): last_recordable_frame was set in ::prepare_to_stop(). We
 684                                    had to set it there because we likely rolled past the stopping point to declick out,
 685                                    and then backed up.
 686                                  */
 687
 688                         } else {
 689                                 /* punch out */
 690
 691                                 last_recordable_frame = _session.transport_frame() + _capture_offset;
 692
 693                                 if (_alignment_style == ExistingMaterial) {
 694                                         last_recordable_frame += existing_material_offset;
 695                                 }
 696                         }
 697                 }
 698         }
 699
 700         last_possibly_recording = possibly_recording;
 701 }
 702
 703 void
 704 Diskstream::route_going_away ()
 705 {
 706         _io.reset ();
 707 }
 708
 709 void
 710 Diskstream::calculate_record_range(OverlapType ot, framepos_t transport_frame, framecnt_t nframes,
 711                                    framecnt_t & rec_nframes, framecnt_t & rec_offset)
 712 {
 713         switch (ot) {
 714         case OverlapNone:
 715                 rec_nframes = 0;
 716                 break;
 717
 718         case OverlapInternal:
 719                 /*     ----------    recrange
 720                          |---|       transrange
 721                 */
 722                 rec_nframes = nframes;
 723                 rec_offset = 0;
 724                 break;
 725
 726         case OverlapStart:
 727                 /*    |--------|    recrange
 728                 -----|          transrange
 729                 */
 730                 rec_nframes = transport_frame + nframes - first_recordable_frame;
 731                 if (rec_nframes) {
 732                         rec_offset = first_recordable_frame - transport_frame;
 733                 }
 734                 break;
 735
 736         case OverlapEnd:
 737                 /*    |--------|    recrange
 738                          |--------  transrange
 739                 */
 740                 rec_nframes = last_recordable_frame - transport_frame;
 741                 rec_offset = 0;
 742                 break;
 743
 744         case OverlapExternal:
 745                 /*    |--------|    recrange
 746                     --------------  transrange
 747                 */
 748                 rec_nframes = last_recordable_frame - first_recordable_frame;
 749                 rec_offset = first_recordable_frame - transport_frame;
 750                 break;
 751         }
 752
 753         DEBUG_TRACE (DEBUG::CaptureAlignment, string_compose ("%1 rec? %2 @ %3 (for %4) FRF %5 LRF %6 : rf %7 @ %8\n",
 754                                                               _name, enum_2_string (ot), transport_frame, nframes,
 755                                                               first_recordable_frame, last_recordable_frame, rec_nframes, rec_offset));
 756 }
 757
 758 void
 759 Diskstream::prepare_to_stop (framepos_t pos)
 760 {
 761         last_recordable_frame = pos + _capture_offset;
 762 }