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