libs/ardour/audio_track.cc

   1 /*
   2     Copyright (C) 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 <boost/scoped_array.hpp>
  21
  22 #include "pbd/boost_debug.h"
  23 #include "pbd/enumwriter.h"
  24 #include "pbd/error.h"
  25
  26 #include "evoral/Curve.hpp"
  27
  28 #include "ardour/amp.h"
  29 #include "ardour/audio_buffer.h"
  30 #include "ardour/audio_diskstream.h"
  31 #include "ardour/audio_track.h"
  32 #include "ardour/audioplaylist.h"
  33 #include "ardour/buffer_set.h"
  34 #include "ardour/delivery.h"
  35 #include "ardour/meter.h"
  36 #include "ardour/playlist_factory.h"
  37 #include "ardour/processor.h"
  38 #include "ardour/profile.h"
  39 #include "ardour/region.h"
  40 #include "ardour/region_factory.h"
  41 #include "ardour/session.h"
  42 #include "ardour/session_playlists.h"
  43 #include "ardour/source.h"
  44 #include "ardour/utils.h"
  45
  46 #include "i18n.h"
  47
  48 using namespace std;
  49 using namespace ARDOUR;
  50 using namespace PBD;
  51
  52 AudioTrack::AudioTrack (Session& sess, string name, Route::Flag flag, TrackMode mode)
  53         : Track (sess, name, flag, mode)
  54 {
  55 }
  56
  57 AudioTrack::~AudioTrack ()
  58 {
  59         if (_freeze_record.playlist && !_session.deletion_in_progress()) {
  60                 _freeze_record.playlist->release();
  61         }
  62 }
  63
  64 boost::shared_ptr<Diskstream>
  65 AudioTrack::create_diskstream ()
  66 {
  67         AudioDiskstream::Flag dflags = AudioDiskstream::Flag (AudioDiskstream::Recordable);
  68
  69         if (_mode == Destructive && !Profile->get_trx()) {
  70                 dflags = AudioDiskstream::Flag (dflags | AudioDiskstream::Destructive);
  71         } else if (_mode == NonLayered){
  72                 dflags = AudioDiskstream::Flag(dflags | AudioDiskstream::NonLayered);
  73         }
  74
  75         return boost::shared_ptr<AudioDiskstream> (new AudioDiskstream (_session, name(), dflags));
  76 }
  77
  78 void
  79 AudioTrack::set_diskstream (boost::shared_ptr<Diskstream> ds)
  80 {
  81         Track::set_diskstream (ds);
  82
  83         _diskstream->set_track (this);
  84         if (Profile->get_trx()) {
  85                 _diskstream->set_destructive (false);
  86         } else {
  87                 _diskstream->set_destructive (_mode == Destructive);
  88         }
  89         _diskstream->set_non_layered (_mode == NonLayered);
  90
  91         if (audio_diskstream()->deprecated_io_node) {
  92
  93                 if (!IO::connecting_legal) {
  94                         IO::ConnectingLegal.connect_same_thread (*this, boost::bind (&AudioTrack::deprecated_use_diskstream_connections, this));
  95                 } else {
  96                         deprecated_use_diskstream_connections ();
  97                 }
  98         }
  99
 100         _diskstream->set_record_enabled (false);
 101         _diskstream->request_input_monitoring (false);
 102
 103         DiskstreamChanged (); /* EMIT SIGNAL */
 104 }
 105
 106 boost::shared_ptr<AudioDiskstream>
 107 AudioTrack::audio_diskstream() const
 108 {
 109         return boost::dynamic_pointer_cast<AudioDiskstream>(_diskstream);
 110 }
 111
 112 int
 113 AudioTrack::set_mode (TrackMode m)
 114 {
 115         if (m != _mode) {
 116
 117                 if (!Profile->get_trx() && _diskstream->set_destructive (m == Destructive)) {
 118                         return -1;
 119                 }
 120
 121                 _diskstream->set_non_layered (m == NonLayered);
 122                 _mode = m;
 123
 124                 TrackModeChanged (); /* EMIT SIGNAL */
 125         }
 126
 127         return 0;
 128 }
 129
 130 bool
 131 AudioTrack::can_use_mode (TrackMode m, bool& bounce_required)
 132 {
 133         switch (m) {
 134         case NonLayered:
 135         case Normal:
 136                 bounce_required = false;
 137                 return true;
 138
 139         case Destructive:
 140                 if (Profile->get_trx()) {
 141                         return false;
 142                 } else {
 143                         return _diskstream->can_become_destructive (bounce_required);
 144                 }
 145                 break;
 146
 147         default:
 148                 return false;
 149         }
 150 }
 151
 152 int
 153 AudioTrack::deprecated_use_diskstream_connections ()
 154 {
 155         boost::shared_ptr<AudioDiskstream> diskstream = audio_diskstream();
 156
 157         if (diskstream->deprecated_io_node == 0) {
 158                 return 0;
 159         }
 160
 161         XMLProperty const * prop;
 162         XMLNode& node (*diskstream->deprecated_io_node);
 163
 164         /* don't do this more than once. */
 165
 166         diskstream->deprecated_io_node = 0;
 167
 168         if ((prop = node.property ("gain")) != 0) {
 169                 _amp->gain_control()->set_value (atof (prop->value().c_str()), PBD::Controllable::NoGroup);
 170         }
 171
 172         if ((prop = node.property ("input-connection")) != 0) {
 173                 boost::shared_ptr<Bundle> c = _session.bundle_by_name (prop->value());
 174
 175                 if (c == 0) {
 176                         error << string_compose(_("Unknown bundle \"%1\" listed for input of %2"), prop->value(), _name) << endmsg;
 177
 178                         if ((c = _session.bundle_by_name (_("in 1"))) == 0) {
 179                                 error << _("No input bundles available as a replacement")
 180                                 << endmsg;
 181                                 return -1;
 182                         } else {
 183                                 info << string_compose (_("Bundle %1 was not available - \"in 1\" used instead"), prop->value())
 184                                << endmsg;
 185                         }
 186                 }
 187
 188                 _input->connect_ports_to_bundle (c, true, this);
 189
 190         } else if ((prop = node.property ("inputs")) != 0) {
 191                 if (_input->set_ports (prop->value())) {
 192                         error << string_compose(_("improper input channel list in XML node (%1)"), prop->value()) << endmsg;
 193                         return -1;
 194                 }
 195         }
 196
 197         return 0;
 198 }
 199
 200 int
 201 AudioTrack::set_state (const XMLNode& node, int version)
 202 {
 203         XMLProperty const * prop;
 204
 205         if ((prop = node.property (X_("mode"))) != 0) {
 206                 _mode = TrackMode (string_2_enum (prop->value(), _mode));
 207         } else {
 208                 _mode = Normal;
 209         }
 210
 211         if (Profile->get_trx() && _mode == Destructive) {
 212                 /* Tracks does not support destructive tracks and trying to
 213                    handle it as a normal track would be wrong.
 214                 */
 215                 error << string_compose (_("%1: this session uses destructive tracks, which are not supported"), PROGRAM_NAME) << endmsg;
 216                 return -1;
 217         }
 218
 219         if (Track::set_state (node, version)) {
 220                 return -1;
 221         }
 222
 223         pending_state = const_cast<XMLNode*> (&node);
 224
 225         if (_session.state_of_the_state() & Session::Loading) {
 226                 _session.StateReady.connect_same_thread (*this, boost::bind (&AudioTrack::set_state_part_two, this));
 227         } else {
 228                 set_state_part_two ();
 229         }
 230
 231         return 0;
 232 }
 233
 234 XMLNode&
 235 AudioTrack::state (bool full_state)
 236 {
 237         XMLNode& root (Track::state(full_state));
 238         XMLNode* freeze_node;
 239         char buf[64];
 240
 241         if (_freeze_record.playlist) {
 242                 XMLNode* inode;
 243
 244                 freeze_node = new XMLNode (X_("freeze-info"));
 245                 freeze_node->add_property ("playlist", _freeze_record.playlist->name());
 246                 freeze_node->add_property ("state", enum_2_string (_freeze_record.state));
 247
 248                 for (vector<FreezeRecordProcessorInfo*>::iterator i = _freeze_record.processor_info.begin(); i != _freeze_record.processor_info.end(); ++i) {
 249                         inode = new XMLNode (X_("processor"));
 250                         (*i)->id.print (buf, sizeof (buf));
 251                         inode->add_property (X_("id"), buf);
 252                         inode->add_child_copy ((*i)->state);
 253
 254                         freeze_node->add_child_nocopy (*inode);
 255                 }
 256
 257                 root.add_child_nocopy (*freeze_node);
 258         }
 259
 260         root.add_property (X_("mode"), enum_2_string (_mode));
 261
 262         return root;
 263 }
 264
 265 void
 266 AudioTrack::set_state_part_two ()
 267 {
 268         XMLNode* fnode;
 269         XMLProperty const * prop;
 270         LocaleGuard lg ();
 271
 272         /* This is called after all session state has been restored but before
 273            have been made ports and connections are established.
 274         */
 275
 276         if (pending_state == 0) {
 277                 return;
 278         }
 279
 280         if ((fnode = find_named_node (*pending_state, X_("freeze-info"))) != 0) {
 281
 282                 _freeze_record.state = Frozen;
 283
 284                 for (vector<FreezeRecordProcessorInfo*>::iterator i = _freeze_record.processor_info.begin(); i != _freeze_record.processor_info.end(); ++i) {
 285                         delete *i;
 286                 }
 287                 _freeze_record.processor_info.clear ();
 288
 289                 if ((prop = fnode->property (X_("playlist"))) != 0) {
 290                         boost::shared_ptr<Playlist> pl = _session.playlists->by_name (prop->value());
 291                         if (pl) {
 292                                 _freeze_record.playlist = boost::dynamic_pointer_cast<AudioPlaylist> (pl);
 293                                 _freeze_record.playlist->use();
 294                         } else {
 295                                 _freeze_record.playlist.reset ();
 296                                 _freeze_record.state = NoFreeze;
 297                         return;
 298                         }
 299                 }
 300
 301                 if ((prop = fnode->property (X_("state"))) != 0) {
 302                         _freeze_record.state = FreezeState (string_2_enum (prop->value(), _freeze_record.state));
 303                 }
 304
 305                 XMLNodeConstIterator citer;
 306                 XMLNodeList clist = fnode->children();
 307
 308                 for (citer = clist.begin(); citer != clist.end(); ++citer) {
 309                         if ((*citer)->name() != X_("processor")) {
 310                                 continue;
 311                         }
 312
 313                         if ((prop = (*citer)->property (X_("id"))) == 0) {
 314                                 continue;
 315                         }
 316
 317                         FreezeRecordProcessorInfo* frii = new FreezeRecordProcessorInfo (*((*citer)->children().front()),
 318                                                                                    boost::shared_ptr<Processor>());
 319                         frii->id = prop->value ();
 320                         _freeze_record.processor_info.push_back (frii);
 321                 }
 322         }
 323 }
 324
 325 /** @param need_butler to be set to true if this track now needs the butler, otherwise it can be left alone
 326  *  or set to false.
 327  */
 328 int
 329 AudioTrack::roll (pframes_t nframes, framepos_t start_frame, framepos_t end_frame, int declick, bool& need_butler)
 330 {
 331         Glib::Threads::RWLock::ReaderLock lm (_processor_lock, Glib::Threads::TRY_LOCK);
 332
 333         if (!lm.locked()) {
 334                 boost::shared_ptr<AudioDiskstream> diskstream = audio_diskstream();
 335                 framecnt_t playback_distance = diskstream->calculate_playback_distance(nframes);
 336                 if (can_internal_playback_seek(::llabs(playback_distance))) {
 337                         /* TODO should declick */
 338                         internal_playback_seek(playback_distance);
 339                 }
 340                 return 0;
 341         }
 342
 343         framepos_t transport_frame;
 344         boost::shared_ptr<AudioDiskstream> diskstream = audio_diskstream();
 345
 346         if (n_outputs().n_total() == 0 && _processors.empty()) {
 347                 return 0;
 348         }
 349
 350         if (!_active) {
 351                 silence (nframes);
 352                 if (_meter_point == MeterInput && (_monitoring & MonitorInput || _diskstream->record_enabled())) {
 353                         _meter->reset();
 354                 }
 355                 return 0;
 356         }
 357
 358         transport_frame = _session.transport_frame();
 359
 360         int dret;
 361         framecnt_t playback_distance;
 362
 363         if ((nframes = check_initial_delay (nframes, transport_frame)) == 0) {
 364
 365                 /* need to do this so that the diskstream sets its
 366                    playback distance to zero, thus causing diskstream::commit
 367                    to do nothing.
 368                 */
 369
 370                 BufferSet bufs; /* empty set, no matter - nothing will happen */
 371
 372                 dret = diskstream->process (bufs, transport_frame, 0, playback_distance, false);
 373                 need_butler = diskstream->commit (playback_distance);
 374                 return dret;
 375         }
 376
 377         if (_mute_control->list() && _mute_control->automation_playback()) {
 378                 bool        valid = false;
 379                 const float mute  = _mute_control->list()->rt_safe_eval(transport_frame, valid);
 380                 if (mute >= 0.5 && !muted()) {
 381                         _mute_control->set_value_unchecked(1.0);  // mute
 382                 } else if (mute < 0.5 && muted()) {
 383                         _mute_control->set_value_unchecked(0.0);  // unmute
 384                 }
 385         }
 386
 387         _silent = false;
 388         _amp->apply_gain_automation(false);
 389
 390         BufferSet& bufs = _session.get_route_buffers (n_process_buffers ());
 391
 392         fill_buffers_with_input (bufs, _input, nframes);
 393
 394         if (_meter_point == MeterInput && (_monitoring & MonitorInput || _diskstream->record_enabled())) {
 395                 _meter->run (bufs, start_frame, end_frame, nframes, true);
 396         }
 397
 398         if ((dret = diskstream->process (bufs, transport_frame, nframes, playback_distance, (monitoring_state() == MonitoringDisk))) != 0) {
 399                 need_butler = diskstream->commit (playback_distance);
 400                 silence (nframes);
 401                 return dret;
 402         }
 403
 404         process_output_buffers (bufs, start_frame, end_frame, nframes, declick, (!diskstream->record_enabled() && _session.transport_rolling()));
 405
 406         for (ProcessorList::iterator i = _processors.begin(); i != _processors.end(); ++i) {
 407                 boost::shared_ptr<Delivery> d = boost::dynamic_pointer_cast<Delivery> (*i);
 408                 if (d) {
 409                         d->flush_buffers (nframes);
 410                 }
 411         }
 412
 413         need_butler = diskstream->commit (playback_distance);
 414
 415         return 0;
 416 }
 417
 418 int
 419 AudioTrack::export_stuff (BufferSet& buffers, framepos_t start, framecnt_t nframes,
 420                           boost::shared_ptr<Processor> endpoint, bool include_endpoint, bool for_export, bool for_freeze)
 421 {
 422         boost::scoped_array<gain_t> gain_buffer (new gain_t[nframes]);
 423         boost::scoped_array<Sample> mix_buffer (new Sample[nframes]);
 424         boost::shared_ptr<AudioDiskstream> diskstream = audio_diskstream();
 425
 426         Glib::Threads::RWLock::ReaderLock rlock (_processor_lock);
 427
 428         boost::shared_ptr<AudioPlaylist> apl = boost::dynamic_pointer_cast<AudioPlaylist>(diskstream->playlist());
 429
 430         assert(apl);
 431         assert(buffers.count().n_audio() >= 1);
 432         assert ((framecnt_t) buffers.get_audio(0).capacity() >= nframes);
 433
 434         if (apl->read (buffers.get_audio(0).data(), mix_buffer.get(), gain_buffer.get(), start, nframes) != nframes) {
 435                 return -1;
 436         }
 437
 438         uint32_t n=1;
 439         Sample* b = buffers.get_audio(0).data();
 440         BufferSet::audio_iterator bi = buffers.audio_begin();
 441         ++bi;
 442         for ( ; bi != buffers.audio_end(); ++bi, ++n) {
 443                 if (n < diskstream->n_channels().n_audio()) {
 444                         if (apl->read (bi->data(), mix_buffer.get(), gain_buffer.get(), start, nframes, n) != nframes) {
 445                                 return -1;
 446                         }
 447                         b = bi->data();
 448                 } else {
 449                         /* duplicate last across remaining buffers */
 450                         memcpy (bi->data(), b, sizeof (Sample) * nframes);
 451                 }
 452         }
 453
 454         bounce_process (buffers, start, nframes, endpoint, include_endpoint, for_export, for_freeze);
 455
 456         return 0;
 457 }
 458
 459 bool
 460 AudioTrack::bounceable (boost::shared_ptr<Processor> endpoint, bool include_endpoint) const
 461 {
 462         if (!endpoint && !include_endpoint) {
 463                 /* no processing - just read from the playlist and create new
 464                    files: always possible.
 465                 */
 466                 return true;
 467         }
 468
 469         Glib::Threads::RWLock::ReaderLock lm (_processor_lock);
 470         uint32_t naudio = n_inputs().n_audio();
 471
 472         for (ProcessorList::const_iterator r = _processors.begin(); r != _processors.end(); ++r) {
 473
 474                 /* if we're not including the endpoint, potentially stop
 475                    right here before we test matching i/o valences.
 476                 */
 477
 478                 if (!include_endpoint && (*r) == endpoint) {
 479                         return true;
 480                 }
 481
 482                 /* ignore any processors that do routing, because we will not
 483                  * use them during a bounce/freeze/export operation.
 484                  */
 485
 486                 if ((*r)->does_routing()) {
 487                         continue;
 488                 }
 489
 490                 /* does the output from the last considered processor match the
 491                  * input to this one?
 492                  */
 493
 494                 if (naudio != (*r)->input_streams().n_audio()) {
 495                         return false;
 496                 }
 497
 498                 /* we're including the endpoint - if we just hit it,
 499                    then stop.
 500                 */
 501
 502                 if ((*r) == endpoint) {
 503                         return true;
 504                 }
 505
 506                 /* save outputs of this processor to test against inputs
 507                    of the next one.
 508                 */
 509
 510                 naudio = (*r)->output_streams().n_audio();
 511         }
 512
 513         return true;
 514 }
 515
 516 boost::shared_ptr<Region>
 517 AudioTrack::bounce (InterThreadInfo& itt)
 518 {
 519         return bounce_range (_session.current_start_frame(), _session.current_end_frame(), itt, main_outs(), false);
 520 }
 521
 522 boost::shared_ptr<Region>
 523 AudioTrack::bounce_range (framepos_t start, framepos_t end, InterThreadInfo& itt,
 524                           boost::shared_ptr<Processor> endpoint, bool include_endpoint)
 525 {
 526         vector<boost::shared_ptr<Source> > srcs;
 527         return _session.write_one_track (*this, start, end, false, srcs, itt, endpoint, include_endpoint, false, false);
 528 }
 529
 530 void
 531 AudioTrack::freeze_me (InterThreadInfo& itt)
 532 {
 533         vector<boost::shared_ptr<Source> > srcs;
 534         string new_playlist_name;
 535         boost::shared_ptr<Playlist> new_playlist;
 536         string dir;
 537         string region_name;
 538         boost::shared_ptr<AudioDiskstream> diskstream = audio_diskstream();
 539
 540         if ((_freeze_record.playlist = boost::dynamic_pointer_cast<AudioPlaylist>(diskstream->playlist())) == 0) {
 541                 return;
 542         }
 543
 544         uint32_t n = 1;
 545
 546         while (n < (UINT_MAX-1)) {
 547
 548                 string candidate;
 549
 550                 candidate = string_compose ("<F%2>%1", _freeze_record.playlist->name(), n);
 551
 552                 if (_session.playlists->by_name (candidate) == 0) {
 553                         new_playlist_name = candidate;
 554                         break;
 555                 }
 556
 557                 ++n;
 558
 559         }
 560
 561         if (n == (UINT_MAX-1)) {
 562           error << string_compose (X_("There are too many frozen versions of playlist \"%1\""
 563                             " to create another one"), _freeze_record.playlist->name())
 564                << endmsg;
 565                 return;
 566         }
 567
 568         boost::shared_ptr<Region> res;
 569
 570         if ((res = _session.write_one_track (*this, _session.current_start_frame(), _session.current_end_frame(),
 571                                         true, srcs, itt, main_outs(), false, false, true)) == 0) {
 572                 return;
 573         }
 574
 575         _freeze_record.processor_info.clear ();
 576
 577         {
 578                 Glib::Threads::RWLock::ReaderLock lm (_processor_lock);
 579
 580                 for (ProcessorList::iterator r = _processors.begin(); r != _processors.end(); ++r) {
 581
 582                         if ((*r)->does_routing() && (*r)->active()) {
 583                                 break;
 584                         }
 585                         if (!boost::dynamic_pointer_cast<PeakMeter>(*r)) {
 586
 587                                 FreezeRecordProcessorInfo* frii  = new FreezeRecordProcessorInfo ((*r)->get_state(), (*r));
 588
 589                                 frii->id = (*r)->id();
 590
 591                                 _freeze_record.processor_info.push_back (frii);
 592
 593                                 /* now deactivate the processor, */
 594                                 if (!boost::dynamic_pointer_cast<Amp>(*r)) {
 595                                         (*r)->deactivate ();
 596                                 }
 597                         }
 598
 599                         _session.set_dirty ();
 600                 }
 601         }
 602
 603         new_playlist = PlaylistFactory::create (DataType::AUDIO, _session, new_playlist_name, false);
 604
 605         /* XXX need main outs automation state _freeze_record.pan_automation_state = _mainpanner->automation_state(); */
 606
 607         region_name = new_playlist_name;
 608
 609         /* create a new region from all filesources, keep it private */
 610
 611         PropertyList plist;
 612
 613         plist.add (Properties::start, 0);
 614         plist.add (Properties::length, srcs[0]->length(srcs[0]->timeline_position()));
 615         plist.add (Properties::name, region_name);
 616         plist.add (Properties::whole_file, true);
 617
 618         boost::shared_ptr<Region> region (RegionFactory::create (srcs, plist, false));
 619
 620         new_playlist->set_orig_track_id (id());
 621         new_playlist->add_region (region, _session.current_start_frame());
 622         new_playlist->set_frozen (true);
 623         region->set_locked (true);
 624
 625         diskstream->use_playlist (boost::dynamic_pointer_cast<AudioPlaylist>(new_playlist));
 626         diskstream->set_record_enabled (false);
 627
 628         _freeze_record.playlist->use(); // prevent deletion
 629
 630         /* reset stuff that has already been accounted for in the freeze process */
 631
 632         set_gain (GAIN_COEFF_UNITY, Controllable::NoGroup);
 633         _amp->gain_control()->set_automation_state (Off);
 634         /* XXX need to use _main_outs _panner->set_automation_state (Off); */
 635
 636         _freeze_record.state = Frozen;
 637         FreezeChange(); /* EMIT SIGNAL */
 638 }
 639
 640 void
 641 AudioTrack::unfreeze ()
 642 {
 643         if (_freeze_record.playlist) {
 644                 _freeze_record.playlist->release();
 645                 audio_diskstream()->use_playlist (_freeze_record.playlist);
 646
 647                 {
 648                         Glib::Threads::RWLock::ReaderLock lm (_processor_lock); // should this be a write lock? jlc
 649                         for (ProcessorList::iterator i = _processors.begin(); i != _processors.end(); ++i) {
 650                                 for (vector<FreezeRecordProcessorInfo*>::iterator ii = _freeze_record.processor_info.begin(); ii != _freeze_record.processor_info.end(); ++ii) {
 651                                         if ((*ii)->id == (*i)->id()) {
 652                                                 (*i)->set_state (((*ii)->state), Stateful::current_state_version);
 653                                                 break;
 654                                         }
 655                                 }
 656                         }
 657                 }
 658
 659                 _freeze_record.playlist.reset ();
 660                 /* XXX need to use _main_outs _panner->set_automation_state (_freeze_record.pan_automation_state); */
 661         }
 662
 663         _freeze_record.state = UnFrozen;
 664         FreezeChange (); /* EMIT SIGNAL */
 665 }
 666
 667 boost::shared_ptr<AudioFileSource>
 668 AudioTrack::write_source (uint32_t n)
 669 {
 670         boost::shared_ptr<AudioDiskstream> ds = boost::dynamic_pointer_cast<AudioDiskstream> (_diskstream);
 671         assert (ds);
 672         return ds->write_source (n);
 673 }
 674
 675 boost::shared_ptr<Diskstream>
 676 AudioTrack::diskstream_factory (XMLNode const & node)
 677 {
 678         return boost::shared_ptr<Diskstream> (new AudioDiskstream (_session, node));
 679 }