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