libs/ardour/crossfade.cc

   1 /*
   2     Copyright (C) 2003-2006 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
  21 #include "pbd/stacktrace.h"
  22
  23 #include "ardour/debug.h"
  24 #include "ardour/types.h"
  25 #include "ardour/crossfade.h"
  26 #include "ardour/audioregion.h"
  27 #include "ardour/playlist.h"
  28 #include "ardour/utils.h"
  29 #include "ardour/session.h"
  30 #include "ardour/source.h"
  31 #include "ardour/region_factory.h"
  32
  33 #include "i18n.h"
  34 #include <locale.h>
  35
  36 using namespace std;
  37 using namespace ARDOUR;
  38 using namespace PBD;
  39
  40 framecnt_t Crossfade::_short_xfade_length = 0;
  41
  42 /* XXX if and when we ever implement parallel processing of the process()
  43    callback, these will need to be handled on a per-thread basis.
  44 */
  45
  46 Sample* Crossfade::crossfade_buffer_out = 0;
  47 Sample* Crossfade::crossfade_buffer_in = 0;
  48
  49
  50 #define CROSSFADE_DEFAULT_PROPERTIES \
  51         _active (Properties::active, _session.config.get_xfades_active ()) \
  52         , _follow_overlap (Properties::follow_overlap, false)
  53
  54
  55 namespace ARDOUR {
  56         namespace Properties {
  57                 PropertyDescriptor<bool> follow_overlap;
  58         }
  59 }
  60
  61 void
  62 Crossfade::make_property_quarks ()
  63 {
  64         Properties::follow_overlap.property_id = g_quark_from_static_string (X_("follow-overlap"));
  65         DEBUG_TRACE (DEBUG::Properties, string_compose ("quark for follow-overlap = %1\n",      Properties::follow_overlap.property_id));
  66 }
  67
  68 void
  69 Crossfade::set_buffer_size (framecnt_t sz)
  70 {
  71         delete [] crossfade_buffer_out;
  72         crossfade_buffer_out = 0;
  73
  74         delete [] crossfade_buffer_in;
  75         crossfade_buffer_in = 0;
  76
  77         if (sz) {
  78                 crossfade_buffer_out = new Sample[sz];
  79                 crossfade_buffer_in = new Sample[sz];
  80         }
  81 }
  82
  83 bool
  84 Crossfade::operator== (const Crossfade& other)
  85 {
  86         return (_in == other._in) && (_out == other._out);
  87 }
  88
  89 Crossfade::Crossfade (boost::shared_ptr<AudioRegion> in, boost::shared_ptr<AudioRegion> out,
  90                       framecnt_t length,
  91                       framepos_t position,
  92                       AnchorPoint ap)
  93         : AudioRegion (in->session(), position, length, in->name() + string ("<>") + out->name())
  94         , CROSSFADE_DEFAULT_PROPERTIES
  95         , _fade_in (Evoral::Parameter(FadeInAutomation)) // linear (gain coefficient) => -inf..+6dB
  96         , _fade_out (Evoral::Parameter(FadeOutAutomation)) // linear (gain coefficient) => -inf..+6dB
  97
  98 {
  99         _in = in;
 100         _out = out;
 101         _anchor_point = ap;
 102         _fixed = true;
 103         _follow_overlap = false;
 104
 105         initialize ();
 106 }
 107
 108 Crossfade::Crossfade (boost::shared_ptr<AudioRegion> a, boost::shared_ptr<AudioRegion> b, CrossfadeModel model, bool act)
 109         : AudioRegion (a->session(), 0, 0, a->name() + string ("<>") + b->name())
 110         , CROSSFADE_DEFAULT_PROPERTIES
 111         , _fade_in (Evoral::Parameter(FadeInAutomation)) // linear (gain coefficient) => -inf..+6dB
 112         , _fade_out (Evoral::Parameter(FadeOutAutomation)) // linear (gain coefficient) => -inf..+6dB
 113 {
 114         _in_update = false;
 115         _fixed = false;
 116         _follow_overlap = false;
 117
 118         if (compute (a, b, model)) {
 119                 throw failed_constructor();
 120         }
 121
 122         _active = act;
 123
 124         initialize ();
 125 }
 126
 127 Crossfade::Crossfade (const Playlist& playlist, XMLNode const & node)
 128         : AudioRegion (playlist.session(), 0, 0, "unnamed crossfade")
 129         , CROSSFADE_DEFAULT_PROPERTIES
 130         , _fade_in (Evoral::Parameter(FadeInAutomation)) // linear (gain coefficient) => -inf..+6dB
 131         , _fade_out (Evoral::Parameter(FadeOutAutomation)) // linear (gain coefficient) => -inf..+6dB
 132
 133 {
 134         boost::shared_ptr<Region> r;
 135         XMLProperty const * prop;
 136         LocaleGuard lg (X_("POSIX"));
 137
 138         /* we have to find the in/out regions before we can do anything else */
 139
 140         if ((prop = node.property ("in")) == 0) {
 141                 error << _("Crossfade: no \"in\" region in state") << endmsg;
 142                 throw failed_constructor();
 143         }
 144
 145         PBD::ID id (prop->value());
 146
 147         r = playlist.find_region (id);
 148
 149         if (!r) {
 150                 /* the `in' region is not in a playlist, which probably means that this crossfade
 151                    is in the undo record, so we have to find the region in the global region map.
 152                 */
 153                 r = RegionFactory::region_by_id (id);
 154         }
 155
 156         if (!r) {
 157                 error << string_compose (_("Crossfade: no \"in\" region %1 found in playlist %2 nor in region map"), id, playlist.name())
 158                       << endmsg;
 159                 throw failed_constructor();
 160         }
 161
 162         if ((_in = boost::dynamic_pointer_cast<AudioRegion> (r)) == 0) {
 163                 throw failed_constructor();
 164         }
 165
 166         if ((prop = node.property ("out")) == 0) {
 167                 error << _("Crossfade: no \"out\" region in state") << endmsg;
 168                 throw failed_constructor();
 169         }
 170
 171         PBD::ID id2 (prop->value());
 172
 173         r = playlist.find_region (id2);
 174
 175         if (!r) {
 176                 r = RegionFactory::region_by_id (id2);
 177         }
 178
 179         if (!r) {
 180                 error << string_compose (_("Crossfade: no \"out\" region %1 found in playlist %2 nor in region map"), id2, playlist.name())
 181                       << endmsg;
 182                 throw failed_constructor();
 183         }
 184
 185         if ((_out = boost::dynamic_pointer_cast<AudioRegion> (r)) == 0) {
 186                 throw failed_constructor();
 187         }
 188
 189         _length = 0;
 190         initialize();
 191         _active = true;
 192
 193         if (set_state (node, Stateful::loading_state_version)) {
 194                 throw failed_constructor();
 195         }
 196 }
 197
 198 Crossfade::Crossfade (boost::shared_ptr<Crossfade> orig, boost::shared_ptr<AudioRegion> newin, boost::shared_ptr<AudioRegion> newout)
 199         : AudioRegion (boost::dynamic_pointer_cast<const AudioRegion> (orig), 0)
 200         , CROSSFADE_DEFAULT_PROPERTIES
 201         , _fade_in (orig->_fade_in)
 202         , _fade_out (orig->_fade_out)
 203 {
 204         _active           = orig->_active;
 205         _in_update        = orig->_in_update;
 206         _anchor_point     = orig->_anchor_point;
 207         _follow_overlap   = orig->_follow_overlap;
 208         _fixed            = orig->_fixed;
 209
 210         _in = newin;
 211         _out = newout;
 212
 213         // copied from Crossfade::initialize()
 214         _in_update = false;
 215
 216         _out->suspend_fade_out ();
 217         _in->suspend_fade_in ();
 218
 219         overlap_type = _in->coverage (_out->position(), _out->last_frame());
 220         layer_relation = (int32_t) (_in->layer() - _out->layer());
 221
 222         // Let's make sure the fade isn't too long
 223         set_xfade_length(_length);
 224 }
 225
 226
 227 Crossfade::~Crossfade ()
 228 {
 229 }
 230
 231 void
 232 Crossfade::initialize ()
 233 {
 234         /* merge source lists from regions */
 235
 236         _sources = _in->sources();
 237         _sources.insert (_sources.end(), _out->sources().begin(), _out->sources().end());
 238
 239         for (SourceList::iterator i = _sources.begin(); i != _sources.end(); ++i) {
 240                 (*i)->inc_use_count ();
 241         }
 242
 243         _master_sources = _in->master_sources();
 244         _master_sources.insert(_master_sources.end(), _out->master_sources().begin(), _out->master_sources().end());
 245
 246         for (SourceList::iterator i = _master_sources.begin(); i != _master_sources.end(); ++i) {
 247                 (*i)->inc_use_count ();
 248         }
 249
 250         _in_update = false;
 251
 252         _out->suspend_fade_out ();
 253         _in->suspend_fade_in ();
 254
 255         _fade_out.freeze ();
 256         _fade_out.clear ();
 257
 258 #define EQUAL_POWER_MINUS_3DB
 259 #ifdef  EQUAL_POWER_MINUS_3DB
 260
 261         _fade_out.add ((_length * 0.000000), 1.000000);
 262         _fade_out.add ((_length * 0.166667), 0.948859);
 263         _fade_out.add ((_length * 0.333333), 0.851507);
 264         _fade_out.add ((_length * 0.500000), 0.707946);
 265         _fade_out.add ((_length * 0.666667), 0.518174);
 266         _fade_out.add ((_length * 0.833333), 0.282192);
 267         _fade_out.add ((_length * 1.000000), 0.000000);
 268
 269 #else // EQUAL_POWER_MINUS_6DB
 270
 271         _fade_out.add ((_length * 0.000000), 1.000000);
 272         _fade_out.add ((_length * 0.166667), 0.833033);
 273         _fade_out.add ((_length * 0.333333), 0.666186);
 274         _fade_out.add ((_length * 0.500000), 0.499459);
 275         _fade_out.add ((_length * 0.666667), 0.332853);
 276         _fade_out.add ((_length * 0.833333), 0.166366);
 277         _fade_out.add ((_length * 1.000000), 0.000000);
 278 #endif
 279
 280         _fade_out.thaw ();
 281
 282         _fade_in.freeze ();
 283         _fade_in.clear ();
 284
 285 #define EQUAL_POWER_MINUS_3DB
 286 #ifdef  EQUAL_POWER_MINUS_3DB
 287
 288         _fade_in.add ((_length * 0.000000), 0.000000);
 289         _fade_in.add ((_length * 0.166667), 0.282192);
 290         _fade_in.add ((_length * 0.333333), 0.518174);
 291         _fade_in.add ((_length * 0.500000), 0.707946);
 292         _fade_in.add ((_length * 0.666667), 0.851507);
 293         _fade_in.add ((_length * 0.833333), 0.948859);
 294         _fade_in.add ((_length * 1.000000), 1.000000);
 295
 296 #else // EQUAL_POWER_MINUS_SIX_DB
 297
 298         _fade_in.add ((_length * 0.000000), 0.000000);
 299         _fade_in.add ((_length * 0.166667), 0.166366);
 300         _fade_in.add ((_length * 0.333333), 0.332853);
 301         _fade_in.add ((_length * 0.500000), 0.499459);
 302         _fade_in.add ((_length * 0.666667), 0.666186);
 303         _fade_in.add ((_length * 0.833333), 0.833033);
 304         _fade_in.add ((_length * 1.000000), 1.000000);
 305
 306 #endif
 307
 308         _fade_in.thaw ();
 309
 310         overlap_type = _in->coverage (_out->position(), _out->last_frame());
 311         layer_relation = (int32_t) (_in->layer() - _out->layer());
 312 }
 313
 314 framecnt_t
 315 Crossfade::read_raw_internal (Sample* buf, framecnt_t start, framecnt_t cnt, int channel) const
 316 {
 317         Sample* mixdown = new Sample[cnt];
 318         float* gain = new float[cnt];
 319         framecnt_t ret;
 320
 321         ret = read_at (buf, mixdown, gain, start, cnt, channel, cnt);
 322
 323         delete [] mixdown;
 324         delete [] gain;
 325
 326         return ret;
 327 }
 328
 329 framecnt_t
 330 Crossfade::read_at (Sample *buf, Sample *mixdown_buffer,
 331                     float *gain_buffer, framepos_t start, framecnt_t cnt, uint32_t chan_n,
 332                     framecnt_t read_frames, framecnt_t skip_frames) const
 333 {
 334         frameoffset_t offset;
 335         framecnt_t to_write;
 336
 337         if (!_active) {
 338                 return 0;
 339         }
 340
 341         if (start < _position) {
 342
 343                 /* handle an initial section of the read area that we do not
 344                    cover.
 345                 */
 346
 347                 offset = _position - start;
 348
 349                 if (offset < cnt) {
 350                         cnt -= offset;
 351                 } else {
 352                         return 0;
 353                 }
 354
 355                 start = _position;
 356                 buf += offset;
 357                 to_write = min (_length.val(), cnt);
 358
 359         } else {
 360
 361                 to_write = min ((_length - (start - _position)), cnt);
 362
 363         }
 364
 365         offset = start - _position;
 366
 367         /* Prevent data from piling up inthe crossfade buffers when reading a transparent region */
 368         if (!(_out->opaque())) {
 369                 memset (crossfade_buffer_out, 0, sizeof (Sample) * to_write);
 370         } else if (!(_in->opaque())) {
 371                 memset (crossfade_buffer_in, 0, sizeof (Sample) * to_write);
 372         }
 373
 374         _out->read_at (crossfade_buffer_out, mixdown_buffer, gain_buffer, start, to_write, chan_n, read_frames, skip_frames);
 375         _in->read_at (crossfade_buffer_in, mixdown_buffer, gain_buffer, start, to_write, chan_n, read_frames, skip_frames);
 376
 377         float* fiv = new float[to_write];
 378         float* fov = new float[to_write];
 379
 380         _fade_in.curve().get_vector (offset, offset+to_write, fiv, to_write);
 381         _fade_out.curve().get_vector (offset, offset+to_write, fov, to_write);
 382
 383         /* note: although we have not explicitly taken into account the return values
 384            from _out->read_at() or _in->read_at(), the length() function does this
 385            implicitly. why? because it computes a value based on the in+out regions'
 386            position and length, and so we know precisely how much data they could return.
 387         */
 388
 389         for (framecnt_t n = 0; n < to_write; ++n) {
 390                 buf[n] = (crossfade_buffer_out[n] * fov[n]) + (crossfade_buffer_in[n] * fiv[n]);
 391         }
 392
 393         delete [] fov;
 394         delete [] fiv;
 395
 396         return to_write;
 397 }
 398
 399 OverlapType
 400 Crossfade::coverage (framepos_t start, framepos_t end) const
 401 {
 402         framepos_t my_end = _position + _length;
 403
 404         if ((start >= _position) && (end <= my_end)) {
 405                 return OverlapInternal;
 406         }
 407         if ((end >= _position) && (end <= my_end)) {
 408                 return OverlapStart;
 409         }
 410         if ((start >= _position) && (start <= my_end)) {
 411                 return OverlapEnd;
 412         }
 413         if ((_position >= start) && (_position <= end) && (my_end <= end)) {
 414                 return OverlapExternal;
 415         }
 416         return OverlapNone;
 417 }
 418
 419 void
 420 Crossfade::set_active (bool yn)
 421 {
 422         if (_active != yn) {
 423                 _active = yn;
 424                 PropertyChanged (PropertyChange (Properties::active));
 425         }
 426 }
 427
 428 bool
 429 Crossfade::refresh ()
 430 {
 431         /* crossfades must be between non-muted regions */
 432
 433         if (_out->muted() || _in->muted()) {
 434                 Invalidated (shared_from_this ());
 435                 return false;
 436         }
 437
 438         /* Top layer shouldn't be transparent */
 439
 440         if (!((layer_relation > 0 ? _in : _out)->opaque())) {
 441                 Invalidated (shared_from_this());
 442                 return false;
 443         }
 444
 445         /* regions must cannot be identically sized and placed */
 446
 447         if (_in->position() == _out->position() && _in->length() == _out->length()) {
 448                 Invalidated (shared_from_this());
 449                 return false;
 450         }
 451
 452         /* layer ordering cannot change */
 453
 454         int32_t new_layer_relation = (int32_t) (_in->layer() - _out->layer());
 455
 456         if (new_layer_relation * layer_relation < 0) { // different sign, layers rotated
 457                 Invalidated (shared_from_this ());
 458                 return false;
 459         }
 460
 461         OverlapType ot = _in->coverage (_out->first_frame(), _out->last_frame());
 462
 463         if (ot == OverlapNone) {
 464                 Invalidated (shared_from_this ());
 465                 return false;
 466         }
 467
 468         bool send_signal;
 469
 470         if (ot != overlap_type) {
 471
 472                 if (_follow_overlap) {
 473
 474                         try {
 475                                 compute (_in, _out, _session.config.get_xfade_model());
 476                         }
 477
 478                         catch (NoCrossfadeHere& err) {
 479                                 Invalidated (shared_from_this ());
 480                                 return false;
 481                         }
 482
 483                         send_signal = true;
 484
 485                 } else {
 486                         Invalidated (shared_from_this ());
 487                         return false;
 488                 }
 489
 490         } else {
 491
 492                 send_signal = update ();
 493         }
 494
 495         if (send_signal) {
 496                 PropertyChange bounds;
 497                 bounds.add (Properties::start);
 498                 bounds.add (Properties::position);
 499                 bounds.add (Properties::length);
 500                 PropertyChanged (bounds); /* EMIT SIGNAL */
 501         }
 502
 503         _in_update = false;
 504
 505         return true;
 506 }
 507
 508 bool
 509 Crossfade::update ()
 510 {
 511         framecnt_t newlen;
 512
 513         if (_follow_overlap) {
 514                 newlen = _out->first_frame() + _out->length() - _in->first_frame();
 515         } else {
 516                 newlen = _length;
 517         }
 518
 519         if (newlen == 0) {
 520                 Invalidated (shared_from_this ());
 521                 return false;
 522         }
 523
 524         _in_update = true;
 525
 526         if ((_follow_overlap && newlen != _length) || (_length > newlen)) {
 527
 528                 double factor =  newlen / (double) _length;
 529
 530                 _fade_out.x_scale (factor);
 531                 _fade_in.x_scale (factor);
 532
 533                 _length = newlen;
 534         }
 535
 536         switch (_anchor_point) {
 537         case StartOfIn:
 538                 _position = _in->first_frame();
 539                 break;
 540
 541         case EndOfIn:
 542                 _position = _in->last_frame() - _length;
 543                 break;
 544
 545         case EndOfOut:
 546                 _position = _out->last_frame() - _length;
 547         }
 548
 549         return true;
 550 }
 551
 552 int
 553 Crossfade::compute (boost::shared_ptr<AudioRegion> a, boost::shared_ptr<AudioRegion> b, CrossfadeModel model)
 554 {
 555         boost::shared_ptr<AudioRegion> top;
 556         boost::shared_ptr<AudioRegion> bottom;
 557         framecnt_t short_xfade_length;
 558
 559         short_xfade_length = _short_xfade_length;
 560
 561         if (a->layer() < b->layer()) {
 562                 top = b;
 563                 bottom = a;
 564         } else {
 565                 top = a;
 566                 bottom = b;
 567         }
 568
 569         /* first check for matching ends */
 570
 571         if (top->first_frame() == bottom->first_frame()) {
 572
 573                 /* Both regions start at the same point */
 574
 575                 if (top->last_frame() < bottom->last_frame()) {
 576
 577                         /* top ends before bottom, so put an xfade
 578                            in at the end of top.
 579                         */
 580
 581                         /* [-------- top ---------- ]
 582                          * {====== bottom =====================}
 583                          */
 584
 585                         _in = bottom;
 586                         _out = top;
 587
 588                         if (top->last_frame() < short_xfade_length) {
 589                                 _position = 0;
 590                         } else {
 591                                 _position = top->last_frame() - short_xfade_length;
 592                         }
 593
 594                         _length = min (short_xfade_length, top->length());
 595                         _follow_overlap = false;
 596                         _anchor_point = EndOfIn;
 597                         _active = true;
 598                         _fixed = true;
 599
 600                 } else {
 601                         /* top ends after (or same time) as bottom - no xfade
 602                          */
 603
 604                         /* [-------- top ------------------------ ]
 605                          * {====== bottom =====================}
 606                          */
 607
 608                         throw NoCrossfadeHere();
 609                 }
 610
 611         } else if (top->last_frame() == bottom->last_frame()) {
 612
 613                 /* Both regions end at the same point */
 614
 615                 if (top->first_frame() > bottom->first_frame()) {
 616
 617                         /* top starts after bottom, put an xfade in at the
 618                            start of top
 619                         */
 620
 621                         /*            [-------- top ---------- ]
 622                          * {====== bottom =====================}
 623                          */
 624
 625                         _in = top;
 626                         _out = bottom;
 627                         _position = top->first_frame();
 628                         _length = min (short_xfade_length, top->length());
 629                         _follow_overlap = false;
 630                         _anchor_point = StartOfIn;
 631                         _active = true;
 632                         _fixed = true;
 633
 634                 } else {
 635                         /* top starts before bottom - no xfade
 636                          */
 637
 638                         /* [-------- top ------------------------ ]
 639                          *    {====== bottom =====================}
 640                          */
 641
 642                         throw NoCrossfadeHere();
 643                 }
 644
 645         } else {
 646
 647                 /* OK, time to do more regular overlapping */
 648
 649                 OverlapType ot = top->coverage (bottom->first_frame(), bottom->last_frame());
 650
 651                 switch (ot) {
 652                 case OverlapNone:
 653                         /* should be NOTREACHED as a precondition of creating
 654                            a new crossfade, but we need to handle it here.
 655                         */
 656                         throw NoCrossfadeHere();
 657                         break;
 658
 659                 case OverlapInternal:
 660                 case OverlapExternal:
 661                         /* should be NOTREACHED because of tests above */
 662                         throw NoCrossfadeHere();
 663                         break;
 664
 665                 case OverlapEnd: /* top covers start of bottom but ends within it */
 666
 667                         /* [---- top ------------------------]
 668                          *                { ==== bottom ============ }
 669                          */
 670
 671                         _in = bottom;
 672                         _out = top;
 673                         _anchor_point = EndOfOut;
 674
 675                         if (model == FullCrossfade) {
 676                                 _position = bottom->first_frame(); // "{"
 677                                 _length = _out->first_frame() + _out->length() - _in->first_frame();
 678                                 /* leave active alone */
 679                                 _follow_overlap = true;
 680                         } else {
 681                                 _length = min (short_xfade_length, top->length());
 682                                 _position = top->last_frame() - _length;  // "]" - length
 683                                 _active = true;
 684                                 _follow_overlap = false;
 685
 686                         }
 687                         break;
 688
 689                 case OverlapStart:   /* top starts within bottom but covers bottom's end */
 690
 691                         /*                   { ==== top ============ }
 692                          *   [---- bottom -------------------]
 693                          */
 694
 695                         _in = top;
 696                         _out = bottom;
 697                         _position = top->first_frame();
 698                         _anchor_point = StartOfIn;
 699
 700                         if (model == FullCrossfade) {
 701                                 _length = _out->first_frame() + _out->length() - _in->first_frame();
 702                                 /* leave active alone */
 703                                 _follow_overlap = true;
 704                         } else {
 705                                 _length = min (short_xfade_length, top->length());
 706                                 _active = true;
 707                                 _follow_overlap = false;
 708
 709                         }
 710
 711                         break;
 712                 }
 713         }
 714
 715         return 0;
 716 }
 717
 718 XMLNode&
 719 Crossfade::get_state ()
 720 {
 721         XMLNode* node = new XMLNode (X_("Crossfade"));
 722         XMLNode* child;
 723         char buf[64];
 724         LocaleGuard lg (X_("POSIX"));
 725
 726         id().print (buf, sizeof (buf));
 727         node->add_property ("id", buf);
 728         _out->id().print (buf, sizeof (buf));
 729         node->add_property ("out", buf);
 730         _in->id().print (buf, sizeof (buf));
 731         node->add_property ("in", buf);
 732         node->add_property ("active", (_active ? "yes" : "no"));
 733         node->add_property ("follow-overlap", (_follow_overlap ? "yes" : "no"));
 734         node->add_property ("fixed", (_fixed ? "yes" : "no"));
 735         snprintf (buf, sizeof(buf), "%" PRId64, _length.val());
 736         node->add_property ("length", buf);
 737         snprintf (buf, sizeof(buf), "%" PRIu32, (uint32_t) _anchor_point);
 738         node->add_property ("anchor-point", buf);
 739         snprintf (buf, sizeof(buf), "%" PRId64, _position.val());
 740         node->add_property ("position", buf);
 741
 742         child = node->add_child ("FadeIn");
 743
 744         for (AutomationList::iterator ii = _fade_in.begin(); ii != _fade_in.end(); ++ii) {
 745                 XMLNode* pnode;
 746
 747                 pnode = new XMLNode ("point");
 748
 749                 snprintf (buf, sizeof (buf), "%" PRId64, (framepos_t) floor ((*ii)->when));
 750                 pnode->add_property ("x", buf);
 751                 snprintf (buf, sizeof (buf), "%.12g", (*ii)->value);
 752                 pnode->add_property ("y", buf);
 753                 child->add_child_nocopy (*pnode);
 754         }
 755
 756         child = node->add_child ("FadeOut");
 757
 758         for (AutomationList::iterator ii = _fade_out.begin(); ii != _fade_out.end(); ++ii) {
 759                 XMLNode* pnode;
 760
 761                 pnode = new XMLNode ("point");
 762
 763                 snprintf (buf, sizeof (buf), "%" PRId64, (framepos_t) floor ((*ii)->when));
 764                 pnode->add_property ("x", buf);
 765                 snprintf (buf, sizeof (buf), "%.12g", (*ii)->value);
 766                 pnode->add_property ("y", buf);
 767                 child->add_child_nocopy (*pnode);
 768         }
 769
 770         return *node;
 771 }
 772
 773 int
 774 Crossfade::set_state (const XMLNode& node, int /*version*/)
 775 {
 776         XMLNodeConstIterator i;
 777         XMLNodeList children;
 778         XMLNode* fi;
 779         XMLNode* fo;
 780         const XMLProperty* prop;
 781         LocaleGuard lg (X_("POSIX"));
 782         PropertyChange what_changed;
 783         framepos_t val;
 784
 785         if ((prop = node.property (X_("id")))) {
 786                 _id = prop->value();
 787         }
 788
 789         if ((prop = node.property ("position")) != 0) {
 790                 sscanf (prop->value().c_str(), "%" PRId64, &val);
 791                 if (val != _position) {
 792                         _position = val;
 793                         what_changed.add (Properties::position);
 794                 }
 795         } else {
 796                 warning << _("old-style crossfade information - no position information") << endmsg;
 797                 _position = _in->first_frame();
 798         }
 799
 800         if ((prop = node.property ("active")) != 0) {
 801                 bool x = string_is_affirmative (prop->value());
 802                 if (x != _active) {
 803                         _active = x;
 804                         what_changed.add (Properties::active);
 805                 }
 806         } else {
 807                 _active = true;
 808         }
 809
 810         if ((prop = node.property ("follow-overlap")) != 0) {
 811                 _follow_overlap = string_is_affirmative (prop->value());
 812         } else {
 813                 _follow_overlap = false;
 814         }
 815
 816         if ((prop = node.property ("fixed")) != 0) {
 817                 _fixed = string_is_affirmative (prop->value());
 818         } else {
 819                 _fixed = false;
 820         }
 821
 822         if ((prop = node.property ("anchor-point")) != 0) {
 823                 _anchor_point = AnchorPoint (atoi ((prop->value().c_str())));
 824         } else {
 825                 _anchor_point = StartOfIn;
 826         }
 827
 828         if ((prop = node.property ("length")) != 0) {
 829
 830                 sscanf (prop->value().c_str(), "%" PRId64, &val);
 831                 if (val != _length) {
 832                         _length = val;
 833                         what_changed.add (Properties::length);
 834                 }
 835
 836         } else {
 837
 838                 /* XXX this branch is legacy code from before
 839                    the point where we stored xfade lengths.
 840                 */
 841
 842                 if ((_length = overlap_length()) == 0) {
 843                         throw failed_constructor();
 844                 }
 845         }
 846
 847         if ((fi = find_named_node (node, "FadeIn")) == 0) {
 848                 return -1;
 849         }
 850
 851         if ((fo = find_named_node (node, "FadeOut")) == 0) {
 852                 return -1;
 853         }
 854
 855         /* fade in */
 856
 857         _fade_in.freeze ();
 858         _fade_in.clear ();
 859
 860         children = fi->children();
 861
 862         for (i = children.begin(); i != children.end(); ++i) {
 863                 if ((*i)->name() == "point") {
 864                         framepos_t x;
 865                         float y;
 866
 867                         prop = (*i)->property ("x");
 868                         sscanf (prop->value().c_str(), "%" PRId64, &x);
 869
 870                         prop = (*i)->property ("y");
 871                         sscanf (prop->value().c_str(), "%f", &y);
 872
 873                         _fade_in.add (x, y);
 874                 }
 875         }
 876
 877         if (_fade_in.size() < 2) {
 878                 /* fade state somehow saved with no points */
 879                 return -1;
 880         }
 881
 882         _fade_in.front()->value = 0.0;
 883         _fade_in.back()->value = 1.0;
 884
 885         _fade_in.thaw ();
 886
 887         /* fade out */
 888
 889         _fade_out.freeze ();
 890         _fade_out.clear ();
 891
 892         children = fo->children();
 893
 894         for (i = children.begin(); i != children.end(); ++i) {
 895                 if ((*i)->name() == "point") {
 896                         framepos_t x;
 897                         float y;
 898                         XMLProperty* prop;
 899
 900                         prop = (*i)->property ("x");
 901                         sscanf (prop->value().c_str(), "%" PRId64, &x);
 902
 903                         prop = (*i)->property ("y");
 904                         sscanf (prop->value().c_str(), "%f", &y);
 905
 906                         _fade_out.add (x, y);
 907                 }
 908         }
 909
 910         if (_fade_out.size() < 2) {
 911                 /* fade state somehow saved with no points */
 912                 return -1;
 913         }
 914
 915         _fade_out.front()->value = 1.0;
 916         _fade_out.back()->value = 0.0;
 917
 918         _fade_out.thaw ();
 919
 920         PropertyChanged (what_changed); /* EMIT SIGNAL */
 921         FadesChanged (); /* EMIT SIGNAL */
 922
 923         return 0;
 924 }
 925
 926 bool
 927 Crossfade::can_follow_overlap () const
 928 {
 929         return !_fixed;
 930 }
 931
 932 void
 933 Crossfade::set_follow_overlap (bool yn)
 934 {
 935         if (yn == _follow_overlap || _fixed) {
 936                 return;
 937         }
 938
 939         _follow_overlap = yn;
 940
 941         if (!yn) {
 942                 set_xfade_length (_short_xfade_length);
 943         } else {
 944                 set_xfade_length (_out->first_frame() + _out->length() - _in->first_frame());
 945         }
 946
 947         PropertyChanged (PropertyChange (Properties::follow_overlap));
 948 }
 949
 950 framecnt_t
 951 Crossfade::set_xfade_length (framecnt_t len)
 952 {
 953         framecnt_t limit = 0;
 954
 955         switch (_anchor_point) {
 956         case StartOfIn:
 957                 limit = _in->length();
 958                 break;
 959
 960         case EndOfIn:
 961                 limit = _in->length();
 962                 break;
 963
 964         case EndOfOut:
 965                 limit = _out->length();
 966                 break;
 967
 968         }
 969
 970         len = min (limit, len);
 971
 972         double factor = len / (double) _length;
 973
 974         _in_update = true;
 975         _fade_out.x_scale (factor);
 976         _fade_in.x_scale (factor);
 977         _in_update = false;
 978
 979         _length = len;
 980
 981         PropertyChanged (PropertyChange (Properties::length));
 982
 983         return len;
 984 }
 985
 986 framecnt_t
 987 Crossfade::overlap_length () const
 988 {
 989         if (_fixed) {
 990                 return _length;
 991         }
 992         return _out->first_frame() + _out->length() - _in->first_frame();
 993 }
 994
 995 void
 996 Crossfade::set_short_xfade_length (framecnt_t n)
 997 {
 998         _short_xfade_length = n;
 999 }