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/crossfade_compare.h"
  27 #include "ardour/audioregion.h"
  28 #include "ardour/playlist.h"
  29 #include "ardour/utils.h"
  30 #include "ardour/session.h"
  31 #include "ardour/source.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& 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* 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         if ((r = playlist.find_region (id)) == 0) {
 148                 error << string_compose (_("Crossfade: no \"in\" region %1 found in playlist %2"), id, playlist.name())
 149                       << endmsg;
 150                 throw failed_constructor();
 151         }
 152
 153         if ((_in = boost::dynamic_pointer_cast<AudioRegion> (r)) == 0) {
 154                 throw failed_constructor();
 155         }
 156
 157         if ((prop = node.property ("out")) == 0) {
 158                 error << _("Crossfade: no \"out\" region in state") << endmsg;
 159                 throw failed_constructor();
 160         }
 161
 162         PBD::ID id2 (prop->value());
 163
 164         if ((r = playlist.find_region (id2)) == 0) {
 165                 error << string_compose (_("Crossfade: no \"out\" region %1 found in playlist %2"), id2, playlist.name())
 166                       << endmsg;
 167                 throw failed_constructor();
 168         }
 169
 170         if ((_out = boost::dynamic_pointer_cast<AudioRegion> (r)) == 0) {
 171                 throw failed_constructor();
 172         }
 173
 174         _length = 0;
 175         initialize();
 176         _active = true;
 177
 178         if (set_state (node, Stateful::loading_state_version)) {
 179                 throw failed_constructor();
 180         }
 181 }
 182
 183 Crossfade::Crossfade (boost::shared_ptr<Crossfade> orig, boost::shared_ptr<AudioRegion> newin, boost::shared_ptr<AudioRegion> newout)
 184         : AudioRegion (boost::dynamic_pointer_cast<const AudioRegion> (orig), 0, true)
 185         , CROSSFADE_DEFAULT_PROPERTIES
 186         , _fade_in (orig->_fade_in)
 187         , _fade_out (orig->_fade_out)
 188 {
 189         _active           = orig->_active;
 190         _in_update        = orig->_in_update;
 191         _anchor_point     = orig->_anchor_point;
 192         _follow_overlap   = orig->_follow_overlap;
 193         _fixed            = orig->_fixed;
 194
 195         _in = newin;
 196         _out = newout;
 197
 198         // copied from Crossfade::initialize()
 199         _in_update = false;
 200
 201         _out->suspend_fade_out ();
 202         _in->suspend_fade_in ();
 203
 204         overlap_type = _in->coverage (_out->position(), _out->last_frame());
 205         layer_relation = (int32_t) (_in->layer() - _out->layer());
 206
 207         // Let's make sure the fade isn't too long
 208         set_xfade_length(_length);
 209 }
 210
 211
 212 Crossfade::~Crossfade ()
 213 {
 214 }
 215
 216 void
 217 Crossfade::initialize ()
 218 {
 219         /* merge source lists from regions */
 220
 221         _sources = _in->sources();
 222         _sources.insert (_sources.end(), _out->sources().begin(), _out->sources().end());
 223         _master_sources = _in->master_sources();
 224         _master_sources.insert(_master_sources.end(), _out->master_sources().begin(), _out->master_sources().end());
 225
 226         _in_update = false;
 227
 228         _out->suspend_fade_out ();
 229         _in->suspend_fade_in ();
 230
 231         _fade_out.freeze ();
 232         _fade_out.clear ();
 233
 234 #define EQUAL_POWER_MINUS_3DB
 235 #ifdef  EQUAL_POWER_MINUS_3DB
 236
 237         _fade_out.add ((_length * 0.000000), 1.000000);
 238         _fade_out.add ((_length * 0.166667), 0.948859);
 239         _fade_out.add ((_length * 0.333333), 0.851507);
 240         _fade_out.add ((_length * 0.500000), 0.707946);
 241         _fade_out.add ((_length * 0.666667), 0.518174);
 242         _fade_out.add ((_length * 0.833333), 0.282192);
 243         _fade_out.add ((_length * 1.000000), 0.000000);
 244
 245 #else // EQUAL_POWER_MINUS_6DB
 246
 247         _fade_out.add ((_length * 0.000000), 1.000000);
 248         _fade_out.add ((_length * 0.166667), 0.833033);
 249         _fade_out.add ((_length * 0.333333), 0.666186);
 250         _fade_out.add ((_length * 0.500000), 0.499459);
 251         _fade_out.add ((_length * 0.666667), 0.332853);
 252         _fade_out.add ((_length * 0.833333), 0.166366);
 253         _fade_out.add ((_length * 1.000000), 0.000000);
 254 #endif
 255
 256         _fade_out.thaw ();
 257
 258         _fade_in.freeze ();
 259         _fade_in.clear ();
 260
 261 #define EQUAL_POWER_MINUS_3DB
 262 #ifdef  EQUAL_POWER_MINUS_3DB
 263
 264         _fade_in.add ((_length * 0.000000), 0.000000);
 265         _fade_in.add ((_length * 0.166667), 0.282192);
 266         _fade_in.add ((_length * 0.333333), 0.518174);
 267         _fade_in.add ((_length * 0.500000), 0.707946);
 268         _fade_in.add ((_length * 0.666667), 0.851507);
 269         _fade_in.add ((_length * 0.833333), 0.948859);
 270         _fade_in.add ((_length * 1.000000), 1.000000);
 271
 272 #else // EQUAL_POWER_MINUS_SIX_DB
 273
 274         _fade_in.add ((_length * 0.000000), 0.000000);
 275         _fade_in.add ((_length * 0.166667), 0.166366);
 276         _fade_in.add ((_length * 0.333333), 0.332853);
 277         _fade_in.add ((_length * 0.500000), 0.499459);
 278         _fade_in.add ((_length * 0.666667), 0.666186);
 279         _fade_in.add ((_length * 0.833333), 0.833033);
 280         _fade_in.add ((_length * 1.000000), 1.000000);
 281
 282 #endif
 283
 284         _fade_in.thaw ();
 285
 286         overlap_type = _in->coverage (_out->position(), _out->last_frame());
 287         layer_relation = (int32_t) (_in->layer() - _out->layer());
 288 }
 289
 290 framecnt_t
 291 Crossfade::read_raw_internal (Sample* buf, framecnt_t start, framecnt_t cnt, int channel) const
 292 {
 293         Sample* mixdown = new Sample[cnt];
 294         float* gain = new float[cnt];
 295         framecnt_t ret;
 296
 297         ret = read_at (buf, mixdown, gain, start, cnt, channel, cnt);
 298
 299         delete [] mixdown;
 300         delete [] gain;
 301
 302         return ret;
 303 }
 304
 305 framecnt_t
 306 Crossfade::read_at (Sample *buf, Sample *mixdown_buffer,
 307                     float *gain_buffer, framepos_t start, framecnt_t cnt, uint32_t chan_n,
 308                     framecnt_t read_frames, framecnt_t skip_frames) const
 309 {
 310         frameoffset_t offset;
 311         framecnt_t to_write;
 312
 313         if (!_active) {
 314                 return 0;
 315         }
 316
 317         if (start < _position) {
 318
 319                 /* handle an initial section of the read area that we do not
 320                    cover.
 321                 */
 322
 323                 offset = _position - start;
 324
 325                 if (offset < cnt) {
 326                         cnt -= offset;
 327                 } else {
 328                         return 0;
 329                 }
 330
 331                 start = _position;
 332                 buf += offset;
 333                 to_write = min (_length.val(), (nframes64_t) cnt);
 334
 335         } else {
 336
 337                 to_write = min ((_length - (start - _position)), cnt);
 338
 339         }
 340
 341         offset = start - _position;
 342
 343         /* Prevent data from piling up inthe crossfade buffers when reading a transparent region */
 344         if (!(_out->opaque())) {
 345                 memset (crossfade_buffer_out, 0, sizeof (Sample) * to_write);
 346         } else if (!(_in->opaque())) {
 347                 memset (crossfade_buffer_in, 0, sizeof (Sample) * to_write);
 348         }
 349
 350         _out->read_at (crossfade_buffer_out, mixdown_buffer, gain_buffer, start, to_write, chan_n, read_frames, skip_frames);
 351         _in->read_at (crossfade_buffer_in, mixdown_buffer, gain_buffer, start, to_write, chan_n, read_frames, skip_frames);
 352
 353         float* fiv = new float[to_write];
 354         float* fov = new float[to_write];
 355
 356         _fade_in.curve().get_vector (offset, offset+to_write, fiv, to_write);
 357         _fade_out.curve().get_vector (offset, offset+to_write, fov, to_write);
 358
 359         /* note: although we have not explicitly taken into account the return values
 360            from _out->read_at() or _in->read_at(), the length() function does this
 361            implicitly. why? because it computes a value based on the in+out regions'
 362            position and length, and so we know precisely how much data they could return.
 363         */
 364
 365         for (framecnt_t n = 0; n < to_write; ++n) {
 366                 buf[n] = (crossfade_buffer_out[n] * fov[n]) + (crossfade_buffer_in[n] * fiv[n]);
 367         }
 368
 369         delete [] fov;
 370         delete [] fiv;
 371
 372         return to_write;
 373 }
 374
 375 OverlapType
 376 Crossfade::coverage (framepos_t start, framepos_t end) const
 377 {
 378         framepos_t my_end = _position + _length;
 379
 380         if ((start >= _position) && (end <= my_end)) {
 381                 return OverlapInternal;
 382         }
 383         if ((end >= _position) && (end <= my_end)) {
 384                 return OverlapStart;
 385         }
 386         if ((start >= _position) && (start <= my_end)) {
 387                 return OverlapEnd;
 388         }
 389         if ((_position >= start) && (_position <= end) && (my_end <= end)) {
 390                 return OverlapExternal;
 391         }
 392         return OverlapNone;
 393 }
 394
 395 void
 396 Crossfade::set_active (bool yn)
 397 {
 398         if (_active != yn) {
 399                 _active = yn;
 400                 PropertyChanged (PropertyChange (Properties::active));
 401         }
 402 }
 403
 404 bool
 405 Crossfade::refresh ()
 406 {
 407         /* crossfades must be between non-muted regions */
 408
 409         if (_out->muted() || _in->muted()) {
 410                 Invalidated (shared_from_this ());
 411                 return false;
 412         }
 413
 414         /* Top layer shouldn't be transparent */
 415
 416         if (!((layer_relation > 0 ? _in : _out)->opaque())) {
 417                 Invalidated (shared_from_this());
 418                 return false;
 419         }
 420
 421         /* layer ordering cannot change */
 422
 423         int32_t new_layer_relation = (int32_t) (_in->layer() - _out->layer());
 424
 425         if (new_layer_relation * layer_relation < 0) { // different sign, layers rotated
 426                 Invalidated (shared_from_this ());
 427                 return false;
 428         }
 429
 430         OverlapType ot = _in->coverage (_out->first_frame(), _out->last_frame());
 431
 432         if (ot == OverlapNone) {
 433                 Invalidated (shared_from_this ());
 434                 return false;
 435         }
 436
 437         bool send_signal;
 438
 439         if (ot != overlap_type) {
 440
 441                 if (_follow_overlap) {
 442
 443                         try {
 444                                 compute (_in, _out, _session.config.get_xfade_model());
 445                         }
 446
 447                         catch (NoCrossfadeHere& err) {
 448                                 Invalidated (shared_from_this ());
 449                                 return false;
 450                         }
 451
 452                         send_signal = true;
 453
 454                 } else {
 455                         Invalidated (shared_from_this ());
 456                         return false;
 457                 }
 458
 459         } else {
 460
 461                 send_signal = update ();
 462         }
 463
 464         if (send_signal) {
 465                 PropertyChange bounds;
 466                 bounds.add (Properties::start);
 467                 bounds.add (Properties::position);
 468                 bounds.add (Properties::length);
 469                 PropertyChanged (bounds); /* EMIT SIGNAL */
 470         }
 471
 472         _in_update = false;
 473
 474         return true;
 475 }
 476
 477 bool
 478 Crossfade::update ()
 479 {
 480         framecnt_t newlen;
 481
 482         if (_follow_overlap) {
 483                 newlen = _out->first_frame() + _out->length() - _in->first_frame();
 484         } else {
 485                 newlen = _length;
 486         }
 487
 488         if (newlen == 0) {
 489                 Invalidated (shared_from_this ());
 490                 return false;
 491         }
 492
 493         _in_update = true;
 494
 495         if ((_follow_overlap && newlen != _length) || (_length > newlen)) {
 496
 497                 double factor =  newlen / (double) _length;
 498
 499                 _fade_out.x_scale (factor);
 500                 _fade_in.x_scale (factor);
 501
 502                 _length = newlen;
 503         }
 504
 505         switch (_anchor_point) {
 506         case StartOfIn:
 507                 _position = _in->first_frame();
 508                 break;
 509
 510         case EndOfIn:
 511                 _position = _in->last_frame() - _length;
 512                 break;
 513
 514         case EndOfOut:
 515                 _position = _out->last_frame() - _length;
 516         }
 517
 518         return true;
 519 }
 520
 521 int
 522 Crossfade::compute (boost::shared_ptr<AudioRegion> a, boost::shared_ptr<AudioRegion> b, CrossfadeModel model)
 523 {
 524         boost::shared_ptr<AudioRegion> top;
 525         boost::shared_ptr<AudioRegion> bottom;
 526         framecnt_t short_xfade_length;
 527
 528         short_xfade_length = _short_xfade_length;
 529
 530         if (a->layer() < b->layer()) {
 531                 top = b;
 532                 bottom = a;
 533         } else {
 534                 top = a;
 535                 bottom = b;
 536         }
 537
 538         /* first check for matching ends */
 539
 540         if (top->first_frame() == bottom->first_frame()) {
 541
 542                 /* Both regions start at the same point */
 543
 544                 if (top->last_frame() < bottom->last_frame()) {
 545
 546                         /* top ends before bottom, so put an xfade
 547                            in at the end of top.
 548                         */
 549
 550                         /* [-------- top ---------- ]
 551                          * {====== bottom =====================}
 552                          */
 553
 554                         _in = bottom;
 555                         _out = top;
 556
 557                         if (top->last_frame() < short_xfade_length) {
 558                                 _position = 0;
 559                         } else {
 560                                 _position = top->last_frame() - short_xfade_length;
 561                         }
 562
 563                         _length = min (short_xfade_length, top->length());
 564                         _follow_overlap = false;
 565                         _anchor_point = EndOfIn;
 566                         _active = true;
 567                         _fixed = true;
 568
 569                 } else {
 570                         /* top ends after (or same time) as bottom - no xfade
 571                          */
 572
 573                         /* [-------- top ------------------------ ]
 574                          * {====== bottom =====================}
 575                          */
 576
 577                         throw NoCrossfadeHere();
 578                 }
 579
 580         } else if (top->last_frame() == bottom->last_frame()) {
 581
 582                 /* Both regions end at the same point */
 583
 584                 if (top->first_frame() > bottom->first_frame()) {
 585
 586                         /* top starts after bottom, put an xfade in at the
 587                            start of top
 588                         */
 589
 590                         /*            [-------- top ---------- ]
 591                          * {====== bottom =====================}
 592                          */
 593
 594                         _in = top;
 595                         _out = bottom;
 596                         _position = top->first_frame();
 597                         _length = min (short_xfade_length, top->length());
 598                         _follow_overlap = false;
 599                         _anchor_point = StartOfIn;
 600                         _active = true;
 601                         _fixed = true;
 602
 603                 } else {
 604                         /* top starts before bottom - no xfade
 605                          */
 606
 607                         /* [-------- top ------------------------ ]
 608                          *    {====== bottom =====================}
 609                          */
 610
 611                         throw NoCrossfadeHere();
 612                 }
 613
 614         } else {
 615
 616                 /* OK, time to do more regular overlapping */
 617
 618                 OverlapType ot = top->coverage (bottom->first_frame(), bottom->last_frame());
 619
 620                 switch (ot) {
 621                 case OverlapNone:
 622                         /* should be NOTREACHED as a precondition of creating
 623                            a new crossfade, but we need to handle it here.
 624                         */
 625                         throw NoCrossfadeHere();
 626                         break;
 627
 628                 case OverlapInternal:
 629                 case OverlapExternal:
 630                         /* should be NOTREACHED because of tests above */
 631                         throw NoCrossfadeHere();
 632                         break;
 633
 634                 case OverlapEnd: /* top covers start of bottom but ends within it */
 635
 636                         /* [---- top ------------------------]
 637                          *                { ==== bottom ============ }
 638                          */
 639
 640                         _in = bottom;
 641                         _out = top;
 642                         _anchor_point = EndOfOut;
 643
 644                         if (model == FullCrossfade) {
 645                                 _position = bottom->first_frame(); // "{"
 646                                 _length = _out->first_frame() + _out->length() - _in->first_frame();
 647                                 /* leave active alone */
 648                                 _follow_overlap = true;
 649                         } else {
 650                                 _length = min (short_xfade_length, top->length());
 651                                 _position = top->last_frame() - _length;  // "]" - length
 652                                 _active = true;
 653                                 _follow_overlap = false;
 654
 655                         }
 656                         break;
 657
 658                 case OverlapStart:   /* top starts within bottom but covers bottom's end */
 659
 660                         /*                   { ==== top ============ }
 661                          *   [---- bottom -------------------]
 662                          */
 663
 664                         _in = top;
 665                         _out = bottom;
 666                         _position = top->first_frame();
 667                         _anchor_point = StartOfIn;
 668
 669                         if (model == FullCrossfade) {
 670                                 _length = _out->first_frame() + _out->length() - _in->first_frame();
 671                                 /* leave active alone */
 672                                 _follow_overlap = true;
 673                         } else {
 674                                 _length = min (short_xfade_length, top->length());
 675                                 _active = true;
 676                                 _follow_overlap = false;
 677
 678                         }
 679
 680                         break;
 681                 }
 682         }
 683
 684         return 0;
 685 }
 686
 687 XMLNode&
 688 Crossfade::get_state ()
 689 {
 690         XMLNode* node = new XMLNode (X_("Crossfade"));
 691         XMLNode* child;
 692         char buf[64];
 693         LocaleGuard lg (X_("POSIX"));
 694
 695         _out->id().print (buf, sizeof (buf));
 696         node->add_property ("out", buf);
 697         _in->id().print (buf, sizeof (buf));
 698         node->add_property ("in", buf);
 699         node->add_property ("active", (_active ? "yes" : "no"));
 700         node->add_property ("follow-overlap", (_follow_overlap ? "yes" : "no"));
 701         node->add_property ("fixed", (_fixed ? "yes" : "no"));
 702         snprintf (buf, sizeof(buf), "%" PRId64, _length.val());
 703         node->add_property ("length", buf);
 704         snprintf (buf, sizeof(buf), "%" PRIu32, (uint32_t) _anchor_point);
 705         node->add_property ("anchor-point", buf);
 706         snprintf (buf, sizeof(buf), "%" PRId64, _position.val());
 707         node->add_property ("position", buf);
 708
 709         child = node->add_child ("FadeIn");
 710
 711         for (AutomationList::iterator ii = _fade_in.begin(); ii != _fade_in.end(); ++ii) {
 712                 XMLNode* pnode;
 713
 714                 pnode = new XMLNode ("point");
 715
 716                 snprintf (buf, sizeof (buf), "%" PRId64, (framepos_t) floor ((*ii)->when));
 717                 pnode->add_property ("x", buf);
 718                 snprintf (buf, sizeof (buf), "%.12g", (*ii)->value);
 719                 pnode->add_property ("y", buf);
 720                 child->add_child_nocopy (*pnode);
 721         }
 722
 723         child = node->add_child ("FadeOut");
 724
 725         for (AutomationList::iterator ii = _fade_out.begin(); ii != _fade_out.end(); ++ii) {
 726                 XMLNode* pnode;
 727
 728                 pnode = new XMLNode ("point");
 729
 730                 snprintf (buf, sizeof (buf), "%" PRId64, (framepos_t) floor ((*ii)->when));
 731                 pnode->add_property ("x", buf);
 732                 snprintf (buf, sizeof (buf), "%.12g", (*ii)->value);
 733                 pnode->add_property ("y", buf);
 734                 child->add_child_nocopy (*pnode);
 735         }
 736
 737         return *node;
 738 }
 739
 740 int
 741 Crossfade::set_state (const XMLNode& node, int /*version*/)
 742 {
 743         XMLNodeConstIterator i;
 744         XMLNodeList children;
 745         XMLNode* fi;
 746         XMLNode* fo;
 747         const XMLProperty* prop;
 748         LocaleGuard lg (X_("POSIX"));
 749         PropertyChange what_changed;
 750         framepos_t val;
 751
 752         if ((prop = node.property ("position")) != 0) {
 753                 sscanf (prop->value().c_str(), "%" PRId64, &val);
 754                 if (val != _position) {
 755                         _position = val;
 756                         what_changed.add (Properties::position);
 757                 }
 758         } else {
 759                 warning << _("old-style crossfade information - no position information") << endmsg;
 760                 _position = _in->first_frame();
 761         }
 762
 763         if ((prop = node.property ("active")) != 0) {
 764                 bool x = string_is_affirmative (prop->value());
 765                 if (x != _active) {
 766                         _active = x;
 767                         what_changed.add (Properties::active);
 768                 }
 769         } else {
 770                 _active = true;
 771         }
 772
 773         if ((prop = node.property ("follow-overlap")) != 0) {
 774                 _follow_overlap = string_is_affirmative (prop->value());
 775         } else {
 776                 _follow_overlap = false;
 777         }
 778
 779         if ((prop = node.property ("fixed")) != 0) {
 780                 _fixed = string_is_affirmative (prop->value());
 781         } else {
 782                 _fixed = false;
 783         }
 784
 785         if ((prop = node.property ("anchor-point")) != 0) {
 786                 _anchor_point = AnchorPoint (atoi ((prop->value().c_str())));
 787         } else {
 788                 _anchor_point = StartOfIn;
 789         }
 790
 791         if ((prop = node.property ("length")) != 0) {
 792
 793                 sscanf (prop->value().c_str(), "%" PRId64, &val);
 794                 if (val != _length) {
 795                         _length = val;
 796                         what_changed.add (Properties::length);
 797                 }
 798
 799         } else {
 800
 801                 /* XXX this branch is legacy code from before
 802                    the point where we stored xfade lengths.
 803                 */
 804
 805                 if ((_length = overlap_length()) == 0) {
 806                         throw failed_constructor();
 807                 }
 808         }
 809
 810         if ((fi = find_named_node (node, "FadeIn")) == 0) {
 811                 return -1;
 812         }
 813
 814         if ((fo = find_named_node (node, "FadeOut")) == 0) {
 815                 return -1;
 816         }
 817
 818         /* fade in */
 819
 820         _fade_in.freeze ();
 821         _fade_in.clear ();
 822
 823         children = fi->children();
 824
 825         for (i = children.begin(); i != children.end(); ++i) {
 826                 if ((*i)->name() == "point") {
 827                         framepos_t x;
 828                         float y;
 829
 830                         prop = (*i)->property ("x");
 831                         sscanf (prop->value().c_str(), "%" PRId64, &x);
 832
 833                         prop = (*i)->property ("y");
 834                         sscanf (prop->value().c_str(), "%f", &y);
 835
 836                         _fade_in.add (x, y);
 837                 }
 838         }
 839
 840         _fade_in.thaw ();
 841
 842         /* fade out */
 843
 844         _fade_out.freeze ();
 845         _fade_out.clear ();
 846
 847         children = fo->children();
 848
 849         for (i = children.begin(); i != children.end(); ++i) {
 850                 if ((*i)->name() == "point") {
 851                         framepos_t x;
 852                         float y;
 853                         XMLProperty* prop;
 854
 855                         prop = (*i)->property ("x");
 856                         sscanf (prop->value().c_str(), "%" PRId64, &x);
 857
 858                         prop = (*i)->property ("y");
 859                         sscanf (prop->value().c_str(), "%f", &y);
 860
 861                         _fade_out.add (x, y);
 862                 }
 863         }
 864
 865         _fade_out.thaw ();
 866
 867         PropertyChanged (what_changed); /* EMIT SIGNAL */
 868         FadesChanged (); /* EMIT SIGNAL */
 869
 870         return 0;
 871 }
 872
 873 bool
 874 Crossfade::can_follow_overlap () const
 875 {
 876         return !_fixed;
 877 }
 878
 879 void
 880 Crossfade::set_follow_overlap (bool yn)
 881 {
 882         if (yn == _follow_overlap || _fixed) {
 883                 return;
 884         }
 885
 886         _follow_overlap = yn;
 887
 888         if (!yn) {
 889                 set_xfade_length (_short_xfade_length);
 890         } else {
 891                 set_xfade_length (_out->first_frame() + _out->length() - _in->first_frame());
 892         }
 893
 894         PropertyChanged (PropertyChange (Properties::follow_overlap));
 895 }
 896
 897 framecnt_t
 898 Crossfade::set_xfade_length (framecnt_t len)
 899 {
 900         framecnt_t limit = 0;
 901
 902         switch (_anchor_point) {
 903         case StartOfIn:
 904                 limit = _in->length();
 905                 break;
 906
 907         case EndOfIn:
 908                 limit = _in->length();
 909                 break;
 910
 911         case EndOfOut:
 912                 limit = _out->length();
 913                 break;
 914
 915         }
 916
 917         len = min (limit, len);
 918
 919         double factor = len / (double) _length;
 920
 921         _in_update = true;
 922         _fade_out.x_scale (factor);
 923         _fade_in.x_scale (factor);
 924         _in_update = false;
 925
 926         _length = len;
 927
 928         PropertyChanged (PropertyChange (Properties::length));
 929
 930         return len;
 931 }
 932
 933 framecnt_t
 934 Crossfade::overlap_length () const
 935 {
 936         if (_fixed) {
 937                 return _length;
 938         }
 939         return _out->first_frame() + _out->length() - _in->first_frame();
 940 }
 941
 942 void
 943 Crossfade::set_short_xfade_length (framecnt_t n)
 944 {
 945         _short_xfade_length = n;
 946 }