fix crash when copy'ing latent plugins
[ardour.git] / libs / ardour / audio_playlist.cc
index 0631c9121b1fcf5e2b2acf257d07dddac6eaf7a0..b00252df7412de461b073557d4bc974462ebde2f 100644 (file)
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2003 Paul Davis 
+    Copyright (C) 2003 Paul Davis
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
 
 #include <cstdlib>
 
-#include <sigc++/bind.h>
+#include "ardour/types.h"
+#include "ardour/debug.h"
+#include "ardour/audioplaylist.h"
+#include "ardour/audioregion.h"
+#include "ardour/region_sorters.h"
+#include "ardour/session.h"
 
-#include <ardour/types.h>
-#include <ardour/configuration.h>
-#include <ardour/audioplaylist.h>
-#include <ardour/audioregion.h>
-#include <ardour/crossfade.h>
-#include <ardour/crossfade_compare.h>
-#include <ardour/session.h>
-#include <pbd/enumwriter.h>
-
-#include "i18n.h"
+#include "pbd/i18n.h"
 
 using namespace ARDOUR;
-using namespace sigc;
 using namespace std;
 using namespace PBD;
 
 AudioPlaylist::AudioPlaylist (Session& session, const XMLNode& node, bool hidden)
        : Playlist (session, node, DataType::AUDIO, hidden)
 {
-       const XMLProperty* prop = node.property("type");
+#ifndef NDEBUG
+       XMLProperty const * prop = node.property("type");
        assert(!prop || DataType(prop->value()) == DataType::AUDIO);
+#endif
 
        in_set_state++;
-       set_state (node);
+       if (set_state (node, Stateful::loading_state_version)) {
+               throw failed_constructor();
+       }
        in_set_state--;
+
+       relayer ();
+
+       load_legacy_crossfades (node, Stateful::loading_state_version);
 }
 
 AudioPlaylist::AudioPlaylist (Session& session, string name, bool hidden)
@@ -58,77 +61,116 @@ AudioPlaylist::AudioPlaylist (Session& session, string name, bool hidden)
 AudioPlaylist::AudioPlaylist (boost::shared_ptr<const AudioPlaylist> other, string name, bool hidden)
        : Playlist (other, name, hidden)
 {
-       RegionList::const_iterator in_o  = other->regions.begin();
-       RegionList::iterator in_n = regions.begin();
-
-       while (in_o != other->regions.end()) {
-               boost::shared_ptr<AudioRegion> ar = boost::dynamic_pointer_cast<AudioRegion>(*in_o);
-
-               // We look only for crossfades which begin with the current region, so we don't get doubles
-               for (Crossfades::const_iterator xfades = other->_crossfades.begin(); xfades != other->_crossfades.end(); ++xfades) {
-                       if ((*xfades)->in() == ar) {
-                               // We found one! Now copy it!
-
-                               RegionList::const_iterator out_o = other->regions.begin();
-                               RegionList::const_iterator out_n = regions.begin();
-
-                               while (out_o != other->regions.end()) {
-                                       
-                                       boost::shared_ptr<AudioRegion>ar2 = boost::dynamic_pointer_cast<AudioRegion>(*out_o);
-                                       
-                                       if ((*xfades)->out() == ar2) {
-                                               boost::shared_ptr<AudioRegion>in  = boost::dynamic_pointer_cast<AudioRegion>(*in_n);
-                                               boost::shared_ptr<AudioRegion>out = boost::dynamic_pointer_cast<AudioRegion>(*out_n);
-                                               boost::shared_ptr<Crossfade> new_fade = boost::shared_ptr<Crossfade> (new Crossfade (*xfades, in, out));
-                                               add_crossfade(new_fade);
-                                               break;
-                                       }
-                                       
-                                       out_o++;
-                                       out_n++;
-                               }
-//                             cerr << "HUH!? second region in the crossfade not found!" << endl;
-                       }
-               }
-
-               in_o++;
-               in_n++;
-       }
 }
 
-AudioPlaylist::AudioPlaylist (boost::shared_ptr<const AudioPlaylist> other, nframes_t start, nframes_t cnt, string name, bool hidden)
+AudioPlaylist::AudioPlaylist (boost::shared_ptr<const AudioPlaylist> other, framepos_t start, framecnt_t cnt, string name, bool hidden)
        : Playlist (other, start, cnt, name, hidden)
 {
-       /* this constructor does NOT notify others (session) */
-}
+       RegionReadLock rlock2 (const_cast<AudioPlaylist*> (other.get()));
+       in_set_state++;
 
-AudioPlaylist::~AudioPlaylist ()
-{
-       GoingAway (); /* EMIT SIGNAL */
+       framepos_t const end = start + cnt - 1;
+
+       /* Audio regions that have been created by the Playlist constructor
+          will currently have the same fade in/out as the regions that they
+          were created from.  This is wrong, so reset the fades here.
+       */
+
+       RegionList::iterator ours = regions.begin ();
+
+       for (RegionList::const_iterator i = other->regions.begin(); i != other->regions.end(); ++i) {
+               boost::shared_ptr<AudioRegion> region = boost::dynamic_pointer_cast<AudioRegion> (*i);
+               assert (region);
+
+               framecnt_t fade_in = 64;
+               framecnt_t fade_out = 64;
 
-       /* drop connections to signals */
+               switch (region->coverage (start, end)) {
+               case Evoral::OverlapNone:
+                       continue;
+
+               case Evoral::OverlapInternal:
+               {
+                       framecnt_t const offset = start - region->position ();
+                       framecnt_t const trim = region->last_frame() - end;
+                       if (region->fade_in()->back()->when > offset) {
+                               fade_in = region->fade_in()->back()->when - offset;
+                       }
+                       if (region->fade_out()->back()->when > trim) {
+                               fade_out = region->fade_out()->back()->when - trim;
+                       }
+                       break;
+               }
+
+               case Evoral::OverlapStart: {
+                       if (end > region->position() + region->fade_in()->back()->when)
+                               fade_in = region->fade_in()->back()->when;  //end is after fade-in, preserve the fade-in
+                       if (end > region->last_frame() - region->fade_out()->back()->when)
+                               fade_out = region->fade_out()->back()->when - ( region->last_frame() - end );  //end is inside the fadeout, preserve the fades endpoint
+                       break;
+               }
+
+               case Evoral::OverlapEnd: {
+                       if (start < region->last_frame() - region->fade_out()->back()->when)  //start is before fade-out, preserve the fadeout
+                               fade_out = region->fade_out()->back()->when;
+
+                       if (start < region->position() + region->fade_in()->back()->when)
+                               fade_in = region->fade_in()->back()->when - (start - region->position());  //end is inside the fade-in, preserve the fade-in endpoint
+                       break;
+               }
+
+               case Evoral::OverlapExternal:
+                       fade_in = region->fade_in()->back()->when;
+                       fade_out = region->fade_out()->back()->when;
+                       break;
+               }
+
+               boost::shared_ptr<AudioRegion> our_region = boost::dynamic_pointer_cast<AudioRegion> (*ours);
+               assert (our_region);
+
+               our_region->set_fade_in_length (fade_in);
+               our_region->set_fade_out_length (fade_out);
+               ++ours;
+       }
 
-       notify_callbacks ();
-       
-       _crossfades.clear ();
+       in_set_state--;
+
+       /* this constructor does NOT notify others (session) */
 }
 
-struct RegionSortByLayer {
+/** Sort by descending layer and then by ascending position */
+struct ReadSorter {
     bool operator() (boost::shared_ptr<Region> a, boost::shared_ptr<Region> b) {
-           return a->layer() < b->layer();
+           if (a->layer() != b->layer()) {
+                   return a->layer() > b->layer();
+           }
+
+           return a->position() < b->position();
     }
 };
 
-ARDOUR::nframes_t
-AudioPlaylist::read (Sample *buf, Sample *mixdown_buffer, float *gain_buffer, nframes_t start,
-                    nframes_t cnt, unsigned chan_n)
+/** A segment of region that needs to be read */
+struct Segment {
+       Segment (boost::shared_ptr<AudioRegion> r, Evoral::Range<framepos_t> a) : region (r), range (a) {}
+
+       boost::shared_ptr<AudioRegion> region; ///< the region
+       Evoral::Range<framepos_t> range;       ///< range of the region to read, in session frames
+};
+
+/** @param start Start position in session frames.
+ *  @param cnt Number of frames to read.
+ */
+ARDOUR::framecnt_t
+AudioPlaylist::read (Sample *buf, Sample *mixdown_buffer, float *gain_buffer, framepos_t start,
+                    framecnt_t cnt, unsigned chan_n)
 {
-       nframes_t end;
+       DEBUG_TRACE (DEBUG::AudioPlayback, string_compose ("Playlist %1 read @ %2 for %3, channel %4, regions %5 mixdown @ %6 gain @ %7\n",
+                                                          name(), start, cnt, chan_n, regions.size(), mixdown_buffer, gain_buffer));
 
        /* optimizing this memset() away involves a lot of conditionals
-          that may well cause more of a hit due to cache misses 
+          that may well cause more of a hit due to cache misses
           and related stuff than just doing this here.
-          
+
           it would be great if someone could measure this
           at some point.
 
@@ -140,635 +182,395 @@ AudioPlaylist::read (Sample *buf, Sample *mixdown_buffer, float *gain_buffer, nf
 
        memset (buf, 0, sizeof (Sample) * cnt);
 
-       /* this function is never called from a realtime thread, so 
+       /* this function is never called from a realtime thread, so
           its OK to block (for short intervals).
        */
 
-       Glib::Mutex::Lock rm (region_lock);
+       Playlist::RegionReadLock rl (this);
 
-       end =  start + cnt - 1;
+       /* Find all the regions that are involved in the bit we are reading,
+          and sort them by descending layer and ascending position.
+       */
+       boost::shared_ptr<RegionList> all = regions_touched_locked (start, start + cnt - 1);
+       all->sort (ReadSorter ());
 
-       _read_data_count = 0;
+       /* This will be a list of the bits of our read range that we have
+          handled completely (ie for which no more regions need to be read).
+          It is a list of ranges in session frames.
+       */
+       Evoral::RangeList<framepos_t> done;
 
-       map<uint32_t,vector<boost::shared_ptr<Region> > > relevant_regions;
-       map<uint32_t,vector<boost::shared_ptr<Crossfade> > > relevant_xfades;
-       vector<uint32_t> relevant_layers;
+       /* This will be a list of the bits of regions that we need to read */
+       list<Segment> to_do;
 
-       for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
-               if ((*i)->coverage (start, end) != OverlapNone) {
-                       relevant_regions[(*i)->layer()].push_back (*i);
-                       relevant_layers.push_back ((*i)->layer());
-               }
-       }
+       /* Now go through the `all' list filling in `to_do' and `done' */
+       for (RegionList::iterator i = all->begin(); i != all->end(); ++i) {
+               boost::shared_ptr<AudioRegion> ar = boost::dynamic_pointer_cast<AudioRegion> (*i);
 
-       for (Crossfades::iterator i = _crossfades.begin(); i != _crossfades.end(); ++i) {
-               if ((*i)->coverage (start, end) != OverlapNone) {
-                       relevant_xfades[(*i)->upper_layer()].push_back (*i);
-               }
-       }
+               /* muted regions don't figure into it at all */
+               if ( ar->muted() )
+                       continue;
 
-//     RegionSortByLayer layer_cmp;
-//     relevant_regions.sort (layer_cmp);
+               /* Work out which bits of this region need to be read;
+                  first, trim to the range we are reading...
+               */
+               Evoral::Range<framepos_t> region_range = ar->range ();
+               region_range.from = max (region_range.from, start);
+               region_range.to = min (region_range.to, start + cnt - 1);
 
-       /* XXX this whole per-layer approach is a hack that
-          should be removed once Crossfades become
-          CrossfadeRegions and we just grab a list of relevant
-          regions and call read_at() on all of them.
-       */
+               /* ... and then remove the bits that are already done */
 
-       sort (relevant_layers.begin(), relevant_layers.end());
+               Evoral::RangeList<framepos_t> region_to_do = Evoral::subtract (region_range, done);
 
-       for (vector<uint32_t>::iterator l = relevant_layers.begin(); l != relevant_layers.end(); ++l) {
+               /* Make a note to read those bits, adding their bodies (the parts between end-of-fade-in
+                  and start-of-fade-out) to the `done' list.
+               */
 
-               vector<boost::shared_ptr<Region> > r (relevant_regions[*l]);
-               vector<boost::shared_ptr<Crossfade> >& x (relevant_xfades[*l]);
+               Evoral::RangeList<framepos_t>::List t = region_to_do.get ();
 
-               for (vector<boost::shared_ptr<Region> >::iterator i = r.begin(); i != r.end(); ++i) {
-                       boost::shared_ptr<AudioRegion> ar = boost::dynamic_pointer_cast<AudioRegion>(*i);
-                       assert(ar);
-                       ar->read_at (buf, mixdown_buffer, gain_buffer, start, cnt, chan_n);
-                       _read_data_count += ar->read_data_count();
-               }
-               
-               for (vector<boost::shared_ptr<Crossfade> >::iterator i = x.begin(); i != x.end(); ++i) {
-                       (*i)->read_at (buf, mixdown_buffer, gain_buffer, start, cnt, chan_n);
+               for (Evoral::RangeList<framepos_t>::List::iterator j = t.begin(); j != t.end(); ++j) {
+                       Evoral::Range<framepos_t> d = *j;
+                       to_do.push_back (Segment (ar, d));
 
-                       /* don't JACK up _read_data_count, since its the same data as we just
-                          read from the regions, and the OS should handle that for us.
-                       */
+                       if (ar->opaque ()) {
+                               /* Cut this range down to just the body and mark it done */
+                               Evoral::Range<framepos_t> body = ar->body_range ();
+                               if (body.from < d.to && body.to > d.from) {
+                                       d.from = max (d.from, body.from);
+                                       d.to = min (d.to, body.to);
+                                       done.add (d);
+                               }
+                       }
                }
        }
 
-       return cnt;
-}
-
-
-void
-AudioPlaylist::remove_dependents (boost::shared_ptr<Region> region)
-{
-       boost::shared_ptr<AudioRegion> r = boost::dynamic_pointer_cast<AudioRegion> (region);
-
-       if (in_set_state) {
-               return;
-       }
-       
-       if (r == 0) {
-               fatal << _("programming error: non-audio Region passed to remove_overlap in audio playlist")
-                     << endmsg;
-               return;
+       /* Now go backwards through the to_do list doing the actual reads */
+       for (list<Segment>::reverse_iterator i = to_do.rbegin(); i != to_do.rend(); ++i) {
+               DEBUG_TRACE (DEBUG::AudioPlayback, string_compose ("\tPlaylist %1 read %2 @ %3 for %4, channel %5, buf @ %6 offset %7\n",
+                                                                  name(), i->region->name(), i->range.from,
+                                                                  i->range.to - i->range.from + 1, (int) chan_n,
+                                                                  buf, i->range.from - start));
+               i->region->read_at (buf + i->range.from - start, mixdown_buffer, gain_buffer, i->range.from, i->range.to - i->range.from + 1, chan_n);
        }
 
-       for (Crossfades::iterator i = _crossfades.begin(); i != _crossfades.end(); ) {
-               
-               if ((*i)->involves (r)) {
-                       i = _crossfades.erase (i);
-               } else {
-                       ++i;
-               }
-       }
+       return cnt;
 }
 
-
 void
-AudioPlaylist::flush_notifications ()
+AudioPlaylist::dump () const
 {
-       Playlist::flush_notifications();
-
-       if (in_flush) {
-               return;
-       }
+       boost::shared_ptr<Region>r;
 
-       in_flush = true;
+       cerr << "Playlist \"" << _name << "\" " << endl
+            << regions.size() << " regions "
+            << endl;
 
-       Crossfades::iterator a;
-       for (a = _pending_xfade_adds.begin(); a != _pending_xfade_adds.end(); ++a) {
-               NewCrossfade (*a); /* EMIT SIGNAL */
+       for (RegionList::const_iterator i = regions.begin(); i != regions.end(); ++i) {
+               r = *i;
+               cerr << "  " << r->name() << " @ " << r << " ["
+                    << r->start() << "+" << r->length()
+                    << "] at "
+                    << r->position()
+                    << " on layer "
+                    << r->layer ()
+                    << endl;
        }
-
-       _pending_xfade_adds.clear ();
-       
-       in_flush = false;
 }
 
-void
-AudioPlaylist::refresh_dependents (boost::shared_ptr<Region> r)
+bool
+AudioPlaylist::destroy_region (boost::shared_ptr<Region> region)
 {
-       boost::shared_ptr<AudioRegion> ar = boost::dynamic_pointer_cast<AudioRegion>(r);
-       set<boost::shared_ptr<Crossfade> > updated;
-
-       if (ar == 0) {
-               return;
-       }
+       boost::shared_ptr<AudioRegion> r = boost::dynamic_pointer_cast<AudioRegion> (region);
 
-       for (Crossfades::iterator x = _crossfades.begin(); x != _crossfades.end();) {
+        if (!r) {
+                return false;
+        }
 
-               Crossfades::iterator tmp;
-               
-               tmp = x;
-               ++tmp;
+       bool changed = false;
 
-               /* only update them once */
+       {
+               RegionWriteLock rlock (this);
 
-               if ((*x)->involves (ar)) {
+               for (RegionList::iterator i = regions.begin(); i != regions.end(); ) {
 
-                       pair<set<boost::shared_ptr<Crossfade> >::iterator, bool> const u = updated.insert (*x);
-                       
-                       if (u.second) {
-                               /* x was successfully inserted into the set, so it has not already been updated */
-                               try {
-                                       (*x)->refresh ();
-                               }
+                       RegionList::iterator tmp = i;
+                       ++tmp;
 
-                               catch (Crossfade::NoCrossfadeHere& err) {
-                                       // relax, Invalidated during refresh
-                               }
+                       if ((*i) == region) {
+                               regions.erase (i);
+                               changed = true;
                        }
+
+                       i = tmp;
                }
 
-               x = tmp;
-       }
-}
+               for (set<boost::shared_ptr<Region> >::iterator x = all_regions.begin(); x != all_regions.end(); ) {
 
-void
-AudioPlaylist::finalize_split_region (boost::shared_ptr<Region> o, boost::shared_ptr<Region> l, boost::shared_ptr<Region> r)
-{
-       boost::shared_ptr<AudioRegion> orig  = boost::dynamic_pointer_cast<AudioRegion>(o);
-       boost::shared_ptr<AudioRegion> left  = boost::dynamic_pointer_cast<AudioRegion>(l);
-       boost::shared_ptr<AudioRegion> right = boost::dynamic_pointer_cast<AudioRegion>(r);
-
-       for (Crossfades::iterator x = _crossfades.begin(); x != _crossfades.end();) {
-               Crossfades::iterator tmp;
-               tmp = x;
-               ++tmp;
-
-               boost::shared_ptr<Crossfade> fade;
-               
-               if ((*x)->_in == orig) {
-                       if (! (*x)->covers(right->position())) {
-                               fade = boost::shared_ptr<Crossfade> (new Crossfade (*x, left, (*x)->_out));
-                       } else {
-                               // Overlap, the crossfade is copied on the left side of the right region instead
-                               fade = boost::shared_ptr<Crossfade> (new Crossfade (*x, right, (*x)->_out));
-                       }
-               }
-               
-               if ((*x)->_out == orig) {
-                       if (! (*x)->covers(right->position())) {
-                               fade = boost::shared_ptr<Crossfade> (new Crossfade (*x, (*x)->_in, right));
-                       } else {
-                               // Overlap, the crossfade is copied on the right side of the left region instead
-                               fade = boost::shared_ptr<Crossfade> (new Crossfade (*x, (*x)->_in, left));
+                       set<boost::shared_ptr<Region> >::iterator xtmp = x;
+                       ++xtmp;
+
+                       if ((*x) == region) {
+                               all_regions.erase (x);
+                               changed = true;
                        }
-               }
-               
-               if (fade) {
-                       _crossfades.remove (*x);
-                       add_crossfade (fade);
-               }
-               x = tmp;
-       }
-}
 
-void
-AudioPlaylist::check_dependents (boost::shared_ptr<Region> r, bool norefresh)
-{
-       boost::shared_ptr<AudioRegion> other;
-       boost::shared_ptr<AudioRegion> region;
-       boost::shared_ptr<AudioRegion> top;
-       boost::shared_ptr<AudioRegion> bottom;
-       boost::shared_ptr<Crossfade>   xfade;
-       RegionList*  touched_regions;
-
-       if (in_set_state || in_partition) {
-               return;
-       }
+                       x = xtmp;
+               }
 
-       if ((region = boost::dynamic_pointer_cast<AudioRegion> (r)) == 0) {
-               fatal << _("programming error: non-audio Region tested for overlap in audio playlist")
-                     << endmsg;
-               return;
+               region->set_playlist (boost::shared_ptr<Playlist>());
        }
 
-       if (!norefresh) {
-               refresh_dependents (r);
+       if (changed) {
+               /* overload this, it normally means "removed", not destroyed */
+               notify_region_removed (region);
        }
 
+       return changed;
+}
 
-       if (!Config->get_auto_xfade()) {
-               return;
+bool
+AudioPlaylist::region_changed (const PropertyChange& what_changed, boost::shared_ptr<Region> region)
+{
+       if (in_flush || in_set_state) {
+               return false;
        }
 
-       for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
-
-               nframes_t xfade_length;
-
-               other = boost::dynamic_pointer_cast<AudioRegion> (*i);
-
-               if (other == region) {
-                       continue;
-               }
-
-               if (other->muted() || region->muted()) {
-                       continue;
-               }
-               
-
-               if (other->layer() < region->layer()) {
-                       top = region;
-                       bottom = other;
-               } else {
-                       top = other;
-                       bottom = region;
-               }
-
-               if (!top->opaque()) {
-                       continue;
-               }
-
-               OverlapType c = top->coverage (bottom->position(), bottom->last_frame());
+       PropertyChange bounds;
+       bounds.add (Properties::start);
+       bounds.add (Properties::position);
+       bounds.add (Properties::length);
 
-               try {
-                       switch (c) {
-                       case OverlapNone:
-                               break;
+       PropertyChange our_interests;
 
-                       case OverlapInternal:
-                                /* {=============== top  =============}
-                                 *     [ ----- bottom  ------- ]
-                                 */
-                               break;
+       our_interests.add (Properties::fade_in_active);
+       our_interests.add (Properties::fade_out_active);
+       our_interests.add (Properties::scale_amplitude);
+       our_interests.add (Properties::envelope_active);
+       our_interests.add (Properties::envelope);
+       our_interests.add (Properties::fade_in);
+       our_interests.add (Properties::fade_out);
 
-                       case OverlapExternal:
-                               /*     [ -------- top ------- ]
-                                * {=========== bottom =============}
-                                */
-                               
-                               /* to avoid discontinuities at the region boundaries of an internal
-                                  overlap (this region is completely within another), we create
-                                  two hidden crossfades at each boundary. this is not dependent
-                                  on the auto-xfade option, because we require it as basic
-                                  audio engineering.
-                               */
-                               
-                               xfade_length = min ((nframes_t) 720, top->length());
-
-                               if (top_region_at (top->first_frame()) == top) {
-                                       xfade = boost::shared_ptr<Crossfade> (new Crossfade (top, bottom, xfade_length, top->first_frame(), StartOfIn));
-                                       add_crossfade (xfade);
-                               }
+       bool parent_wants_notify;
 
-                               if (top_region_at (top->last_frame() - 1) == top) {
+       parent_wants_notify = Playlist::region_changed (what_changed, region);
+       /* if bounds changed, we have already done notify_contents_changed ()*/
+       if ((parent_wants_notify || what_changed.contains (our_interests)) && !what_changed.contains (bounds)) {
+               notify_contents_changed ();
+       }
 
-                                       /* 
-                                          only add a fade out if there is no region on top of the end of 'top' (which 
-                                          would cover it).
-                                       */
-                                       
-                                       xfade = boost::shared_ptr<Crossfade> (new Crossfade (bottom, top, xfade_length, top->last_frame() - xfade_length, EndOfOut));
-                                       add_crossfade (xfade);
-                               }
-                               break;
-                       case OverlapStart:
+       return true;
+}
 
-                               /*                   { ==== top ============ } 
-                                *   [---- bottom -------------------] 
-                                */
+void
+AudioPlaylist::pre_combine (vector<boost::shared_ptr<Region> >& copies)
+{
+       RegionSortByPosition cmp;
+       boost::shared_ptr<AudioRegion> ar;
 
-                               if (Config->get_xfade_model() == FullCrossfade) {
-                                       touched_regions = regions_touched (top->first_frame(), bottom->last_frame());
-                                       if (touched_regions->size() <= 2) {
-                                               xfade = boost::shared_ptr<Crossfade> (new Crossfade (region, other, Config->get_xfade_model(), Config->get_xfades_active()));
-                                               add_crossfade (xfade);
-                                       }
-                               } else {
-
-                                       touched_regions = regions_touched (top->first_frame(), 
-                                                                          top->first_frame() + min ((nframes_t)Config->get_short_xfade_seconds() * _session.frame_rate(), 
-                                                                                                    top->length()));
-                                       if (touched_regions->size() <= 2) {
-                                               xfade = boost::shared_ptr<Crossfade> (new Crossfade (region, other, Config->get_xfade_model(), Config->get_xfades_active()));
-                                               add_crossfade (xfade);
-                                       }
-                               }
-                               break;
-                       case OverlapEnd:
+       sort (copies.begin(), copies.end(), cmp);
 
+       ar = boost::dynamic_pointer_cast<AudioRegion> (copies.front());
 
-                               /* [---- top ------------------------] 
-                                *                { ==== bottom ============ } 
-                                */ 
+       /* disable fade in of the first region */
 
-                               if (Config->get_xfade_model() == FullCrossfade) {
+       if (ar) {
+               ar->set_fade_in_active (false);
+       }
 
-                                       touched_regions = regions_touched (bottom->first_frame(), top->last_frame());
-                                       if (touched_regions->size() <= 2) {
-                                               xfade = boost::shared_ptr<Crossfade> (new Crossfade (region, other, 
-                                                                                                    Config->get_xfade_model(), Config->get_xfades_active()));
-                                               add_crossfade (xfade);
-                                       }
+       ar = boost::dynamic_pointer_cast<AudioRegion> (copies.back());
 
-                               } else {
-                                       touched_regions = regions_touched (bottom->first_frame(), 
-                                                                          bottom->first_frame() + min ((nframes_t)Config->get_short_xfade_seconds() * _session.frame_rate(), 
-                                                                                                       bottom->length()));
-                                       if (touched_regions->size() <= 2) {
-                                               xfade = boost::shared_ptr<Crossfade> (new Crossfade (region, other, Config->get_xfade_model(), Config->get_xfades_active()));
-                                               add_crossfade (xfade);
-                                       }
-                               }
-                               break;
-                       default:
-                               xfade = boost::shared_ptr<Crossfade> (new Crossfade (region, other, 
-                                                                                    Config->get_xfade_model(), Config->get_xfades_active()));
-                               add_crossfade (xfade);
-                       }
-               }
+       /* disable fade out of the last region */
 
-               catch (failed_constructor& err) {
-                       continue;
-               }
-               
-               catch (Crossfade::NoCrossfadeHere& err) {
-                       continue;
-               }
-               
+       if (ar) {
+               ar->set_fade_out_active (false);
        }
 }
 
 void
-AudioPlaylist::add_crossfade (boost::shared_ptr<Crossfade> xfade)
+AudioPlaylist::post_combine (vector<boost::shared_ptr<Region> >& originals, boost::shared_ptr<Region> compound_region)
 {
-       Crossfades::iterator ci;
+       RegionSortByPosition cmp;
+       boost::shared_ptr<AudioRegion> ar;
+       boost::shared_ptr<AudioRegion> cr;
 
-       for (ci = _crossfades.begin(); ci != _crossfades.end(); ++ci) {
-               if (*(*ci) == *xfade) { // Crossfade::operator==()
-                       break;
-               }
+       if ((cr = boost::dynamic_pointer_cast<AudioRegion> (compound_region)) == 0) {
+               return;
        }
-       
-       if (ci != _crossfades.end()) {
-               // it will just go away
-       } else {
-               _crossfades.push_back (xfade);
 
-               xfade->Invalidated.connect (mem_fun (*this, &AudioPlaylist::crossfade_invalidated));
-               xfade->StateChanged.connect (mem_fun (*this, &AudioPlaylist::crossfade_changed));
+       sort (originals.begin(), originals.end(), cmp);
+
+       ar = boost::dynamic_pointer_cast<AudioRegion> (originals.front());
+
+       /* copy the fade in of the first into the compound region */
 
-               notify_crossfade_added (xfade);
+       if (ar) {
+               cr->set_fade_in (ar->fade_in());
        }
-}
-       
-void AudioPlaylist::notify_crossfade_added (boost::shared_ptr<Crossfade> x)
-{
-       if (g_atomic_int_get(&block_notifications)) {
-               _pending_xfade_adds.insert (_pending_xfade_adds.end(), x);
-       } else {
 
-               NewCrossfade (x); /* EMIT SIGNAL */
+       ar = boost::dynamic_pointer_cast<AudioRegion> (originals.back());
+
+       if (ar) {
+               /* copy the fade out of the last into the compound region */
+               cr->set_fade_out (ar->fade_out());
        }
 }
 
 void
-AudioPlaylist::crossfade_invalidated (boost::shared_ptr<Region> r)
+AudioPlaylist::pre_uncombine (vector<boost::shared_ptr<Region> >& originals, boost::shared_ptr<Region> compound_region)
 {
-       Crossfades::iterator i;
-       boost::shared_ptr<Crossfade> xfade = boost::dynamic_pointer_cast<Crossfade> (r);
-
-       xfade->in()->resume_fade_in ();
-       xfade->out()->resume_fade_out ();
+       RegionSortByPosition cmp;
+       boost::shared_ptr<AudioRegion> ar;
+       boost::shared_ptr<AudioRegion> cr = boost::dynamic_pointer_cast<AudioRegion>(compound_region);
 
-       if ((i = find (_crossfades.begin(), _crossfades.end(), xfade)) != _crossfades.end()) {
-               _crossfades.erase (i);
+       if (!cr) {
+               return;
        }
-}
 
-int
-AudioPlaylist::set_state (const XMLNode& node)
-{
-       XMLNode *child;
-       XMLNodeList nlist;
-       XMLNodeConstIterator niter;
+       sort (originals.begin(), originals.end(), cmp);
 
-       in_set_state++;
-       freeze ();
+       /* no need to call clear_changes() on the originals because that is
+        * done within Playlist::uncombine ()
+        */
 
-       Playlist::set_state (node);
+       for (vector<boost::shared_ptr<Region> >::iterator i = originals.begin(); i != originals.end(); ++i) {
 
-       nlist = node.children();
+               if ((ar = boost::dynamic_pointer_cast<AudioRegion> (*i)) == 0) {
+                       continue;
+               }
 
-       for (niter = nlist.begin(); niter != nlist.end(); ++niter) {
+               /* scale the uncombined regions by any gain setting for the
+                * compound one.
+                */
 
-               child = *niter;
+               ar->set_scale_amplitude (ar->scale_amplitude() * cr->scale_amplitude());
 
-               if (child->name() != "Crossfade") {
-                       continue;
-               }
+               if (i == originals.begin()) {
 
-               try {
-                       boost::shared_ptr<Crossfade> xfade = boost::shared_ptr<Crossfade> (new Crossfade (*((const Playlist *)this), *child));
-                       _crossfades.push_back (xfade);
-                       xfade->Invalidated.connect (mem_fun (*this, &AudioPlaylist::crossfade_invalidated));
-                       xfade->StateChanged.connect (mem_fun (*this, &AudioPlaylist::crossfade_changed));
-                       NewCrossfade(xfade);
-               }
-               
-               catch (failed_constructor& err) {
-                       //      cout << string_compose (_("could not create crossfade object in playlist %1"),
-                       //        _name) 
-                       //    << endl;
-                       continue;
-               }
-       }
+                       /* copy the compound region's fade in back into the first
+                          original region.
+                       */
 
-       thaw ();
-       in_set_state--;
+                       if (cr->fade_in()->back()->when <= ar->length()) {
+                               /* don't do this if the fade is longer than the
+                                * region
+                                */
+                               ar->set_fade_in (cr->fade_in());
+                       }
 
-       return 0;
-}
 
-void
-AudioPlaylist::clear (bool with_signals)
-{
-       _crossfades.clear ();
-       Playlist::clear (with_signals);
-}
+               } else if (*i == originals.back()) {
 
-XMLNode&
-AudioPlaylist::state (bool full_state)
-{
-       XMLNode& node = Playlist::state (full_state);
+                       /* copy the compound region's fade out back into the last
+                          original region.
+                       */
+
+                       if (cr->fade_out()->back()->when <= ar->length()) {
+                               /* don't do this if the fade is longer than the
+                                * region
+                                */
+                               ar->set_fade_out (cr->fade_out());
+                       }
 
-       if (full_state) {
-               for (Crossfades::iterator i = _crossfades.begin(); i != _crossfades.end(); ++i) {
-                       node.add_child_nocopy ((*i)->get_state());
                }
+
+               _session.add_command (new StatefulDiffCommand (*i));
        }
-       
-       return node;
 }
 
-void
-AudioPlaylist::dump () const
+int
+AudioPlaylist::set_state (const XMLNode& node, int version)
 {
-       boost::shared_ptr<Region>r;
-       boost::shared_ptr<Crossfade> x;
-
-       cerr << "Playlist \"" << _name << "\" " << endl
-            << regions.size() << " regions "
-            << _crossfades.size() << " crossfades"
-            << endl;
-
-       for (RegionList::const_iterator i = regions.begin(); i != regions.end(); ++i) {
-               r = *i;
-               cerr << "  " << r->name() << " @ " << r << " [" 
-                    << r->start() << "+" << r->length() 
-                    << "] at " 
-                    << r->position()
-                    << " on layer "
-                    << r->layer ()
-                    << endl;
-       }
-
-       for (Crossfades::const_iterator i = _crossfades.begin(); i != _crossfades.end(); ++i) {
-               x = *i;
-               cerr << "  xfade [" 
-                    << x->out()->name()
-                    << ','
-                    << x->in()->name()
-                    << " @ "
-                    << x->position()
-                    << " length = " 
-                    << x->length ()
-                    << " active ? "
-                    << (x->active() ? "yes" : "no")
-                    << endl;
-       }
+       return Playlist::set_state (node, version);
 }
 
-bool
-AudioPlaylist::destroy_region (boost::shared_ptr<Region> region)
+void
+AudioPlaylist::load_legacy_crossfades (const XMLNode& node, int version)
 {
-       boost::shared_ptr<AudioRegion> r = boost::dynamic_pointer_cast<AudioRegion> (region);
-       bool changed = false;
-       Crossfades::iterator c, ctmp;
-       set<boost::shared_ptr<Crossfade> > unique_xfades;
+       /* Read legacy Crossfade nodes and set up region fades accordingly */
 
-       if (r == 0) {
-               fatal << _("programming error: non-audio Region passed to remove_overlap in audio playlist")
-                     << endmsg;
-               /*NOTREACHED*/
-               return false;
-       }
+       XMLNodeList children = node.children ();
+       for (XMLNodeConstIterator i = children.begin(); i != children.end(); ++i) {
+               if ((*i)->name() == X_("Crossfade")) {
 
-       { 
-               RegionLock rlock (this);
+                       XMLProperty const * p = (*i)->property (X_("active"));
+                       assert (p);
 
-               for (RegionList::iterator i = regions.begin(); i != regions.end(); ) {
-                       
-                       RegionList::iterator tmp = i;
-                       ++tmp;
-                       
-                       if ((*i) == region) {
-                               regions.erase (i);
-                               changed = true;
+                       if (!string_is_affirmative (p->value())) {
+                               continue;
                        }
-                       
-                       i = tmp;
-               }
 
-               for (set<boost::shared_ptr<Region> >::iterator x = all_regions.begin(); x != all_regions.end(); ) {
-
-                       set<boost::shared_ptr<Region> >::iterator xtmp = x;
-                       ++xtmp;
-                       
-                       if ((*x) == region) {
-                               all_regions.erase (x);
-                               changed = true;
+                       if ((p = (*i)->property (X_("in"))) == 0) {
+                               continue;
                        }
-                       
-                       x = xtmp;
-               }
 
-               region->set_playlist (boost::shared_ptr<Playlist>());
-       }
+                       boost::shared_ptr<Region> in = region_by_id (PBD::ID (p->value ()));
 
-       for (c = _crossfades.begin(); c != _crossfades.end(); ) {
-               ctmp = c;
-               ++ctmp;
+                       if (!in) {
+                               warning << string_compose (_("Legacy crossfade involved an incoming region not present in playlist \"%1\" - crossfade discarded"),
+                                                          name())
+                                       << endmsg;
+                               continue;
+                       }
 
-               if ((*c)->involves (r)) {
-                       unique_xfades.insert (*c);
-                       _crossfades.erase (c);
-               }
-               
-               c = ctmp;
-       }
+                       boost::shared_ptr<AudioRegion> in_a = boost::dynamic_pointer_cast<AudioRegion> (in);
+                       assert (in_a);
 
-       if (changed) {
-               /* overload this, it normally means "removed", not destroyed */
-               notify_region_removed (region);
-       }
+                       if ((p = (*i)->property (X_("out"))) == 0) {
+                               continue;
+                       }
 
-       return changed;
-}
+                       boost::shared_ptr<Region> out = region_by_id (PBD::ID (p->value ()));
 
-void
-AudioPlaylist::crossfade_changed (Change ignored)
-{
-       if (in_flush || in_set_state) {
-               return;
-       }
+                       if (!out) {
+                               warning << string_compose (_("Legacy crossfade involved an outgoing region not present in playlist \"%1\" - crossfade discarded"),
+                                                          name())
+                                       << endmsg;
+                               continue;
+                       }
 
-       /* XXX is there a loop here? can an xfade change not happen
-          due to a playlist change? well, sure activation would
-          be an example. maybe we should check the type of change
-          that occured.
-       */
+                       boost::shared_ptr<AudioRegion> out_a = boost::dynamic_pointer_cast<AudioRegion> (out);
+                       assert (out_a);
 
-       notify_modified ();
-}
+                       /* now decide whether to add a fade in or fade out
+                        * xfade and to which region
+                        */
 
-bool
-AudioPlaylist::region_changed (Change what_changed, boost::shared_ptr<Region> region)
-{
-       if (in_flush || in_set_state) {
-               return false;
-       }
+                       if (in->layer() <= out->layer()) {
 
-       Change our_interests = Change (AudioRegion::FadeInChanged|
-                                      AudioRegion::FadeOutChanged|
-                                      AudioRegion::FadeInActiveChanged|
-                                      AudioRegion::FadeOutActiveChanged|
-                                      AudioRegion::EnvelopeActiveChanged|
-                                      AudioRegion::ScaleAmplitudeChanged|
-                                      AudioRegion::EnvelopeChanged);
-       bool parent_wants_notify;
+                               /* incoming region is below the outgoing one,
+                                * so apply a fade out to the outgoing one
+                                */
 
-       parent_wants_notify = Playlist::region_changed (what_changed, region);
+                               const XMLNodeList c = (*i)->children ();
 
-       if ((parent_wants_notify || (what_changed & our_interests))) {
-               notify_modified ();
-       }
+                               for (XMLNodeConstIterator j = c.begin(); j != c.end(); ++j) {
+                                       if ((*j)->name() == X_("FadeOut")) {
+                                               out_a->fade_out()->set_state (**j, version);
+                                       } else if ((*j)->name() == X_("FadeIn")) {
+                                               out_a->inverse_fade_out()->set_state (**j, version);
+                                       }
+                               }
 
-       return true; 
-}
+                               out_a->set_fade_out_active (true);
 
-void
-AudioPlaylist::crossfades_at (nframes_t frame, Crossfades& clist)
-{
-       RegionLock rlock (this);
+                       } else {
 
-       for (Crossfades::iterator i = _crossfades.begin(); i != _crossfades.end(); ++i) {
-               nframes_t start, end;
+                               /* apply a fade in to the incoming region,
+                                * since its above the outgoing one
+                                */
 
-               start = (*i)->position();
-               end = start + (*i)->overlap_length(); // not length(), important difference
+                               const XMLNodeList c = (*i)->children ();
 
-               if (frame >= start && frame <= end) {
-                       clist.push_back (*i);
-               } 
+                               for (XMLNodeConstIterator j = c.begin(); j != c.end(); ++j) {
+                                       if ((*j)->name() == X_("FadeIn")) {
+                                               in_a->fade_in()->set_state (**j, version);
+                                       } else if ((*j)->name() == X_("FadeOut")) {
+                                               in_a->inverse_fade_in()->set_state (**j, version);
+                                       }
+                               }
+
+                               in_a->set_fade_in_active (true);
+                       }
+               }
        }
 }
-