tweaks to be ready for more information timecode display in Timecode clock mode
[ardour.git] / libs / ardour / session_transport.cc
index aa398f76dd63b9b2a0e3367519ea6510d5c6ea98..6141716301c23615e5fb8db2331b50dbcf8c0386 100644 (file)
 
 */
 
+#ifdef WAF_BUILD
+#include "libardour-config.h"
+#endif
+
 #include <cmath>
 #include <cerrno>
 #include <unistd.h>
 
-#include <sigc++/bind.h>
-#include <sigc++/retype.h>
-
 #include "pbd/undo.h"
 #include "pbd/error.h"
-#include <glibmm/thread.h>
+#include "pbd/enumwriter.h"
 #include "pbd/pthread_utils.h"
 #include "pbd/memento_command.h"
-#include "pbd/stacktrace.h"
 
 #include "midi++/mmc.h"
 #include "midi++/port.h"
+#include "midi++/manager.h"
 
-#include "ardour/ardour.h"
-#include "ardour/audio_diskstream.h"
 #include "ardour/audioengine.h"
 #include "ardour/auditioner.h"
 #include "ardour/butler.h"
+#include "ardour/click.h"
+#include "ardour/debug.h"
 #include "ardour/location.h"
 #include "ardour/session.h"
 #include "ardour/slave.h"
+#include "ardour/operations.h"
 
 #include "i18n.h"
 
 using namespace std;
 using namespace ARDOUR;
-using namespace sigc;
 using namespace PBD;
 
+void
+Session::add_post_transport_work (PostTransportWork ptw)
+{
+       PostTransportWork oldval;
+       PostTransportWork newval;
+       int tries = 0;
+
+       while (tries < 8) {
+               oldval = (PostTransportWork) g_atomic_int_get (&_post_transport_work);
+               newval = PostTransportWork (oldval | ptw);
+               if (g_atomic_int_compare_and_exchange (&_post_transport_work, oldval, newval)) {
+                       /* success */
+                       return;
+               }
+       }
+
+       error << "Could not set post transport work! Crazy thread madness, call the programmers" << endmsg;
+}
+
 void
 Session::request_input_change_handling ()
 {
        if (!(_state_of_the_state & (InitialConnecting|Deletion))) {
-               Event* ev = new Event (Event::InputConfigurationChange, Event::Add, Event::Immediate, 0, 0.0);
+               SessionEvent* ev = new SessionEvent (SessionEvent::InputConfigurationChange, SessionEvent::Add, SessionEvent::Immediate, 0, 0.0);
                queue_event (ev);
        }
 }
 
 void
-Session::request_slave_source (SlaveSource src)
+Session::request_sync_source (Slave* new_slave)
 {
-       Event* ev = new Event (Event::SetSlaveSource, Event::Add, Event::Immediate, 0, 0.0);
+       SessionEvent* ev = new SessionEvent (SessionEvent::SetSyncSource, SessionEvent::Add, SessionEvent::Immediate, 0, 0.0);
+       bool seamless;
+
+       seamless = Config->get_seamless_loop ();
 
-       if (src == JACK) {
-               /* could set_seamless_loop() be disposed of entirely?*/
+       if (dynamic_cast<JACK_Slave*>(new_slave)) {
+               /* JACK cannot support seamless looping at present */
                Config->set_seamless_loop (false);
        } else {
-               Config->set_seamless_loop (true);
+               /* reset to whatever the value was before we last switched slaves */
+               Config->set_seamless_loop (_was_seamless);
        }
-       ev->slave = src;
+
+       /* save value of seamless from before the switch */
+       _was_seamless = seamless;
+
+       ev->slave = new_slave;
+       DEBUG_TRACE (DEBUG::Slave, "sent request for new slave\n");
        queue_event (ev);
 }
 
 void
-Session::request_transport_speed (double speed)
+Session::request_transport_speed (double speed, bool as_default)
 {
-       Event* ev = new Event (Event::SetTransportSpeed, Event::Add, Event::Immediate, 0, speed);
+       SessionEvent* ev = new SessionEvent (SessionEvent::SetTransportSpeed, SessionEvent::Add, SessionEvent::Immediate, 0, speed);
+       ev->third_yes_or_no = true;
+       DEBUG_TRACE (DEBUG::Transport, string_compose ("Request transport speed = %1 as default = %2\n", speed, as_default));
        queue_event (ev);
 }
 
+/** Request a new transport speed, but if the speed parameter is exactly zero then use
+ *  a very small +ve value to prevent the transport actually stopping.  This method should
+ *  be used by callers who are varying transport speed but don't ever want to stop it.
+ */
+void
+Session::request_transport_speed_nonzero (double speed, bool as_default)
+{
+       if (speed == 0) {
+               speed = DBL_EPSILON;
+       }
+
+       request_transport_speed (speed, as_default);
+}
+
 void
-Session::request_diskstream_speed (Diskstream& ds, double speed)
+Session::request_track_speed (Track* tr, double speed)
 {
-       Event* ev = new Event (Event::SetDiskstreamSpeed, Event::Add, Event::Immediate, 0, speed);
-       ev->set_ptr (&ds);
+       SessionEvent* ev = new SessionEvent (SessionEvent::SetTrackSpeed, SessionEvent::Add, SessionEvent::Immediate, 0, speed);
+       ev->set_ptr (tr);
        queue_event (ev);
 }
 
 void
-Session::request_stop (bool abort)
+Session::request_stop (bool abort, bool clear_state)
 {
-       Event* ev = new Event (Event::SetTransportSpeed, Event::Add, Event::Immediate, 0, 0.0, abort);
+       SessionEvent* ev = new SessionEvent (SessionEvent::SetTransportSpeed, SessionEvent::Add, SessionEvent::Immediate, 0, 0.0, abort, clear_state);
+       DEBUG_TRACE (DEBUG::Transport, string_compose ("Request transport stop, abort = %1, clear state = %2\n", abort, clear_state));
        queue_event (ev);
 }
 
 void
-Session::request_locate (nframes_t target_frame, bool with_roll)
+Session::request_locate (framepos_t target_frame, bool with_roll)
 {
-       Event *ev = new Event (with_roll ? Event::LocateRoll : Event::Locate, Event::Add, Event::Immediate, target_frame, 0, false);
+       SessionEvent *ev = new SessionEvent (with_roll ? SessionEvent::LocateRoll : SessionEvent::Locate, SessionEvent::Add, SessionEvent::Immediate, target_frame, 0, false);
+       DEBUG_TRACE (DEBUG::Transport, string_compose ("Request locate to %1\n", target_frame));
        queue_event (ev);
 }
 
 void
-Session::force_locate (nframes_t target_frame, bool with_roll)
+Session::force_locate (framepos_t target_frame, bool with_roll)
 {
-       Event *ev = new Event (with_roll ? Event::LocateRoll : Event::Locate, Event::Add, Event::Immediate, target_frame, 0, true);
+       SessionEvent *ev = new SessionEvent (with_roll ? SessionEvent::LocateRoll : SessionEvent::Locate, SessionEvent::Add, SessionEvent::Immediate, target_frame, 0, true);
+       DEBUG_TRACE (DEBUG::Transport, string_compose ("Request forced locate to %1\n", target_frame));
        queue_event (ev);
 }
 
 void
-Session::request_play_loop (bool yn)
+Session::request_play_loop (bool yn, bool leave_rolling)
 {
-       Event* ev;
-       Location *location = _locations.auto_loop_location();
+       SessionEvent* ev;
+       Location *location = _locations->auto_loop_location();
 
        if (location == 0 && yn) {
                error << _("Cannot loop - no loop range defined")
@@ -122,68 +170,114 @@ Session::request_play_loop (bool yn)
                return;
        }
 
-       ev = new Event (Event::SetLoop, Event::Add, Event::Immediate, 0, 0.0, yn);
+       ev = new SessionEvent (SessionEvent::SetLoop, SessionEvent::Add, SessionEvent::Immediate, 0, (leave_rolling ? 1.0 : 0.0), yn);
+       DEBUG_TRACE (DEBUG::Transport, string_compose ("Request set loop = %1, leave rolling ? %2\n", yn, leave_rolling));
        queue_event (ev);
 
-       if (!yn && Config->get_seamless_loop() && transport_rolling()) {
-               // request an immediate locate to refresh the diskstreams
+       if (!leave_rolling && !yn && Config->get_seamless_loop() && transport_rolling()) {
+               // request an immediate locate to refresh the tracks
                // after disabling looping
                request_locate (_transport_frame-1, false);
        }
 }
 
 void
-Session::realtime_stop (bool abort)
+Session::request_play_range (list<AudioRange>* range, bool leave_rolling)
 {
-       /* assume that when we start, we'll be moving forwards */
+       SessionEvent* ev = new SessionEvent (SessionEvent::SetPlayAudioRange, SessionEvent::Add, SessionEvent::Immediate, 0, (leave_rolling ? 1.0 : 0.0));
+       if (range) {
+               ev->audio_range = *range;
+       } else {
+               ev->audio_range.clear ();
+       }
+       DEBUG_TRACE (DEBUG::Transport, string_compose ("Request play range, leave rolling ? %1\n", leave_rolling));
+       queue_event (ev);
+}
 
-       // FIXME: where should this really be? [DR]
-       //send_full_time_code();
-       deliver_mmc (MIDI::MachineControl::cmdStop, 0);
-       deliver_mmc (MIDI::MachineControl::cmdLocate, _transport_frame);
+void
+Session::realtime_stop (bool abort, bool clear_state)
+{
+       DEBUG_TRACE (DEBUG::Transport, string_compose ("realtime stop @ %1\n", _transport_frame));
+       PostTransportWork todo = PostTransportWork (0);
+
+       /* assume that when we start, we'll be moving forwards */
 
        if (_transport_speed < 0.0f) {
-               post_transport_work = PostTransportWork (post_transport_work | PostTransportStop | PostTransportReverse);
+               todo = (PostTransportWork (todo | PostTransportStop | PostTransportReverse));
        } else {
-               post_transport_work = PostTransportWork (post_transport_work | PostTransportStop);
+               todo = PostTransportWork (todo | PostTransportStop);
+       }
+
+       /* call routes */
+
+       boost::shared_ptr<RouteList> r = routes.reader ();
+
+       for (RouteList::iterator i = r->begin (); i != r->end(); ++i) {
+               (*i)->realtime_handle_transport_stopped ();
        }
 
        if (actively_recording()) {
 
                /* move the transport position back to where the
                   request for a stop was noticed. we rolled
-                  past that point to pick up delayed input.
+                  past that point to pick up delayed input (and/or to delick)
                */
 
-#ifndef LEAVE_TRANSPORT_UNADJUSTED
-               decrement_transport_position (_worst_output_latency);
-#endif
+               if (worst_playback_latency() > current_block_size) {
+                       /* we rolled past the stop point to pick up data that had
+                          not yet arrived. move back to where the stop occured.
+                       */
+                       decrement_transport_position (current_block_size + (worst_input_latency() - current_block_size));
+               } else {
+                       decrement_transport_position (current_block_size);
+               }
 
                /* the duration change is not guaranteed to have happened, but is likely */
 
-               post_transport_work = PostTransportWork (post_transport_work | PostTransportDuration);
+               todo = PostTransportWork (todo | PostTransportDuration);
        }
 
        if (abort) {
-               post_transport_work = PostTransportWork (post_transport_work | PostTransportAbort);
+               todo = PostTransportWork (todo | PostTransportAbort);
+       }
+
+       if (clear_state) {
+               todo = PostTransportWork (todo | PostTransportClearSubstate);
        }
 
-       _clear_event_type (Event::StopOnce);
-       _clear_event_type (Event::RangeStop);
-       _clear_event_type (Event::RangeLocate);
+       if (todo) {
+               add_post_transport_work (todo);
+       }
+
+       _clear_event_type (SessionEvent::StopOnce);
+       _clear_event_type (SessionEvent::RangeStop);
+       _clear_event_type (SessionEvent::RangeLocate);
 
-       disable_record (true);
+       /* if we're going to clear loop state, then force disabling record BUT only if we're not doing latched rec-enable */
+       disable_record (true, (!Config->get_latched_record_enable() && clear_state));
 
        reset_slave_state ();
 
        _transport_speed = 0;
        _target_transport_speed = 0;
 
+       g_atomic_int_set (&_playback_load, 100);
+       g_atomic_int_set (&_capture_load, 100);
+
        if (config.get_use_video_sync()) {
                waiting_for_sync_offset = true;
        }
 
-       transport_sub_state = ((Config->get_slave_source() == None && config.get_auto_return()) ? AutoReturning : 0);
+       transport_sub_state = 0;
+}
+
+void
+Session::realtime_locate ()
+{
+       boost::shared_ptr<RouteList> r = routes.reader ();
+       for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
+               (*i)->realtime_locate ();
+       }
 }
 
 void
@@ -191,29 +285,56 @@ Session::butler_transport_work ()
 {
   restart:
        bool finished;
+       PostTransportWork ptw;
        boost::shared_ptr<RouteList> r = routes.reader ();
-       boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
 
        int on_entry = g_atomic_int_get (&_butler->should_do_transport_work);
        finished = true;
+       ptw = post_transport_work();
 
-       if (post_transport_work & PostTransportCurveRealloc) {
+       DEBUG_TRACE (DEBUG::Transport, string_compose ("Butler transport work, todo = %1\n", enum_2_string (ptw)));
+
+       if (ptw & PostTransportAdjustPlaybackBuffering) {
+               for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
+                       boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+                       if (tr) {
+                               tr->adjust_playback_buffering ();
+                               /* and refill those buffers ... */
+                       }
+                       (*i)->non_realtime_locate (_transport_frame);
+               }
+
+       }
+
+       if (ptw & PostTransportAdjustCaptureBuffering) {
+               for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
+                       boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+                       if (tr) {
+                               tr->adjust_capture_buffering ();
+                       }
+               }
+       }
+
+       if (ptw & PostTransportCurveRealloc) {
                for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
                        (*i)->curve_reallocate();
                }
        }
 
-       if (post_transport_work & PostTransportInputChange) {
-               for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-                       (*i)->non_realtime_input_change ();
+       if (ptw & PostTransportInputChange) {
+               for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
+                       boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+                       if (tr) {
+                               tr->non_realtime_input_change ();
+                       }
                }
        }
 
-       if (post_transport_work & PostTransportSpeed) {
+       if (ptw & PostTransportSpeed) {
                non_realtime_set_speed ();
        }
 
-       if (post_transport_work & PostTransportReverse) {
+       if (ptw & PostTransportReverse) {
 
                clear_clicks();
                cumulative_rf_motion = 0;
@@ -221,12 +342,11 @@ Session::butler_transport_work ()
 
                /* don't seek if locate will take care of that in non_realtime_stop() */
 
-               if (!(post_transport_work & PostTransportLocate)) {
+               if (!(ptw & PostTransportLocate)) {
+
+                       for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
+                               (*i)->non_realtime_locate (_transport_frame);
 
-                       for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-                               if (!(*i)->hidden()) {
-                                       (*i)->non_realtime_locate (_transport_frame);
-                               }
                                if (on_entry != g_atomic_int_get (&_butler->should_do_transport_work)) {
                                        /* new request, stop seeking, and start again */
                                        g_atomic_int_dec_and_test (&_butler->should_do_transport_work);
@@ -236,19 +356,19 @@ Session::butler_transport_work ()
                }
        }
 
-       if (post_transport_work & PostTransportLocate) {
+       if (ptw & PostTransportLocate) {
                non_realtime_locate ();
        }
 
-       if (post_transport_work & PostTransportStop) {
-               non_realtime_stop (post_transport_work & PostTransportAbort, on_entry, finished);
+       if (ptw & PostTransportStop) {
+               non_realtime_stop (ptw & PostTransportAbort, on_entry, finished);
                if (!finished) {
                        g_atomic_int_dec_and_test (&_butler->should_do_transport_work);
                        goto restart;
                }
        }
 
-       if (post_transport_work & PostTransportOverWrite) {
+       if (ptw & PostTransportOverWrite) {
                non_realtime_overwrite (on_entry, finished);
                if (!finished) {
                        g_atomic_int_dec_and_test (&_butler->should_do_transport_work);
@@ -256,31 +376,35 @@ Session::butler_transport_work ()
                }
        }
 
-       if (post_transport_work & PostTransportAudition) {
+       if (ptw & PostTransportAudition) {
                non_realtime_set_audition ();
        }
 
        g_atomic_int_dec_and_test (&_butler->should_do_transport_work);
+
+       DEBUG_TRACE (DEBUG::Transport, X_("Butler transport work all done\n"));
 }
 
 void
 Session::non_realtime_set_speed ()
 {
-       boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
-
-       for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-               (*i)->non_realtime_set_speed ();
+       boost::shared_ptr<RouteList> rl = routes.reader();
+       for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
+               boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+               if (tr) {
+                       tr->non_realtime_set_speed ();
+               }
        }
 }
 
 void
 Session::non_realtime_overwrite (int on_entry, bool& finished)
 {
-       boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
-
-       for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-               if ((*i)->pending_overwrite) {
-                       (*i)->overwrite_existing_buffers ();
+       boost::shared_ptr<RouteList> rl = routes.reader();
+       for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
+               boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+               if (tr && tr->pending_overwrite ()) {
+                       tr->overwrite_existing_buffers ();
                }
                if (on_entry != g_atomic_int_get (&_butler->should_do_transport_work)) {
                        finished = false;
@@ -293,11 +417,16 @@ Session::non_realtime_overwrite (int on_entry, bool& finished)
 void
 Session::non_realtime_locate ()
 {
-       boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
-
-       for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
+       boost::shared_ptr<RouteList> rl = routes.reader();
+       for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
                (*i)->non_realtime_locate (_transport_frame);
        }
+
+       /* XXX: it would be nice to generate the new clicks here (in the non-RT thread)
+          rather than clearing them so that the RT thread has to spend time constructing
+          them (in Session::click).
+        */
+       clear_clicks ();
 }
 
 
@@ -308,14 +437,15 @@ Session::non_realtime_stop (bool abort, int on_entry, bool& finished)
        time_t     xnow;
        bool       did_record;
        bool       saved;
+       PostTransportWork ptw = post_transport_work();
 
        did_record = false;
        saved = false;
 
-       boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
-
-       for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-               if ((*i)->get_captured_frames () != 0) {
+       boost::shared_ptr<RouteList> rl = routes.reader();
+       for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
+               boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+               if (tr && tr->get_captured_frames () != 0) {
                        did_record = true;
                        break;
                }
@@ -330,47 +460,31 @@ Session::non_realtime_stop (bool abort, int on_entry, bool& finished)
                auditioner->cancel_audition ();
        }
 
-       clear_clicks();
        cumulative_rf_motion = 0;
        reset_rf_scale (0);
 
        if (did_record) {
-               begin_reversible_command ("capture");
-
-               Location* loc = _locations.end_location();
-               bool change_end = false;
-
-               if (_transport_frame < loc->end()) {
-
-                       /* stopped recording before current end */
-
-                       if (config.get_end_marker_is_free()) {
-
-                               /* first capture for this session, move end back to where we are */
-
-                               change_end = true;
-                       }
-
-               } else if (_transport_frame > loc->end()) {
+               begin_reversible_command (Operations::capture);
+               _have_captured = true;
+       }
 
-                       /* stopped recording after the current end, extend it */
+       DEBUG_TRACE (DEBUG::Transport, X_("Butler PTW: DS stop\n"));
 
-                       change_end = true;
-               }
+       if (abort && did_record) {
+               /* no reason to save the session file when we remove sources
+                */
+               _state_of_the_state = StateOfTheState (_state_of_the_state|InCleanup);
+       }
 
-               if (change_end) {
-                        XMLNode &before = loc->get_state();
-                        loc->set_end(_transport_frame);
-                        XMLNode &after = loc->get_state();
-                        add_command (new MementoCommand<Location>(*loc, &before, &after));
+       for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
+               boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+               if (tr) {
+                       tr->transport_stopped_wallclock (*now, xnow, abort);
                }
-
-               config.set_end_marker_is_free (false);
-               _have_captured = true;
        }
 
-       for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-               (*i)->transport_stopped (*now, xnow, abort);
+       if (abort && did_record) {
+               _state_of_the_state = StateOfTheState (_state_of_the_state & ~InCleanup);
        }
 
        boost::shared_ptr<RouteList> r = routes.reader ();
@@ -386,14 +500,18 @@ Session::non_realtime_stop (bool abort, int on_entry, bool& finished)
        }
 
        if (_engine.running()) {
-               update_latency_compensation (true, abort);
+               PostTransportWork ptw = post_transport_work ();
+               for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
+                       (*i)->nonrealtime_handle_transport_stopped (abort, (ptw & PostTransportLocate), (!(ptw & PostTransportLocate) || pending_locate_flush));
+               }
+               update_latency_compensation ();
        }
 
        bool const auto_return_enabled =
-               (Config->get_slave_source() == None && config.get_auto_return());
+               (!config.get_external_sync() && config.get_auto_return());
 
        if (auto_return_enabled ||
-           (post_transport_work & PostTransportLocate) ||
+           (ptw & PostTransportLocate) ||
            (_requested_return_frame >= 0) ||
            synced_to_jack()) {
 
@@ -402,74 +520,112 @@ Session::non_realtime_stop (bool abort, int on_entry, bool& finished)
                }
 
                if ((auto_return_enabled || synced_to_jack() || _requested_return_frame >= 0) &&
-                   !(post_transport_work & PostTransportLocate)) {
+                   !(ptw & PostTransportLocate)) {
+
+                       /* no explicit locate queued */
 
                        bool do_locate = false;
 
                        if (_requested_return_frame >= 0) {
+
+                               /* explicit return request pre-queued in event list. overrides everything else */
+
+                               cerr << "explicit auto-return to " << _requested_return_frame << endl;
+
                                _transport_frame = _requested_return_frame;
-                               _requested_return_frame = -1;
                                do_locate = true;
+
                        } else {
-                               _transport_frame = _last_roll_location;
-                       }
+                               if (config.get_auto_return()) {
 
-                       if (synced_to_jack() && !play_loop) {
-                               do_locate = true;
+                                       if (play_loop) {
+
+                                               /* don't try to handle loop play when synced to JACK */
+
+                                               if (!synced_to_jack()) {
+
+                                                       Location *location = _locations->auto_loop_location();
+
+                                                       if (location != 0) {
+                                                               _transport_frame = location->start();
+                                                       } else {
+                                                               _transport_frame = _last_roll_location;
+                                                       }
+                                                       do_locate = true;
+                                               }
+
+                                       } else if (_play_range) {
+
+                                               /* return to start of range */
+
+                                               if (!current_audio_range.empty()) {
+                                                       _transport_frame = current_audio_range.front().start;
+                                                       do_locate = true;
+                                               }
+
+                                       } else {
+
+                                               /* regular auto-return */
+
+                                               _transport_frame = _last_roll_location;
+                                               do_locate = true;
+                                       }
+                               }
                        }
 
+                       _requested_return_frame = -1;
+
                        if (do_locate) {
-                               // cerr << "non-realtimestop: transport locate to " << _transport_frame << endl;
                                _engine.transport_locate (_transport_frame);
                        }
                }
 
-#ifdef LEAVE_TRANSPORT_UNADJUSTED
-               for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-                       if (!(*i)->hidden()) {
-                               (*i)->non_realtime_locate (_transport_frame);
-                       }
-                       if (on_entry != g_atomic_int_get (&_butler->should_do_transport_work)) {
-                               finished = false;
-                               /* we will be back */
-                               return;
-                       }
-               }
-#endif
        }
 
-        have_looped = false;
+       clear_clicks();
 
-        send_full_time_code (0);
-       deliver_mmc (MIDI::MachineControl::cmdStop, 0);
-       deliver_mmc (MIDI::MachineControl::cmdLocate, _transport_frame);
+       /* do this before seeking, because otherwise the tracks will do the wrong thing in seamless loop mode.
+       */
 
-       if (did_record) {
+       if (ptw & PostTransportClearSubstate) {
+               _play_range = false;
+               unset_play_loop ();
+       }
 
-               /* XXX its a little odd that we're doing this here
-                  when realtime_stop(), which has already executed,
-                  will have done this.
-                  JLC - so let's not because it seems unnecessary and breaks loop record
-               */
-#if 0
-               if (!Config->get_latched_record_enable()) {
-                       g_atomic_int_set (&_record_status, Disabled);
-               } else {
-                       g_atomic_int_set (&_record_status, Enabled);
+       /* this for() block can be put inside the previous if() and has the effect of ... ??? what */
+
+       DEBUG_TRACE (DEBUG::Transport, X_("Butler PTW: locate\n"));
+       for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
+               DEBUG_TRACE (DEBUG::Transport, string_compose ("Butler PTW: locate on %1\n", (*i)->name()));
+               (*i)->non_realtime_locate (_transport_frame);
+
+               if (on_entry != g_atomic_int_get (&_butler->should_do_transport_work)) {
+                       finished = false;
+                       /* we will be back */
+                       return;
+               }
+       }
+
+       have_looped = false;
+
+       if (!_engine.freewheeling()) {
+               send_full_time_code (_transport_frame);
+               
+               if (!dynamic_cast<MTC_Slave*>(_slave)) {
+                       MIDI::Manager::instance()->mmc()->send (MIDI::MachineControlCommand (MIDI::MachineControl::cmdStop));
+                       send_mmc_locate (_transport_frame);
                }
-               RecordStateChanged (); /* emit signal */
-#endif
        }
 
-       if ((post_transport_work & PostTransportLocate) && get_record_enabled()) {
+       if ((ptw & PostTransportLocate) && get_record_enabled()) {
                /* capture start has been changed, so save pending state */
                save_state ("", true);
                saved = true;
        }
 
-        /* always try to get rid of this */
+       /* always try to get rid of this */
 
-        remove_pending_capture_state ();
+       remove_pending_capture_state ();
 
        /* save the current state of things if appropriate */
 
@@ -477,28 +633,25 @@ Session::non_realtime_stop (bool abort, int on_entry, bool& finished)
                save_state (_current_snapshot_name);
        }
 
-       if (post_transport_work & PostTransportDuration) {
-               DurationChanged (); /* EMIT SIGNAL */
-       }
-
-       if (post_transport_work & PostTransportStop) {
+       if (ptw & PostTransportStop) {
                _play_range = false;
-
-               /* do not turn off autoloop on stop */
-
+               play_loop = false;
        }
 
-        nframes_t tf = _transport_frame;
-
-        PositionChanged (tf); /* EMIT SIGNAL */
+       PositionChanged (_transport_frame); /* EMIT SIGNAL */
+       DEBUG_TRACE (DEBUG::Transport, string_compose ("send TSC with speed = %1\n", _transport_speed));
        TransportStateChange (); /* EMIT SIGNAL */
 
        /* and start it up again if relevant */
 
-       if ((post_transport_work & PostTransportLocate) && Config->get_slave_source() == None && pending_locate_roll) {
+       if ((ptw & PostTransportLocate) && !config.get_external_sync() && pending_locate_roll) {
                request_transport_speed (1.0);
-               pending_locate_roll = false;
        }
+
+       /* Even if we didn't do a pending locate roll this time, we don't want it hanging
+          around for next time.
+       */
+       pending_locate_roll = false;
 }
 
 void
@@ -508,7 +661,7 @@ Session::check_declick_out ()
 
        /* this is called after a process() iteration. if PendingDeclickOut was set,
           it means that we were waiting to declick the output (which has just been
-          done) before doing something else. this is where we do that "something else".
+          done) before maybe doing something else. this is where we do that "something else".
 
           note: called from the audio thread.
        */
@@ -522,6 +675,27 @@ Session::check_declick_out ()
                        stop_transport (pending_abort);
                        transport_sub_state &= ~(PendingDeclickOut|PendingLocate);
                }
+
+       } else if (transport_sub_state & PendingLoopDeclickOut) {
+               /* Nothing else to do here; we've declicked, and the loop event will be along shortly */
+               transport_sub_state &= ~PendingLoopDeclickOut;
+       }
+}
+
+void
+Session::unset_play_loop ()
+{
+       play_loop = false;
+       clear_events (SessionEvent::AutoLoop);
+       clear_events (SessionEvent::AutoLoopDeclick);
+
+       // set all tracks to NOT use internal looping
+       boost::shared_ptr<RouteList> rl = routes.reader ();
+       for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
+               boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+               if (tr && !tr->hidden()) {
+                       tr->set_loop (0);
+               }
        }
 }
 
@@ -530,79 +704,77 @@ Session::set_play_loop (bool yn)
 {
        /* Called from event-handling context */
 
-       if ((actively_recording() && yn) || _locations.auto_loop_location() == 0) {
+       Location *loc;
+
+       if (yn == play_loop || (actively_recording() && yn) || (loc = _locations->auto_loop_location()) == 0) {
+               /* nothing to do, or can't change loop status while recording */
                return;
        }
 
-       set_dirty();
-
        if (yn && Config->get_seamless_loop() && synced_to_jack()) {
-               warning << _("Seamless looping cannot be supported while Ardour is using JACK transport.\n"
-                            "Recommend changing the configured options")
+               warning << string_compose (
+                       _("Seamless looping cannot be supported while %1 is using JACK transport.\n"
+                         "Recommend changing the configured options"), PROGRAM_NAME)
                        << endmsg;
                return;
        }
 
+       if (yn) {
 
-       if ((play_loop = yn)) {
-
-               Location *loc;
+               play_loop = true;
 
+               if (loc) {
 
-               if ((loc = _locations.auto_loop_location()) != 0) {
+                       unset_play_range ();
 
                        if (Config->get_seamless_loop()) {
-                               // set all diskstreams to use internal looping
-                               boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
-                               for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-                                       if (!(*i)->hidden()) {
-                                               (*i)->set_loop (loc);
+                               // set all tracks to use internal looping
+                               boost::shared_ptr<RouteList> rl = routes.reader ();
+                               for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
+                                       boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+                                       if (tr && !tr->hidden()) {
+                                               tr->set_loop (loc);
                                        }
                                }
                        }
                        else {
-                               // set all diskstreams to NOT use internal looping
-                               boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
-                               for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-                                       if (!(*i)->hidden()) {
-                                               (*i)->set_loop (0);
+                               // set all tracks to NOT use internal looping
+                               boost::shared_ptr<RouteList> rl = routes.reader ();
+                               for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
+                                       boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+                                       if (tr && !tr->hidden()) {
+                                               tr->set_loop (0);
                                        }
                                }
                        }
 
-                       /* stick in the loop event */
+                       /* Put the delick and loop events in into the event list.  The declick event will
+                          cause a de-clicking fade-out just before the end of the loop, and it will also result
+                          in a fade-in when the loop restarts.  The AutoLoop event will peform the actual loop.
+                       */
 
-                       Event* event = new Event (Event::AutoLoop, Event::Replace, loc->end(), loc->start(), 0.0f);
-                       merge_event (event);
+                       framepos_t dcp;
+                       framecnt_t dcl;
+                       auto_loop_declick_range (loc, dcp, dcl);
+                       merge_event (new SessionEvent (SessionEvent::AutoLoopDeclick, SessionEvent::Replace, dcp, dcl, 0.0f));
+                       merge_event (new SessionEvent (SessionEvent::AutoLoop, SessionEvent::Replace, loc->end(), loc->start(), 0.0f));
 
-                       /* locate to start of loop and roll if current pos is outside of the loop range */
-                       if (_transport_frame < loc->start() || _transport_frame > loc->end()) {
-                               event = new Event (Event::LocateRoll, Event::Add, Event::Immediate, loc->start(), 0, !synced_to_jack());
-                               merge_event (event);
-                       }
-                       else {
-                               // locate to current position (+ 1 to force reload)
-                               event = new Event (Event::LocateRoll, Event::Add, Event::Immediate, _transport_frame + 1, 0, !synced_to_jack());
-                               merge_event (event);
-                       }
-               }
+                       /* locate to start of loop and roll. 
 
+                          args: positition, roll=true, flush=true, with_loop=false, force buffer refill if seamless looping
+                       */
 
+                       start_locate (loc->start(), true, true, false, Config->get_seamless_loop());
+               }
 
        } else {
-               clear_events (Event::AutoLoop);
-
-               // set all diskstreams to NOT use internal looping
-               boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
-               for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-                       if (!(*i)->hidden()) {
-                               (*i)->set_loop (0);
-                       }
-               }
 
+               unset_play_loop ();
        }
-}
 
+       DEBUG_TRACE (DEBUG::Transport, string_compose ("send TSC2 with speed = %1\n", _transport_speed));
+       TransportStateChange ();
+}
 void
 Session::flush_all_inserts ()
 {
@@ -614,17 +786,25 @@ Session::flush_all_inserts ()
 }
 
 void
-Session::start_locate (nframes_t target_frame, bool with_roll, bool with_flush, bool with_loop)
+Session::start_locate (framepos_t target_frame, bool with_roll, bool with_flush, bool with_loop, bool force)
 {
        if (synced_to_jack()) {
 
                double sp;
-               nframes_t pos;
+               framepos_t pos;
 
                _slave->speed_and_position (sp, pos);
 
                if (target_frame != pos) {
 
+                       if (config.get_jack_time_master()) {
+                               /* actually locate now, since otherwise jack_timebase_callback
+                                  will use the incorrect _transport_frame and report an old
+                                  and incorrect time to Jack transport
+                               */
+                               locate (target_frame, with_roll, with_flush, with_loop, force);
+                       }
+
                        /* tell JACK to change transport position, and we will
                           follow along later in ::follow_slave()
                        */
@@ -638,53 +818,62 @@ Session::start_locate (nframes_t target_frame, bool with_roll, bool with_flush,
                }
 
        } else {
-               locate (target_frame, with_roll, with_flush, with_loop);
+               locate (target_frame, with_roll, with_flush, with_loop, force);
        }
 }
 
 int
-Session::micro_locate (nframes_t distance)
+Session::micro_locate (framecnt_t distance)
 {
-       boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
-
-       for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-               if (!(*i)->can_internal_playback_seek (distance)) {
+       boost::shared_ptr<RouteList> rl = routes.reader();
+       for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
+               boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+               if (tr && !tr->can_internal_playback_seek (distance)) {
                        return -1;
                }
        }
 
-       for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-               (*i)->internal_playback_seek (distance);
+       for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
+               boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+               if (tr) {
+                       tr->internal_playback_seek (distance);
+               }
        }
 
        _transport_frame += distance;
        return 0;
 }
 
+/** @param with_mmc true to send a MMC locate command when the locate is done */
 void
-Session::locate (nframes_t target_frame, bool with_roll, bool with_flush, bool with_loop)
+Session::locate (framepos_t target_frame, bool with_roll, bool with_flush, bool for_seamless_loop, bool force, bool with_mmc)
 {
-       if (actively_recording() && !with_loop) {
+       /* Locates for seamless looping are fairly different from other
+        * locates. They assume that the diskstream buffers for each track
+        * already have the correct data in them, and thus there is no need to
+        * actually tell the tracks to locate. What does need to be done,
+        * though, is all the housekeeping that is associated with non-linear
+        * changes in the value of _transport_frame. 
+        */
+
+       if (actively_recording() && !for_seamless_loop) {
                return;
        }
 
-       if (_transport_frame == target_frame && !loop_changing && !with_loop) {
+       if (!force && _transport_frame == target_frame && !loop_changing && !for_seamless_loop) {
                if (with_roll) {
                        set_transport_speed (1.0, false);
                }
                loop_changing = false;
+               Located (); /* EMIT SIGNAL */
                return;
        }
 
-       // Update Timecode time
-       // [DR] FIXME: find out exactly where this should go below
-       _transport_frame = target_frame;
-       timecode_time(_transport_frame, transmitting_timecode_time);
-       outbound_mtc_timecode_frame = _transport_frame;
-       next_quarter_frame_to_send = 0;
-
-       if (_transport_speed && (!with_loop || loop_changing)) {
-               /* schedule a declick. we'll be called again when its done */
+       if (_transport_speed && !for_seamless_loop) {
+               /* Schedule a declick.  We'll be called again when its done.
+                  We only do it this way for ordinary locates, not those
+                  due to **seamless** loops.
+               */
 
                if (!(transport_sub_state & PendingDeclickOut)) {
                        transport_sub_state |= (PendingDeclickOut|PendingLocate);
@@ -695,25 +884,49 @@ Session::locate (nframes_t target_frame, bool with_roll, bool with_flush, bool w
                }
        }
 
-       if (transport_rolling() && (!auto_play_legal || !config.get_auto_play()) && !with_roll && !(synced_to_jack() && play_loop)) {
-               realtime_stop (false);
+       // Update Timecode time
+       // [DR] FIXME: find out exactly where this should go below
+       _transport_frame = target_frame;
+       _last_roll_or_reversal_location = target_frame;
+       timecode_time(_transport_frame, transmitting_timecode_time);
+       outbound_mtc_timecode_frame = _transport_frame;
+       next_quarter_frame_to_send = 0;
+
+       /* do "stopped" stuff if:
+        *
+        * we are rolling AND
+        *    no autoplay in effect AND
+         *       we're not going to keep rolling after the locate AND
+         *           !(playing a loop with JACK sync)
+         *
+        */
+
+       bool transport_was_stopped = !transport_rolling();
+
+       if (transport_was_stopped && (!auto_play_legal || !config.get_auto_play()) && !with_roll && !(synced_to_jack() && play_loop)) {
+               realtime_stop (false, true); // XXX paul - check if the 2nd arg is really correct
+               transport_was_stopped = true;
+       } else {
+               /* otherwise tell the world that we located */
+               realtime_locate ();
        }
 
-       if ( !with_loop || loop_changing) {
+       if (force || !for_seamless_loop || loop_changing) {
 
-               post_transport_work = PostTransportWork (post_transport_work | PostTransportLocate);
+               PostTransportWork todo = PostTransportLocate;
 
-               if (with_roll) {
-                       post_transport_work = PostTransportWork (post_transport_work | PostTransportRoll);
+               if (with_roll && transport_was_stopped) {
+                       todo = PostTransportWork (todo | PostTransportRoll);
                }
 
+               add_post_transport_work (todo);
                _butler->schedule_transport_work ();
 
        } else {
 
                /* this is functionally what clear_clicks() does but with a tentative lock */
 
-               Glib::RWLock::WriterLock clickm (click_lock, Glib::TRY_LOCK);
+               Glib::Threads::RWLock::WriterLock clickm (click_lock, Glib::Threads::TRY_LOCK);
 
                if (clickm.locked()) {
 
@@ -728,53 +941,50 @@ Session::locate (nframes_t target_frame, bool with_roll, bool with_flush, bool w
        if (with_roll) {
                /* switch from input if we're going to roll */
                if (Config->get_monitoring_model() == HardwareMonitoring) {
-
-                       boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
-
-                       for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-                               if ((*i)->record_enabled ()) {
-                                       //cerr << "switching from input" << __FILE__ << __LINE__ << endl << endl;
-                                       (*i)->monitor_input (!config.get_auto_input());
-                               }
-                       }
+                       set_track_monitor_input_status (!config.get_auto_input());
                }
        } else {
                /* otherwise we're going to stop, so do the opposite */
                if (Config->get_monitoring_model() == HardwareMonitoring) {
-                       boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
-
-                       for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-                               if ((*i)->record_enabled ()) {
-                                       //cerr << "switching to input" << __FILE__ << __LINE__ << endl << endl;
-                                       (*i)->monitor_input (true);
-                               }
-                       }
+                       set_track_monitor_input_status (true);
                }
        }
 
        /* cancel looped playback if transport pos outside of loop range */
        if (play_loop) {
-               Location* al = _locations.auto_loop_location();
 
-               if (al && (_transport_frame < al->start() || _transport_frame > al->end())) {
-                       // cancel looping directly, this is called from event handling context
-                       set_play_loop (false);
-               }
-               else if (al && _transport_frame == al->start()) {
-                       if (with_loop) {
-                               // this is only necessary for seamless looping
+               Location* al = _locations->auto_loop_location();
 
-                               boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
+               if (al) {
+                       if (_transport_frame < al->start() || _transport_frame > al->end()) {
 
-                               for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-                                       if ((*i)->record_enabled ()) {
-                                               // tell it we've looped, so it can deal with the record state
-                                               (*i)->transport_looped(_transport_frame);
+                               // located outside the loop: cancel looping directly, this is called from event handling context
+
+                               set_play_loop (false);
+                               
+                       } else if (_transport_frame == al->start()) {
+
+                               // located to start of loop - this is looping, basically
+
+                               if (for_seamless_loop) {
+
+                                       // this is only necessary for seamless looping
+                                       
+                                       boost::shared_ptr<RouteList> rl = routes.reader();
+
+                                       for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
+                                               boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+
+                                               if (tr && tr->record_enabled ()) {
+                                                       // tell it we've looped, so it can deal with the record state
+                                                       tr->transport_looped (_transport_frame);
+                                               }
                                        }
                                }
+
+                               have_looped = true;
+                               TransportLooped(); // EMIT SIGNAL
                        }
-                       have_looped = true;
-                       TransportLooped(); // EMIT SIGNAL
                }
        }
 
@@ -782,17 +992,34 @@ Session::locate (nframes_t target_frame, bool with_roll, bool with_flush, bool w
 
        _send_timecode_update = true;
 
+       if (with_mmc) {
+               send_mmc_locate (_transport_frame);
+       }
+
        Located (); /* EMIT SIGNAL */
 }
 
 /** Set the transport speed.
- * @param speed New speed
- * @param abort
+ *  Called from the process thread.
+ *  @param speed New speed
  */
 void
-Session::set_transport_speed (double speed, bool abort)
+Session::set_transport_speed (double speed, bool abort, bool clear_state, bool as_default)
 {
+       DEBUG_TRACE (DEBUG::Transport, string_compose ("@ %5 Set transport speed to %1, abort = %2 clear_state = %3, current = %4 as_default %6\n", 
+                                                      speed, abort, clear_state, _transport_speed, _transport_frame, as_default));
+
        if (_transport_speed == speed) {
+               if (as_default && speed == 0.0) { // => reset default transport speed. hacky or what?
+                       _default_transport_speed = 1.0;
+               }
+               return;
+       }
+
+       if (actively_recording() && speed != 1.0 && speed != 0.0) {
+               /* no varispeed during recording */
+               DEBUG_TRACE (DEBUG::Transport, string_compose ("No varispeed during recording cur_speed %1, frame %2\n", 
+                                                      _transport_speed, _transport_frame));
                return;
        }
 
@@ -812,42 +1039,31 @@ Session::set_transport_speed (double speed, bool abort)
 
                /* we are rolling and we want to stop */
 
-               if (Config->get_monitoring_model() == HardwareMonitoring)
-               {
-                       boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
-
-                       for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-                               if ((*i)->record_enabled ()) {
-                                       //cerr << "switching to input" << __FILE__ << __LINE__ << endl << endl;
-                                       (*i)->monitor_input (true);
-                               }
-                       }
+               if (Config->get_monitoring_model() == HardwareMonitoring) {
+                       set_track_monitor_input_status (true);
                }
 
                if (synced_to_jack ()) {
+                       if (clear_state) {
+                               /* do this here because our response to the slave won't
+                                  take care of it.
+                               */
+                               _play_range = false;
+                               unset_play_loop ();
+                       }
                        _engine.transport_stop ();
                } else {
                        stop_transport (abort);
                }
 
+               unset_play_loop ();
+
        } else if (transport_stopped() && speed == 1.0) {
 
                /* we are stopped and we want to start rolling at speed 1 */
 
-               if (!get_record_enabled() && Config->get_stop_at_session_end() && _transport_frame >= current_end_frame()) {
-                       return;
-               }
-
-               if (Config->get_monitoring_model() == HardwareMonitoring) {
-
-                       boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
-
-                       for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-                               if (config.get_auto_input() && (*i)->record_enabled ()) {
-                                       //cerr << "switching from input" << __FILE__ << __LINE__ << endl << endl;
-                                       (*i)->monitor_input (false);
-                               }
-                       }
+               if (Config->get_monitoring_model() == HardwareMonitoring && config.get_auto_input()) {
+                       set_track_monitor_input_status (false);
                }
 
                if (synced_to_jack()) {
@@ -858,12 +1074,12 @@ Session::set_transport_speed (double speed, bool abort)
 
        } else {
 
-               if (!get_record_enabled() && Config->get_stop_at_session_end() && _transport_frame >= current_end_frame()) {
-                       return;
-               }
+               /* not zero, not 1.0 ... varispeed */
 
                if ((synced_to_jack()) && speed != 0.0 && speed != 1.0) {
-                       warning << _("Global varispeed cannot be supported while Ardour is connected to JACK transport control")
+                       warning << string_compose (
+                               _("Global varispeed cannot be supported while %1 is connected to JACK transport control"),
+                               PROGRAM_NAME)
                                << endmsg;
                        return;
                }
@@ -886,38 +1102,56 @@ Session::set_transport_speed (double speed, bool abort)
                   before the last stop, then we have to do extra work.
                */
 
+               PostTransportWork todo = PostTransportWork (0);
+
                if ((_transport_speed && speed * _transport_speed < 0.0) || (_last_transport_speed * speed < 0.0) || (_last_transport_speed == 0.0f && speed < 0.0f)) {
-                       post_transport_work = PostTransportWork (post_transport_work | PostTransportReverse);
+                       todo = PostTransportWork (todo | PostTransportReverse);
+                       _last_roll_or_reversal_location = _transport_frame;
                }
 
                _last_transport_speed = _transport_speed;
                _transport_speed = speed;
 
-               boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
-               for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-                       if ((*i)->realtime_set_speed ((*i)->speed(), true)) {
-                               post_transport_work = PostTransportWork (post_transport_work | PostTransportSpeed);
+               if (as_default) {
+                       _default_transport_speed = speed;
+               }
+
+               boost::shared_ptr<RouteList> rl = routes.reader();
+               for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
+                       boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+                       if (tr && tr->realtime_set_speed (tr->speed(), true)) {
+                               todo = PostTransportWork (todo | PostTransportSpeed);
                        }
                }
 
-               if (post_transport_work & (PostTransportSpeed|PostTransportReverse)) {
+               if (todo) {
+                       add_post_transport_work (todo);
                        _butler->schedule_transport_work ();
                }
+
+               DEBUG_TRACE (DEBUG::Transport, string_compose ("send TSC3 with speed = %1\n", _transport_speed));
+               TransportStateChange (); /* EMIT SIGNAL */
        }
 }
 
 
 /** Stop the transport.  */
 void
-Session::stop_transport (bool abort)
+Session::stop_transport (bool abort, bool clear_state)
 {
        if (_transport_speed == 0.0f) {
                return;
        }
 
-       if (actively_recording() && !(transport_sub_state & StopPendingCapture) &&
-           _worst_output_latency > current_block_size)
-       {
+       if (actively_recording() && !(transport_sub_state & StopPendingCapture) && worst_input_latency() > current_block_size) {
+
+               boost::shared_ptr<RouteList> rl = routes.reader();
+               for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
+                       boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+                       if (tr) {
+                               tr->prepare_to_stop (_transport_frame);
+                       }
+               }
 
                /* we need to capture the audio that has still not yet been received by the system
                   at the time the stop is requested, so we have to roll past that time.
@@ -927,9 +1161,14 @@ Session::stop_transport (bool abort)
                   and then we'll really be stopped.
                */
 
-               Event *ev = new Event (Event::StopOnce, Event::Replace,
-                                      _transport_frame + _worst_output_latency - current_block_size,
-                                      0, 0, abort);
+               DEBUG_TRACE (DEBUG::Transport, string_compose ("stop transport requested @ %1, scheduled for + %2 - %3 = %4, abort = %5\n",
+                                                              _transport_frame, _worst_input_latency, current_block_size,
+                                                              _transport_frame - _worst_input_latency - current_block_size,
+                                                              abort));
+
+               SessionEvent *ev = new SessionEvent (SessionEvent::StopOnce, SessionEvent::Replace,
+                                                    _transport_frame + _worst_input_latency - current_block_size,
+                                                    0, 0, abort);
 
                merge_event (ev);
                transport_sub_state |= StopPendingCapture;
@@ -937,22 +1176,37 @@ Session::stop_transport (bool abort)
                return;
        }
 
-
        if ((transport_sub_state & PendingDeclickOut) == 0) {
+
+               if (!(transport_sub_state & StopPendingCapture)) {
+                       boost::shared_ptr<RouteList> rl = routes.reader();
+                       for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
+                               boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+                               if (tr) {
+                                       tr->prepare_to_stop (_transport_frame);
+                               }
+                       }
+               }
+
                transport_sub_state |= PendingDeclickOut;
                /* we'll be called again after the declick */
                pending_abort = abort;
                return;
        }
 
-       realtime_stop (abort);
+       realtime_stop (abort, clear_state);
        _butler->schedule_transport_work ();
 }
 
+/** Called from the process thread */
 void
 Session::start_transport ()
 {
+       DEBUG_TRACE (DEBUG::Transport, "start_transport\n");
+
        _last_roll_location = _transport_frame;
+       _last_roll_or_reversal_location = _transport_frame;
+
        have_looped = false;
 
        /* if record status is Enabled, move it to Recording. if its
@@ -978,16 +1232,26 @@ Session::start_transport ()
 
        transport_sub_state |= PendingDeclickIn;
 
-       _transport_speed = 1.0;
-       _target_transport_speed = 1.0;
+       _transport_speed = _default_transport_speed;
+       _target_transport_speed = _transport_speed;
 
-       boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
-       for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-               (*i)->realtime_set_speed ((*i)->speed(), true);
+       boost::shared_ptr<RouteList> rl = routes.reader();
+       for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
+               boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+               if (tr) {
+                       tr->realtime_set_speed (tr->speed(), true);
+               }
        }
 
-       deliver_mmc(MIDI::MachineControl::cmdDeferredPlay, _transport_frame);
+       if (!_engine.freewheeling()) {
+               Timecode::Time time;
+               timecode_time_subframes (_transport_frame, time);
+               if (!dynamic_cast<MTC_Slave*>(_slave)) {
+                       MIDI::Manager::instance()->mmc()->send (MIDI::MachineControlCommand (MIDI::MachineControl::cmdDeferredPlay));
+               }
+       }
 
+       DEBUG_TRACE (DEBUG::Transport, string_compose ("send TSC4 with speed = %1\n", _transport_speed));
        TransportStateChange (); /* EMIT SIGNAL */
 }
 
@@ -997,36 +1261,39 @@ Session::start_transport ()
 void
 Session::post_transport ()
 {
-       if (post_transport_work & PostTransportAudition) {
-               if (auditioner && auditioner->active()) {
+       PostTransportWork ptw = post_transport_work ();
+
+       if (ptw & PostTransportAudition) {
+               if (auditioner && auditioner->auditioning()) {
                        process_function = &Session::process_audition;
                } else {
                        process_function = &Session::process_with_events;
                }
        }
 
-       if (post_transport_work & PostTransportStop) {
+       if (ptw & PostTransportStop) {
 
                transport_sub_state = 0;
        }
 
-       if (post_transport_work & PostTransportLocate) {
+       if (ptw & PostTransportLocate) {
 
-               if (((Config->get_slave_source() == None && (auto_play_legal && config.get_auto_play())) && !_exporting) || (post_transport_work & PostTransportRoll)) {
+               if (((!config.get_external_sync() && (auto_play_legal && config.get_auto_play())) && !_exporting) || (ptw & PostTransportRoll)) {
                        start_transport ();
-
                } else {
                        transport_sub_state = 0;
                }
        }
 
        set_next_event ();
-
-       post_transport_work = PostTransportWork (0);
+       /* XXX is this really safe? shouldn't we just be unsetting the bits that we actually
+          know were handled ?
+       */
+       set_post_transport_work (PostTransportWork (0));
 }
 
 void
-Session::reset_rf_scale (nframes_t motion)
+Session::reset_rf_scale (framecnt_t motion)
 {
        cumulative_rf_motion += motion;
 
@@ -1046,165 +1313,171 @@ Session::reset_rf_scale (nframes_t motion)
 }
 
 void
-Session::set_slave_source (SlaveSource src)
+Session::use_sync_source (Slave* new_slave)
 {
-       bool reverse = false;
-       bool non_rt_required = false;
+       /* Runs in process() context */
 
-       if (_transport_speed) {
-               error << _("please stop the transport before adjusting slave settings") << endmsg;
-               return;
-       }
+       bool non_rt_required = false;
 
-//     if (src == JACK && Config->get_jack_time_master()) {
-//             return;
-//     }
+       /* XXX this deletion is problematic because we're in RT context */
 
        delete _slave;
-       _slave = 0;
+       _slave = new_slave;
 
-       if (_transport_speed < 0.0) {
-               reverse = true;
+       DEBUG_TRACE (DEBUG::Slave, string_compose ("set new slave to %1\n", _slave));
+
+       send_full_time_code (_transport_frame);
+
+       boost::shared_ptr<RouteList> rl = routes.reader();
+       for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
+               boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+               if (tr && !tr->hidden()) {
+                       if (tr->realtime_set_speed (tr->speed(), true)) {
+                               non_rt_required = true;
+                       }
+                       tr->set_slaved (_slave != 0);
+               }
        }
 
-       switch (src) {
-       case None:
-               stop_transport ();
-               break;
+       if (non_rt_required) {
+               add_post_transport_work (PostTransportSpeed);
+               _butler->schedule_transport_work ();
+       }
+
+       set_dirty();
+}
+
+void
+Session::drop_sync_source ()
+{
+       request_sync_source (0);
+}
 
+void
+Session::switch_to_sync_source (SyncSource src)
+{
+       Slave* new_slave;
+
+       DEBUG_TRACE (DEBUG::Slave, string_compose ("Setting up sync source %1\n", enum_2_string (src)));
+
+       switch (src) {
        case MTC:
-               if (_mtc_port) {
-                       try {
-                               _slave = new MTC_Slave (*this, *_mtc_port);
-                       }
+               if (_slave && dynamic_cast<MTC_Slave*>(_slave)) {
+                       return;
+               }
 
-                       catch (failed_constructor& err) {
-                               return;
-                       }
+               try {
+                       new_slave = new MTC_Slave (*this, *MIDI::Manager::instance()->mtc_input_port());
+               }
 
-               } else {
-                       error << _("No MTC port defined: MTC slaving is impossible.") << endmsg;
+               catch (failed_constructor& err) {
                        return;
                }
                break;
 
-       case MIDIClock:
-               if (_midi_clock_port) {
-                       try {
-                               _slave = new MIDIClock_Slave (*this, *_midi_clock_port, 24);
-                       }
+       case LTC:
+#ifdef HAVE_LTC
+               if (_slave && dynamic_cast<LTC_Slave*>(_slave)) {
+                       return;
+               }
 
-                       catch (failed_constructor& err) {
-                               return;
-                       }
+               try {
+                       new_slave = new LTC_Slave (*this);
+               }
 
-               } else {
-                       error << _("No MIDI Clock port defined: MIDI Clock slaving is impossible.") << endmsg;
+               catch (failed_constructor& err) {
                        return;
                }
+#else
+               return;
+#endif
                break;
 
-       case JACK:
-               _slave = new JACK_Slave (_engine.jack());
-               break;
+       case MIDIClock:
+               if (_slave && dynamic_cast<MIDIClock_Slave*>(_slave)) {
+                       return;
+               }
 
-       };
+               try {
+                       new_slave = new MIDIClock_Slave (*this, *MIDI::Manager::instance()->midi_clock_input_port(), 24);
+               }
 
-       Config->set_slave_source (src);
+               catch (failed_constructor& err) {
+                       return;
+               }
+               break;
 
-       boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
-       for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-               if (!(*i)->hidden()) {
-                       if ((*i)->realtime_set_speed ((*i)->speed(), true)) {
-                               non_rt_required = true;
-                       }
-                       (*i)->set_slaved (_slave);
+       case JACK:
+               if (_slave && dynamic_cast<JACK_Slave*>(_slave)) {
+                       return;
                }
-       }
 
-       if (reverse) {
-               reverse_diskstream_buffers ();
-       }
+               if (config.get_video_pullup() != 0.0f) {
+                       return;
+               }
 
-       if (non_rt_required) {
-               post_transport_work = PostTransportWork (post_transport_work | PostTransportSpeed);
-               _butler->schedule_transport_work ();
-       }
+               new_slave = new JACK_Slave (_engine.jack());
+               break;
 
-       set_dirty();
-}
+       default:
+               new_slave = 0;
+               break;
+       };
 
-void
-Session::reverse_diskstream_buffers ()
-{
-       post_transport_work = PostTransportWork (post_transport_work | PostTransportReverse);
-       _butler->schedule_transport_work ();
+       request_sync_source (new_slave);
 }
 
 void
-Session::set_diskstream_speed (Diskstream* stream, double speed)
+Session::set_track_speed (Track* track, double speed)
 {
-       if (stream->realtime_set_speed (speed, false)) {
-               post_transport_work = PostTransportWork (post_transport_work | PostTransportSpeed);
+       if (track->realtime_set_speed (speed, false)) {
+               add_post_transport_work (PostTransportSpeed);
                _butler->schedule_transport_work ();
                set_dirty ();
        }
 }
 
 void
-Session::set_audio_range (list<AudioRange>& range)
+Session::unset_play_range ()
 {
-       Event *ev = new Event (Event::SetAudioRange, Event::Add, Event::Immediate, 0, 0.0f);
-       ev->audio_range = range;
-       queue_event (ev);
+       _play_range = false;
+       _clear_event_type (SessionEvent::RangeStop);
+       _clear_event_type (SessionEvent::RangeLocate);
 }
 
 void
-Session::request_play_range (bool yn)
+Session::set_play_range (list<AudioRange>& range, bool leave_rolling)
 {
-       Event* ev = new Event (Event::SetPlayRange, Event::Add, Event::Immediate, 0, 0.0f, yn);
-       queue_event (ev);
-}
+       SessionEvent* ev;
 
-void
-Session::set_play_range (bool yn)
-{
        /* Called from event-processing context */
 
-       if (_play_range != yn) {
-               _play_range = yn;
-               setup_auto_play ();
+       unset_play_range ();
 
-               if (!_play_range) {
+       if (range.empty()) {
+               /* _play_range set to false in unset_play_range()
+                */
+               if (!leave_rolling) {
                        /* stop transport */
-                       Event* ev = new Event (Event::SetTransportSpeed, Event::Add, Event::Immediate, 0, 0.0f, false);
+                       SessionEvent* ev = new SessionEvent (SessionEvent::SetTransportSpeed, SessionEvent::Add, SessionEvent::Immediate, 0, 0.0f, false);
                        merge_event (ev);
                }
+               return;
        }
-}
 
-void
-Session::setup_auto_play ()
-{
-       /* Called from event-processing context */
+       _play_range = true;
 
-       Event* ev;
+       /* cancel loop play */
+       unset_play_loop ();
 
-       _clear_event_type (Event::RangeStop);
-       _clear_event_type (Event::RangeLocate);
-
-       if (!_play_range) {
-               return;
-       }
-
-       list<AudioRange>::size_type sz = current_audio_range.size();
+       list<AudioRange>::size_type sz = range.size();
 
        if (sz > 1) {
 
-               list<AudioRange>::iterator i = current_audio_range.begin();
+               list<AudioRange>::iterator i = range.begin();
                list<AudioRange>::iterator next;
 
-               while (i != current_audio_range.end()) {
+               while (i != range.end()) {
 
                        next = i;
                        ++next;
@@ -1212,7 +1485,7 @@ Session::setup_auto_play ()
                        /* locating/stopping is subject to delays for declicking.
                         */
 
-                       nframes_t requested_frame = (*i).end;
+                       framepos_t requested_frame = i->end;
 
                        if (requested_frame > current_block_size) {
                                requested_frame -= current_block_size;
@@ -1220,10 +1493,10 @@ Session::setup_auto_play ()
                                requested_frame = 0;
                        }
 
-                       if (next == current_audio_range.end()) {
-                               ev = new Event (Event::RangeStop, Event::Add, requested_frame, 0, 0.0f);
+                       if (next == range.end()) {
+                               ev = new SessionEvent (SessionEvent::RangeStop, SessionEvent::Add, requested_frame, 0, 0.0f);
                        } else {
-                               ev = new Event (Event::RangeLocate, Event::Add, requested_frame, (*next).start, 0.0f);
+                               ev = new SessionEvent (SessionEvent::RangeLocate, SessionEvent::Add, requested_frame, (*next).start, 0.0f);
                        }
 
                        merge_event (ev);
@@ -1233,32 +1506,39 @@ Session::setup_auto_play ()
 
        } else if (sz == 1) {
 
-               ev = new Event (Event::RangeStop, Event::Add, current_audio_range.front().end, 0, 0.0f);
+               ev = new SessionEvent (SessionEvent::RangeStop, SessionEvent::Add, range.front().end, 0, 0.0f);
                merge_event (ev);
 
        }
 
+       /* save range so we can do auto-return etc. */
+
+       current_audio_range = range;
+
        /* now start rolling at the right place */
 
-       ev = new Event (Event::LocateRoll, Event::Add, Event::Immediate, current_audio_range.front().start, 0.0f, false);
+       ev = new SessionEvent (SessionEvent::LocateRoll, SessionEvent::Add, SessionEvent::Immediate, range.front().start, 0.0f, false);
        merge_event (ev);
+
+       DEBUG_TRACE (DEBUG::Transport, string_compose ("send TSC5 with speed = %1\n", _transport_speed));
+       TransportStateChange ();
 }
 
 void
-Session::request_roll_at_and_return (nframes_t start, nframes_t return_to)
+Session::request_bounded_roll (framepos_t start, framepos_t end)
 {
-       Event *ev = new Event (Event::LocateRollLocate, Event::Add, Event::Immediate, return_to, 1.0);
-       ev->target2_frame = start;
-       queue_event (ev);
-}
+       AudioRange ar (start, end, 0);
+       list<AudioRange> lar;
 
+       lar.push_back (ar);
+       request_play_range (&lar, true);
+}
 void
-Session::request_bounded_roll (nframes_t start, nframes_t end)
+Session::request_roll_at_and_return (framepos_t start, framepos_t return_to)
 {
-       request_stop ();
-       Event *ev = new Event (Event::StopOnce, Event::Replace, end, Event::Immediate, 0.0);
+       SessionEvent *ev = new SessionEvent (SessionEvent::LocateRollLocate, SessionEvent::Add, SessionEvent::Immediate, return_to, 1.0);
+       ev->target2_frame = start;
        queue_event (ev);
-       request_locate (start, true);
 }
 
 void
@@ -1273,14 +1553,17 @@ Session::engine_halted ()
           the picture.
        */
 
-       g_atomic_int_set (&_butler->should_do_transport_work, 0);
-       post_transport_work = PostTransportWork (0);
-       _butler->stop ();
+       if (_butler) {
+               g_atomic_int_set (&_butler->should_do_transport_work, 0);
+               set_post_transport_work (PostTransportWork (0));
+               _butler->stop ();
+       }
 
-       realtime_stop (false);
+       realtime_stop (false, true);
        non_realtime_stop (false, 0, ignored);
        transport_sub_state = 0;
 
+       DEBUG_TRACE (DEBUG::Transport, string_compose ("send TSC6 with speed = %1\n", _transport_speed));
        TransportStateChange (); /* EMIT SIGNAL */
 }
 
@@ -1288,7 +1571,7 @@ Session::engine_halted ()
 void
 Session::xrun_recovery ()
 {
-       Xrun (transport_frame()); //EMIT SIGNAL
+       Xrun (_transport_frame); /* EMIT SIGNAL */
 
        if (Config->get_stop_recording_on_xrun() && actively_recording()) {
 
@@ -1301,66 +1584,20 @@ Session::xrun_recovery ()
 }
 
 void
-Session::update_latency_compensation (bool with_stop, bool abort)
+Session::route_processors_changed (RouteProcessorChange c)
 {
-       bool update_jack = false;
-
-       if (_state_of_the_state & Deletion) {
+       if (ignore_route_processor_changes) {
                return;
        }
 
-       _worst_track_latency = 0;
-
-#undef DEBUG_LATENCY
-#ifdef DEBUG_LATENCY
-       cerr << "\n---------------------------------\nUPDATE LATENCY\n";
-#endif
-
-       boost::shared_ptr<RouteList> r = routes.reader ();
-
-       for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
-
-               if (with_stop) {
-                       (*i)->handle_transport_stopped (abort, (post_transport_work & PostTransportLocate),
-                                                       (!(post_transport_work & PostTransportLocate) || pending_locate_flush));
-               }
-
-               nframes_t old_latency = (*i)->output()->signal_latency ();
-               nframes_t track_latency = (*i)->update_total_latency ();
-
-               if (old_latency != track_latency) {
-                       (*i)->input()->update_port_total_latencies ();
-                       (*i)->output()->update_port_total_latencies ();
-                       update_jack = true;
-               }
-
-               if (!(*i)->is_hidden() && ((*i)->active())) {
-                       _worst_track_latency = max (_worst_track_latency, track_latency);
-               }
-       }
-
-       if (update_jack) {
-               _engine.update_total_latencies ();
-       }
-
-#ifdef DEBUG_LATENCY
-       cerr << "\tworst was " << _worst_track_latency << endl;
-#endif
-
-       for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
-               (*i)->set_latency_delay (_worst_track_latency);
+       if (c.type == RouteProcessorChange::MeterPointChange) {
+               return;
        }
 
-       set_worst_io_latencies ();
-
-       /* reflect any changes in latencies into capture offsets
-       */
-
-       boost::shared_ptr<DiskstreamList> dsl = diskstreams.reader();
+       update_latency_compensation ();
+       resort_routes ();
 
-       for (DiskstreamList::iterator i = dsl->begin(); i != dsl->end(); ++i) {
-               (*i)->set_capture_offset ();
-       }
+       set_dirty ();
 }
 
 void
@@ -1378,3 +1615,51 @@ Session::reset_jack_connection (jack_client_t* jack)
                js->reset_client (jack);
        }
 }
+
+bool
+Session::maybe_stop (framepos_t limit)
+{
+       if ((_transport_speed > 0.0f && _transport_frame >= limit) || (_transport_speed < 0.0f && _transport_frame == 0)) {
+               if (synced_to_jack () && config.get_jack_time_master ()) {
+                       _engine.transport_stop ();
+               } else if (!synced_to_jack ()) {
+                       stop_transport ();
+               }
+               return true;
+       }
+       return false;
+}
+
+void
+Session::send_mmc_locate (framepos_t t)
+{
+       if (!_engine.freewheeling()) {
+               Timecode::Time time;
+               timecode_time_subframes (t, time);
+               MIDI::Manager::instance()->mmc()->send (MIDI::MachineControlCommand (time));
+       }
+}
+
+/** Ask the transport to not send timecode until further notice.  The suspension
+ *  will come into effect some finite time after this call, and timecode_transmission_suspended()
+ *  should be checked by the caller to find out when.
+ */
+void
+Session::request_suspend_timecode_transmission ()
+{
+       SessionEvent* ev = new SessionEvent (SessionEvent::SetTimecodeTransmission, SessionEvent::Add, SessionEvent::Immediate, 0, 0, false);
+       queue_event (ev);
+}
+
+void
+Session::request_resume_timecode_transmission ()
+{
+       SessionEvent* ev = new SessionEvent (SessionEvent::SetTimecodeTransmission, SessionEvent::Add, SessionEvent::Immediate, 0, 0, true);
+       queue_event (ev);
+}
+
+bool
+Session::timecode_transmission_suspended () const
+{
+       return g_atomic_int_get (&_suspend_timecode_transmission) == 1;
+}