remove debug output
[ardour.git] / libs / ardour / session_process.cc
index 0cba1e807cd7ad9c76d89df4c1ff3addefcf597f..fa5d16632da170cf574c04fc2ab5f03971c49f9e 100644 (file)
 #include "ardour/butler.h"
 #include "ardour/cycle_timer.h"
 #include "ardour/debug.h"
+#include "ardour/disk_reader.h"
 #include "ardour/graph.h"
 #include "ardour/port.h"
 #include "ardour/process_thread.h"
+#include "ardour/scene_changer.h"
 #include "ardour/session.h"
 #include "ardour/slave.h"
 #include "ardour/ticker.h"
 #include "ardour/types.h"
+#include "ardour/vca.h"
+#include "ardour/vca_manager.h"
 
-#include "midi++/manager.h"
 #include "midi++/mmc.h"
 
-#include "i18n.h"
-
-#include <xmmintrin.h>
+#include "pbd/i18n.h"
 
 using namespace ARDOUR;
 using namespace PBD;
@@ -77,6 +78,29 @@ Session::process (pframes_t nframes)
 
        (this->*process_function) (nframes);
 
+       /* realtime-safe meter-position and processor-order changes
+        *
+        * ideally this would be done in
+        * Route::process_output_buffers() but various functions
+        * callig it hold a _processor_lock reader-lock
+        */
+       boost::shared_ptr<RouteList> r = routes.reader ();
+       for (RouteList::const_iterator i = r->begin(); i != r->end(); ++i) {
+               if ((*i)->apply_processor_changes_rt()) {
+                       _rt_emit_pending = true;
+               }
+       }
+       if (_rt_emit_pending) {
+               if (!_rt_thread_active) {
+                       emit_route_signals ();
+               }
+               if (pthread_mutex_trylock (&_rt_emit_mutex) == 0) {
+                       pthread_cond_signal (&_rt_emit_cond);
+                       pthread_mutex_unlock (&_rt_emit_mutex);
+                       _rt_emit_pending = false;
+               }
+       }
+
        _engine.main_thread()->drop_buffers ();
 
        /* deliver MIDI clock. Note that we need to use the transport frame
@@ -86,9 +110,12 @@ Session::process (pframes_t nframes)
         */
 
        try {
-               if (!_engine.freewheeling() && Config->get_send_midi_clock() && transport_speed() == 1.0f && midi_clock->has_midi_port()) {
-                       midi_clock->tick (transport_at_start);
+               if (!_silent && !_engine.freewheeling() && Config->get_send_midi_clock() && (transport_speed() == 1.0f || transport_speed() == 0.0f) && midi_clock->has_midi_port()) {
+                       midi_clock->tick (transport_at_start, nframes);
                }
+
+               _scene_changer->run (transport_at_start, transport_at_start + nframes);
+
        } catch (...) {
                /* don't bother with a message */
        }
@@ -106,16 +133,23 @@ int
 Session::no_roll (pframes_t nframes)
 {
        PT_TIMING_CHECK (4);
-       
+
        framepos_t end_frame = _transport_frame + nframes; // FIXME: varispeed + no_roll ??
        int ret = 0;
-       int declick = get_transport_declick_required();
+       int declick = (config.get_use_transport_fades() ? get_transport_declick_required() : false);
        boost::shared_ptr<RouteList> r = routes.reader ();
 
        if (_click_io) {
                _click_io->silence (nframes);
        }
 
+       ltc_tx_send_time_code_for_cycle (_transport_frame, end_frame, _target_transport_speed, _transport_speed, nframes);
+
+       VCAList v = _vca_manager->vcas ();
+       for (VCAList::const_iterator i = v.begin(); i != v.end(); ++i) {
+               (*i)->automation_run (_transport_frame, nframes);
+       }
+
        if (_process_graph) {
                DEBUG_TRACE(DEBUG::ProcessThreads,"calling graph/no-roll\n");
                _process_graph->routes_no_roll( nframes, _transport_frame, end_frame, non_realtime_work_pending(), declick);
@@ -123,7 +157,7 @@ Session::no_roll (pframes_t nframes)
                PT_TIMING_CHECK (10);
                for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 
-                       if ((*i)->is_hidden()) {
+                       if ((*i)->is_auditioner()) {
                                continue;
                        }
 
@@ -148,27 +182,32 @@ Session::no_roll (pframes_t nframes)
 int
 Session::process_routes (pframes_t nframes, bool& need_butler)
 {
-       int  declick = get_transport_declick_required();
+       int declick = (config.get_use_transport_fades() ? get_transport_declick_required() : false);
        boost::shared_ptr<RouteList> r = routes.reader ();
 
-       if (transport_sub_state & StopPendingCapture) {
-               /* force a declick out */
-               declick = -1;
-       }
-
        const framepos_t start_frame = _transport_frame;
        const framepos_t end_frame = _transport_frame + floor (nframes * _transport_speed);
-       
+
+       VCAList v = _vca_manager->vcas ();
+       for (VCAList::const_iterator i = v.begin(); i != v.end(); ++i) {
+               (*i)->automation_run (start_frame, nframes);
+       }
+
+       _global_locate_pending = locate_pending ();
+
        if (_process_graph) {
                DEBUG_TRACE(DEBUG::ProcessThreads,"calling graph/process-routes\n");
-               _process_graph->process_routes (nframes, start_frame, end_frame, declick, need_butler);
+               if (_process_graph->process_routes (nframes, start_frame, end_frame, declick, need_butler) < 0) {
+                       stop_transport ();
+                       return -1;
+               }
        } else {
 
                for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
 
                        int ret;
 
-                       if ((*i)->is_hidden()) {
+                       if ((*i)->is_auditioner()) {
                                continue;
                        }
 
@@ -182,44 +221,7 @@ Session::process_routes (pframes_t nframes, bool& need_butler)
                        }
 
                        if (b) {
-                               need_butler = true;
-                       }
-               }
-       }
-
-       return 0;
-}
-
-/** @param need_butler to be set to true by this method if it needs the butler,
- *  otherwise it must be left alone.
- */
-int
-Session::silent_process_routes (pframes_t nframes, bool& need_butler)
-{
-       boost::shared_ptr<RouteList> r = routes.reader ();
-
-       const framepos_t start_frame = _transport_frame;
-       const framepos_t end_frame = _transport_frame + lrintf(nframes * _transport_speed);
-
-       if (_process_graph) {
-               _process_graph->silent_process_routes (nframes, start_frame, end_frame, need_butler);
-       } else {
-               for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
-
-                       int ret;
-
-                       if ((*i)->is_hidden()) {
-                               continue;
-                       }
-
-                       bool b = false;
-
-                       if ((ret = (*i)->silent_roll (nframes, start_frame, end_frame, b)) < 0) {
-                               stop_transport ();
-                               return -1;
-                       }
-
-                       if (b) {
+                               DEBUG_TRACE (DEBUG::Butler, string_compose ("%1 rolled and needs butler\n", (*i)->name()));
                                need_butler = true;
                        }
                }
@@ -239,7 +241,7 @@ Session::get_track_statistics ()
 
                boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
 
-               if (!tr || tr->hidden()) {
+               if (!tr || tr->is_private_route()) {
                        continue;
                }
 
@@ -260,7 +262,7 @@ void
 Session::process_with_events (pframes_t nframes)
 {
        PT_TIMING_CHECK (3);
-       
+
        SessionEvent*  ev;
        pframes_t      this_nframes;
        framepos_t     end_frame;
@@ -290,6 +292,47 @@ Session::process_with_events (pframes_t nframes)
                process_event (ev);
        }
 
+       /* count in */
+       if (_transport_speed != 1.0 && _count_in_samples > 0) {
+               _count_in_samples = 0;
+       }
+
+       if (_count_in_samples > 0) {
+               framecnt_t ns = std::min ((framecnt_t)nframes, _count_in_samples);
+
+               no_roll (ns);
+               run_click (_transport_frame - _count_in_samples, ns);
+
+               _count_in_samples -= ns;
+               nframes -= ns;
+
+               /* process events.. */
+               if (!events.empty() && next_event != events.end()) {
+                       SessionEvent* this_event = *next_event;
+                       Events::iterator the_next_one = next_event;
+                       ++the_next_one;
+
+                       while (this_event && this_event->action_frame == _transport_frame) {
+                               process_event (this_event);
+                               if (the_next_one == events.end()) {
+                                       this_event = 0;
+                               } else {
+                                       this_event = *the_next_one;
+                                       ++the_next_one;
+                               }
+                       }
+                       set_next_event ();
+               }
+
+               check_declick_out ();
+
+               if (nframes == 0) {
+                       return;
+               } else {
+                       _engine.split_cycle (ns);
+               }
+       }
+
        /* Decide on what to do with quarter-frame MTC during this cycle */
 
        bool const was_sending_qf_mtc = _send_qf_mtc;
@@ -325,7 +368,7 @@ Session::process_with_events (pframes_t nframes)
         * and prepare for rolling)
         */
        if (_send_timecode_update) {
-               send_full_time_code (_transport_frame);
+               send_full_time_code (_transport_frame, nframes);
        }
 
        if (!process_can_proceed()) {
@@ -334,16 +377,27 @@ Session::process_with_events (pframes_t nframes)
        }
 
        if (events.empty() || next_event == events.end()) {
-               process_without_events (nframes);
-               return;
+               try_run_lua (nframes); // also during export ?? ->move to process_without_events()
+               /* lua scripts may inject events */
+               while (_n_lua_scripts > 0 && pending_events.read (&ev, 1) == 1) {
+                       merge_event (ev);
+               }
+               if (events.empty() || next_event == events.end()) {
+                       process_without_events (nframes);
+                       return;
+               }
        }
 
-       if (_transport_speed == 1.0) {
-               frames_moved = (framecnt_t) nframes;
+       if (locate_pending()) {
+               frames_moved = 0;
        } else {
-               interpolation.set_target_speed (fabs(_target_transport_speed));
-               interpolation.set_speed (fabs(_transport_speed));
-               frames_moved = (framecnt_t) interpolation.interpolate (0, nframes, 0, 0);
+               if (_transport_speed == 1.0) {
+                       frames_moved = (framecnt_t) nframes;
+               } else {
+                       interpolation.set_target_speed (_target_transport_speed);
+                       interpolation.set_speed (_transport_speed);
+                       frames_moved = (framecnt_t) interpolation.interpolate (0, nframes, 0, 0);
+               }
        }
 
        end_frame = _transport_frame + frames_moved;
@@ -372,6 +426,8 @@ Session::process_with_events (pframes_t nframes)
                        send_midi_time_code_for_cycle (_transport_frame, end_frame, nframes);
                }
 
+               ltc_tx_send_time_code_for_cycle (_transport_frame, end_frame, _target_transport_speed, _transport_speed, nframes);
+
                framepos_t stop_limit = compute_stop_limit ();
 
                if (maybe_stop (stop_limit)) {
@@ -390,7 +446,11 @@ Session::process_with_events (pframes_t nframes)
                while (nframes) {
 
                        this_nframes = nframes; /* real (jack) time relative */
-                       frames_moved = (framecnt_t) floor (_transport_speed * nframes); /* transport relative */
+                       if (locate_pending()) {
+                               frames_moved = 0;
+                       } else {
+                               frames_moved = (framecnt_t) floor (_transport_speed * nframes); /* transport relative */
+                       }
 
                        /* running an event, position transport precisely to its time */
                        if (this_event && this_event->action_frame <= end_frame && this_event->action_frame >= _transport_frame) {
@@ -399,6 +459,8 @@ Session::process_with_events (pframes_t nframes)
                                this_nframes = abs (floor(frames_moved / _transport_speed));
                        }
 
+                       try_run_lua (this_nframes);
+
                        if (this_nframes) {
 
                                click (_transport_frame, this_nframes);
@@ -414,7 +476,7 @@ Session::process_with_events (pframes_t nframes)
 
                                if (frames_moved < 0) {
                                        decrement_transport_position (-frames_moved);
-                               } else {
+                               } else if (frames_moved) {
                                        increment_transport_position (frames_moved);
                                }
 
@@ -422,7 +484,9 @@ Session::process_with_events (pframes_t nframes)
                                check_declick_out ();
                        }
 
-                       _engine.split_cycle (this_nframes);
+                       if (nframes > 0) {
+                               _engine.split_cycle (this_nframes);
+                       }
 
                        /* now handle this event and all others scheduled for the same time */
 
@@ -453,6 +517,7 @@ Session::process_with_events (pframes_t nframes)
        } /* implicit release of route lock */
 
        if (session_needs_butler) {
+               DEBUG_TRACE (DEBUG::Butler, "p-with-events: session needs butler, call it\n");
                _butler->summon ();
        }
 }
@@ -513,7 +578,9 @@ Session::follow_slave (pframes_t nframes)
                slave_speed = 0.0f;
        }
 
-       if (_slave->is_always_synced() || Config->get_timecode_source_is_synced()) {
+       if (_slave->is_always_synced() ||
+                       (Config->get_timecode_source_is_synced() && (dynamic_cast<TimecodeSlave*>(_slave)) != 0)
+                       ) {
 
                /* if the TC source is synced, then we assume that its
                   speed is binary: 0.0 or 1.0
@@ -531,7 +598,7 @@ Session::follow_slave (pframes_t nframes)
                */
 
                if (_slave_state == Running) {
-                       calculate_moving_average_of_slave_delta(dir, this_delta);
+                       calculate_moving_average_of_slave_delta(dir, abs(this_delta));
                }
        }
 
@@ -541,7 +608,9 @@ Session::follow_slave (pframes_t nframes)
                                                   _slave_state, slave_transport_frame, slave_speed, this_delta, average_slave_delta));
 
 
-       if (_slave_state == Running && !_slave->is_always_synced() && !Config->get_timecode_source_is_synced()) {
+       if (_slave_state == Running && !_slave->is_always_synced() && !(Config->get_timecode_source_is_synced() && (dynamic_cast<TimecodeSlave*>(_slave)) != 0)) {
+
+               /* may need to varispeed to sync with slave */
 
                if (_transport_speed != 0.0f) {
 
@@ -572,7 +641,7 @@ Session::follow_slave (pframes_t nframes)
 #endif
 
                        if (_slave->give_slave_full_control_over_transport_speed()) {
-                               set_transport_speed (slave_speed, false, false);
+                               set_transport_speed (slave_speed, 0, false, false);
                                //std::cout << "set speed = " << slave_speed << "\n";
                        } else {
                                float adjusted_speed = slave_speed + (1.5 * (delta /  float(_current_frame_rate)));
@@ -582,25 +651,34 @@ Session::follow_slave (pframes_t nframes)
                                                                           slave_speed));
                        }
 
-#if 1
-                       if (!actively_recording() && (framecnt_t) abs(average_slave_delta) > _slave->resolution()) {
-                               cerr << "average slave delta greater than slave resolution (" << _slave->resolution() << "), going to silent motion\n";
-                               goto silent_motion;
+                       if (!actively_recording() && (framecnt_t) average_slave_delta > _slave->resolution()) {
+                               DEBUG_TRACE (DEBUG::Slave, string_compose ("average slave delta %1 greater than slave resolution %2 => silent motion\n", average_slave_delta, _slave->resolution()));
+                               /* run routes as normal, but no disk output */
+                               DiskReader::set_no_disk_output (true);
+                               return true;
+                       }
+
+                       if (!have_first_delta_accumulator) {
+                               DEBUG_TRACE (DEBUG::Slave, "waiting for first slave delta accumulator to be ready\n");
+                               /* run routes as normal, but no disk output */
+                               DiskReader::set_no_disk_output (true);
+                               return true;
                        }
-#endif
                }
        }
 
 
-       if (_slave_state == Running && !non_realtime_work_pending()) {
+       if (!have_first_delta_accumulator) {
+               DiskReader::set_no_disk_output (true);
+       } else {
+               DiskReader::set_no_disk_output (false);
+       }
+
+       if ((_slave_state == Running) && (0 == (post_transport_work () & ~PostTransportSpeed))) {
                /* speed is set, we're locked, and good to go */
                return true;
        }
 
-  silent_motion:
-       DEBUG_TRACE (DEBUG::Slave, "silent motion\n")
-       follow_slave_silently (nframes, slave_speed);
-
   noroll:
        /* don't move at all */
        DEBUG_TRACE (DEBUG::Slave, "no roll\n")
@@ -628,7 +706,7 @@ Session::calculate_moving_average_of_slave_delta (int dir, framecnt_t this_delta
                average_slave_delta /= (int32_t) delta_accumulator_size;
                if (average_slave_delta < 0L) {
                        average_dir = -1;
-                       average_slave_delta = abs(average_slave_delta);
+                       average_slave_delta = average_slave_delta;
                } else {
                        average_dir = 1;
                }
@@ -653,7 +731,10 @@ Session::track_slave_state (float slave_speed, framepos_t slave_transport_frame,
 
                        } else {
 
-                               _slave_state = Running;
+                               DEBUG_TRACE (DEBUG::Slave, string_compose ("slave stopped -> running at %1\n", slave_transport_frame));
+
+                               memset (delta_accumulator, 0, sizeof (int32_t) * delta_accumulator_size);
+                               average_slave_delta = 0L;
 
                                Location* al = _locations->auto_loop_location();
 
@@ -663,8 +744,10 @@ Session::track_slave_state (float slave_speed, framepos_t slave_transport_frame,
                                }
 
                                if (slave_transport_frame != _transport_frame) {
+                                       DEBUG_TRACE (DEBUG::Slave, string_compose ("require locate to run. eng: %1 -> sl: %2\n", _transport_frame, slave_transport_frame));
                                        locate (slave_transport_frame, false, false);
                                }
+                               _slave_state = Running;
                        }
                        break;
 
@@ -713,9 +796,6 @@ Session::track_slave_state (float slave_speed, framepos_t slave_transport_frame,
                                        cerr << "cannot micro-seek\n";
                                        /* XXX what? */
                                }
-
-                               memset (delta_accumulator, 0, sizeof (int32_t) * delta_accumulator_size);
-                               average_slave_delta = 0L;
                        }
                }
 
@@ -738,39 +818,7 @@ Session::track_slave_state (float slave_speed, framepos_t slave_transport_frame,
                        force_locate (slave_transport_frame, false);
                }
 
-               _slave_state = Stopped;
-       }
-}
-
-void
-Session::follow_slave_silently (pframes_t nframes, float slave_speed)
-{
-       if (slave_speed && _transport_speed) {
-
-               /* something isn't right, but we should move with the master
-                  for now.
-               */
-
-               bool need_butler;
-
-               silent_process_routes (nframes, need_butler);
-
-               get_track_statistics ();
-
-               if (need_butler) {
-                       _butler->summon ();
-               }
-
-               int32_t frames_moved = (int32_t) floor (_transport_speed * nframes);
-
-               if (frames_moved < 0) {
-                       decrement_transport_position (-frames_moved);
-               } else {
-                       increment_transport_position (frames_moved);
-               }
-
-               framepos_t const stop_limit = compute_stop_limit ();
-               maybe_stop (stop_limit);
+               reset_slave_state();
        }
 }
 
@@ -787,31 +835,38 @@ Session::process_without_events (pframes_t nframes)
 
        if (!_exporting && _slave) {
                if (!follow_slave (nframes)) {
+                       ltc_tx_send_time_code_for_cycle (_transport_frame, _transport_frame, 0, 0 , nframes);
                        return;
                }
        }
 
        if (_transport_speed == 0) {
-               fail_roll (nframes);
+               no_roll (nframes);
                return;
        }
 
-       if (_transport_speed == 1.0) {
-               frames_moved = (framecnt_t) nframes;
+       if (locate_pending()) {
+               frames_moved = 0;
        } else {
-               interpolation.set_target_speed (fabs(_target_transport_speed));
-               interpolation.set_speed (fabs(_transport_speed));
-               frames_moved = (framecnt_t) interpolation.interpolate (0, nframes, 0, 0);
+               if (_transport_speed == 1.0) {
+                       frames_moved = (framecnt_t) nframes;
+               } else {
+                       interpolation.set_target_speed (_target_transport_speed);
+                       interpolation.set_speed (_transport_speed);
+                       frames_moved = (framecnt_t) interpolation.interpolate (0, nframes, 0, 0);
+               }
        }
 
        if (!_exporting && !timecode_transmission_suspended()) {
                send_midi_time_code_for_cycle (_transport_frame, _transport_frame + frames_moved, nframes);
        }
 
+       ltc_tx_send_time_code_for_cycle (_transport_frame, _transport_frame + frames_moved, _target_transport_speed, _transport_speed, nframes);
+
        framepos_t const stop_limit = compute_stop_limit ();
 
        if (maybe_stop (stop_limit)) {
-               fail_roll (nframes);
+               no_roll (nframes);
                return;
        }
 
@@ -828,19 +883,9 @@ Session::process_without_events (pframes_t nframes)
 
        get_track_statistics ();
 
-       /* XXX: I'm not sure whether this is correct, but at least it
-          matches process_with_events, so that this new frames_moved
-          is -ve when transport speed is -ve.  This means that the
-          transport position is updated correctly when we are in
-          reverse.  It seems a bit wrong that we're not using the
-          interpolator to compute this.
-       */
-
-       frames_moved = (framecnt_t) floor (_transport_speed * nframes);
-
        if (frames_moved < 0) {
                decrement_transport_position (-frames_moved);
-       } else {
+       } else if (frames_moved) {
                increment_transport_position (frames_moved);
        }
 
@@ -848,6 +893,7 @@ Session::process_without_events (pframes_t nframes)
        check_declick_out ();
 
        if (session_needs_butler) {
+               DEBUG_TRACE (DEBUG::Butler, "p-without-events: session needs butler, call it\n");
                _butler->summon ();
        }
 }
@@ -862,7 +908,7 @@ Session::process_audition (pframes_t nframes)
        boost::shared_ptr<RouteList> r = routes.reader ();
 
        for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
-               if (!(*i)->is_hidden()) {
+               if (!(*i)->is_auditioner()) {
                        (*i)->silence (nframes);
                }
        }
@@ -870,13 +916,14 @@ Session::process_audition (pframes_t nframes)
        /* run the auditioner, and if it says we need butler service, ask for it */
 
        if (auditioner->play_audition (nframes) > 0) {
+               DEBUG_TRACE (DEBUG::Butler, "auditioner needs butler, call it\n");
                _butler->summon ();
        }
 
        /* if using a monitor section, run it because otherwise we don't hear anything */
 
-       if (auditioner->needs_monitor()) {
-               _monitor_out->passthru (_transport_frame, _transport_frame + nframes, nframes, false);
+       if (_monitor_out && auditioner->needs_monitor()) {
+               _monitor_out->monitor_run (_transport_frame, _transport_frame + nframes, nframes, false);
        }
 
        /* handle pending events */
@@ -956,6 +1003,7 @@ Session::queue_event (SessionEvent* ev)
        } else if (_state_of_the_state & Loading) {
                merge_event (ev);
        } else {
+               Glib::Threads::Mutex::Lock lm (rb_write_lock);
                pending_events.write (&ev, 1);
        }
 }
@@ -1010,7 +1058,7 @@ Session::process_event (SessionEvent* ev)
 
        switch (ev->type) {
        case SessionEvent::SetLoop:
-               set_play_loop (ev->yes_or_no);
+               set_play_loop (ev->yes_or_no, ev->speed);
                break;
 
        case SessionEvent::AutoLoop:
@@ -1057,6 +1105,15 @@ Session::process_event (SessionEvent* ev)
                _send_timecode_update = true;
                break;
 
+       case SessionEvent::Skip:
+               if (Config->get_skip_playback()) {
+                       start_locate (ev->target_frame, true, true, false);
+                       _send_timecode_update = true;
+               }
+               remove = false;
+               del = false;
+               break;
+
        case SessionEvent::LocateRollLocate:
                // locate is handled by ::request_roll_at_and_return()
                _requested_return_frame = ev->target_frame;
@@ -1065,12 +1122,12 @@ Session::process_event (SessionEvent* ev)
 
 
        case SessionEvent::SetTransportSpeed:
-               set_transport_speed (ev->speed, ev->yes_or_no, ev->second_yes_or_no, ev->third_yes_or_no);
+               set_transport_speed (ev->speed, ev->target_frame, ev->yes_or_no, ev->second_yes_or_no, ev->third_yes_or_no);
                break;
 
        case SessionEvent::PunchIn:
                // cerr << "PunchIN at " << transport_frame() << endl;
-               if (config.get_punch_in() && record_status() == Enabled) {
+               if (config.get_punch_in() && record_status() == Enabled && !preroll_record_punch_enabled()) {
                        enable_record ();
                }
                remove = false;
@@ -1079,17 +1136,25 @@ Session::process_event (SessionEvent* ev)
 
        case SessionEvent::PunchOut:
                // cerr << "PunchOUT at " << transport_frame() << endl;
-               if (config.get_punch_out()) {
+               if (config.get_punch_out() && !preroll_record_punch_enabled()) {
                        step_back_from_record ();
                }
                remove = false;
                del = false;
                break;
 
+       case SessionEvent::RecordStart:
+               if (preroll_record_punch_enabled() && record_status() == Enabled) {
+                       enable_record ();
+               }
+               remove = false;
+               del = false;
+               break;
+
        case SessionEvent::StopOnce:
                if (!non_realtime_work_pending()) {
-                       stop_transport (ev->yes_or_no);
                        _clear_event_type (SessionEvent::StopOnce);
+                       stop_transport (ev->yes_or_no);
                }
                remove = false;
                del = false;
@@ -1114,11 +1179,8 @@ Session::process_event (SessionEvent* ev)
                overwrite_some_buffers (static_cast<Track*>(ev->ptr));
                break;
 
-       case SessionEvent::SetTrackSpeed:
-               set_track_speed (static_cast<Track*> (ev->ptr), ev->speed);
-               break;
-
        case SessionEvent::SetSyncSource:
+               DEBUG_TRACE (DEBUG::Slave, "seen request for new slave\n");
                use_sync_source (ev->slave);
                break;
 
@@ -1128,15 +1190,14 @@ Session::process_event (SessionEvent* ev)
                ev->region.reset ();
                break;
 
-       case SessionEvent::InputConfigurationChange:
-               add_post_transport_work (PostTransportInputChange);
-               _butler->schedule_transport_work ();
-               break;
-
        case SessionEvent::SetPlayAudioRange:
                set_play_range (ev->audio_range, (ev->speed == 1.0f));
                break;
 
+       case SessionEvent::CancelPlayAudioRange:
+               unset_play_range();
+               break;
+
        case SessionEvent::RealTimeOperation:
                process_rtop (ev);
                del = false; // other side of RT request needs to clean up
@@ -1156,7 +1217,7 @@ Session::process_event (SessionEvent* ev)
 
        default:
          fatal << string_compose(_("Programming error: illegal event type in process_event (%1)"), ev->type) << endmsg;
-               /*NOTREACHED*/
+               abort(); /*NOTREACHED*/
                break;
        };
 
@@ -1175,7 +1236,15 @@ Session::compute_stop_limit () const
        if (!Config->get_stop_at_session_end ()) {
                return max_framepos;
        }
-       
+
+       if (_slave) {
+               return max_framepos;
+       }
+
+       if (preroll_record_punch_enabled ()) {
+               return max_framepos;
+       }
+
        bool const punching_in = (config.get_punch_in () && _locations->auto_punch_location());
        bool const punching_out = (config.get_punch_out () && _locations->auto_punch_location());
 
@@ -1192,3 +1261,79 @@ Session::compute_stop_limit () const
 
        return current_end_frame ();
 }
+
+
+
+/* dedicated thread for signal emission.
+ *
+ * while sending cross-thread signals from the process thread
+ * is fine in general, PBD::Signal's use of boost::function and
+ * boost:bind can produce a vast overhead which is not
+ * acceptable for low latency.
+ *
+ * This works around the issue by moving the boost overhead
+ * out of the RT thread. The overall load is probably higher but
+ * the realtime thread remains unaffected.
+ */
+
+void
+Session::emit_route_signals ()
+{
+       // TODO use RAII to allow using these signals in other places
+       BatchUpdateStart(); /* EMIT SIGNAL */
+       boost::shared_ptr<RouteList> r = routes.reader ();
+       for (RouteList::const_iterator ci = r->begin(); ci != r->end(); ++ci) {
+               (*ci)->emit_pending_signals ();
+       }
+       BatchUpdateEnd(); /* EMIT SIGNAL */
+}
+
+void
+Session::emit_thread_start ()
+{
+       if (_rt_thread_active) {
+               return;
+       }
+       _rt_thread_active = true;
+
+       if (pthread_create (&_rt_emit_thread, NULL, emit_thread, this)) {
+               _rt_thread_active = false;
+       }
+}
+
+void
+Session::emit_thread_terminate ()
+{
+       if (!_rt_thread_active) {
+               return;
+       }
+       _rt_thread_active = false;
+
+       if (pthread_mutex_lock (&_rt_emit_mutex) == 0) {
+               pthread_cond_signal (&_rt_emit_cond);
+               pthread_mutex_unlock (&_rt_emit_mutex);
+       }
+
+       void *status;
+       pthread_join (_rt_emit_thread, &status);
+}
+
+void *
+Session::emit_thread (void *arg)
+{
+       Session *s = static_cast<Session *>(arg);
+       s->emit_thread_run ();
+       pthread_exit (0);
+       return 0;
+}
+
+void
+Session::emit_thread_run ()
+{
+       pthread_mutex_lock (&_rt_emit_mutex);
+       while (_rt_thread_active) {
+               emit_route_signals();
+               pthread_cond_wait (&_rt_emit_cond, &_rt_emit_mutex);
+       }
+       pthread_mutex_unlock (&_rt_emit_mutex);
+}