diff options
Diffstat (limited to 'libs/ardour')
| -rw-r--r-- | libs/ardour/ardour/slave.h | 30 | ||||
| -rw-r--r-- | libs/ardour/mtc_slave.cc | 636 |
2 files changed, 343 insertions, 323 deletions
diff --git a/libs/ardour/ardour/slave.h b/libs/ardour/ardour/slave.h index 1602b8bc8e..be6b966560 100644 --- a/libs/ardour/ardour/slave.h +++ b/libs/ardour/ardour/slave.h @@ -32,8 +32,6 @@ #include "midi++/parser.h" #include "midi++/types.h" -class PIChaser; - namespace MIDI { class Port; } @@ -243,7 +241,6 @@ class MTC_Slave : public Slave { MIDI::Port* port; PBD::ScopedConnectionList port_connections; bool can_notify_on_unknown_rate; - PIChaser* pic; static const int frame_tolerance; @@ -253,18 +250,28 @@ class MTC_Slave : public Slave { MIDI::byte last_mtc_fps_byte; framepos_t window_begin; framepos_t window_end; - framepos_t last_mtc_timestamp; - framepos_t last_mtc_frame; + framepos_t first_mtc_timestamp; bool did_reset_tc_format; TimecodeFormat saved_tc_format; - size_t speed_accumulator_size; - double* speed_accumulator; - size_t speed_accumulator_cnt; - bool have_first_speed_accumulator; - double average_speed; Glib::Threads::Mutex reset_lock; uint32_t reset_pending; bool reset_position; + int transport_direction; + int busy_guard1; + int busy_guard2; + + /* DLL - chase MTC */ + double t0; ///< time at the beginning of the MTC quater frame + double t1; ///< calculated end of the MTC quater frame + double e2; ///< second order loop error + double b, c, omega; ///< DLL filter coefficients + + /* DLL - sync engine */ + int engine_dll_initstate; + double te0; ///< time at the beginning of the engine process + double te1; ///< calculated sync time + double ee2; ///< second order loop error + double be, ce, oe; ///< DLL filter coefficients void reset (bool with_pos); void queue_reset (bool with_pos); @@ -276,7 +283,8 @@ class MTC_Slave : public Slave { void read_current (SafeTime *) const; void reset_window (framepos_t); bool outside_window (framepos_t) const; - void process_apparent_speed (double); + void init_mtc_dll(framepos_t, double); + void init_engine_dll (framepos_t, framepos_t); }; class MIDIClock_Slave : public Slave { diff --git a/libs/ardour/mtc_slave.cc b/libs/ardour/mtc_slave.cc index 770c5046a8..f5b70317dd 100644 --- a/libs/ardour/mtc_slave.cc +++ b/libs/ardour/mtc_slave.cc @@ -1,5 +1,6 @@ /* Copyright (C) 2002-4 Paul Davis + Overhaul 2012 Robin Gareus <robin@gareus.org> This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -45,7 +46,6 @@ using namespace PBD; recently received position (and without the direction of timecode reversing too), we will stop+locate+wait+chase. */ - const int MTC_Slave::frame_tolerance = 2; MTC_Slave::MTC_Slave (Session& s, MIDI::Port& p) @@ -55,76 +55,230 @@ MTC_Slave::MTC_Slave (Session& s, MIDI::Port& p) did_reset_tc_format = false; reset_pending = 0; reset_position = false; - - pic = new PIChaser(); - - last_mtc_fps_byte = session.get_mtc_timecode_bits (); mtc_frame = 0; + engine_dll_initstate = 0; + busy_guard1 = busy_guard2 = 0; - speed_accumulator_size = 16; - speed_accumulator = new double[speed_accumulator_size]; + last_mtc_fps_byte = session.get_mtc_timecode_bits (); - rebind (p); reset (true); + rebind (p); } MTC_Slave::~MTC_Slave() { - port_connections.drop_connections (); + port_connections.drop_connections(); + + while (busy_guard1 != busy_guard2) { + /* make sure MIDI parser is not currently calling any callbacks in here, + * else there's a segfault ahead! + * + * XXX this is called from jack rt-context :( + * TODO fix libs/ardour/session_transport.cc:1321 (delete _slave;) + */ + sched_yield(); + } if (did_reset_tc_format) { session.config.set_timecode_format (saved_tc_format); } +} + +void +MTC_Slave::rebind (MIDI::Port& p) +{ + port_connections.drop_connections (); - delete pic; - delete [] speed_accumulator; + port = &p; + + port->parser()->mtc_time.connect_same_thread (port_connections, boost::bind (&MTC_Slave::update_mtc_time, this, _1, _2, _3)); + port->parser()->mtc_qtr.connect_same_thread (port_connections, boost::bind (&MTC_Slave::update_mtc_qtr, this, _1, _2, _3)); + port->parser()->mtc_status.connect_same_thread (port_connections, boost::bind (&MTC_Slave::update_mtc_status, this, _1)); } bool MTC_Slave::give_slave_full_control_over_transport_speed() const { - return true; // for PiC control */ + return true; // DLL align to engine transport // return false; // for Session-level computed varispeed } +ARDOUR::framecnt_t +MTC_Slave::resolution () const +{ + return (framecnt_t) session.frames_per_timecode_frame(); +} + +ARDOUR::framecnt_t +MTC_Slave::seekahead_distance () const +{ + return session.frames_per_timecode_frame() * 2 * transport_direction; +} + +bool +MTC_Slave::outside_window (framepos_t pos) const +{ + return ((pos < window_begin) || (pos > window_end)); +} + + +bool +MTC_Slave::locked () const +{ + return port->parser()->mtc_locked(); +} + +bool +MTC_Slave::ok() const +{ + return true; +} + void -MTC_Slave::rebind (MIDI::Port& p) +MTC_Slave::queue_reset (bool reset_pos) { - port_connections.drop_connections (); + Glib::Threads::Mutex::Lock lm (reset_lock); + reset_pending++; + if (reset_pos) { + reset_position = true; + } +} - port = &p; +void +MTC_Slave::maybe_reset () +{ + Glib::Threads::Mutex::Lock lm (reset_lock); - port->parser()->mtc_time.connect_same_thread (port_connections, boost::bind (&MTC_Slave::update_mtc_time, this, _1, _2, _3)); - port->parser()->mtc_qtr.connect_same_thread (port_connections, boost::bind (&MTC_Slave::update_mtc_qtr, this, _1, _2, _3)); - port->parser()->mtc_status.connect_same_thread (port_connections, boost::bind (&MTC_Slave::update_mtc_status, this, _1)); + if (reset_pending) { + reset (reset_position); + reset_pending = 0; + reset_position = false; + } +} + +void +MTC_Slave::reset (bool with_position) +{ + DEBUG_TRACE (DEBUG::MTC, string_compose ("MTC_Slave reset %1\n", with_position?"with position":"without position")); + if (with_position) { + last_inbound_frame = 0; + current.guard1++; + current.position = 0; + current.timestamp = 0; + current.speed = 0; + current.guard2++; + } else { + last_inbound_frame = 0; + current.guard1++; + current.timestamp = 0; + current.speed = 0; + current.guard2++; + } + first_mtc_timestamp = 0; + window_begin = 0; + window_end = 0; + transport_direction = 1; +} + +void +MTC_Slave::handle_locate (const MIDI::byte* mmc_tc) +{ + MIDI::byte mtc[5]; + DEBUG_TRACE (DEBUG::MTC, "MTC_Slave::handle_locate\n"); + + mtc[4] = last_mtc_fps_byte; + mtc[3] = mmc_tc[0] & 0xf; /* hrs only */ + mtc[2] = mmc_tc[1]; + mtc[1] = mmc_tc[2]; + mtc[0] = mmc_tc[3]; + + update_mtc_time (mtc, true, 0); +} + +void +MTC_Slave::read_current (SafeTime *st) const +{ + int tries = 0; + + do { + if (tries == 10) { + error << _("MTC Slave: atomic read of current time failed, sleeping!") << endmsg; + usleep (20); + tries = 0; + } + *st = current; + tries++; + + } while (st->guard1 != st->guard2); +} + +void +MTC_Slave::init_mtc_dll(framepos_t mtc_frame, double qtr) +{ + omega = 2.0 * M_PI * (session.frames_per_timecode_frame() / 4.0) / double(session.frame_rate()); + b = 1.4142135623730950488 * omega; + c = omega * omega; + + e2 = qtr; + t0 = double(mtc_frame); + t1 = t0 + e2; + DEBUG_TRACE (DEBUG::MTC, string_compose ("[re-]init MTC DLL %1 %2 %3\n", t0, t1, e2)); } + +/* called from MIDI parser */ void MTC_Slave::update_mtc_qtr (Parser& /*p*/, int which_qtr, framepos_t now) { - DEBUG_TRACE (DEBUG::MTC, string_compose ("qtr frame %1 at %2\n", which_qtr, now)); + busy_guard1++; + const framepos_t qtr = (session.frames_per_timecode_frame() / 4); + const double qtr_d = (session.frames_per_timecode_frame() / 4.0); + + mtc_frame += qtr * transport_direction; + + DEBUG_TRACE (DEBUG::MTC, string_compose ("qtr frame %1 at %2 -> mtc_frame: %3\n", which_qtr, now, mtc_frame)); + + double mtc_speed = 0; + if (first_mtc_timestamp != 0) { + /* update MTC DLL and calculate speed */ + const double e = double(transport_direction) * (double(now) - double(current.timestamp) - qtr_d); + t0 = t1; + t1 += b * e + e2; + e2 += c * e; + + mtc_speed = (t1 - t0) / qtr_d; + DEBUG_TRACE (DEBUG::MTC, string_compose ("qtr frame DLL t0:%1 t1:%2 err:%3 spd:%4\n", t0, t1, e, mtc_speed)); + } + + current.guard1++; + current.position = mtc_frame; + current.timestamp = now; + current.speed = mtc_speed; + current.guard2++; + maybe_reset (); last_inbound_frame = now; + + busy_guard2++; } +/* called from MIDI parser _after_ update_mtc_qtr() + * when a full TC has been received + * OR on locate */ void MTC_Slave::update_mtc_time (const byte *msg, bool was_full, framepos_t now) { + busy_guard1++; + /* "now" can be zero if this is called from a context where we do not have or do not want to use a timestamp indicating when this MTC time was received. example: when we received a locate command via MMC. */ - if (now) { - maybe_reset (); - } - + //DEBUG_TRACE (DEBUG::MTC, string_compose ("MTC::update_mtc_time - TID:%1\n", ::pthread_self())); Timecode::Time timecode; TimecodeFormat tc_format; bool reset_tc = true; - framepos_t window_root = -1; - - DEBUG_TRACE (DEBUG::MTC, string_compose ("full mtc time known at %1, full ? %2\n", now, was_full)); timecode.hours = msg[3]; timecode.minutes = msg[2]; @@ -133,6 +287,12 @@ MTC_Slave::update_mtc_time (const byte *msg, bool was_full, framepos_t now) last_mtc_fps_byte = msg[4]; + DEBUG_TRACE (DEBUG::MTC, string_compose ("full mtc time known at %1, full ? %2\n", now, was_full)); + + if (now) { + maybe_reset (); + } + switch (msg[4]) { case MTC_24_FPS: timecode.rate = 24; @@ -179,12 +339,12 @@ MTC_Slave::update_mtc_time (const byte *msg, bool was_full, framepos_t now) session.config.set_timecode_format (tc_format); } - DEBUG_TRACE (DEBUG::MTC, string_compose ("MTC time timestamp = %1 TC %2 = frame %3 (from full message ? %4)\n", + DEBUG_TRACE (DEBUG::MTC, string_compose ("MTC at %1 TC %2 = mtc_frame %3 (from full message ? %4)\n", now, timecode, mtc_frame, was_full)); if (was_full || outside_window (mtc_frame)) { - - session.timecode_to_sample (timecode, mtc_frame, true, false); + DEBUG_TRACE (DEBUG::MTC, string_compose ("update_mtc_time: full TC or outside window. - TID:%1\n", ::pthread_self())); + session.timecode_to_sample (timecode, mtc_frame, true, false); // sets mtc_frame session.request_locate (mtc_frame, false); session.request_transport_speed (0); update_mtc_status (MIDI::MTC_Stopped); @@ -203,7 +363,7 @@ MTC_Slave::update_mtc_time (const byte *msg, bool was_full, framepos_t now) consideration. */ - session.timecode_to_sample (timecode, mtc_frame, true, false); + session.timecode_to_sample (timecode, mtc_frame, true, false); // sets mtc_frame /* We received the last quarter frame 7 quarter frames (1.75 mtc frames) after the instance when the contents of the mtc quarter @@ -211,125 +371,54 @@ MTC_Slave::update_mtc_time (const byte *msg, bool was_full, framepos_t now) frames. Also compensate for audio latency. */ - mtc_frame += (long) (1.75 * session.frames_per_timecode_frame()) + session.worst_playback_latency(); + DEBUG_TRACE (DEBUG::MTC, string_compose ("new mtc_frame = %1 | %2 FPTC | LAT: %3\n", + mtc_frame, session.frames_per_timecode_frame(), session.worst_playback_latency())); + + long int mtc_off = (long) (1.75 * session.frames_per_timecode_frame()) + session.worst_playback_latency(); + double qtr = (session.frames_per_timecode_frame() / 4.0); + + switch (port->parser()->mtc_running()) { + case MTC_Backward: + mtc_frame -= mtc_off; + qtr *= -1.0; + break; + case MTC_Forward: + mtc_frame += mtc_off; + break; + default: + break; + } + DEBUG_TRACE (DEBUG::MTC, string_compose ("new mtc_frame (w/latency comp) = %1\n", mtc_frame)); if (now) { - - if (last_mtc_timestamp == 0) { - - last_mtc_timestamp = now; - last_mtc_frame = mtc_frame; - - } else { - - if (give_slave_full_control_over_transport_speed()) { - /* PIC - * - * its not the average, but we will assign it to current.speed below - */ - - static framepos_t last_seen_timestamp = 0; - static framepos_t last_seen_position = 0; - - if ((now - last_seen_timestamp) < 300) { - mtc_frame = (mtc_frame + last_seen_position)/2; - } - - last_seen_timestamp = now; - last_seen_position = mtc_frame; - - - - } else { - - /* Non-PiC - */ - - framepos_t time_delta = (now - last_mtc_timestamp); - - if (time_delta != 0) { - double apparent_speed = (mtc_frame - last_mtc_frame) / (double) (time_delta); - - process_apparent_speed (apparent_speed); - DEBUG_TRACE (DEBUG::Slave, string_compose ("apparent speed was %1 average is now %2\n", apparent_speed, average_speed)); - } else { - DEBUG_TRACE (DEBUG::Slave, string_compose ("no apparent calc, average is %1\n", average_speed)); - } - - /* every second, recalibrate the starting point for the speed measurement */ - if (mtc_frame - last_mtc_frame > session.frame_rate()) { - last_mtc_timestamp = now; - last_mtc_frame = mtc_frame; - } - } + if (first_mtc_timestamp == 0 || current.timestamp == 0) { + first_mtc_timestamp = now; + init_mtc_dll(mtc_frame, qtr); } - current.guard1++; current.position = mtc_frame; current.timestamp = now; - current.speed = average_speed; current.guard2++; - window_root = mtc_frame; + reset_window (mtc_frame); } } if (now) { last_inbound_frame = now; } - - if (window_root >= 0) { - reset_window (window_root); - } -} - -void -MTC_Slave::process_apparent_speed (double this_speed) -{ - DEBUG_TRACE (DEBUG::MTC, string_compose ("speed cnt %1 sz %2 have %3\n", speed_accumulator_cnt, speed_accumulator_size, have_first_speed_accumulator)); - - /* clamp to an expected range */ - - if (this_speed > 4.0 || this_speed < -4.0) { - this_speed = average_speed; - } - - if (speed_accumulator_cnt >= speed_accumulator_size) { - have_first_speed_accumulator = true; - speed_accumulator_cnt = 0; - } - - speed_accumulator[speed_accumulator_cnt++] = this_speed; - - if (have_first_speed_accumulator) { - average_speed = 0.0; - for (size_t i = 0; i < speed_accumulator_size; ++i) { - average_speed += speed_accumulator[i]; - } - average_speed /= speed_accumulator_size; - } -} - -void -MTC_Slave::handle_locate (const MIDI::byte* mmc_tc) -{ - MIDI::byte mtc[5]; - - mtc[4] = last_mtc_fps_byte; - mtc[3] = mmc_tc[0] & 0xf; /* hrs only */ - mtc[2] = mmc_tc[1]; - mtc[1] = mmc_tc[2]; - mtc[0] = mmc_tc[3]; - - update_mtc_time (mtc, true, 0); + busy_guard2++; } void MTC_Slave::update_mtc_status (MIDI::MTC_Status status) { /* XXX !!! thread safety ... called from MIDI I/O context - and process() context (via ::speed_and_position()) - */ + * on locate (via ::update_mtc_time()) + */ + DEBUG_TRACE (DEBUG::MTC, string_compose("MTC_Slave::update_mtc_status - TID:%1\n", ::pthread_self())); + return; // why was this fn needed anyway ? it just messes up things -> use reset. + busy_guard1++; switch (status) { case MTC_Stopped: @@ -357,186 +446,12 @@ MTC_Slave::update_mtc_status (MIDI::MTC_Status status) current.guard2++; break; } - -} - -void -MTC_Slave::read_current (SafeTime *st) const -{ - int tries = 0; - - do { - if (tries == 10) { - error << _("MTC Slave: atomic read of current time failed, sleeping!") << endmsg; - usleep (20); - tries = 0; - } - *st = current; - tries++; - - } while (st->guard1 != st->guard2); -} - -bool -MTC_Slave::locked () const -{ - return port->parser()->mtc_locked(); -} - -bool -MTC_Slave::ok() const -{ - return true; -} - -bool -MTC_Slave::speed_and_position (double& speed, framepos_t& pos) -{ - framepos_t now = session.engine().frame_time(); - SafeTime last; - framecnt_t elapsed; - bool in_control = false; - - read_current (&last); - - if (last.timestamp == 0) { - speed = 0; - pos = last.position; - DEBUG_TRACE (DEBUG::MTC, string_compose ("first call to MTC_Slave::speed_and_position, pos = %1\n", last.position)); - return true; - } - - /* no timecode for 1/4 second ? conclude that its stopped */ - - if (last_inbound_frame && now > last_inbound_frame && now - last_inbound_frame > session.frame_rate() / 4) { - speed = 0; - pos = last.position; - session.request_locate (pos, false); - session.request_transport_speed (0); - queue_reset (false); - DEBUG_TRACE (DEBUG::MTC, "MTC not seen for 1/4 second - reset pending\n"); - return false; - } - - DEBUG_TRACE (DEBUG::MTC, string_compose ("MTC::speed_and_position %1 %2\n", last.speed, last.position)); - - if (give_slave_full_control_over_transport_speed()) { - in_control = (session.slave_state() == Session::Running); - framepos_t pic_want_locate = 0; - //framepos_t slave_pos = session.audible_frame(); - framepos_t slave_pos = session.transport_frame(); - static double average_speed = 0; - - framepos_t ref_now = session.engine().frame_time_at_cycle_start(); - average_speed = pic->get_ratio (last.timestamp, last.position, ref_now, slave_pos, in_control, session.engine().frames_per_cycle()); - - pic_want_locate = pic->want_locate(); - - if (in_control && pic_want_locate) { - last.speed = average_speed + (double) (pic_want_locate - session.transport_frame()) / (double)session.get_block_size(); - std::cout << "locate req " << pic_want_locate << " speed: " << average_speed << "\n"; - } else { - last.speed = average_speed; - } - } - - if (last.speed == 0.0f) { - - elapsed = 0; - - } else { - - /* scale elapsed time by the current MTC speed */ - - if (last.timestamp && (now > last.timestamp)) { - elapsed = (framecnt_t) floor (last.speed * (now - last.timestamp)); - DEBUG_TRACE (DEBUG::MTC, string_compose ("last timecode received @ %1, now = %2, elapsed frames = %3 w/speed= %4\n", - last.timestamp, now, elapsed, last.speed)); - } else { - elapsed = 0; /* XXX is this right? */ - } - } - - /* now add the most recent timecode value plus the estimated elapsed interval */ - - if (in_control) { - pos = session.transport_frame(); - } else { - pos = last.position + elapsed; - } - - speed = last.speed; - - DEBUG_TRACE (DEBUG::MTC, string_compose ("MTC::speed_and_position FINAL %1 %2\n", last.speed, pos)); - - - DEBUG_TRACE (DEBUG::MTC, string_compose ("last = %1 elapsed = %2 pos = %3 speed = %4\n", last.position, elapsed, pos, speed)); - - return true; -} - -ARDOUR::framecnt_t -MTC_Slave::resolution () const -{ - return (framecnt_t) session.frames_per_timecode_frame(); -} - -void -MTC_Slave::queue_reset (bool reset_pos) -{ - Glib::Threads::Mutex::Lock lm (reset_lock); - reset_pending++; - if (reset_pos) { - reset_position = true; - } -} - -void -MTC_Slave::maybe_reset () -{ - Glib::Threads::Mutex::Lock lm (reset_lock); - - if (reset_pending) { - reset (reset_position); - reset_pending = 0; - reset_position = false; - } -} - -void -MTC_Slave::reset (bool with_position) -{ - if (with_position) { - last_inbound_frame = 0; - current.guard1++; - current.position = 0; - current.timestamp = 0; - current.speed = 0; - current.guard2++; - } else { - last_inbound_frame = 0; - current.guard1++; - current.timestamp = 0; - current.speed = 0; - current.guard2++; - } - - window_begin = 0; - window_end = 0; - last_mtc_frame = 0; - last_mtc_timestamp = 0; - - average_speed = 0; - have_first_speed_accumulator = false; - speed_accumulator_cnt = 0; - - pic->reset(); + busy_guard2++; } void MTC_Slave::reset_window (framepos_t root) { - /* if we're waiting for the master to catch us after seeking ahead, keep the window of acceptable MTC frames wide open. otherwise, shrink it down to just 2 video frames ahead of the window root (taking direction into account). @@ -545,14 +460,16 @@ MTC_Slave::reset_window (framepos_t root) switch (port->parser()->mtc_running()) { case MTC_Forward: window_begin = root; + transport_direction = 1; if (session.slave_state() == Session::Running) { window_end = root + (session.frames_per_timecode_frame() * frame_tolerance); } else { - window_end = root + seekahead_distance (); + window_end = root + labs(seekahead_distance ()); } break; case MTC_Backward: + transport_direction = -1; if (session.slave_state() == Session::Running) { framecnt_t const d = session.frames_per_timecode_frame() * frame_tolerance; if (root > d) { @@ -562,7 +479,7 @@ MTC_Slave::reset_window (framepos_t root) window_begin = 0; } } else { - framecnt_t const d = seekahead_distance (); + framecnt_t const d = labs(seekahead_distance ()); if (root > d) { window_begin = root - d; } else { @@ -580,15 +497,110 @@ MTC_Slave::reset_window (framepos_t root) DEBUG_TRACE (DEBUG::MTC, string_compose ("legal MTC window now %1 .. %2\n", window_begin, window_end)); } -ARDOUR::framecnt_t -MTC_Slave::seekahead_distance () const +void +MTC_Slave::init_engine_dll (framepos_t pos, framepos_t inc) { - /* 1 second */ - return session.frame_rate(); + /* the bandwidth of the DLL is a trade-off, + * because the max-speed of the transport in ardour is + * limited to +-8.0, a larger bandwidth would cause oscillations + * + * But this is only really a problem if the user performs manual + * seeks while transport is running and slaved to MTC. + */ + oe = 2.0 * M_PI * double(inc/6.0) / double(session.frame_rate()); + be = 1.4142135623730950488 * oe; + ce = oe * oe; + + ee2 = double(transport_direction * inc); + te0 = double(pos); + te1 = te0 + ee2; + DEBUG_TRACE (DEBUG::MTC, string_compose ("[re-]init Engine DLL %1 %2 %3\n", te0, te1, ee2)); } +/* main entry point from session_process.cc + * in jack_process callback context */ bool -MTC_Slave::outside_window (framepos_t pos) const +MTC_Slave::speed_and_position (double& speed, framepos_t& pos) { - return ((pos < window_begin) || (pos > window_end)); + framepos_t now = session.engine().frame_time_at_cycle_start(); + framepos_t sess_pos = session.transport_frame(); // corresponds to now + + SafeTime last; + framecnt_t elapsed; + + read_current (&last); + + /* re-init engine DLL here when state changed (direction, first_mtc_timestamp) */ + if (last.timestamp == 0) { engine_dll_initstate = 0; } + else if (engine_dll_initstate != transport_direction) { + engine_dll_initstate = transport_direction; + init_engine_dll(last.position, session.engine().frames_per_cycle()); + } + + if (last.timestamp == 0) { + speed = 0; + pos = last.position; + DEBUG_TRACE (DEBUG::MTC, string_compose ("first call to MTC_Slave::speed_and_position, pos = %1\n", last.position)); + return true; + } + + /* no timecode for two frames - conclude that it's stopped */ + if (last_inbound_frame && now > last_inbound_frame && now - last_inbound_frame > labs(seekahead_distance())) { + speed = 0; + pos = last.position; + session.request_locate (pos, false); + session.request_transport_speed (0); + queue_reset (false); + DEBUG_TRACE (DEBUG::MTC, "MTC not seen for 2 frames - reset pending\n"); + return false; + } + + + + DEBUG_TRACE (DEBUG::MTC, string_compose ("MTC::speed_and_position mtc-tme: %1 mtc-pos: %2\n", last.timestamp, last.position)); + DEBUG_TRACE (DEBUG::MTC, string_compose ("MTC::speed_and_position eng-tme: %1 eng-pos: %2\n", now, sess_pos)); + + double speed_flt = last.speed; ///< MTC speed from MTC-quarter-frame DLL + + /* interpolate position according to speed and time since last quarter-frame*/ + if (speed_flt == 0.0f) { + elapsed = 0; + } + else + { + /* scale elapsed time by the current MTC speed */ + if (last.timestamp && (now > last.timestamp)) { + elapsed = (framecnt_t) rint (speed_flt * (now - last.timestamp)); + } else { + elapsed = 0; + } + if (give_slave_full_control_over_transport_speed()) { + /* there is a frame-delta engine vs MTC position + * mostly due to quantization and rounding of (speed * nframes) + * thus we use an other DLL.. + */ + + /* update engine DLL and calculate speed */ + const double e = double (last.position + elapsed - sess_pos); + te0 = te1; + te1 += be * e + ee2; + ee2 += ce * e; + speed_flt = (te1 - te0) / double(session.engine().frames_per_cycle()); + DEBUG_TRACE (DEBUG::MTC, string_compose ("engine DLL t0:%1 t1:%2 err:%3 spd:%4\n", te0, te1, e, speed_flt)); + } + } + + pos = last.position + elapsed; + speed = speed_flt; + + /* may happen if the user performs a seek in the timeline while slaved to running MTC + * engine-DLL can oscillate back before 0. + * also see note in MTC_Slave::init_engine_dll + */ + if (pos <0) queue_reset(true); + + DEBUG_TRACE (DEBUG::MTC, string_compose ("MTCsync spd: %1 pos: %2 | last-pos: %3 elapsed: %4 delta: %5\n", + speed, pos, last.position, elapsed, pos - sess_pos)); + + return true; } |