diff --git a/libs/ardour/ardour/slave.h b/libs/ardour/ardour/slave.h index fe764d555d..fb1f18448b 100644 --- a/libs/ardour/ardour/slave.h +++ b/libs/ardour/ardour/slave.h @@ -240,9 +240,9 @@ class MIDIClock_Slave : public Slave, public sigc::trackable { /// the timestamp of the first MIDI clock message nframes_t first_timestamp; - /// the time stamp and transport position of the last inbound MIDI clock message + /// the time stamp and should-be transport position of the last inbound MIDI clock message nframes_t last_timestamp; - double last_position; + double should_be_position; //the delay locked loop (DLL), see www.kokkinizita.net/papers/usingdll.pdf diff --git a/libs/ardour/midi_clock_slave.cc b/libs/ardour/midi_clock_slave.cc index 09583ae7c6..c3ca87c651 100644 --- a/libs/ardour/midi_clock_slave.cc +++ b/libs/ardour/midi_clock_slave.cc @@ -123,37 +123,36 @@ MIDIClock_Slave::update_midi_clock (Parser& parser, nframes_t timestamp) // the number of midi clock messages (zero-based) static long midi_clock_count; - calculate_one_ppqn_in_frames_at(last_position); + calculate_one_ppqn_in_frames_at(should_be_position); - nframes_t timestamp_relative_to_transport = timestamp - first_timestamp; + nframes_t elapsed_since_start = timestamp - first_timestamp; + double error = 0; - if (_starting || last_timestamp == 0) { - midi_clock_count = 0; - + if (_starting || last_timestamp == 0) { first_timestamp = timestamp; - timestamp_relative_to_transport = last_position; + elapsed_since_start = should_be_position; // calculate filter coefficients calculate_filter_coefficients(); // initialize DLL e2 = double(one_ppqn_in_frames) / double(session.frame_rate()); - t0 = double(timestamp_relative_to_transport) / double(session.frame_rate()); + t0 = double(elapsed_since_start) / double(session.frame_rate()); t1 = t0 + e2; // let ardour go after first MIDI Clock Event _starting = false; } else { midi_clock_count++; - last_position += one_ppqn_in_frames; + should_be_position += one_ppqn_in_frames; calculate_filter_coefficients(); // calculate loop error // we use session.transport_frame() instead of t1 here // because t1 is used to calculate the transport speed, // so the loop will compensate for accumulating rounding errors - e = (double(last_position) - double(session.transport_frame())) - / double(session.frame_rate()); + error = (double(should_be_position) - double(session.audible_frame())); + e = error / double(session.frame_rate()); // update DLL t0 = t1; @@ -162,19 +161,24 @@ MIDIClock_Slave::update_midi_clock (Parser& parser, nframes_t timestamp) } #ifdef DEBUG_MIDI_CLOCK - std::cerr + cerr << "MIDI Clock #" << midi_clock_count //<< "@" << timestamp - << " (transport-relative: " << timestamp_relative_to_transport << " should be: " << last_position << ", delta: " << (double(last_position) - double(session.transport_frame())) <<" )" - << " transport: " << session.transport_frame() + << " arrived at: " << elapsed_since_start << " (elapsed time) " + << " should-be transport: " << should_be_position + << " audible: " << session.audible_frame() + << " real transport: " << session.transport_frame() + << " error: " << error //<< " engine: " << session.engine().frame_time() << " real delta: " << timestamp - last_timestamp - << " reference: " << one_ppqn_in_frames + << " should-be delta: " << one_ppqn_in_frames << " t1-t0: " << (t1 -t0) * session.frame_rate() << " t0: " << t0 * session.frame_rate() << " t1: " << t1 * session.frame_rate() << " frame-rate: " << session.frame_rate() - << std::endl; + << endl; + + cerr << "frames since cycle start: " << session.engine().frames_since_cycle_start() << endl; #endif // DEBUG_MIDI_CLOCK last_timestamp = timestamp; @@ -184,7 +188,7 @@ void MIDIClock_Slave::start (Parser& parser, nframes_t timestamp) { #ifdef DEBUG_MIDI_CLOCK - cerr << "MIDIClock_Slave got start message at time " << timestamp << " session time: " << session.engine().frame_time() << endl; + cerr << "MIDIClock_Slave got start message at time " << timestamp << " engine time: " << session.engine().frame_time() << endl; #endif if (!_started) { @@ -199,7 +203,7 @@ void MIDIClock_Slave::reset () { - last_position = 0; + should_be_position = 0; last_timestamp = 0; _starting = false; @@ -233,7 +237,7 @@ MIDIClock_Slave::stop (Parser& parser, nframes_t timestamp) _started = false; // locate to last MIDI clock position session.request_transport_speed(0.0); - session.request_locate(last_position, false); + session.request_locate(should_be_position, false); last_timestamp = 0; } } @@ -248,14 +252,19 @@ MIDIClock_Slave::position (Parser& parser, byte* message, size_t size) } assert(size == 3); - byte lsb = message[0]; - byte msb = message[1]; + byte lsb = message[1]; + byte msb = message[2]; assert((lsb <= 0x7f) && (msb <= 0x7f)); uint16_t position_in_sixteenth_notes = (uint16_t(msb) << 7) | uint16_t(lsb); nframes_t position_in_frames = calculate_song_position(position_in_sixteenth_notes); + + #ifdef DEBUG_MIDI_CLOCK + cerr << "Song Position: " << position_in_sixteenth_notes << " frames: " << position_in_frames << endl; + #endif + session.request_locate(position_in_frames, false); - last_position = position_in_frames; + should_be_position = position_in_frames; last_timestamp = 0; } @@ -288,9 +297,9 @@ MIDIClock_Slave::stop_if_no_more_clock_events(nframes_t& pos, nframes_t now) #ifdef DEBUG_MIDI_CLOCK cerr << "No MIDI Clock frames received for some time, stopping!" << endl; #endif - pos = last_position; + pos = should_be_position; session.request_transport_speed (0); - session.request_locate (last_position, false); + session.request_locate (should_be_position, false); return true; } else { return false; @@ -302,12 +311,12 @@ MIDIClock_Slave::speed_and_position (double& speed, nframes_t& pos) { if (!_started || _starting) { speed = 0.0; - pos = last_position; + pos = should_be_position; return true; } nframes_t engine_now = session.engine().frame_time(); - + if (stop_if_no_more_clock_events(pos, engine_now)) { return false; } @@ -320,12 +329,16 @@ MIDIClock_Slave::speed_and_position (double& speed, nframes_t& pos) // we are in between MIDI clock messages // so we interpolate position according to speed nframes_t elapsed = engine_now - last_timestamp; - pos = nframes_t (last_position + double(elapsed) * speed); + pos = nframes_t (should_be_position + double(elapsed) * speed); } else { // A new MIDI clock message has arrived this cycle - pos = last_position; + pos = should_be_position; } - + + #ifdef DEBUG_MIDI_CLOCK + cerr << "speed_and_position: " << speed << " & " << pos << " <-> " << session.transport_frame() << " (transport)" << endl; + #endif + return true; }