2 Copyright (C) 2002 Paul Davis
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 #ifndef __ardour_slave_h__
21 #define __ardour_slave_h__
25 #include <glibmm/thread.h>
26 #include <boost/signals2.hpp>
28 #include <jack/jack.h>
30 #include "pbd/signals.h"
32 #include "ardour/types.h"
33 #include "midi++/parser.h"
34 #include "midi++/types.h"
50 * @brief The Slave interface can be used to sync ARDOURs tempo to an external source
51 * like MTC, MIDI Clock, etc.
53 * The name of the interface may be a bit misleading: A subclass of Slave actually
54 * acts as a time master for ARDOUR, that means ARDOUR will try to follow the
55 * speed and transport position of the implementation of Slave.
56 * Therefore it is rather that class, that makes ARDOUR a slave by connecting it
57 * to its external time master.
65 * This is the most important function to implement:
66 * Each process cycle, Session::follow_slave will call this method.
67 * and after the method call they should
69 * Session::follow_slave will then try to follow the given
70 * <em>position</em> using a delay locked loop (DLL),
71 * starting with the first given transport speed.
72 * If the values of speed and position contradict each other,
73 * ARDOUR will always follow the position and disregard the speed.
74 * Although, a correct speed is important so that ARDOUR
75 * can sync to the master time source quickly.
77 * For background information on delay locked loops,
78 * see http://www.kokkinizita.net/papers/usingdll.pdf
80 * The method has the following precondition:
83 * Slave::ok() should return true, otherwise playback will stop
84 * immediately and the method will not be called
87 * when the references speed and position are passed into the Slave
88 * they are uninitialized
92 * After the method call the following postconditions should be met:
95 * The first position value on transport start should be 0,
96 * otherwise ARDOUR will try to locate to the new position
97 * rather than move to it
100 * the references speed and position should be assigned
101 * to the Slaves current requested transport speed
102 * and transport position.
105 * Slave::resolution() should be greater than the maximum distance of
106 * ARDOURs transport position to the slaves requested transport position.
108 * <li>Slave::locked() should return true, otherwise Session::no_roll will be called</li>
109 * <li>Slave::starting() should be false, otherwise the transport will not move until it becomes true</li> *
112 * @param speed - The transport speed requested
113 * @param position - The transport position requested
114 * @return - The return value is currently ignored (see Session::follow_slave)
116 virtual bool speed_and_position (double& speed, framepos_t& position) = 0;
119 * reports to ARDOUR whether the Slave is currently synced to its external
122 * @return - when returning false, the transport will stop rolling
124 virtual bool locked() const = 0;
127 * reports to ARDOUR whether the slave is in a sane state
129 * @return - when returning false, the transport will be stopped and the slave
130 * disconnected from ARDOUR.
132 virtual bool ok() const = 0;
135 * reports to ARDOUR whether the slave is in the process of starting
138 * @return - when returning false, transport will not move until this method returns true
140 virtual bool starting() const { return false; }
143 * @return - the timing resolution of the Slave - If the distance of ARDOURs transport
144 * to the slave becomes greater than the resolution, sound will stop
146 virtual nframes_t resolution() const = 0;
149 * @return - when returning true, ARDOUR will wait for seekahead_distance() before transport
152 virtual bool requires_seekahead () const = 0;
155 * @return the number of frames that this slave wants to seek ahead. Relevant
156 * only if requires_seekahead() returns true.
159 virtual framepos_t seekahead_distance() const { return 0; }
162 * @return - when returning true, ARDOUR will use transport speed 1.0 no matter what
165 virtual bool is_always_synced() const { return false; }
168 * @return - whether ARDOUR should use the slave speed without any adjustments
170 virtual bool give_slave_full_control_over_transport_speed() const { return false; }
173 /// We need this wrapper for testability, it's just too hard to mock up a session class
174 class ISlaveSessionProxy {
176 virtual ~ISlaveSessionProxy() {}
177 virtual TempoMap& tempo_map() const { return *((TempoMap *) 0); }
178 virtual nframes_t frame_rate() const { return 0; }
179 virtual framepos_t audible_frame () const { return 0; }
180 virtual framepos_t transport_frame () const { return 0; }
181 virtual nframes_t frames_since_cycle_start () const { return 0; }
182 virtual framepos_t frame_time () const { return 0; }
184 virtual void request_locate (framepos_t /*frame*/, bool with_roll = false) {
187 virtual void request_transport_speed (double /*speed*/) {}
191 /// The Session Proxy for use in real Ardour
192 class SlaveSessionProxy : public ISlaveSessionProxy {
196 SlaveSessionProxy(Session &s) : session(s) {}
198 TempoMap& tempo_map() const;
199 nframes_t frame_rate() const;
200 framepos_t audible_frame () const;
201 framepos_t transport_frame () const;
202 nframes_t frames_since_cycle_start () const;
203 framepos_t frame_time () const;
205 void request_locate (framepos_t frame, bool with_roll = false);
206 void request_transport_speed (double speed);
212 framepos_t timestamp;
225 class MTC_Slave : public Slave {
227 MTC_Slave (Session&, MIDI::Port&);
230 void rebind (MIDI::Port&);
231 bool speed_and_position (double&, framepos_t&);
235 void handle_locate (const MIDI::byte*);
237 nframes_t resolution() const;
238 bool requires_seekahead () const { return true; }
239 framepos_t seekahead_distance() const;
240 bool give_slave_full_control_over_transport_speed() const;
245 PBD::ScopedConnectionList port_connections;
246 bool can_notify_on_unknown_rate;
249 static const int frame_tolerance;
252 framepos_t mtc_frame; /* current time */
253 framepos_t last_inbound_frame; /* when we got it; audio clocked */
254 MIDI::byte last_mtc_fps_byte;
255 framepos_t window_begin;
256 framepos_t window_end;
257 framepos_t last_mtc_timestamp;
258 framepos_t last_mtc_frame;
259 bool did_reset_tc_format;
260 TimecodeFormat saved_tc_format;
261 size_t speed_accumulator_size;
262 double* speed_accumulator;
263 size_t speed_accumulator_cnt;
264 bool have_first_speed_accumulator;
265 double average_speed;
266 Glib::Mutex reset_lock;
267 uint32_t reset_pending;
270 void reset (bool with_pos);
271 void queue_reset (bool with_pos);
274 void update_mtc_qtr (MIDI::Parser&, int, nframes_t);
275 void update_mtc_time (const MIDI::byte *, bool, nframes_t);
276 void update_mtc_status (MIDI::MTC_Status);
277 void read_current (SafeTime *) const;
278 void reset_window (framepos_t);
279 bool outside_window (framepos_t) const;
280 void process_apparent_speed (double);
283 class MIDIClock_Slave : public Slave {
285 MIDIClock_Slave (Session&, MIDI::Port&, int ppqn = 24);
287 /// Constructor for unit tests
288 MIDIClock_Slave (ISlaveSessionProxy* session_proxy = 0, int ppqn = 24);
291 void rebind (MIDI::Port&);
292 bool speed_and_position (double&, framepos_t&);
296 bool starting() const;
298 nframes_t resolution() const;
299 bool requires_seekahead () const { return false; }
300 bool give_slave_full_control_over_transport_speed() const { return true; }
302 void set_bandwidth (double a_bandwith) { bandwidth = a_bandwith; }
305 ISlaveSessionProxy* session;
307 PBD::ScopedConnectionList port_connections;
309 /// pulses per quarter note for one MIDI clock frame (default 24)
312 /// the duration of one ppqn in frame time
313 double one_ppqn_in_frames;
315 /// the timestamp of the first MIDI clock message
316 nframes_t first_timestamp;
318 /// the time stamp and should-be transport position of the last inbound MIDI clock message
319 nframes_t last_timestamp;
320 double should_be_position;
322 /// the number of midi clock messages received (zero-based)
324 long midi_clock_count;
326 //the delay locked loop (DLL), see www.kokkinizita.net/papers/usingdll.pdf
328 /// time at the beginning of the MIDI clock frame
331 /// calculated end of the MIDI clock frame
334 /// loop error = real value - expected value
337 /// second order loop error
340 /// DLL filter bandwidth
343 /// DLL filter coefficients
347 void start (MIDI::Parser& parser, framepos_t timestamp);
348 void contineu (MIDI::Parser& parser, framepos_t timestamp);
349 void stop (MIDI::Parser& parser, framepos_t timestamp);
350 void position (MIDI::Parser& parser, MIDI::byte* message, size_t size);
351 // we can't use continue because it is a C++ keyword
352 void calculate_one_ppqn_in_frames_at(framepos_t time);
353 framepos_t calculate_song_position(uint16_t song_position_in_sixteenth_notes);
354 void calculate_filter_coefficients();
355 void update_midi_clock (MIDI::Parser& parser, framepos_t timestamp);
356 void read_current (SafeTime *) const;
357 bool stop_if_no_more_clock_events(framepos_t& pos, framepos_t now);
359 /// whether transport should be rolling
362 /// is true if the MIDI Start message has just been received until
363 /// the first MIDI Clock Event
367 class JACK_Slave : public Slave
370 JACK_Slave (jack_client_t*);
373 bool speed_and_position (double& speed, framepos_t& pos);
375 bool starting() const { return _starting; }
378 nframes_t resolution() const { return 1; }
379 bool requires_seekahead () const { return false; }
380 void reset_client (jack_client_t* jack);
381 bool is_always_synced() const { return true; }
391 #endif /* __ardour_slave_h__ */