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/threads.h>
27 #include <jack/jack.h>
29 #include "pbd/signals.h"
31 #include "ardour/types.h"
32 #include "midi++/parser.h"
33 #include "midi++/types.h"
47 * @brief The Slave interface can be used to sync ARDOURs tempo to an external source
48 * like MTC, MIDI Clock, etc.
50 * The name of the interface may be a bit misleading: A subclass of Slave actually
51 * acts as a time master for ARDOUR, that means ARDOUR will try to follow the
52 * speed and transport position of the implementation of Slave.
53 * Therefore it is rather that class, that makes ARDOUR a slave by connecting it
54 * to its external time master.
62 * This is the most important function to implement:
63 * Each process cycle, Session::follow_slave will call this method.
64 * and after the method call they should
66 * Session::follow_slave will then try to follow the given
67 * <em>position</em> using a delay locked loop (DLL),
68 * starting with the first given transport speed.
69 * If the values of speed and position contradict each other,
70 * ARDOUR will always follow the position and disregard the speed.
71 * Although, a correct speed is important so that ARDOUR
72 * can sync to the master time source quickly.
74 * For background information on delay locked loops,
75 * see http://www.kokkinizita.net/papers/usingdll.pdf
77 * The method has the following precondition:
80 * Slave::ok() should return true, otherwise playback will stop
81 * immediately and the method will not be called
84 * when the references speed and position are passed into the Slave
85 * they are uninitialized
89 * After the method call the following postconditions should be met:
92 * The first position value on transport start should be 0,
93 * otherwise ARDOUR will try to locate to the new position
94 * rather than move to it
97 * the references speed and position should be assigned
98 * to the Slaves current requested transport speed
99 * and transport position.
102 * Slave::resolution() should be greater than the maximum distance of
103 * ARDOURs transport position to the slaves requested transport position.
105 * <li>Slave::locked() should return true, otherwise Session::no_roll will be called</li>
106 * <li>Slave::starting() should be false, otherwise the transport will not move until it becomes true</li> *
109 * @param speed - The transport speed requested
110 * @param position - The transport position requested
111 * @return - The return value is currently ignored (see Session::follow_slave)
113 virtual bool speed_and_position (double& speed, framepos_t& position) = 0;
116 * reports to ARDOUR whether the Slave is currently synced to its external
119 * @return - when returning false, the transport will stop rolling
121 virtual bool locked() const = 0;
124 * reports to ARDOUR whether the slave is in a sane state
126 * @return - when returning false, the transport will be stopped and the slave
127 * disconnected from ARDOUR.
129 virtual bool ok() const = 0;
132 * reports to ARDOUR whether the slave is in the process of starting
135 * @return - when returning false, transport will not move until this method returns true
137 virtual bool starting() const { return false; }
140 * @return - the timing resolution of the Slave - If the distance of ARDOURs transport
141 * to the slave becomes greater than the resolution, sound will stop
143 virtual framecnt_t resolution() const = 0;
146 * @return - when returning true, ARDOUR will wait for seekahead_distance() before transport
149 virtual bool requires_seekahead () const = 0;
152 * @return the number of frames that this slave wants to seek ahead. Relevant
153 * only if requires_seekahead() returns true.
156 virtual framecnt_t seekahead_distance() const { return 0; }
159 * @return - when returning true, ARDOUR will use transport speed 1.0 no matter what
162 virtual bool is_always_synced() const { return false; }
165 * @return - whether ARDOUR should use the slave speed without any adjustments
167 virtual bool give_slave_full_control_over_transport_speed() const { return false; }
170 /// We need this wrapper for testability, it's just too hard to mock up a session class
171 class ISlaveSessionProxy {
173 virtual ~ISlaveSessionProxy() {}
174 virtual TempoMap& tempo_map() const { return *((TempoMap *) 0); }
175 virtual framecnt_t frame_rate() const { return 0; }
176 virtual framepos_t audible_frame () const { return 0; }
177 virtual framepos_t transport_frame () const { return 0; }
178 virtual pframes_t frames_since_cycle_start () const { return 0; }
179 virtual framepos_t frame_time () const { return 0; }
181 virtual void request_locate (framepos_t /*frame*/, bool with_roll = false) {
184 virtual void request_transport_speed (double /*speed*/) {}
188 /// The Session Proxy for use in real Ardour
189 class SlaveSessionProxy : public ISlaveSessionProxy {
193 SlaveSessionProxy(Session &s) : session(s) {}
195 TempoMap& tempo_map() const;
196 framecnt_t frame_rate() const;
197 framepos_t audible_frame () const;
198 framepos_t transport_frame () const;
199 pframes_t frames_since_cycle_start () const;
200 framepos_t frame_time () const;
202 void request_locate (framepos_t frame, bool with_roll = false);
203 void request_transport_speed (double speed);
209 framepos_t timestamp;
222 class MTC_Slave : public Slave {
224 MTC_Slave (Session&, MIDI::Port&);
227 void rebind (MIDI::Port&);
228 bool speed_and_position (double&, framepos_t&);
232 void handle_locate (const MIDI::byte*);
234 framecnt_t resolution () const;
235 bool requires_seekahead () const { return true; }
236 framecnt_t seekahead_distance() const;
237 bool give_slave_full_control_over_transport_speed() const;
242 PBD::ScopedConnectionList port_connections;
243 bool can_notify_on_unknown_rate;
245 static const int frame_tolerance;
248 framepos_t mtc_frame; /* current time */
249 framepos_t last_inbound_frame; /* when we got it; audio clocked */
250 MIDI::byte last_mtc_fps_byte;
251 framepos_t window_begin;
252 framepos_t window_end;
253 framepos_t first_mtc_timestamp;
254 bool did_reset_tc_format;
255 TimecodeFormat saved_tc_format;
256 Glib::Threads::Mutex reset_lock;
257 uint32_t reset_pending;
259 int transport_direction;
263 /* DLL - chase MTC */
264 double t0; ///< time at the beginning of the MTC quater frame
265 double t1; ///< calculated end of the MTC quater frame
266 double e2; ///< second order loop error
267 double b, c, omega; ///< DLL filter coefficients
269 /* DLL - sync engine */
270 int engine_dll_initstate;
271 double te0; ///< time at the beginning of the engine process
272 double te1; ///< calculated sync time
273 double ee2; ///< second order loop error
274 double be, ce, oe; ///< DLL filter coefficients
276 void reset (bool with_pos);
277 void queue_reset (bool with_pos);
280 void update_mtc_qtr (MIDI::Parser&, int, framepos_t);
281 void update_mtc_time (const MIDI::byte *, bool, framepos_t);
282 void update_mtc_status (MIDI::MTC_Status);
283 void read_current (SafeTime *) const;
284 void reset_window (framepos_t);
285 bool outside_window (framepos_t) const;
286 void init_mtc_dll(framepos_t, double);
287 void init_engine_dll (framepos_t, framepos_t);
290 class MIDIClock_Slave : public Slave {
292 MIDIClock_Slave (Session&, MIDI::Port&, int ppqn = 24);
294 /// Constructor for unit tests
295 MIDIClock_Slave (ISlaveSessionProxy* session_proxy = 0, int ppqn = 24);
298 void rebind (MIDI::Port&);
299 bool speed_and_position (double&, framepos_t&);
303 bool starting() const;
305 framecnt_t resolution () const;
306 bool requires_seekahead () const { return false; }
307 bool give_slave_full_control_over_transport_speed() const { return true; }
309 void set_bandwidth (double a_bandwith) { bandwidth = a_bandwith; }
312 ISlaveSessionProxy* session;
314 PBD::ScopedConnectionList port_connections;
316 /// pulses per quarter note for one MIDI clock frame (default 24)
319 /// the duration of one ppqn in frame time
320 double one_ppqn_in_frames;
322 /// the timestamp of the first MIDI clock message
323 framepos_t first_timestamp;
325 /// the time stamp and should-be transport position of the last inbound MIDI clock message
326 framepos_t last_timestamp;
327 double should_be_position;
329 /// the number of midi clock messages received (zero-based)
331 long midi_clock_count;
333 //the delay locked loop (DLL), see www.kokkinizita.net/papers/usingdll.pdf
335 /// time at the beginning of the MIDI clock frame
338 /// calculated end of the MIDI clock frame
341 /// loop error = real value - expected value
344 /// second order loop error
347 /// DLL filter bandwidth
350 /// DLL filter coefficients
354 void start (MIDI::Parser& parser, framepos_t timestamp);
355 void contineu (MIDI::Parser& parser, framepos_t timestamp);
356 void stop (MIDI::Parser& parser, framepos_t timestamp);
357 void position (MIDI::Parser& parser, MIDI::byte* message, size_t size);
358 // we can't use continue because it is a C++ keyword
359 void calculate_one_ppqn_in_frames_at(framepos_t time);
360 framepos_t calculate_song_position(uint16_t song_position_in_sixteenth_notes);
361 void calculate_filter_coefficients();
362 void update_midi_clock (MIDI::Parser& parser, framepos_t timestamp);
363 void read_current (SafeTime *) const;
364 bool stop_if_no_more_clock_events(framepos_t& pos, framepos_t now);
366 /// whether transport should be rolling
369 /// is true if the MIDI Start message has just been received until
370 /// the first MIDI Clock Event
374 class JACK_Slave : public Slave
377 JACK_Slave (jack_client_t*);
380 bool speed_and_position (double& speed, framepos_t& pos);
382 bool starting() const { return _starting; }
385 framecnt_t resolution () const { return 1; }
386 bool requires_seekahead () const { return false; }
387 void reset_client (jack_client_t* jack);
388 bool is_always_synced() const { return true; }
398 #endif /* __ardour_slave_h__ */