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 <jack/jack.h>
27 #include <sigc++/signal.h>
28 #include "ardour/types.h"
29 #include "midi++/parser.h"
30 #include "midi++/types.h"
44 * @brief The Slave interface can be used to sync ARDOURs tempo to an external source
45 * like MTC, MIDI Clock, etc.
47 * The name of the interface may be a bit misleading: A subclass of Slave actually
48 * acts as a time master for ARDOUR, that means ARDOUR will try to follow the
49 * speed and transport position of the implementation of Slave.
50 * Therefore it is rather that class, that makes ARDOUR a slave by connecting it
51 * to its external time master.
59 * This is the most important function to implement:
60 * Each process cycle, Session::follow_slave will call this method.
61 * and after the method call they should
63 * Session::follow_slave will then try to follow the given
64 * <emph>position</emph> using a delay locked loop (DLL),
65 * starting with the first given transport speed.
66 * If the values of speed and position contradict each other,
67 * ARDOUR will always follow the position and disregard the speed.
68 * Although, a correct speed is important so that ARDOUR
69 * can sync to the master time source quickly.
71 * For background information on delay locked loops,
72 * see http://www.kokkinizita.net/papers/usingdll.pdf
74 * The method has the following precondition:
77 * Slave::ok() should return true, otherwise playback will stop
78 * immediately and the method will not be called
81 * when the references speed and position are passed into the Slave
82 * they are uninitialized
86 * After the method call the following postconditions should be met:
89 * The first position value on transport start should be 0,
90 * otherwise ARDOUR will try to locate to the new position
91 * rather than move to it
94 * the references speed and position should be assigned
95 * to the Slaves current requested transport speed
96 * and transport position.
99 * Slave::resolution() should be greater than the maximum distance of
100 * ARDOURs transport position to the slaves requested transport position.
102 * <li>Slave::locked() should return true, otherwise Session::no_roll will be called</li>
103 * <li>Slave::starting() should be false, otherwise the transport will not move until it becomes true</li> *
106 * @param speed - The transport speed requested
107 * @param position - The transport position requested
108 * @return - The return value is currently ignored (see Session::follow_slave)
110 virtual bool speed_and_position (double& speed, nframes64_t& position) = 0;
113 * reports to ARDOUR whether the Slave is currently synced to its external
116 * @return - when returning false, the transport will stop rolling
118 virtual bool locked() const = 0;
121 * reports to ARDOUR whether the slave is in a sane state
123 * @return - when returning false, the transport will be stopped and the slave
124 * disconnected from ARDOUR.
126 virtual bool ok() const = 0;
129 * reports to ARDOUR whether the slave is in the process of starting
132 * @return - when returning false, transport will not move until this method returns true
134 virtual bool starting() const { return false; }
137 * @return - the timing resolution of the Slave - If the distance of ARDOURs transport
138 * to the slave becomes greater than the resolution, sound will stop
140 virtual nframes_t resolution() const = 0;
143 * @return - when returning true, ARDOUR will wait for one second before transport
146 virtual bool requires_seekahead () const = 0;
149 * @return - when returning true, ARDOUR will use transport speed 1.0 no matter what
152 virtual bool is_always_synced() const { return false; }
155 * @return - whether ARDOUR should use the slave speed without any adjustments
157 virtual bool give_slave_full_control_over_transport_speed() const { return false; }
160 /// We need this wrapper for testability, it's just too hard to mock up a session class
161 class ISlaveSessionProxy {
163 virtual TempoMap& tempo_map() const { return *((TempoMap *) 0); }
164 virtual nframes_t frame_rate() const { return 0; }
165 virtual nframes64_t audible_frame () const { return 0; }
166 virtual nframes64_t transport_frame () const { return 0; }
167 virtual nframes_t frames_since_cycle_start () const { return 0; }
168 virtual nframes64_t frame_time () const { return 0; }
170 virtual void request_locate (nframes64_t /*frame*/, bool with_roll = false) {
173 virtual void request_transport_speed (double /*speed*/) {}
177 /// The Session Proxy for use in real Ardour
178 class SlaveSessionProxy : public ISlaveSessionProxy {
182 SlaveSessionProxy(Session &s) : session(s) {}
184 TempoMap& tempo_map() const;
185 nframes_t frame_rate() const;
186 nframes64_t audible_frame () const;
187 nframes64_t transport_frame () const;
188 nframes_t frames_since_cycle_start () const;
189 nframes64_t frame_time () const;
191 void request_locate (nframes64_t frame, bool with_roll = false);
192 void request_transport_speed (double speed);
208 class MTC_Slave : public Slave, public sigc::trackable {
210 MTC_Slave (Session&, MIDI::Port&);
213 void rebind (MIDI::Port&);
214 bool speed_and_position (double&, nframes64_t&);
218 void handle_locate (const MIDI::byte*);
220 nframes_t resolution() const;
221 bool requires_seekahead () const { return true; }
226 std::vector<sigc::connection> connections;
227 bool can_notify_on_unknown_rate;
230 nframes_t mtc_frame; /* current time */
231 nframes_t last_inbound_frame; /* when we got it; audio clocked */
232 MIDI::byte last_mtc_fps_byte;
235 nframes_t first_mtc_frame;
236 nframes_t first_mtc_time;
238 static const int32_t accumulator_size = 128;
239 double accumulator[accumulator_size];
240 int32_t accumulator_index;
241 bool have_first_accumulated_speed;
244 void update_mtc_qtr (MIDI::Parser&);
245 void update_mtc_time (const MIDI::byte *, bool);
246 void update_mtc_status (MIDI::Parser::MTC_Status);
247 void read_current (SafeTime *) const;
250 class MIDIClock_Slave : public Slave, public sigc::trackable {
252 MIDIClock_Slave (Session&, MIDI::Port&, int ppqn = 24);
254 /// Constructor for unit tests
255 MIDIClock_Slave (ISlaveSessionProxy* session_proxy, int ppqn = 24);
258 void rebind (MIDI::Port&);
259 bool speed_and_position (double&, nframes64_t&);
263 bool starting() const;
265 nframes_t resolution() const;
266 bool requires_seekahead () const { return false; }
267 bool give_slave_full_control_over_transport_speed() const { return true; }
269 void set_bandwidth (double a_bandwith) { bandwidth = a_bandwith; }
272 ISlaveSessionProxy* session;
274 std::vector<sigc::connection> connections;
276 /// pulses per quarter note for one MIDI clock frame (default 24)
279 /// the duration of one ppqn in frame time
280 double one_ppqn_in_frames;
282 /// the timestamp of the first MIDI clock message
283 nframes_t first_timestamp;
285 /// the time stamp and should-be transport position of the last inbound MIDI clock message
286 nframes_t last_timestamp;
287 double should_be_position;
289 /// the number of midi clock messages received (zero-based)
291 long midi_clock_count;
293 //the delay locked loop (DLL), see www.kokkinizita.net/papers/usingdll.pdf
295 /// time at the beginning of the MIDI clock frame
298 /// calculated end of the MIDI clock frame
301 /// loop error = real value - expected value
304 /// second order loop error
307 /// DLL filter bandwidth
310 /// DLL filter coefficients
314 void start (MIDI::Parser& parser, nframes64_t timestamp);
315 void contineu (MIDI::Parser& parser, nframes64_t timestamp);
316 void stop (MIDI::Parser& parser, nframes64_t timestamp);
317 void position (MIDI::Parser& parser, MIDI::byte* message, size_t size);
318 // we can't use continue because it is a C++ keyword
319 void calculate_one_ppqn_in_frames_at(nframes64_t time);
320 nframes64_t calculate_song_position(uint16_t song_position_in_sixteenth_notes);
321 void calculate_filter_coefficients();
322 void update_midi_clock (MIDI::Parser& parser, nframes64_t timestamp);
323 void read_current (SafeTime *) const;
324 bool stop_if_no_more_clock_events(nframes64_t& pos, nframes64_t now);
326 /// whether transport should be rolling
329 /// is true if the MIDI Start message has just been received until
330 /// the first MIDI Clock Event
334 class ADAT_Slave : public Slave
340 bool speed_and_position (double& speed, nframes64_t& pos) {
346 bool locked() const { return false; }
347 bool ok() const { return false; }
348 nframes_t resolution() const { return 1; }
349 bool requires_seekahead () const { return true; }
352 class JACK_Slave : public Slave
355 JACK_Slave (jack_client_t*);
358 bool speed_and_position (double& speed, nframes64_t& pos);
360 bool starting() const { return _starting; }
363 nframes_t resolution() const { return 1; }
364 bool requires_seekahead () const { return false; }
365 void reset_client (jack_client_t* jack);
366 bool is_always_synced() const { return true; }
376 #endif /* __ardour_slave_h__ */