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"
46 * @brief The Slave interface can be used to sync ARDOURs tempo to an external source
47 * like MTC, MIDI Clock, etc.
49 * The name of the interface may be a bit misleading: A subclass of Slave actually
50 * acts as a time master for ARDOUR, that means ARDOUR will try to follow the
51 * speed and transport position of the implementation of Slave.
52 * Therefore it is rather that class, that makes ARDOUR a slave by connecting it
53 * to its external time master.
61 * This is the most important function to implement:
62 * Each process cycle, Session::follow_slave will call this method.
63 * and after the method call they should
65 * Session::follow_slave will then try to follow the given
66 * <emph>position</emph> using a delay locked loop (DLL),
67 * starting with the first given transport speed.
68 * If the values of speed and position contradict each other,
69 * ARDOUR will always follow the position and disregard the speed.
70 * Although, a correct speed is important so that ARDOUR
71 * can sync to the master time source quickly.
73 * For background information on delay locked loops,
74 * see http://www.kokkinizita.net/papers/usingdll.pdf
76 * The method has the following precondition:
79 * Slave::ok() should return true, otherwise playback will stop
80 * immediately and the method will not be called
83 * when the references speed and position are passed into the Slave
84 * they are uninitialized
88 * After the method call the following postconditions should be met:
91 * The first position value on transport start should be 0,
92 * otherwise ARDOUR will try to locate to the new position
93 * rather than move to it
96 * the references speed and position should be assigned
97 * to the Slaves current requested transport speed
98 * and transport position.
101 * Slave::resolution() should be greater than the maximum distance of
102 * ARDOURs transport position to the slaves requested transport position.
104 * <li>Slave::locked() should return true, otherwise Session::no_roll will be called</li>
105 * <li>Slave::starting() should be false, otherwise the transport will not move until it becomes true</li> *
108 * @param speed - The transport speed requested
109 * @param position - The transport position requested
110 * @return - The return value is currently ignored (see Session::follow_slave)
112 virtual bool speed_and_position (double& speed, nframes64_t& position) = 0;
115 * reports to ARDOUR whether the Slave is currently synced to its external
118 * @return - when returning false, the transport will stop rolling
120 virtual bool locked() const = 0;
123 * reports to ARDOUR whether the slave is in a sane state
125 * @return - when returning false, the transport will be stopped and the slave
126 * disconnected from ARDOUR.
128 virtual bool ok() const = 0;
131 * reports to ARDOUR whether the slave is in the process of starting
134 * @return - when returning false, transport will not move until this method returns true
136 virtual bool starting() const { return false; }
139 * @return - the timing resolution of the Slave - If the distance of ARDOURs transport
140 * to the slave becomes greater than the resolution, sound will stop
142 virtual nframes_t resolution() const = 0;
145 * @return - when returning true, ARDOUR will wait for seekahead_distance() before transport
148 virtual bool requires_seekahead () const = 0;
151 * @return the number of frames that this slave wants to seek ahead. Relevant
152 * only if @func requires_seekahead() returns true.
155 virtual nframes64_t seekahead_distance() const { return 0; }
158 * @return - when returning true, ARDOUR will use transport speed 1.0 no matter what
161 virtual bool is_always_synced() const { return false; }
164 * @return - whether ARDOUR should use the slave speed without any adjustments
166 virtual bool give_slave_full_control_over_transport_speed() const { return false; }
169 /// We need this wrapper for testability, it's just too hard to mock up a session class
170 class ISlaveSessionProxy {
172 virtual TempoMap& tempo_map() const { return *((TempoMap *) 0); }
173 virtual nframes_t frame_rate() const { return 0; }
174 virtual nframes64_t audible_frame () const { return 0; }
175 virtual nframes64_t transport_frame () const { return 0; }
176 virtual nframes_t frames_since_cycle_start () const { return 0; }
177 virtual nframes64_t frame_time () const { return 0; }
179 virtual void request_locate (nframes64_t /*frame*/, bool with_roll = false) {
182 virtual void request_transport_speed (double /*speed*/) {}
186 /// The Session Proxy for use in real Ardour
187 class SlaveSessionProxy : public ISlaveSessionProxy {
191 SlaveSessionProxy(Session &s) : session(s) {}
193 TempoMap& tempo_map() const;
194 nframes_t frame_rate() const;
195 nframes64_t audible_frame () const;
196 nframes64_t transport_frame () const;
197 nframes_t frames_since_cycle_start () const;
198 nframes64_t frame_time () const;
200 void request_locate (nframes64_t frame, bool with_roll = false);
201 void request_transport_speed (double speed);
206 nframes64_t position;
207 nframes64_t timestamp;
220 class MTC_Slave : public Slave, public sigc::trackable {
222 MTC_Slave (Session&, MIDI::Port&);
225 void rebind (MIDI::Port&);
226 bool speed_and_position (double&, nframes64_t&);
230 void handle_locate (const MIDI::byte*);
232 nframes_t resolution() const;
233 bool requires_seekahead () const { return true; }
234 nframes64_t seekahead_distance() const;
235 bool give_slave_full_control_over_transport_speed() const;
240 std::vector<sigc::connection> connections;
241 bool can_notify_on_unknown_rate;
245 nframes_t mtc_frame; /* current time */
246 nframes_t last_inbound_frame; /* when we got it; audio clocked */
247 MIDI::byte last_mtc_fps_byte;
248 nframes64_t window_begin;
249 nframes64_t window_end;
250 nframes64_t last_mtc_timestamp;
251 nframes64_t last_mtc_frame;
252 bool did_reset_tc_format;
253 TimecodeFormat saved_tc_format;
254 size_t speed_accumulator_size;
255 double* speed_accumulator;
256 size_t speed_accumulator_cnt;
257 bool have_first_speed_accumulator;
258 double average_speed;
261 void update_mtc_qtr (MIDI::Parser&, int, nframes_t);
262 void update_mtc_time (const MIDI::byte *, bool, nframes_t);
263 void update_mtc_status (MIDI::MTC_Status);
264 void read_current (SafeTime *) const;
265 void reset_window (nframes64_t);
266 bool outside_window (nframes64_t) const;
267 void process_apparent_speed (double);
270 class MIDIClock_Slave : public Slave, public sigc::trackable {
272 MIDIClock_Slave (Session&, MIDI::Port&, int ppqn = 24);
274 /// Constructor for unit tests
275 MIDIClock_Slave (ISlaveSessionProxy* session_proxy, int ppqn = 24);
278 void rebind (MIDI::Port&);
279 bool speed_and_position (double&, nframes64_t&);
283 bool starting() const;
285 nframes_t resolution() const;
286 bool requires_seekahead () const { return false; }
287 bool give_slave_full_control_over_transport_speed() const { return true; }
289 void set_bandwidth (double a_bandwith) { bandwidth = a_bandwith; }
292 ISlaveSessionProxy* session;
294 std::vector<sigc::connection> connections;
296 /// pulses per quarter note for one MIDI clock frame (default 24)
299 /// the duration of one ppqn in frame time
300 double one_ppqn_in_frames;
302 /// the timestamp of the first MIDI clock message
303 nframes_t first_timestamp;
305 /// the time stamp and should-be transport position of the last inbound MIDI clock message
306 nframes_t last_timestamp;
307 double should_be_position;
309 /// the number of midi clock messages received (zero-based)
311 long midi_clock_count;
313 //the delay locked loop (DLL), see www.kokkinizita.net/papers/usingdll.pdf
315 /// time at the beginning of the MIDI clock frame
318 /// calculated end of the MIDI clock frame
321 /// loop error = real value - expected value
324 /// second order loop error
327 /// DLL filter bandwidth
330 /// DLL filter coefficients
334 void start (MIDI::Parser& parser, nframes64_t timestamp);
335 void contineu (MIDI::Parser& parser, nframes64_t timestamp);
336 void stop (MIDI::Parser& parser, nframes64_t timestamp);
337 void position (MIDI::Parser& parser, MIDI::byte* message, size_t size);
338 // we can't use continue because it is a C++ keyword
339 void calculate_one_ppqn_in_frames_at(nframes64_t time);
340 nframes64_t calculate_song_position(uint16_t song_position_in_sixteenth_notes);
341 void calculate_filter_coefficients();
342 void update_midi_clock (MIDI::Parser& parser, nframes64_t timestamp);
343 void read_current (SafeTime *) const;
344 bool stop_if_no_more_clock_events(nframes64_t& pos, nframes64_t now);
346 /// whether transport should be rolling
349 /// is true if the MIDI Start message has just been received until
350 /// the first MIDI Clock Event
354 class JACK_Slave : public Slave
357 JACK_Slave (jack_client_t*);
360 bool speed_and_position (double& speed, nframes64_t& pos);
362 bool starting() const { return _starting; }
365 nframes_t resolution() const { return 1; }
366 bool requires_seekahead () const { return false; }
367 void reset_client (jack_client_t* jack);
368 bool is_always_synced() const { return true; }
378 #endif /* __ardour_slave_h__ */