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 "timecode/time.h"
33 #include "ardour/types.h"
34 #include "midi++/parser.h"
35 #include "midi++/types.h"
53 * @brief The Slave interface can be used to sync ARDOURs tempo to an external source
54 * like MTC, MIDI Clock, etc.
56 * The name of the interface may be a bit misleading: A subclass of Slave actually
57 * acts as a time master for ARDOUR, that means ARDOUR will try to follow the
58 * speed and transport position of the implementation of Slave.
59 * Therefore it is rather that class, that makes ARDOUR a slave by connecting it
60 * to its external time master.
68 * This is the most important function to implement:
69 * Each process cycle, Session::follow_slave will call this method.
70 * and after the method call they should
72 * Session::follow_slave will then try to follow the given
73 * <em>position</em> using a delay locked loop (DLL),
74 * starting with the first given transport speed.
75 * If the values of speed and position contradict each other,
76 * ARDOUR will always follow the position and disregard the speed.
77 * Although, a correct speed is important so that ARDOUR
78 * can sync to the master time source quickly.
80 * For background information on delay locked loops,
81 * see http://www.kokkinizita.net/papers/usingdll.pdf
83 * The method has the following precondition:
86 * Slave::ok() should return true, otherwise playback will stop
87 * immediately and the method will not be called
90 * when the references speed and position are passed into the Slave
91 * they are uninitialized
95 * After the method call the following postconditions should be met:
98 * The first position value on transport start should be 0,
99 * otherwise ARDOUR will try to locate to the new position
100 * rather than move to it
103 * the references speed and position should be assigned
104 * to the Slaves current requested transport speed
105 * and transport position.
108 * Slave::resolution() should be greater than the maximum distance of
109 * ARDOURs transport position to the slaves requested transport position.
111 * <li>Slave::locked() should return true, otherwise Session::no_roll will be called</li>
112 * <li>Slave::starting() should be false, otherwise the transport will not move until it becomes true</li> *
115 * @param speed - The transport speed requested
116 * @param position - The transport position requested
117 * @return - The return value is currently ignored (see Session::follow_slave)
119 virtual bool speed_and_position (double& speed, framepos_t& position) = 0;
122 * reports to ARDOUR whether the Slave is currently synced to its external
125 * @return - when returning false, the transport will stop rolling
127 virtual bool locked() const = 0;
130 * reports to ARDOUR whether the slave is in a sane state
132 * @return - when returning false, the transport will be stopped and the slave
133 * disconnected from ARDOUR.
135 virtual bool ok() const = 0;
138 * reports to ARDOUR whether the slave is in the process of starting
141 * @return - when returning false, transport will not move until this method returns true
143 virtual bool starting() const { return false; }
146 * @return - the timing resolution of the Slave - If the distance of ARDOURs transport
147 * to the slave becomes greater than the resolution, sound will stop
149 virtual framecnt_t resolution() const = 0;
152 * @return - when returning true, ARDOUR will wait for seekahead_distance() before transport
155 virtual bool requires_seekahead () const = 0;
158 * @return the number of frames that this slave wants to seek ahead. Relevant
159 * only if requires_seekahead() returns true.
162 virtual framecnt_t seekahead_distance() const { return 0; }
165 * @return - when returning true, ARDOUR will use transport speed 1.0 no matter what
168 virtual bool is_always_synced() const { return false; }
171 * @return - whether ARDOUR should use the slave speed without any adjustments
173 virtual bool give_slave_full_control_over_transport_speed() const { return false; }
176 /// We need this wrapper for testability, it's just too hard to mock up a session class
177 class ISlaveSessionProxy {
179 virtual ~ISlaveSessionProxy() {}
180 virtual TempoMap& tempo_map() const { return *((TempoMap *) 0); }
181 virtual framecnt_t frame_rate() const { return 0; }
182 virtual framepos_t audible_frame () const { return 0; }
183 virtual framepos_t transport_frame () const { return 0; }
184 virtual pframes_t frames_since_cycle_start () const { return 0; }
185 virtual framepos_t frame_time () const { return 0; }
187 virtual void request_locate (framepos_t /*frame*/, bool with_roll = false) {
190 virtual void request_transport_speed (double /*speed*/) {}
194 /// The Session Proxy for use in real Ardour
195 class SlaveSessionProxy : public ISlaveSessionProxy {
199 SlaveSessionProxy(Session &s) : session(s) {}
201 TempoMap& tempo_map() const;
202 framecnt_t frame_rate() const;
203 framepos_t audible_frame () const;
204 framepos_t transport_frame () const;
205 pframes_t frames_since_cycle_start () const;
206 framepos_t frame_time () const;
208 void request_locate (framepos_t frame, bool with_roll = false);
209 void request_transport_speed (double speed);
215 framepos_t timestamp;
228 class TimecodeSlave : public Slave {
232 virtual Timecode::TimecodeFormat apparent_timecode_format() const = 0;
234 /* this is intended to be used by a UI and polled from a timeout. it should
235 return a string describing the current position of the TC source. it
236 should NOT do any computation, but should use a cached value
237 of the TC source position.
239 virtual std::string approximate_current_position() const = 0;
242 class MTC_Slave : public TimecodeSlave {
244 MTC_Slave (Session&, MIDI::Port&);
247 void rebind (MIDI::Port&);
248 bool speed_and_position (double&, framepos_t&);
252 void handle_locate (const MIDI::byte*);
254 framecnt_t resolution () const;
255 bool requires_seekahead () const { return true; }
256 framecnt_t seekahead_distance() const;
257 bool give_slave_full_control_over_transport_speed() const;
259 Timecode::TimecodeFormat apparent_timecode_format() const;
260 std::string approximate_current_position() const;
265 PBD::ScopedConnectionList port_connections;
266 bool can_notify_on_unknown_rate;
268 static const int frame_tolerance;
271 framepos_t mtc_frame; /* current time */
272 framepos_t last_inbound_frame; /* when we got it; audio clocked */
273 MIDI::byte last_mtc_fps_byte;
274 framepos_t window_begin;
275 framepos_t window_end;
276 framepos_t first_mtc_timestamp;
277 bool did_reset_tc_format;
278 Timecode::TimecodeFormat saved_tc_format;
279 Glib::Threads::Mutex reset_lock;
280 uint32_t reset_pending;
282 int transport_direction;
286 double speedup_due_to_tc_mismatch;
287 double quarter_frame_duration;
288 Timecode::TimecodeFormat mtc_timecode;
289 Timecode::TimecodeFormat a3e_timecode;
290 bool printed_timecode_warning;
292 /* DLL - chase MTC */
293 double t0; ///< time at the beginning of the MTC quater frame
294 double t1; ///< calculated end of the MTC quater frame
295 double e2; ///< second order loop error
296 double b, c, omega; ///< DLL filter coefficients
298 /* DLL - sync engine */
299 int engine_dll_initstate;
300 double te0; ///< time at the beginning of the engine process
301 double te1; ///< calculated sync time
302 double ee2; ///< second order loop error
303 double be, ce, oe; ///< DLL filter coefficients
305 void reset (bool with_pos);
306 void queue_reset (bool with_pos);
309 void update_mtc_qtr (MIDI::Parser&, int, framepos_t);
310 void update_mtc_time (const MIDI::byte *, bool, framepos_t);
311 void update_mtc_status (MIDI::MTC_Status);
312 void read_current (SafeTime *) const;
313 void reset_window (framepos_t);
314 bool outside_window (framepos_t) const;
315 void init_mtc_dll(framepos_t, double);
316 void init_engine_dll (framepos_t, framepos_t);
320 class LTC_Slave : public TimecodeSlave {
322 LTC_Slave (Session&);
325 bool speed_and_position (double&, framepos_t&);
330 framecnt_t resolution () const;
331 bool requires_seekahead () const { return true; }
332 framecnt_t seekahead_distance() const;
333 bool give_slave_full_control_over_transport_speed() const;
335 Timecode::TimecodeFormat apparent_timecode_format() const;
336 std::string approximate_current_position() const;
339 int parse_ltc(const jack_nframes_t, const jack_default_audio_sample_t * const, const framecnt_t);
340 bool process_ltc(framepos_t, framecnt_t);
341 void init_ltc_dll(framepos_t, double);
344 bool did_reset_tc_format;
345 Timecode::TimecodeFormat saved_tc_format;
348 double frames_per_ltc_frame;
350 framecnt_t last_timestamp;
351 framecnt_t last_ltc_frame;
352 framepos_t ltc_transport_pos;
355 /* DLL - chase MTC */
356 double t0; ///< time at the beginning of the MTC quater frame
357 double t1; ///< calculated end of the MTC quater frame
358 double e2; ///< second order loop error
359 double b, c, omega; ///< DLL filter coefficients
363 class MIDIClock_Slave : public Slave {
365 MIDIClock_Slave (Session&, MIDI::Port&, int ppqn = 24);
367 /// Constructor for unit tests
368 MIDIClock_Slave (ISlaveSessionProxy* session_proxy = 0, int ppqn = 24);
371 void rebind (MIDI::Port&);
372 bool speed_and_position (double&, framepos_t&);
376 bool starting() const;
378 framecnt_t resolution () const;
379 bool requires_seekahead () const { return false; }
380 bool give_slave_full_control_over_transport_speed() const { return true; }
382 void set_bandwidth (double a_bandwith) { bandwidth = a_bandwith; }
385 ISlaveSessionProxy* session;
387 PBD::ScopedConnectionList port_connections;
389 /// pulses per quarter note for one MIDI clock frame (default 24)
392 /// the duration of one ppqn in frame time
393 double one_ppqn_in_frames;
395 /// the timestamp of the first MIDI clock message
396 framepos_t first_timestamp;
398 /// the time stamp and should-be transport position of the last inbound MIDI clock message
399 framepos_t last_timestamp;
400 double should_be_position;
402 /// the number of midi clock messages received (zero-based)
404 long midi_clock_count;
406 //the delay locked loop (DLL), see www.kokkinizita.net/papers/usingdll.pdf
408 /// time at the beginning of the MIDI clock frame
411 /// calculated end of the MIDI clock frame
414 /// loop error = real value - expected value
417 /// second order loop error
420 /// DLL filter bandwidth
423 /// DLL filter coefficients
427 void start (MIDI::Parser& parser, framepos_t timestamp);
428 void contineu (MIDI::Parser& parser, framepos_t timestamp);
429 void stop (MIDI::Parser& parser, framepos_t timestamp);
430 void position (MIDI::Parser& parser, MIDI::byte* message, size_t size);
431 // we can't use continue because it is a C++ keyword
432 void calculate_one_ppqn_in_frames_at(framepos_t time);
433 framepos_t calculate_song_position(uint16_t song_position_in_sixteenth_notes);
434 void calculate_filter_coefficients();
435 void update_midi_clock (MIDI::Parser& parser, framepos_t timestamp);
436 void read_current (SafeTime *) const;
437 bool stop_if_no_more_clock_events(framepos_t& pos, framepos_t now);
439 /// whether transport should be rolling
442 /// is true if the MIDI Start message has just been received until
443 /// the first MIDI Clock Event
447 class JACK_Slave : public Slave
450 JACK_Slave (jack_client_t*);
453 bool speed_and_position (double& speed, framepos_t& pos);
455 bool starting() const { return _starting; }
458 framecnt_t resolution () const { return 1; }
459 bool requires_seekahead () const { return false; }
460 void reset_client (jack_client_t* jack);
461 bool is_always_synced() const { return true; }
471 #endif /* __ardour_slave_h__ */