The Slave interface can be used to sync ARDOURs tempo to an external source like MTC, MIDI Clock, etc. More...
#include <slave.h>
Public Member Functions | |
| Slave () | |
| virtual | ~Slave () |
| virtual bool | speed_and_position (double &speed, framepos_t &position)=0 |
| virtual bool | locked () const =0 |
| virtual bool | ok () const =0 |
| virtual bool | starting () const |
| virtual framecnt_t | resolution () const =0 |
| virtual bool | requires_seekahead () const =0 |
| virtual framecnt_t | seekahead_distance () const |
| virtual bool | is_always_synced () const |
| virtual bool | give_slave_full_control_over_transport_speed () const |
| virtual std::string | approximate_current_delta () const |
Detailed Description
The Slave interface can be used to sync ARDOURs tempo to an external source like MTC, MIDI Clock, etc.
The name of the interface may be a bit misleading: A subclass of Slave actually acts as a time master for ARDOUR, that means ARDOUR will try to follow the speed and transport position of the implementation of Slave. Therefore it is rather that class, that makes ARDOUR a slave by connecting it to its external time master.
Constructor & Destructor Documentation
Member Function Documentation
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inlinevirtual |
- Returns
- - current time-delta between engine and sync-source
Reimplemented in ARDOUR::MIDIClock_Slave, ARDOUR::LTC_Slave, and ARDOUR::MTC_Slave.
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inlinevirtual |
- Returns
- - whether ARDOUR should use the slave speed without any adjustments
Reimplemented in ARDOUR::MIDIClock_Slave, ARDOUR::LTC_Slave, and ARDOUR::MTC_Slave.
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inlinevirtual |
- Returns
- - when returning true, ARDOUR will use transport speed 1.0 no matter what the slave returns
Reimplemented in ARDOUR::Engine_Slave.
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pure virtual |
reports to ARDOUR whether the Slave is currently synced to its external time source.
- Returns
- - when returning false, the transport will stop rolling
Implemented in ARDOUR::Engine_Slave, ARDOUR::MIDIClock_Slave, ARDOUR::LTC_Slave, and ARDOUR::MTC_Slave.
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pure virtual |
reports to ARDOUR whether the slave is in a sane state
- Returns
- - when returning false, the transport will be stopped and the slave disconnected from ARDOUR.
Implemented in ARDOUR::Engine_Slave, ARDOUR::MIDIClock_Slave, ARDOUR::LTC_Slave, and ARDOUR::MTC_Slave.
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pure virtual |
- Returns
- - when returning true, ARDOUR will wait for seekahead_distance() before transport starts rolling
Implemented in ARDOUR::Engine_Slave, ARDOUR::MIDIClock_Slave, ARDOUR::LTC_Slave, and ARDOUR::MTC_Slave.
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pure virtual |
- Returns
- - the timing resolution of the Slave - If the distance of ARDOURs transport to the slave becomes greater than the resolution, sound will stop
Implemented in ARDOUR::Engine_Slave, ARDOUR::MIDIClock_Slave, ARDOUR::LTC_Slave, and ARDOUR::MTC_Slave.
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inlinevirtual |
- Returns
- the number of frames that this slave wants to seek ahead. Relevant only if requires_seekahead() returns true.
Reimplemented in ARDOUR::LTC_Slave, and ARDOUR::MTC_Slave.
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pure virtual |
This is the most important function to implement: Each process cycle, Session::follow_slave will call this method. and after the method call they should
Session::follow_slave will then try to follow the given position using a delay locked loop (DLL), starting with the first given transport speed. If the values of speed and position contradict each other, ARDOUR will always follow the position and disregard the speed. Although, a correct speed is important so that ARDOUR can sync to the master time source quickly.
For background information on delay locked loops, see http://www.kokkinizita.net/papers/usingdll.pdf
The method has the following precondition:
- Slave::ok() should return true, otherwise playback will stop immediately and the method will not be called
- when the references speed and position are passed into the Slave they are uninitialized
After the method call the following postconditions should be met:
- The first position value on transport start should be 0, otherwise ARDOUR will try to locate to the new position rather than move to it
- the references speed and position should be assigned to the Slaves current requested transport speed and transport position.
- Slave::resolution() should be greater than the maximum distance of ARDOURs transport position to the slaves requested transport position.
- Slave::locked() should return true, otherwise Session::no_roll will be called
- Slave::starting() should be false, otherwise the transport will not move until it becomes true *
- Returns
- - The return value is currently ignored (see Session::follow_slave)
Implemented in ARDOUR::Engine_Slave, ARDOUR::MIDIClock_Slave, ARDOUR::LTC_Slave, and ARDOUR::MTC_Slave.
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inlinevirtual |
reports to ARDOUR whether the slave is in the process of starting to roll
- Returns
- - when returning false, transport will not move until this method returns true
Reimplemented in ARDOUR::Engine_Slave, and ARDOUR::MIDIClock_Slave.
The documentation for this class was generated from the following file:
- /usr/local/music/src/ardour/4.0/libs/ardour/ardour/slave.h
