JACK (Jack Audio Connection Kit) server driver. More...

#include <JackAudioDriver.h>

Inheritance diagram for JackAudioDriver:

Public Types
enum class	Timebase { Master = 1 , Slave = 0 , None = -1 }
	Whether Hydrogen or another program is Jack timebase master. More...

Public Member Functions
	JackAudioDriver (JackProcessCallback m_processCallback)
	Constructor of the JACK server driver.

	~JackAudioDriver ()
	Destructor of the JACK server driver.

void	clearPerTrackAudioBuffers (uint32_t nFrames)
	Resets the buffers contained in m_pTrackOutputPortsL and m_pTrackOutputPortsR.

virtual int	connect () override
	Connects to output ports via the JACK server.

void	deactivate ()
	Deactivates the JACK client of Hydrogen and disconnects all ports belonging to it.

virtual void	disconnect () override
	Disconnects the JACK client of the Hydrogen from the JACK server.

virtual unsigned	getBufferSize () override

bool	getConnectDefaults ()

float	getMasterBpm () const

virtual float *	getOut_L () override
	Get content in the left stereo output port.

virtual float *	getOut_R () override
	Get content in the right stereo output port.

virtual unsigned	getSampleRate () override

Timebase	getTimebaseState () const

float *	getTrackOut_L (std::shared_ptr< Instrument > instr, std::shared_ptr< InstrumentComponent > pCompo)
	Convenience function looking up the track number of a component of an instrument using in m_trackMap using their IDs Instrument::__id and InstrumentComponent::__related_drumkit_componentID.

float *	getTrackOut_L (unsigned nTrack)
	Get content of left output port of a specific track.

float *	getTrackOut_R (std::shared_ptr< Instrument > instr, std::shared_ptr< InstrumentComponent > pCompo)
	Convenience function looking up the track number of a component of an instrument using in m_trackMap using their IDs Instrument::__id and InstrumentComponent::__related_drumkit_componentID.

float *	getTrackOut_R (unsigned nTrack)
	Get content of right output port of a specific track.

virtual int	getXRuns () const override
	Get the number of XRuns that occurred since the audio driver has started.

virtual int	init (unsigned bufferSize) override
	Initializes the JACK audio driver.

void	initTimebaseMaster ()
	Registers Hydrogen as JACK timebase master.

void	locateTransport (long long nFrame)
	Re-positions the transport position to nFrame.

void	makeTrackOutputs (std::shared_ptr< Song > pSong)
	Creates per component output ports for each instrument.

void	releaseTimebaseMaster ()
	Release Hydrogen from the JACK timebase master responsibilities.

void	relocateUsingBBT ()
	Uses the bar-beat-tick information to relocate the transport position.

void	setConnectDefaults (bool flag)

void	startTransport ()
	Tells the JACK server to start transport.

void	stopTransport ()
	Tells the JACK server to stop transport.

void	updateTransportPosition ()
	The function queries the transport position and additional information from the JACK server, writes them to m_JackTransportPos and in m_JackTransportState, and updates the AudioEngine in case of a mismatch.

Public Member Functions inherited from Object< JackAudioDriver >
	Object ()

	Object (const Object< JackAudioDriver > &other)

Public Member Functions inherited from Base
	Base ()

	Base (const Base &other)

virtual const char *	class_name () const

void	Print (bool bShort=true) const
	Prints content of toQString() via DEBUGLOG.

virtual QString	toQString (const QString &sPrefix="", bool bShort=true) const
	Formatted string version for debugging purposes.

Public Member Functions inherited from AudioOutput
	AudioOutput ()=default

virtual	~AudioOutput ()

virtual int	getLatency ()
	Approximate audio latency (in frames) A reasonable approximation is the buffer time on most audio systems.

Public Member Functions inherited from Object< AudioOutput >
	Object ()

	Object (const Object< AudioOutput > &other)

Static Public Member Functions
static bool	checkSupport ()
	Attempts to call several JACK executables in order to check for existing JACK support.

static int	jackDriverBufferSize (jack_nframes_t nframes, void *arg)
	Callback function for the JACK audio server to set the buffer size jackServerBufferSize.

static int	jackDriverSampleRate (jack_nframes_t nframes, void *param)
	Callback function for the JACK audio server to set the sample rate jackServerSampleRate.

static int	jackXRunCallback (void *arg)
	Report an XRun event to the GUI.

Static Public Member Functions inherited from Base
static const char *	_class_name ()
	return the class name

static QString	base_clock (const QString &sMsg)
	Measures the current time and stores it in __last_clock.

static QString	base_clock_in (const QString &sMsg)

static int	bootstrap (Logger *logger, bool count=false)
	must be called before any Object instantiation !

static bool	count_active ()

static int	getAliveObjectCount ()

static object_map_t	getObjectMap ()

static Logger *	logger ()
	return the logger instance

static int	objects_count ()

static void	printObjectMapDiff (object_map_t map)
	Creates the difference between a snapshot of the object map and its current state and prints it to std::cout.

static void	set_count (bool flag)
	enable/disable class instances counting

static void	write_objects_map_to (std::ostream &out, object_map_t *map=nullptr)
	output the full objects map to a given ostream

static void	write_objects_map_to_cerr ()
	output objects map to stderr

Static Public Member Functions inherited from AudioOutput
static QStringList	getDevices ()

Data Fields
jack_client_t *	m_pClient
	Object holding the external client session with the JACK server.

Static Public Attributes
static jack_nframes_t	jackServerBufferSize = 0
	Buffer size of the JACK audio server.

static unsigned long	jackServerSampleRate = 0
	Sample rate of the JACK audio server.

static int	jackServerXRuns = 0
	Number of XRuns since the driver started.

static JackAudioDriver *	pJackDriverInstance = nullptr
	Instance of the JackAudioDriver.

Static Public Attributes inherited from Base
static QString	sPrintIndention = " "
	String used to format the debugging string output of some core classes.

Private Member Functions
bool	compareAdjacentBBT () const
	Compares the BBT information stored in m_JackTransportPos and m_previousJackTransportPos with respect to the tempo and the transport position in bars, beats, and ticks.

void	printState () const
	Show debugging information.

void	setTrackOutput (int n, std::shared_ptr< Instrument > instr, std::shared_ptr< InstrumentComponent > pCompo, std::shared_ptr< Song > pSong)
	Renames the n 'th port of JACK client and creates it if it's not already present.

Static Private Member Functions
static QString	checkExecutable (const QString &sExecutable, const QString &sOption)
	Calls sExecutable in a subprocess using the sOption CLI option and reports the results.

static void	jackDriverShutdown (void *arg)
	Callback function for the JACK audio server to shutting down the JACK driver.

static void	JackTimebaseCallback (jack_transport_state_t state, jack_nframes_t nFrames, jack_position_t pJackPosition, int new_pos, void arg)
	Callback function for the JACK server to supply additional timebase information.

static void	printJackTransportPos (const jack_position_t *pPos)

Private Attributes
bool	m_bConnectDefaults
	Specifies whether the default left and right (master) audio JACK ports will be automatically connected to the system's sink when registering the JACK client in connect().

jack_position_t	m_JackTransportPos
	Current transport position obtained using jack_transport_query() (jack/transport.h).

jack_transport_state_t	m_JackTransportState
	Current transport state returned by jack_transport_query() (jack/transport.h).

int	m_nTimebaseTracking
	Whether Hydrogen or another program is Jack timebase master.

int	m_nTrackPortCount
	Total number of output ports currently in use.

jack_port_t *	m_pOutputPort1
	Left source port.

jack_port_t *	m_pOutputPort2
	Right source port.

jack_position_t	m_previousJackTransportPos
	Used for detecting changes in the BBT transport information with external timebase master application, which do not propagate these changes on time.

JackProcessCallback	m_processCallback
	Main process callback.

jack_port_t *	m_pTrackOutputPortsL [MAX_INSTRUMENTS]
	Vector of all left audio output ports currently used by the local JACK client.

jack_port_t *	m_pTrackOutputPortsR [MAX_INSTRUMENTS]
	Vector of all right audio output ports currently used by the local JACK client.

QString	m_sOutputPortName1
	Destination of the left source port m_pOutputPort1, for which a connection will be established in connect().

QString	m_sOutputPortName2
	Destination of the right source port m_pOutputPort2, for which a connection will be established in connect().

Timebase	m_timebaseState
	More user-friendly version of m_nTimebaseTracking.

int	m_trackMap [MAX_INSTRUMENTS][MAX_COMPONENTS]
	Matrix containing the track number of each component of all instruments.

Additional Inherited Members
Protected Member Functions inherited from Object< JackAudioDriver >
	~Object ()

Protected Member Functions inherited from Base
	~Base ()

Protected Member Functions inherited from Object< AudioOutput >
	~Object ()

Static Protected Member Functions inherited from Base
static void	registerClass (const char name, const atomic_obj_cpt_t counters)

Static Protected Attributes inherited from Base
static bool	__count = false
	should we count class instances

static timeval	__last_clock = { 0, 0 }

static Logger *	__logger = nullptr

Detailed Description

JACK (Jack Audio Connection Kit) server driver.

Transport Control:

Each JACK client can start and stop the transport or relocate the current transport position. The request will take place in cycles. During the first the status of the transport changes to JackTransportStarting to inform all clients a change is about to happen. During the second the status is again JackTransportRolling and the transport position is updated according to the request.

Also note that Hydrogen overwrites its local TransportPosition only with the transport position of the JACK server if there is a mismatch due to a relocation triggered by another JACK client. During normal transport the current position TransportPosition::m_nFrames will be always the same as the one of JACK during a cycle and incremented by the buffer size in audioEngine_process() at the very end of the cycle. The same happens for the transport information of the JACK server but in parallel.

Timebase Master:

The timebase master is responsible for providing additional transport information to the JACK server apart from the transport position in frames, like current beat, bar, tick, tick size, speed etc. Of all these information Hydrogen does only use the provided tempo (and overrides all internal ones). Therefore, unlike many other application, it does not respond to changes in measure (since these would have to be mapped to the length of the current pattern). Every client can be registered as timebase master by supplying a callback (for Hydrogen this would be JackTimebaseCallback()) but there can be at most one timebase master at a time. Having none at all is perfectly fine too. Apart from this additional responsibility, the registered client has no other rights compared to others.

After the status of the JACK transport has changed from JackTransportStarting to JackTransportRolling, the timebase master needs an additional cycle to update its information.

Definition at line 94 of file JackAudioDriver.h.

Member Enumeration Documentation

◆ Timebase

enum class Timebase

strong

Whether Hydrogen or another program is Jack timebase master.

Enumerator
Master	Hydrogen itself is timebase master.
Slave	An external program is timebase master and Hydrogen will disregard all tempo markers on the Timeline and, instead, only use the BPM provided by JACK.
None	Only normal clients registered.

Definition at line 101 of file JackAudioDriver.h.

Constructor & Destructor Documentation

◆ JackAudioDriver()

JackAudioDriver ( JackProcessCallback m_processCallback )

Constructor of the JACK server driver.

Parameters

m_processCallback Function that is called by the AudioEngine during every processing cycle.

Definition at line 99 of file JackAudioDriver.cpp.

◆ ~JackAudioDriver()

~JackAudioDriver ( )

Destructor of the JACK server driver.

Calling disconnect().

Definition at line 127 of file JackAudioDriver.cpp.

Member Function Documentation

◆ checkExecutable()

QString checkExecutable	(	const QString &	sExecutable,
		const QString &	sOption )

staticprivate

Calls sExecutable in a subprocess using the sOption CLI option and reports the results.

Returns: An empty string indicates, that the call exited with a code other than zero.

Definition at line 1247 of file JackAudioDriver.cpp.

◆ checkSupport()

bool checkSupport ( )

static

Attempts to call several JACK executables in order to check for existing JACK support.

In an earlier version I tried checking the presence of the libjack.so shared library. But this one comes preinstalled with most Linux distribution regardless of JACK itself is present or not.

Returns: Whether or not JACK support appears to be functional.

Definition at line 1209 of file JackAudioDriver.cpp.

◆ clearPerTrackAudioBuffers()

void clearPerTrackAudioBuffers ( uint32_t nFrames )

Resets the buffers contained in m_pTrackOutputPortsL and m_pTrackOutputPortsR.

Parameters

nFrames Size of the buffers used in the audio process callback function.

Definition at line 255 of file JackAudioDriver.cpp.

◆ compareAdjacentBBT()

bool compareAdjacentBBT ( ) const

private

Compares the BBT information stored in m_JackTransportPos and m_previousJackTransportPos with respect to the tempo and the transport position in bars, beats, and ticks.

Returns: true If m_JackTransportPos is expected to follow m_previousJackTransportPos.

Definition at line 408 of file JackAudioDriver.cpp.

◆ connect()

int connect ( )

overridevirtual

Connects to output ports via the JACK server.

Returns

0 : on success.

1 : The activation of the JACK client using did fail.
2 : The connections to m_sOutputPortName1 and m_sOutputPortName2 could not be established and the there were either no JACK ports holding the JackPortIsInput flag found or no connection to them could be established.

Implements AudioOutput.

Definition at line 132 of file JackAudioDriver.cpp.

◆ deactivate()

void deactivate ( )

Deactivates the JACK client of Hydrogen and disconnects all ports belonging to it.

Definition at line 233 of file JackAudioDriver.cpp.

◆ disconnect()

void disconnect ( )

overridevirtual

Disconnects the JACK client of the Hydrogen from the JACK server.

Implements AudioOutput.

Definition at line 213 of file JackAudioDriver.cpp.

◆ getBufferSize()

unsigned getBufferSize ( )

overridevirtual

Returns: Global variable jackServerBufferSize.

Implements AudioOutput.

Definition at line 245 of file JackAudioDriver.cpp.

◆ getConnectDefaults()

bool getConnectDefaults ( )

inline

Returns: m_bConnectDefaults

Definition at line 180 of file JackAudioDriver.h.

◆ getMasterBpm()

float getMasterBpm ( ) const

Returns: the BPM reported by the timebase master or NAN if there is no external timebase master.

Definition at line 1162 of file JackAudioDriver.cpp.

◆ getOut_L()

float * getOut_L ( )

overridevirtual

Get content in the left stereo output port.

Returns: Pointer to buffer content of type jack_default_audio_sample_t* (jack/types.h)

Implements AudioOutput.

Definition at line 602 of file JackAudioDriver.cpp.

◆ getOut_R()

float * getOut_R ( )

overridevirtual

Get content in the right stereo output port.

Returns: Pointer to buffer content of type jack_default_audio_sample_t* (jack/types.h)

Implements AudioOutput.

Definition at line 616 of file JackAudioDriver.cpp.

◆ getSampleRate()

unsigned getSampleRate ( )

overridevirtual

Returns: Global variable jackServerSampleRate.

Implements AudioOutput.

Definition at line 250 of file JackAudioDriver.cpp.

◆ getTimebaseState()

JackAudioDriver::Timebase getTimebaseState ( ) const

Returns: m_timebaseState

Definition at line 1156 of file JackAudioDriver.cpp.

◆ getTrackOut_L() [1/2]

float * getTrackOut_L	(	std::shared_ptr< Instrument >	instr,
		std::shared_ptr< InstrumentComponent >	pCompo )

Convenience function looking up the track number of a component of an instrument using in m_trackMap using their IDs Instrument::__id and InstrumentComponent::__related_drumkit_componentID.

Using the track number it then calls getTrackOut_L( unsigned ) and returns its result.

Parameters

instr	Pointer to an Instrument
pCompo	Pointer to one of the instrument's components.

Returns: Pointer to buffer content of type jack_default_audio_sample_t* (jack/types.h)

Definition at line 650 of file JackAudioDriver.cpp.

◆ getTrackOut_L() [2/2]

float * getTrackOut_L ( unsigned nTrack )

Get content of left output port of a specific track.

Parameters

nTrack Track number. Must not be bigger than m_nTrackPortCount.

Returns: Pointer to buffer content of type jack_default_audio_sample_t* (jack/types.h)

Definition at line 622 of file JackAudioDriver.cpp.

◆ getTrackOut_R() [1/2]

float * getTrackOut_R	(	std::shared_ptr< Instrument >	instr,
		std::shared_ptr< InstrumentComponent >	pCompo )

Convenience function looking up the track number of a component of an instrument using in m_trackMap using their IDs Instrument::__id and InstrumentComponent::__related_drumkit_componentID.

Using the track number it then calls getTrackOut_R( unsigned ) and returns its result.

Parameters

instr	Pointer to an Instrument
pCompo	Pointer to one of the instrument's components.

Returns: Pointer to buffer content of type jack_default_audio_sample_t* (jack/types.h)

Definition at line 655 of file JackAudioDriver.cpp.

◆ getTrackOut_R() [2/2]

float * getTrackOut_R ( unsigned nTrack )

Get content of right output port of a specific track.

Parameters

nTrack Track number. Must not be bigger than m_nTrackPortCount.

Returns: Pointer to buffer content of type jack_default_audio_sample_t* (jack/types.h)

Definition at line 636 of file JackAudioDriver.cpp.

◆ getXRuns()

int getXRuns ( ) const

overridevirtual

Get the number of XRuns that occurred since the audio driver has started.

Reimplemented from AudioOutput.

Definition at line 1172 of file JackAudioDriver.cpp.

◆ init()

int init ( unsigned bufferSize )

overridevirtual

Initializes the JACK audio driver.

Parameters

bufferSize Unused and only present to assure compatibility with the JACK API.

Returns

0 : on success.
-1 : if the pointer m_pClient obtained via jack_client_open() (jack/jack.h) is 0.
4 : unable to register the "out_L" and/or "out_R" output ports for the JACK client using jack_port_register() (jack/jack.h).

Implements AudioOutput.

Definition at line 677 of file JackAudioDriver.cpp.

◆ initTimebaseMaster()

void initTimebaseMaster ( )

Registers Hydrogen as JACK timebase master.

Definition at line 992 of file JackAudioDriver.cpp.

◆ jackDriverBufferSize()

int jackDriverBufferSize	(	jack_nframes_t	nframes,
		void *	arg )

static

Callback function for the JACK audio server to set the buffer size jackServerBufferSize.

Parameters

nframes	New buffer size.
arg	Not used

Returns: 0 on success

Definition at line 71 of file JackAudioDriver.cpp.

◆ jackDriverSampleRate()

int jackDriverSampleRate	(	jack_nframes_t	nframes,
		void *	param )

static

Callback function for the JACK audio server to set the sample rate jackServerSampleRate.

Parameters

nframes	New sample rate.
param	Object inheriting from the #Logger class.

Returns: 0 on success

Definition at line 58 of file JackAudioDriver.cpp.

◆ jackDriverShutdown()

void jackDriverShutdown ( void * arg )

staticprivate

Callback function for the JACK audio server to shutting down the JACK driver.

Parameters

arg Unused.

Definition at line 80 of file JackAudioDriver.cpp.

◆ JackTimebaseCallback()

void JackTimebaseCallback	(	jack_transport_state_t	state,
		jack_nframes_t	nFrames,
		jack_position_t *	pJackPosition,
		int	new_pos,
		void *	arg )

staticprivate

Callback function for the JACK server to supply additional timebase information.

The function it will be called after the audioEngine_process() function and only if the m_JackTransportState is JackTransportRolling.

What is the BBT information?

There is no formal definition in the JACK API but the way it is interpreted by Hydrogen is the following:

bar: Number of patterns passed since the beginning of the song. beat: Number of quarters passed since the beginning of the pattern. tick: Number of ticks passed since the last beat (with respect to the current frame).

A tick is an internal measure representing the smallest resolution of the transport position in terms of the patterns. It consist of pAudioEngine->getTickSize() frames, which changes depending on the current tempo.

Parameters

state	Unused.
nFrames	Unused.
pJackPosition	Current transport position.
new_pos	Unused.
arg	Pointer to a JackAudioDriver instance.

Definition at line 1078 of file JackAudioDriver.cpp.

◆ jackXRunCallback()

int jackXRunCallback ( void * arg )

static

Report an XRun event to the GUI.

Definition at line 87 of file JackAudioDriver.cpp.

◆ locateTransport()

void locateTransport ( long long nFrame )

Re-positions the transport position to nFrame.

The new position takes effect in two process cycles during which JACK's state will be in JackTransportStarting and the transport won't be rolling.

Parameters

nFrame Requested new transport position.

Definition at line 978 of file JackAudioDriver.cpp.

◆ makeTrackOutputs()

void makeTrackOutputs ( std::shared_ptr< Song > pSong )

Creates per component output ports for each instrument.

Definition at line 872 of file JackAudioDriver.cpp.

◆ printJackTransportPos()

void printJackTransportPos ( const jack_position_t * pPos )

staticprivate

Definition at line 1191 of file JackAudioDriver.cpp.

◆ printState()

void printState ( ) const

private

Show debugging information.

Definition at line 1176 of file JackAudioDriver.cpp.

◆ releaseTimebaseMaster()

void releaseTimebaseMaster ( )

Release Hydrogen from the JACK timebase master responsibilities.

This causes the JackTimebaseCallback() callback function to not be called by the JACK server anymore.

Definition at line 1051 of file JackAudioDriver.cpp.

◆ relocateUsingBBT()

void relocateUsingBBT ( )

Uses the bar-beat-tick information to relocate the transport position.

This type of operation is triggered whenever the transport position gets relocated or the tempo is changed using Jack in the presence of an external timebase master.

Definition at line 274 of file JackAudioDriver.cpp.

◆ setConnectDefaults()

void setConnectDefaults ( bool flag )

inline

Parameters

flag	Sets m_bConnectDefaults

Definition at line 176 of file JackAudioDriver.h.

◆ setTrackOutput()

void setTrackOutput	(	int	n,
		std::shared_ptr< Instrument >	instr,
		std::shared_ptr< InstrumentComponent >	pCompo,
		std::shared_ptr< Song >	pSong )

private

Renames the n 'th port of JACK client and creates it if it's not already present.

If the track number n is bigger than the number of ports currently in usage m_nTrackPortCount, n + 1 - m_nTrackPortCount new stereo ports will be created using jack_port_register() (jack/jack.h) and m_nTrackPortCount updated to n + 1.

Afterwards, the n 'th port is renamed to a concatenation of "Track_", DrumkitComponent::__name, "_", n + 1, "_", Instrument::__name, and "_L", or "_R" using either jack_port_rename() (if HAVE_JACK_PORT_RENAME is defined) or jack_port_set_name() (both jack/jack.h). The former renaming function triggers a PortRename notifications to clients that have registered a port rename handler.

Parameters

n	Track number for which a port should be renamed (and created).
instr	Pointer to the corresponding Instrument.
pCompo	Pointer to the corresponding InstrumentComponent.
pSong	Pointer to the corresponding Song.

Definition at line 918 of file JackAudioDriver.cpp.

◆ startTransport()

void startTransport ( )

Tells the JACK server to start transport.

Definition at line 960 of file JackAudioDriver.cpp.

◆ stopTransport()

void stopTransport ( )

Tells the JACK server to stop transport.

Definition at line 969 of file JackAudioDriver.cpp.

◆ updateTransportPosition()

void updateTransportPosition ( )

The function queries the transport position and additional information from the JACK server, writes them to m_JackTransportPos and in m_JackTransportState, and updates the AudioEngine in case of a mismatch.

Definition at line 490 of file JackAudioDriver.cpp.

Field Documentation

◆ jackServerBufferSize

jack_nframes_t jackServerBufferSize = 0

static

Buffer size of the JACK audio server.

Definition at line 316 of file JackAudioDriver.h.

◆ jackServerSampleRate

unsigned long jackServerSampleRate = 0

static

Sample rate of the JACK audio server.

Definition at line 312 of file JackAudioDriver.h.

◆ jackServerXRuns

int jackServerXRuns = 0

static

Number of XRuns since the driver started.

Definition at line 322 of file JackAudioDriver.h.

◆ m_bConnectDefaults

bool m_bConnectDefaults

private

Specifies whether the default left and right (master) audio JACK ports will be automatically connected to the system's sink when registering the JACK client in connect().

Definition at line 557 of file JackAudioDriver.h.

◆ m_JackTransportPos

jack_position_t m_JackTransportPos

private

Current transport position obtained using jack_transport_query() (jack/transport.h).

It corresponds to the first frame of the current cycle.

The valid member of m_JackTransportPos will show which fields contain valid data. Thus, if it is set to JackPositionBBT, bar, beat, and tick information are provided by the current timebase master in addition to the transport information in frames. It is of class jack_position_bits_t (jack/types.h) and is an enumerator with five different options:

JackPositionBBT = 0x10 : Bar, Beat, Tick
JackPositionTimecode = 0x20 : External timecode
JackBBTFrameOffset = 0x40 : Frame offset of BBT information
JackAudioVideoRatio = 0x80 : audio frames per video frame
JackVideoFrameOffset = 0x100 : frame offset of first video frame

Definition at line 545 of file JackAudioDriver.h.

◆ m_JackTransportState

jack_transport_state_t m_JackTransportState

private

Current transport state returned by jack_transport_query() (jack/transport.h).

It is valid for the entire cycle and can have five different values:

JackTransportStopped = 0 : Transport is halted
JackTransportRolling = 1 : Transport is playing
JackTransportLooping = 2 : For OLD_TRANSPORT, now ignored
JackTransportStarting = 3 : Waiting for sync ready
JackTransportNetStarting = 4 : Waiting for sync ready on the network

The actual number of states depends on your JACK version. The listing above was done for version 1.9.12.

Definition at line 522 of file JackAudioDriver.h.

◆ m_nTimebaseTracking

int m_nTimebaseTracking

private

Whether Hydrogen or another program is Jack timebase master.

m_nTimebaseTracking > 0 - Hydrogen itself is timebase master.
m_nTimebaseTracking == 0 - an external program is timebase master and Hydrogen will disregard all tempo marker on the Timeline and, instead, only use the BPM provided by JACK.
m_nTimebaseTracking < 0 - only normal clients registered.

While Hydrogen can unregister as timebase master on its own, it can not be observed directly whether another application has taken over as timebase master. When the JACK server is releasing Hydrogen in the later case, it won't advertise this fact but simply won't call the JackTimebaseCallback() anymore. But since this will be called in every cycle after updateTransportPosition(), we can use this variable to determine if Hydrogen is still timebase master.

As Hydrogen registered as timebase master using initTimebaseMaster() it will be initialized with 1, decremented in updateTransportPosition(), and reset to 1 in JackTimebaseCallback(). Whenever it is zero in updateTransportPosition(), m_nTimebaseTracking will be updated accordingly.

Definition at line 584 of file JackAudioDriver.h.

◆ m_nTrackPortCount

int m_nTrackPortCount

private

Total number of output ports currently in use.

Definition at line 493 of file JackAudioDriver.h.

◆ m_pClient

jack_client_t* m_pClient

Object holding the external client session with the JACK server.

Definition at line 116 of file JackAudioDriver.h.

◆ m_pOutputPort1

jack_port_t* m_pOutputPort1

private

Left source port.

Definition at line 465 of file JackAudioDriver.h.

◆ m_pOutputPort2

jack_port_t* m_pOutputPort2

private

Right source port.

Definition at line 469 of file JackAudioDriver.h.

◆ m_previousJackTransportPos

jack_position_t m_previousJackTransportPos

private

Used for detecting changes in the BBT transport information with external timebase master application, which do not propagate these changes on time.

Definition at line 550 of file JackAudioDriver.h.

◆ m_processCallback

JackProcessCallback m_processCallback

private

Main process callback.

Definition at line 461 of file JackAudioDriver.h.

◆ m_pTrackOutputPortsL

jack_port_t* m_pTrackOutputPortsL[MAX_INSTRUMENTS]

private

Vector of all left audio output ports currently used by the local JACK client.

Definition at line 498 of file JackAudioDriver.h.

◆ m_pTrackOutputPortsR

jack_port_t* m_pTrackOutputPortsR[MAX_INSTRUMENTS]

private

Vector of all right audio output ports currently used by the local JACK client.

Definition at line 503 of file JackAudioDriver.h.

◆ m_sOutputPortName1

QString m_sOutputPortName1

private

Destination of the left source port m_pOutputPort1, for which a connection will be established in connect().

Definition at line 474 of file JackAudioDriver.h.

◆ m_sOutputPortName2

QString m_sOutputPortName2

private

Destination of the right source port m_pOutputPort2, for which a connection will be established in connect().

Definition at line 479 of file JackAudioDriver.h.

◆ m_timebaseState

Timebase m_timebaseState

private

More user-friendly version of m_nTimebaseTracking.

Definition at line 589 of file JackAudioDriver.h.

◆ m_trackMap

int m_trackMap[MAX_INSTRUMENTS][MAX_COMPONENTS]

private

Matrix containing the track number of each component of all instruments.

Its rows represent the instruments and its columns their components. m_trackMap[2][1]=6 thus therefore mean the output of the second component of the third instrument is assigned the seventh output port. Since its total size is defined by MAX_INSTRUMENTS and MAX_COMPONENTS, most of its entries will be zero.

Definition at line 489 of file JackAudioDriver.h.

◆ pJackDriverInstance

JackAudioDriver * pJackDriverInstance = nullptr

static

Instance of the JackAudioDriver.

Definition at line 320 of file JackAudioDriver.h.

Public Types

Public Member Functions

Static Public Member Functions

Data Fields

Static Public Attributes

Private Member Functions

Static Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ Timebase

Constructor & Destructor Documentation

◆ JackAudioDriver()

◆ ~JackAudioDriver()

Member Function Documentation

◆ checkExecutable()

◆ checkSupport()

◆ clearPerTrackAudioBuffers()

◆ compareAdjacentBBT()

◆ connect()

◆ deactivate()

◆ disconnect()

◆ getBufferSize()

◆ getConnectDefaults()

◆ getMasterBpm()

◆ getOut_L()

◆ getOut_R()

◆ getSampleRate()

◆ getTimebaseState()

◆ getTrackOut_L() [1/2]

◆ getTrackOut_L() [2/2]

◆ getTrackOut_R() [1/2]

◆ getTrackOut_R() [2/2]

◆ getXRuns()

◆ init()

◆ initTimebaseMaster()

◆ jackDriverBufferSize()

◆ jackDriverSampleRate()

◆ jackDriverShutdown()

◆ JackTimebaseCallback()

◆ jackXRunCallback()

◆ locateTransport()

◆ makeTrackOutputs()

◆ printJackTransportPos()

◆ printState()

◆ releaseTimebaseMaster()

◆ relocateUsingBBT()

◆ setConnectDefaults()

◆ setTrackOutput()

◆ startTransport()

◆ stopTransport()

◆ updateTransportPosition()

Field Documentation

◆ jackServerBufferSize

◆ jackServerSampleRate

◆ jackServerXRuns

◆ m_bConnectDefaults

◆ m_JackTransportPos

◆ m_JackTransportState

◆ m_nTimebaseTracking

◆ m_nTrackPortCount

◆ m_pClient

◆ m_pOutputPort1

◆ m_pOutputPort2

◆ m_previousJackTransportPos

◆ m_processCallback

◆ m_pTrackOutputPortsL

◆ m_pTrackOutputPortsR

◆ m_sOutputPortName1

◆ m_sOutputPortName2

◆ m_timebaseState

◆ m_trackMap

◆ pJackDriverInstance