IIR filter class wrapper for integration into parser structure. More...

Inheritance diagram for MHAFilter::iir_filter_t:

Public Member Functions
	iir_filter_t (std::string help="IIR filter structure", std::string def_A="[1]", std::string def_B="[1]", unsigned int channels=1)
	Constructor of the IIR filter. More...

void	filter (mha_wave_t y, const mha_wave_t x)
	The filter processes the audio signal. More...

mha_real_t	filter (mha_real_t x, unsigned int ch)
	Filter a single audio sample. More...

void	resize (unsigned int channels)
	Change the number of channels after object creation. More...

Public Member Functions inherited from MHAParser::parser_t
	parser_t (const std::string &help_text="")
	Construct detached node to be used in the configuration tree. More...

	~parser_t ()

void	insert_item (const std::string &, base_t *)
	Register a parser item into this sub-parser. More...

void	remove_item (const std::string &)
	Remove an item by name. More...

void	force_remove_item (const std::string &)
	Remove an item by name. More...

void	remove_item (const base_t *)
	Remove an item by address. More...

Public Member Functions inherited from MHAParser::base_t
	base_t (const std::string &)
	Constructor for base class of all parser nodes. More...

	base_t (const base_t &)
	Copy constructor for base_t. More...

base_t &	operator= (const base_t &)=default

	base_t (base_t &&)=delete

base_t &	operator= (base_t &&)=delete

virtual	~base_t ()

virtual std::string	parse (const std::string &)
	Causes this node to process a command in the openMHA configuration language. More...

virtual void	parse (const char , char , unsigned int)
	This function parses a command and writes the parsing result into a C character array. More...

virtual void	parse (const std::vector< std::string > &, std::vector< std::string > &)

virtual std::string	query_perm (const std::string &)

virtual std::string	query_range (const std::string &)

std::string	query_version (const std::string &)

std::string	query_id (const std::string &)

std::string	query_subst (const std::string &)

std::string	query_addsubst (const std::string &)

std::string	query_help (const std::string &)

std::string	query_cmds (const std::string &)

void	set_node_id (const std::string &)
	Set the identification string of this parser node. More...

void	set_help (const std::string &)
	Set the help comment of a variable or parser. More...

void	add_parent_on_insert (parser_t *, std::string)

void	rm_parent_on_remove (parser_t *)

const std::string &	fullname () const
	Return the full dot-separated path name of this parser node in the openMHA configuration tree. More...

Private Member Functions
void	update_filter ()

Private Member Functions inherited from MHAPlugin::config_t< iir_filter_state_t >
	config_t ()

	~config_t ()

iir_filter_state_t *	poll_config ()
	Receive the latest run time configuration. More...

iir_filter_state_t *	peek_config () const
	Receive the latest run time configuration without changing the configuration pointer. More...

void	push_config (iir_filter_state_t *ncfg)
	Push a new run time configuration into the configuration fifo. More...

void	cleanup_unused_cfg ()
	To be called by the push_config() for housekeeping. More...

void	remove_all_cfg ()
	To be called on Plugin destruction, will delete all runtime configuration list nodes and objects regardless of their in_use flag. More...

Private Attributes
MHAParser::vfloat_t	A

MHAParser::vfloat_t	B

MHAEvents::patchbay_t< iir_filter_t >	connector

unsigned int	nchannels

Private Attributes inherited from MHAPlugin::config_t< iir_filter_state_t >
iir_filter_state_t *	cfg
	Pointer to the runtime configuration currently used by the signal processing thread. More...

Additional Inherited Members
Public Attributes inherited from MHAParser::base_t
MHAEvents::emitter_t	writeaccess
	Event emitted on write access. More...

MHAEvents::emitter_t	valuechanged
	Event emitted if the value has changed. More...

MHAEvents::emitter_t	readaccess
	Event emitted on read access. More...

MHAEvents::emitter_t	prereadaccess
	Event emitted on read access, before the data field is accessed. More...

Protected Member Functions inherited from MHAParser::parser_t
std::string	op_subparse (expression_t &)

std::string	op_setval (expression_t &)

std::string	op_query (expression_t &)

std::string	query_type (const std::string &)

std::string	query_dump (const std::string &)

std::string	query_entries (const std::string &)

std::string	query_readfile (const std::string &)

std::string	query_savefile (const std::string &)

std::string	query_savefile_compact (const std::string &)

std::string	query_savemons (const std::string &)

std::string	query_val (const std::string &)

std::string	query_listids (const std::string &)

void	set_id_string (const std::string &)

bool	has_entry (const std::string &)

Protected Member Functions inherited from MHAParser::base_t
void	activate_query (const std::string &, query_t)

void	notify ()

Protected Attributes inherited from MHAParser::base_t
query_map_t	queries

bool	data_is_initialized

Detailed Description

IIR filter class wrapper for integration into parser structure.

This class implements an infinite impulse response filter. Since it inherits from MHAParser::parser_t, it can easily be integrated in the openMHA configuration tree. It provides the configuration language variables "A" (vector of recursive filter coefficients) and "B" (vector of non-recursive filter coefficients).

The filter instance reacts to changes in filter coefficients through the openMHA configuration language, and uses the updated coefficients in the next invocation of the filter method.

Update of the coefficients is thread-safe and non-blocking. Simply add this subparser to your parser items and use the "filter" member function. Filter states are reset to all 0 on update.

Constructor & Destructor Documentation

◆ iir_filter_t()

MHAFilter::iir_filter_t::iir_filter_t	(	std::string	help = `"IIR filter structure"`,
		std::string	def_A = `"[1]"`,
		std::string	def_B = `"[1]"`,
		unsigned int	channels = `1`
	)

Constructor of the IIR filter.

Initialises the sub-parser structure and the memory for holding the filter's state.

Parameters

help	The help string for the parser that groups the configuration variables of this filter. Could be used to describe the purpose of this IIR filter.
def_A	The initial value of the vector of the recursive filter coefficients, represented as string.
def_B	The initial value of the vector of the non-recursive filter coefficients, represented as string.
channels	The number of indipendent audio channels to process with this filter. Needed to allocate a state vector for each audio channel.

Member Function Documentation

◆ filter() [1/2]

void MHAFilter::iir_filter_t::filter	(	mha_wave_t *	y,
		const mha_wave_t *	x
	)

The filter processes the audio signal.

All channels in the audio signal are processed using the same filter coefficients. Indipendent state is stored between calls for each audio channel.

Parameters

y	Pointer to output signal holder. The output signal is stored here. Has to have the same signal dimensions as the input signal x. In-place processing (y and x pointing to the same signal holder) is possible.
x	Pointer to input signal holder. Number of channels has to be the same as given to the constructor, or to the resize method.

◆ filter() [2/2]

mha_real_t MHAFilter::iir_filter_t::filter	(	mha_real_t	x,
		unsigned int	ch
	)

Filter a single audio sample.

Parameters

x	The single audio sample
ch	Zero-based channel index. Use and change the state of channel ch. ch has to be less than the number of channels given to the constructor or the resize method.

Returns: the filtered result sample.

◆ resize()

void MHAFilter::iir_filter_t::resize ( unsigned int channels )

Change the number of channels after object creation.

Parameters

channels The new number of channels. Old filter states are lost.

◆ update_filter()

void MHAFilter::iir_filter_t::update_filter ( )

private

Member Data Documentation

◆ A

MHAParser::vfloat_t MHAFilter::iir_filter_t::A

private

◆ B

MHAParser::vfloat_t MHAFilter::iir_filter_t::B

private

◆ connector

MHAEvents::patchbay_t<iir_filter_t> MHAFilter::iir_filter_t::connector

private

◆ nchannels

unsigned int MHAFilter::iir_filter_t::nchannels

private

The documentation for this class was generated from the following files:

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ iir_filter_t()

Member Function Documentation

◆ filter() [1/2]

◆ filter() [2/2]

◆ resize()

◆ update_filter()

Member Data Documentation

◆ A

◆ B

◆ connector

◆ nchannels