silence_gen.c File Reference

#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include "floating_fudge.h"
#include <assert.h>
#include <limits.h>
#include "spandsp/telephony.h"
#include "spandsp/logging.h"
#include "spandsp/async.h"
#include "spandsp/silence_gen.h"

Functions
int	silence_gen (silence_gen_state_t *s, int16_t *amp, int max_len)
	Generate a block of silent audio samples.
void	silence_gen_always (silence_gen_state_t *s)
	Set a silence generator context to output continuous silence.
void	silence_gen_set (silence_gen_state_t *s, int silent_samples)
	Set a silence generator context to output a specified period of silence.
void	silence_gen_alter (silence_gen_state_t *s, int silent_samples)
	Alter the period of a silence generator context by a specified amount.
int	silence_gen_remainder (silence_gen_state_t *s)
	Find how long a silence generator context has to run.
int	silence_gen_generated (silence_gen_state_t *s)
	Find the total silence generated to date.
void	silence_gen_status_handler (silence_gen_state_t *s, modem_tx_status_func_t handler, void *user_data)
	Change the status reporting function associated with a silence generator context.
silence_gen_state_t *	silence_gen_init (silence_gen_state_t *s, int silent_samples)
	Initialise a timed silence generator context.
int	span_dummy_rx (void *user_data, const int16_t amp[], int len)
	Dummy receive callback.
int	span_dummy_mod (void *user_data, int16_t amp[], int len)
	Dummy signal modifier callback.

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Detailed Description

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Function Documentation

int silence_gen	(	silence_gen_state_t *	s,
		int16_t *	amp,
		int	max_len
	)

Generate a block of silent audio samples.

Generate a block of silent audio samples.

Parameters:

	s	The silence generator context.
	amp	The audio sample buffer.
	max_len	The number of samples to be generated.

Returns:

The number of samples actually generated. This will be zero when there is nothing to send.

References SIG_STATUS_SHUTDOWN_COMPLETE.

void silence_gen_alter	(	silence_gen_state_t *	s,
		int	silent_samples
	)

Alter the period of a silence generator context by a specified amount.

Alter the period of a silence generator context by a specified amount.

Parameters:

	s	The silence generator context.
	silent_samples	The number of samples to change the setting by. A positive number increases the duration. A negative number reduces it. The duration is prevented from going negative.

void silence_gen_always

(

silence_gen_state_t *

s

)

Set a silence generator context to output continuous silence.

Set a silence generator context to output continuous silence.

Parameters:

s

The silence generator context.

int silence_gen_generated

(

silence_gen_state_t *

s

)

Find the total silence generated to date.

Find the total silence generated to date by a silence generator context.

Parameters:

s

The silence generator context.

Returns:

The number of samples generated.

silence_gen_state_t* silence_gen_init	(	silence_gen_state_t *	s,
		int	silent_samples
	)

Initialise a timed silence generator context.

Initialise a timed silence generator context.

Parameters:

	s	The silence generator context.
	silent_samples	The initial number of samples to set the silence to.

Returns:

A pointer to the silence generator context.

int silence_gen_remainder

(

silence_gen_state_t *

s

)

Find how long a silence generator context has to run.

Find how long a silence generator context has to run.

Parameters:

s

The silence generator context.

Returns:

The number of samples remaining.

void silence_gen_set	(	silence_gen_state_t *	s,
		int	silent_samples
	)

Set a silence generator context to output a specified period of silence.

Set a silence generator context to output a specified period of silence.

Parameters:

	s	The silence generator context.
	silent_samples	The number of samples to be generated.

Referenced by t38_gateway_tx().

void silence_gen_status_handler	(	silence_gen_state_t *	s,
		modem_tx_status_func_t	handler,
		void *	user_data
	)

Change the status reporting function associated with a silence generator context.

Change the status reporting function associated with a silence generator context.

Parameters:

	s	The silence generator context.
	handler	The callback routine used to report status changes.
	user_data	An opaque pointer.

int span_dummy_mod	(	void *	user_data,
		int16_t	amp[],
		int	len
	)

Dummy signal modifier callback.

A dummy routine to use as a signal modifier callback, when we aren't really trying to process the signal. It just returns without affecting anything.

Parameters:

	user_data	The context.
	amp	The signal.buffer
	len	The length of the signal buffer

Returns:

0.

int span_dummy_rx	(	void *	user_data,
		const int16_t	amp[],
		int	len
	)

Dummy receive callback.

A dummy routine to use as a receive callback, when we aren't really trying to process what is received. It just absorbs and ignores the data.

Parameters:

	user_data	The context.
	amp	The signal.buffer
	len	The length of the signal buffer

Returns:

0.