silence_gen.c File Reference

#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <tgmath.h>
#include <math.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"
#include "spandsp/private/silence_gen.h"

Functions

 SPAN_DECLARE_NONSTD (int)
 Get the next bit of a transmitted serial bit stream.
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_tsilence_gen_init (silence_gen_state_t *s, int silent_samples)
 Initialise a timed silence generator context.
int silence_gen_release (silence_gen_state_t *s)
int silence_gen_free (silence_gen_state_t *s)
int span_dummy_mod (void *user_data, int16_t amp[], int len)
 Dummy signal modifier callback.

Detailed Description


Function Documentation

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 SPAN_DECLARE_NONSTD().

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.
SPAN_DECLARE_NONSTD ( int   ) 

Get the next bit of a transmitted serial bit stream.

Get the next bit of data from a T.38 rate adapting non-ECM buffer context.

Get a bit of received non-ECM image data.

Get the next bit of a transmitted serial bit stream.

Parameters:
user_data An opaque point which must point to a transmitter context.
Returns:
the next bit, or PUTBIT_END_OF_DATA to indicate the data stream has ended.

Get the next bit of a transmitted serial bit stream.

Process a block of received V.8 audio samples.

Fake processing of a missing block of received V.29 modem audio samples.

Fake processing of a missing block of received V.27ter modem audio samples.

Generate a block of V.22bis modem audio samples.

Fake processing of a missing block of received V.22bis modem audio samples.

Process a block of received V.18 audio samples.

Fake processing of a missing block of received V.17 modem audio samples.

Generate a block of FAX audio samples.

Apply fake received audio processing.

Generate a block of T.31 modem audio samples.

Fake processing of a missing block of received T.31 modem audio samples.

Dummy receive fillin callback.

Dummy receive callback.

Process a block of samples through an instance of the modem connect tones detector.

Get the next sequence of bytes for transmission.

Get the next byte for transmission.

Fake processing of a missing block of received FSK modem audio samples.

Process a block of received FSK modem audio samples.

Apply T.30 transmit processing to generate a block of audio samples.

Apply fake T.30 receive processing when a block of audio samples is missing (e.g due to packet loss).

Parameters:
s The FAX context.
len The number of samples to fake.
Returns:
The number of samples unprocessed. This should only be non-zero if the software has reached the end of the FAX call.

Apply T.30 transmit processing to generate a block of audio samples.

Parameters:
s The FAX 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.

Process a block of received FSK modem audio samples.

Parameters:
s The modem context.
amp The audio sample buffer.
len The number of samples in the buffer.
Returns:
The number of samples unprocessed.

Fake processing of a missing block of received FSK modem audio samples (e.g due to packet loss).

Parameters:
s The modem context.
len The number of samples to fake.
Returns:
The number of samples unprocessed.
Parameters:
s A pointer to an HDLC transmitter context.
Returns:
The next byte for transmission.
Parameters:
s A pointer to an HDLC transmitter context.
buf The buffer for the data.
max_len The number of bytes to get.
Returns:
The number of bytes actually got.
Parameters:
s The context.
amp An array of signal samples.
len The number of samples in the array.
Returns:
The number of unprocessed samples.

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.

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

Parameters:
user_data The context.
len The length of the signal buffer
Returns:
0.

Fake processing of a missing block of received T.31 modem audio samples (e.g due to packet loss).

Parameters:
s The T.31 modem context.
len The number of samples to fake.
Returns:
The number of samples unprocessed.

Generate a block of T.31 modem audio samples.

Parameters:
s The T.31 modem context.
amp The audio sample buffer.
max_len The number of samples to be generated.
Returns:
The number of samples actually generated.

Apply fake processing when a block of audio samples is missing (e.g due to packet loss).

Parameters:
s The T.38 context.
len The number of samples to fake.
Returns:
The number of samples unprocessed. This should only be non-zero if the software has reached the end of the FAX call.

Generate a block of FAX audio samples.

Parameters:
s The T.38 context.
amp The audio sample buffer.
max_len The number of samples to be generated.
Returns:
The number of samples actually generated.

Fake processing of a missing block of received V.17 modem audio samples. (e.g due to packet loss).

Parameters:
s The modem context.
len The number of samples to fake.
Returns:
The number of samples unprocessed.

Process a block of received V.18 audio samples.

Parameters:
s The V.18 context.
amp The audio sample buffer.
len The number of samples in the buffer.

Fake processing of a missing block of received V.22bis modem audio samples. (e.g due to packet loss).

Parameters:
s The modem context.
len The number of samples to fake.
Returns:
The number of samples unprocessed.

Generate a block of V.22bis modem audio samples.

Parameters:
s The modem context.
amp The audio sample buffer.
len The number of samples to be generated.
Returns:
The number of samples actually generated.

Fake processing of a missing block of received V.27ter modem audio samples. (e.g due to packet loss).

Parameters:
s The modem context.
len The number of samples to fake.
Returns:
The number of samples unprocessed.

Fake processing of a missing block of received V.29 modem audio samples. (e.g due to packet loss).

Parameters:
s The modem context.
len The number of samples to fake.
Returns:
The number of samples unprocessed.

Process a block of received V.8 audio samples.

Parameters:
s The V.8 context.
amp The audio sample buffer.
len The number of samples in the buffer.
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.

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