func_pitchshift.c File Reference

Pitch Shift Audio Effect. More...

#include "asterisk.h"
#include "asterisk/module.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/utils.h"
#include "asterisk/audiohook.h"
#include <math.h>

Include dependency graph for func_pitchshift.c:

Go to the source code of this file.

Data Structures
struct	fft_data
struct	pitchshift_data

Macros
#define	HIGH   1.25
#define	HIGHER   1.5
#define	HIGHEST   2
#define	LOW   .85
#define	LOWER   .7
#define	LOWEST   .5
#define	M_PI   3.14159265358979323846
#define	MAX_FRAME_LENGTH   256

Functions
	AST_MODULE_INFO_STANDARD_EXTENDED (ASTERISK_GPL_KEY, "Audio Effects Dialplan Functions")
static void	destroy_callback (void *data)
static int	load_module (void)
static int	pitch_shift (struct ast_frame *f, float amount, struct fft_data *fft_data)
static int	pitchshift_cb (struct ast_audiohook *audiohook, struct ast_channel *chan, struct ast_frame *f, enum ast_audiohook_direction direction)
static int	pitchshift_helper (struct ast_channel *chan, const char *cmd, char *data, const char *value)
static void	smb_fft (float *fft_buffer, long fft_frame_size, long sign)
static void	smb_pitch_shift (float pitchShift, long num_samps_to_process, long fft_frame_size, long osamp, float sample_rate, int16_t *indata, int16_t *outdata, struct fft_data *fft_data)
static int	unload_module (void)

Variables
static struct ast_custom_function	pitch_shift_function
static const struct ast_datastore_info	pitchshift_datastore

Detailed Description

Pitch Shift Audio Effect.

Author

David Vossel dvoss.nosp@m.el@d.nosp@m.igium.nosp@m..com

Definition in file func_pitchshift.c.

Macro Definition Documentation

HIGH

#define HIGH   1.25

Definition at line 120 of file func_pitchshift.c.

Referenced by pitchshift_helper().

HIGHER

#define HIGHER   1.5

Definition at line 119 of file func_pitchshift.c.

Referenced by pitchshift_helper().

HIGHEST

#define HIGHEST   2

Definition at line 118 of file func_pitchshift.c.

Referenced by pitchshift_helper().

LOW

#define LOW   .85

Definition at line 121 of file func_pitchshift.c.

Referenced by pitchshift_helper().

LOWER

#define LOWER   .7

Definition at line 122 of file func_pitchshift.c.

Referenced by pitchshift_helper().

LOWEST

#define LOWEST   .5

Definition at line 123 of file func_pitchshift.c.

Referenced by pitchshift_helper().

M_PI

#define M_PI   3.14159265358979323846

Definition at line 114 of file func_pitchshift.c.

Referenced by smb_fft(), and smb_pitch_shift().

MAX_FRAME_LENGTH

#define MAX_FRAME_LENGTH   256

Definition at line 116 of file func_pitchshift.c.

Referenced by pitch_shift().

Function Documentation

AST_MODULE_INFO_STANDARD_EXTENDED()

AST_MODULE_INFO_STANDARD_EXTENDED	(	ASTERISK_GPL_KEY	,
		"Audio Effects Dialplan Functions"
	)

Referenced by load_module().

destroy_callback()

static void destroy_callback ( void *  data )

static

Definition at line 151 of file func_pitchshift.c.

References ast_audiohook_destroy(), ast_free, and pitchshift_data::audiohook.

{
 struct pitchshift_data *shift = data;

 ast_audiohook_destroy(&shift->audiohook);
 ast_free(shift);
};

load_module()

static int load_module ( void  )

static

Definition at line 504 of file func_pitchshift.c.

References ast_custom_function_register, AST_MODULE_INFO_STANDARD_EXTENDED(), AST_MODULE_LOAD_DECLINE, AST_MODULE_LOAD_SUCCESS, and ASTERISK_GPL_KEY.

{
 int res = ast_custom_function_register(&pitch_shift_function);
 return res ? AST_MODULE_LOAD_DECLINE : AST_MODULE_LOAD_SUCCESS;
}

pitch_shift()

static int pitch_shift ( struct ast_frame *  f, float  amount, struct fft_data *  fft_data  )

static

Definition at line 478 of file func_pitchshift.c.

References ast_format_get_sample_rate(), ast_frame::data, ast_frame_subclass::format, if(), MAX_FRAME_LENGTH, ast_frame::ptr, ast_frame::samples, smb_pitch_shift(), and ast_frame::subclass.

Referenced by pitchshift_cb().

{
 int16_t *fun = (int16_t *) f->data.ptr;
 int samples;

 /* an amount of 1 has no effect */
 if (!amount || amount == 1 || !fun || (f->samples % 32)) {
 return 0;
 }
 for (samples = 0; samples < f->samples; samples += 32) {
 smb_pitch_shift(amount, 32, MAX_FRAME_LENGTH, 32, ast_format_get_sample_rate(f->subclass.format), fun+samples, fun+samples, fft);
 }

 return 0;
}

pitchshift_cb()

static int pitchshift_cb ( struct ast_audiohook *  audiohook, struct ast_channel *  chan, struct ast_frame *  f, enum ast_audiohook_direction  direction  )

static

Definition at line 164 of file func_pitchshift.c.

References AST_AUDIOHOOK_DIRECTION_WRITE, AST_AUDIOHOOK_STATUS_DONE, ast_channel_datastore_find(), ast_datastore::data, NULL, pitch_shift(), pitchshift_data::rx, fft_data::shift_amount, ast_audiohook::status, and pitchshift_data::tx.

Referenced by pitchshift_helper().

{
 struct ast_datastore *datastore = NULL;
 struct pitchshift_data *shift = NULL;


 if (!f) {
 return 0;
 }
 if (audiohook->status == AST_AUDIOHOOK_STATUS_DONE) {
 return -1;
 }

 if (!(datastore = ast_channel_datastore_find(chan, &pitchshift_datastore, NULL))) {
 return -1;
 }

 shift = datastore->data;

 if (direction == AST_AUDIOHOOK_DIRECTION_WRITE) {
 pitch_shift(f, shift->tx.shift_amount, &shift->tx);
 } else {
 pitch_shift(f, shift->rx.shift_amount, &shift->rx);
 }

 return 0;
}

pitchshift_helper()

static int pitchshift_helper ( struct ast_channel *  chan, const char *  cmd, char *  data, const char *  value  )

static

Definition at line 192 of file func_pitchshift.c.

References ast_audiohook_attach(), ast_audiohook_init(), AST_AUDIOHOOK_MANIPULATE_ALL_RATES, AST_AUDIOHOOK_TYPE_MANIPULATE, ast_calloc, ast_channel_datastore_add(), ast_channel_datastore_find(), ast_channel_lock, ast_channel_unlock, ast_datastore_alloc, ast_datastore_free(), ast_log, pitchshift_data::audiohook, ast_datastore::data, HIGH, HIGHER, HIGHEST, LOG_ERROR, LOG_WARNING, LOW, LOWER, LOWEST, ast_audiohook::manipulate_callback, NULL, pitchshift_cb(), pitchshift_data::rx, fft_data::shift_amount, and pitchshift_data::tx.

{
 struct ast_datastore *datastore = NULL;
 struct pitchshift_data *shift = NULL;
 int new = 0;
 float amount = 0;

 if (!chan) {
 ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
 return -1;
 }

 ast_channel_lock(chan);
 if (!(datastore = ast_channel_datastore_find(chan, &pitchshift_datastore, NULL))) {
 ast_channel_unlock(chan);

 if (!(datastore = ast_datastore_alloc(&pitchshift_datastore, NULL))) {
 return 0;
 }
 if (!(shift = ast_calloc(1, sizeof(*shift)))) {
 ast_datastore_free(datastore);
 return 0;
 }

 ast_audiohook_init(&shift->audiohook, AST_AUDIOHOOK_TYPE_MANIPULATE, "pitch_shift", AST_AUDIOHOOK_MANIPULATE_ALL_RATES);
 shift->audiohook.manipulate_callback = pitchshift_cb;
 datastore->data = shift;
 new = 1;
 } else {
 ast_channel_unlock(chan);
 shift = datastore->data;
 }


 if (!strcasecmp(value, "highest")) {
 amount = HIGHEST;
 } else if (!strcasecmp(value, "higher")) {
 amount = HIGHER;
 } else if (!strcasecmp(value, "high")) {
 amount = HIGH;
 } else if (!strcasecmp(value, "lowest")) {
 amount = LOWEST;
 } else if (!strcasecmp(value, "lower")) {
 amount = LOWER;
 } else if (!strcasecmp(value, "low")) {
 amount = LOW;
 } else {
 if (!sscanf(value, "%30f", &amount) || (amount <= 0) || (amount > 4)) {
 goto cleanup_error;
 }
 }

 if (!strcasecmp(data, "rx")) {
 shift->rx.shift_amount = amount;
 } else if (!strcasecmp(data, "tx")) {
 shift->tx.shift_amount = amount;
 } else if (!strcasecmp(data, "both")) {
 shift->rx.shift_amount = amount;
 shift->tx.shift_amount = amount;
 } else {
 goto cleanup_error;
 }

 if (new) {
 ast_channel_lock(chan);
 ast_channel_datastore_add(chan, datastore);
 ast_channel_unlock(chan);
 ast_audiohook_attach(chan, &shift->audiohook);
 }

 return 0;

cleanup_error:

 ast_log(LOG_ERROR, "Invalid argument provided to the %s function\n", cmd);
 if (new) {
 ast_datastore_free(datastore);
 }
 return -1;
}

smb_fft()

static void smb_fft ( float *  fft_buffer, long  fft_frame_size, long  sign  )

static

Definition at line 273 of file func_pitchshift.c.

References cos, and M_PI.

Referenced by smb_pitch_shift().

{
 float wr, wi, arg, *p1, *p2, temp;
 float tr, ti, ur, ui, *p1r, *p1i, *p2r, *p2i;
 long i, bitm, j, le, le2, k;

 for (i = 2; i < 2 * fft_frame_size - 2; i += 2) {
 for (bitm = 2, j = 0; bitm < 2 * fft_frame_size; bitm <<= 1) {
 if (i & bitm) {
 j++;
 }
 j <<= 1;
 }
 if (i < j) {
 p1 = fft_buffer + i; p2 = fft_buffer + j;
 temp = *p1; *(p1++) = *p2;
 *(p2++) = temp; temp = *p1;
 *p1 = *p2; *p2 = temp;
 }
 }
 for (k = 0, le = 2; k < (long) (log(fft_frame_size) / log(2.) + .5); k++) {
 le <<= 1;
 le2 = le>>1;
 ur = 1.0;
 ui = 0.0;
 arg = M_PI / (le2>>1);
 wr = cos(arg);
 wi = sign * sin(arg);
 for (j = 0; j < le2; j += 2) {
 p1r = fft_buffer+j; p1i = p1r + 1;
 p2r = p1r + le2; p2i = p2r + 1;
 for (i = j; i < 2 * fft_frame_size; i += le) {
 tr = *p2r * ur - *p2i * ui;
 ti = *p2r * ui + *p2i * ur;
 *p2r = *p1r - tr; *p2i = *p1i - ti;
 *p1r += tr; *p1i += ti;
 p1r += le; p1i += le;
 p2r += le; p2i += le;
 }
 tr = ur * wr - ui * wi;
 ui = ur * wi + ui * wr;
 ur = tr;
 }
 }
}

smb_pitch_shift()

static void smb_pitch_shift ( float  pitchShift, long  num_samps_to_process, long  fft_frame_size, long  osamp, float  sample_rate, int16_t *  indata, int16_t *  outdata, struct fft_data *  fft_data  )

static

Definition at line 319 of file func_pitchshift.c.

References fft_data::ana_freq, fft_data::ana_magn, cos, fft_data::fft_worksp, fft_data::gRover, fft_data::in_fifo, fft_data::last_phase, M_PI, fft_data::out_fifo, fft_data::output_accum, smb_fft(), step_size(), fft_data::sum_phase, fft_data::syn_freq, fft_data::sys_magn, tmp(), and window.

Referenced by pitch_shift().

{
 float *in_fifo = fft_data->in_fifo;
 float *out_fifo = fft_data->out_fifo;
 float *fft_worksp = fft_data->fft_worksp;
 float *last_phase = fft_data->last_phase;
 float *sum_phase = fft_data->sum_phase;
 float *output_accum = fft_data->output_accum;
 float *ana_freq = fft_data->ana_freq;
 float *ana_magn = fft_data->ana_magn;
 float *syn_freq = fft_data->syn_freq;
 float *sys_magn = fft_data->sys_magn;

 double magn, phase, tmp, window, real, imag;
 double freq_per_bin, expct;
 long i,k, qpd, index, in_fifo_latency, step_size, fft_frame_size2;

 /* set up some handy variables */
 fft_frame_size2 = fft_frame_size / 2;
 step_size = fft_frame_size / osamp;
 freq_per_bin = sample_rate / (double) fft_frame_size;
 expct = 2. * M_PI * (double) step_size / (double) fft_frame_size;
 in_fifo_latency = fft_frame_size-step_size;

 if (fft_data->gRover == 0) {
 fft_data->gRover = in_fifo_latency;
 }

 /* main processing loop */
 for (i = 0; i < num_samps_to_process; i++){

 /* As long as we have not yet collected enough data just read in */
 in_fifo[fft_data->gRover] = indata[i];
 outdata[i] = out_fifo[fft_data->gRover - in_fifo_latency];
 fft_data->gRover++;

 /* now we have enough data for processing */
 if (fft_data->gRover >= fft_frame_size) {
 fft_data->gRover = in_fifo_latency;

 /* do windowing and re,im interleave */
 for (k = 0; k < fft_frame_size;k++) {
 window = -.5 * cos(2. * M_PI * (double) k / (double) fft_frame_size) + .5;
 fft_worksp[2*k] = in_fifo[k] * window;
 fft_worksp[2*k+1] = 0.;
 }

 /* ***************** ANALYSIS ******************* */
 /* do transform */
 smb_fft(fft_worksp, fft_frame_size, -1);

 /* this is the analysis step */
 for (k = 0; k <= fft_frame_size2; k++) {

 /* de-interlace FFT buffer */
 real = fft_worksp[2*k];
 imag = fft_worksp[2*k+1];

 /* compute magnitude and phase */
 magn = 2. * sqrt(real * real + imag * imag);
 phase = atan2(imag, real);

 /* compute phase difference */
 tmp = phase - last_phase[k];
 last_phase[k] = phase;

 /* subtract expected phase difference */
 tmp -= (double) k * expct;

 /* map delta phase into +/- Pi interval */
 qpd = tmp / M_PI;
 if (qpd >= 0) {
 qpd += qpd & 1;
 } else {
 qpd -= qpd & 1;
 }
 tmp -= M_PI * (double) qpd;

 /* get deviation from bin frequency from the +/- Pi interval */
 tmp = osamp * tmp / (2. * M_PI);

 /* compute the k-th partials' true frequency */
 tmp = (double) k * freq_per_bin + tmp * freq_per_bin;

 /* store magnitude and true frequency in analysis arrays */
 ana_magn[k] = magn;
 ana_freq[k] = tmp;

 }

 /* ***************** PROCESSING ******************* */
 /* this does the actual pitch shifting */
 memset(sys_magn, 0, fft_frame_size * sizeof(float));
 memset(syn_freq, 0, fft_frame_size * sizeof(float));
 for (k = 0; k <= fft_frame_size2; k++) {
 index = k * pitchShift;
 if (index <= fft_frame_size2) {
 sys_magn[index] += ana_magn[k];
 syn_freq[index] = ana_freq[k] * pitchShift;
 }
 }

 /* ***************** SYNTHESIS ******************* */
 /* this is the synthesis step */
 for (k = 0; k <= fft_frame_size2; k++) {

 /* get magnitude and true frequency from synthesis arrays */
 magn = sys_magn[k];
 tmp = syn_freq[k];

 /* subtract bin mid frequency */
 tmp -= (double) k * freq_per_bin;

 /* get bin deviation from freq deviation */
 tmp /= freq_per_bin;

 /* take osamp into account */
 tmp = 2. * M_PI * tmp / osamp;

 /* add the overlap phase advance back in */
 tmp += (double) k * expct;

 /* accumulate delta phase to get bin phase */
 sum_phase[k] += tmp;
 phase = sum_phase[k];

 /* get real and imag part and re-interleave */
 fft_worksp[2*k] = magn * cos(phase);
 fft_worksp[2*k+1] = magn * sin(phase);
 }

 /* zero negative frequencies */
 for (k = fft_frame_size + 2; k < 2 * fft_frame_size; k++) {
 fft_worksp[k] = 0.;
 }

 /* do inverse transform */
 smb_fft(fft_worksp, fft_frame_size, 1);

 /* do windowing and add to output accumulator */
 for (k = 0; k < fft_frame_size; k++) {
 window = -.5 * cos(2. * M_PI * (double) k / (double) fft_frame_size) + .5;
 output_accum[k] += 2. * window * fft_worksp[2*k] / (fft_frame_size2 * osamp);
 }
 for (k = 0; k < step_size; k++) {
 out_fifo[k] = output_accum[k];
 }

 /* shift accumulator */
 memmove(output_accum, output_accum+step_size, fft_frame_size * sizeof(float));

 /* move input FIFO */
 for (k = 0; k < in_fifo_latency; k++) {
 in_fifo[k] = in_fifo[k+step_size];
 }
 }
 }
}

unload_module()

static int unload_module ( void  )

static

Definition at line 499 of file func_pitchshift.c.

References ast_custom_function_unregister().

{
 return ast_custom_function_unregister(&pitch_shift_function);
}

Variable Documentation

pitch_shift_function

struct ast_custom_function pitch_shift_function

static

Initial value:

= {
 .name = "PITCH_SHIFT",
 .write = pitchshift_helper,
}

Definition at line 494 of file func_pitchshift.c.

pitchshift_datastore

const struct ast_datastore_info pitchshift_datastore

static

Initial value:

= {
 .type = "pitchshift",
 .destroy = destroy_callback
}

Definition at line 159 of file func_pitchshift.c.