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src_sinc.c
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src_sinc.c
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/*
** Copyright (c) 2002-2021, Erik de Castro Lopo <erikd@mega-nerd.com>
** All rights reserved.
**
** This code is released under 2-clause BSD license. Please see the
** file at : https://github.com/libsndfile/libsamplerate/blob/master/COPYING
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "common.h"
#define SINC_MAGIC_MARKER MAKE_MAGIC (' ', 's', 'i', 'n', 'c', ' ')
/*========================================================================================
*/
#define MAKE_INCREMENT_T(x) ((increment_t) (x))
#define SHIFT_BITS 12
#define FP_ONE ((double) (((increment_t) 1) << SHIFT_BITS))
#define INV_FP_ONE (1.0 / FP_ONE)
/* Customixe max channls from Kconfig. */
#ifndef CONFIG_CHAN_NR
#define MAX_CHANNELS 128
#else
#define MAX_CHANNELS CONFIG_CHAN_NR
#endif
/*========================================================================================
*/
typedef int32_t increment_t ;
typedef float coeff_t ;
typedef int _CHECK_SHIFT_BITS[2 * (SHIFT_BITS < sizeof (increment_t) * 8 - 1) - 1]; /* sanity check. */
#ifdef ENABLE_SINC_FAST_CONVERTER
#include "fastest_coeffs.h"
#endif
#ifdef ENABLE_SINC_MEDIUM_CONVERTER
#include "mid_qual_coeffs.h"
#endif
#ifdef ENABLE_SINC_BEST_CONVERTER
#include "high_qual_coeffs.h"
#endif
typedef struct
{ int sinc_magic_marker ;
long in_count, in_used ;
long out_count, out_gen ;
int coeff_half_len, index_inc ;
double src_ratio, input_index ;
coeff_t const *coeffs ;
int b_current, b_end, b_real_end, b_len ;
/* Sure hope noone does more than 128 channels at once. */
double left_calc [MAX_CHANNELS], right_calc [MAX_CHANNELS] ;
float *buffer ;
} SINC_FILTER ;
static SRC_ERROR sinc_multichan_vari_process (SRC_STATE *state, SRC_DATA *data) ;
static SRC_ERROR sinc_hex_vari_process (SRC_STATE *state, SRC_DATA *data) ;
static SRC_ERROR sinc_quad_vari_process (SRC_STATE *state, SRC_DATA *data) ;
static SRC_ERROR sinc_stereo_vari_process (SRC_STATE *state, SRC_DATA *data) ;
static SRC_ERROR sinc_mono_vari_process (SRC_STATE *state, SRC_DATA *data) ;
static SRC_ERROR prepare_data (SINC_FILTER *filter, int channels, SRC_DATA *data, int half_filter_chan_len) WARN_UNUSED ;
static void sinc_reset (SRC_STATE *state) ;
static SRC_STATE *sinc_copy (SRC_STATE *state) ;
static void sinc_close (SRC_STATE *state) ;
static SRC_STATE_VT sinc_multichan_state_vt =
{
sinc_multichan_vari_process,
sinc_multichan_vari_process,
sinc_reset,
sinc_copy,
sinc_close
} ;
static SRC_STATE_VT sinc_hex_state_vt =
{
sinc_hex_vari_process,
sinc_hex_vari_process,
sinc_reset,
sinc_copy,
sinc_close
} ;
static SRC_STATE_VT sinc_quad_state_vt =
{
sinc_quad_vari_process,
sinc_quad_vari_process,
sinc_reset,
sinc_copy,
sinc_close
} ;
static SRC_STATE_VT sinc_stereo_state_vt =
{
sinc_stereo_vari_process,
sinc_stereo_vari_process,
sinc_reset,
sinc_copy,
sinc_close
} ;
static SRC_STATE_VT sinc_mono_state_vt =
{
sinc_mono_vari_process,
sinc_mono_vari_process,
sinc_reset,
sinc_copy,
sinc_close
} ;
static inline increment_t
double_to_fp (double x)
{ return (increment_t) (psf_lrint ((x) * FP_ONE)) ;
} /* double_to_fp */
static inline increment_t
int_to_fp (int x)
{ return (((increment_t) (x)) << SHIFT_BITS) ;
} /* int_to_fp */
static inline int
fp_to_int (increment_t x)
{ return (((x) >> SHIFT_BITS)) ;
} /* fp_to_int */
static inline increment_t
fp_fraction_part (increment_t x)
{ return ((x) & ((((increment_t) 1) << SHIFT_BITS) - 1)) ;
} /* fp_fraction_part */
static inline double
fp_to_double (increment_t x)
{ return fp_fraction_part (x) * INV_FP_ONE ;
} /* fp_to_double */
static inline int
int_div_ceil (int divident, int divisor) /* == (int) ceil ((float) divident / divisor) */
{ assert (divident >= 0 && divisor > 0) ; /* For positive numbers only */
return (divident + (divisor - 1)) / divisor ;
}
/*----------------------------------------------------------------------------------------
*/
LIBSAMPLERATE_DLL_PRIVATE const char*
sinc_get_name (int src_enum)
{
switch (src_enum)
{ case SRC_SINC_BEST_QUALITY :
return "Best Sinc Interpolator" ;
case SRC_SINC_MEDIUM_QUALITY :
return "Medium Sinc Interpolator" ;
case SRC_SINC_FASTEST :
return "Fastest Sinc Interpolator" ;
default: break ;
} ;
return NULL ;
} /* sinc_get_descrition */
LIBSAMPLERATE_DLL_PRIVATE const char*
sinc_get_description (int src_enum)
{
switch (src_enum)
{ case SRC_SINC_FASTEST :
return "Band limited sinc interpolation, fastest, 97dB SNR, 80% BW." ;
case SRC_SINC_MEDIUM_QUALITY :
return "Band limited sinc interpolation, medium quality, 121dB SNR, 90% BW." ;
case SRC_SINC_BEST_QUALITY :
return "Band limited sinc interpolation, best quality, 144dB SNR, 96% BW." ;
default :
break ;
} ;
return NULL ;
} /* sinc_get_descrition */
static SINC_FILTER *
sinc_filter_new (int converter_type, int channels)
{
assert (converter_type == SRC_SINC_FASTEST ||
converter_type == SRC_SINC_MEDIUM_QUALITY ||
converter_type == SRC_SINC_BEST_QUALITY) ;
assert (channels > 0 && channels <= MAX_CHANNELS) ;
SINC_FILTER *priv = (SINC_FILTER *) calloc (1, sizeof (SINC_FILTER)) ;
if (priv)
{
priv->sinc_magic_marker = SINC_MAGIC_MARKER ;
switch (converter_type)
{
#ifdef ENABLE_SINC_FAST_CONVERTER
case SRC_SINC_FASTEST :
priv->coeffs = fastest_coeffs.coeffs ;
priv->coeff_half_len = ARRAY_LEN (fastest_coeffs.coeffs) - 2 ;
priv->index_inc = fastest_coeffs.increment ;
break ;
#endif
#ifdef ENABLE_SINC_MEDIUM_CONVERTER
case SRC_SINC_MEDIUM_QUALITY :
priv->coeffs = slow_mid_qual_coeffs.coeffs ;
priv->coeff_half_len = ARRAY_LEN (slow_mid_qual_coeffs.coeffs) - 2 ;
priv->index_inc = slow_mid_qual_coeffs.increment ;
break ;
#endif
#ifdef ENABLE_SINC_BEST_CONVERTER
case SRC_SINC_BEST_QUALITY :
priv->coeffs = slow_high_qual_coeffs.coeffs ;
priv->coeff_half_len = ARRAY_LEN (slow_high_qual_coeffs.coeffs) - 2 ;
priv->index_inc = slow_high_qual_coeffs.increment ;
break ;
#endif
}
priv->b_len = 3 * (int) psf_lrint ((priv->coeff_half_len + 2.0) / priv->index_inc * SRC_MAX_RATIO + 1) ;
priv->b_len = MAX (priv->b_len, 4096) ;
priv->b_len *= channels ;
priv->b_len += 1 ; // There is a <= check against samples_in_hand requiring a buffer bigger than the calculation above
priv->buffer = (float *) calloc (priv->b_len + channels, sizeof (float)) ;
if (!priv->buffer)
{
free (priv) ;
priv = NULL ;
}
}
return priv ;
}
LIBSAMPLERATE_DLL_PRIVATE SRC_STATE *
sinc_state_new (int converter_type, int channels, SRC_ERROR *error)
{
assert (converter_type == SRC_SINC_FASTEST ||
converter_type == SRC_SINC_MEDIUM_QUALITY ||
converter_type == SRC_SINC_BEST_QUALITY) ;
assert (channels > 0) ;
assert (error != NULL) ;
if (channels > MAX_CHANNELS)
{
*error = SRC_ERR_BAD_CHANNEL_COUNT ;
return NULL ;
}
SRC_STATE *state = (SRC_STATE *) calloc (1, sizeof (SRC_STATE)) ;
if (!state)
{
*error = SRC_ERR_MALLOC_FAILED ;
return NULL ;
}
state->channels = channels ;
state->mode = SRC_MODE_PROCESS ;
if (state->channels == 1)
state->vt = &sinc_mono_state_vt ;
else if (state->channels == 2)
state->vt = &sinc_stereo_state_vt ;
else if (state->channels == 4)
state->vt = &sinc_quad_state_vt ;
else if (state->channels == 6)
state->vt = &sinc_hex_state_vt ;
else
state->vt = &sinc_multichan_state_vt ;
state->private_data = sinc_filter_new (converter_type, state->channels) ;
if (!state->private_data)
{
free (state) ;
*error = SRC_ERR_MALLOC_FAILED ;
return NULL ;
}
sinc_reset (state) ;
*error = SRC_ERR_NO_ERROR ;
return state ;
}
static void
sinc_reset (SRC_STATE *state)
{ SINC_FILTER *filter ;
filter = (SINC_FILTER*) state->private_data ;
if (filter == NULL)
return ;
filter->b_current = filter->b_end = 0 ;
filter->b_real_end = -1 ;
filter->src_ratio = filter->input_index = 0.0 ;
memset (filter->buffer, 0, filter->b_len * sizeof (filter->buffer [0])) ;
/* Set this for a sanity check */
memset (filter->buffer + filter->b_len, 0xAA, state->channels * sizeof (filter->buffer [0])) ;
} /* sinc_reset */
static SRC_STATE *
sinc_copy (SRC_STATE *state)
{
assert (state != NULL) ;
if (state->private_data == NULL)
return NULL ;
SRC_STATE *to = (SRC_STATE *) calloc (1, sizeof (SRC_STATE)) ;
if (!to)
return NULL ;
memcpy (to, state, sizeof (SRC_STATE)) ;
SINC_FILTER* from_filter = (SINC_FILTER*) state->private_data ;
SINC_FILTER *to_filter = (SINC_FILTER *) calloc (1, sizeof (SINC_FILTER)) ;
if (!to_filter)
{
free (to) ;
return NULL ;
}
memcpy (to_filter, from_filter, sizeof (SINC_FILTER)) ;
to_filter->buffer = (float *) malloc (sizeof (float) * (from_filter->b_len + state->channels)) ;
if (!to_filter->buffer)
{
free (to) ;
free (to_filter) ;
return NULL ;
}
memcpy (to_filter->buffer, from_filter->buffer, sizeof (float) * (from_filter->b_len + state->channels)) ;
to->private_data = to_filter ;
return to ;
} /* sinc_copy */
/*========================================================================================
** Beware all ye who dare pass this point. There be dragons here.
*/
static inline double
calc_output_single (SINC_FILTER *filter, increment_t increment, increment_t start_filter_index)
{ double fraction, left, right, icoeff ;
increment_t filter_index, max_filter_index ;
int data_index, coeff_count, indx ;
/* Convert input parameters into fixed point. */
max_filter_index = int_to_fp (filter->coeff_half_len) ;
/* First apply the left half of the filter. */
filter_index = start_filter_index ;
coeff_count = (max_filter_index - filter_index) / increment ;
filter_index = filter_index + coeff_count * increment ;
data_index = filter->b_current - coeff_count ;
if (data_index < 0) /* Avoid underflow access to filter->buffer. */
{ int steps = -data_index ;
/* If the assert triggers we would have to take care not to underflow/overflow */
assert (steps <= int_div_ceil (filter_index, increment)) ;
filter_index -= increment * steps ;
data_index += steps ;
}
left = 0.0 ;
while (filter_index >= MAKE_INCREMENT_T (0))
{ fraction = fp_to_double (filter_index) ;
indx = fp_to_int (filter_index) ;
assert (indx >= 0 && indx + 1 < filter->coeff_half_len + 2) ;
icoeff = filter->coeffs [indx] + fraction * (filter->coeffs [indx + 1] - filter->coeffs [indx]) ;
assert (data_index >= 0 && data_index < filter->b_len) ;
assert (data_index < filter->b_end) ;
left += icoeff * filter->buffer [data_index] ;
filter_index -= increment ;
data_index = data_index + 1 ;
} ;
/* Now apply the right half of the filter. */
filter_index = increment - start_filter_index ;
coeff_count = (max_filter_index - filter_index) / increment ;
filter_index = filter_index + coeff_count * increment ;
data_index = filter->b_current + 1 + coeff_count ;
right = 0.0 ;
do
{ fraction = fp_to_double (filter_index) ;
indx = fp_to_int (filter_index) ;
assert (indx < filter->coeff_half_len + 2) ;
icoeff = filter->coeffs [indx] + fraction * (filter->coeffs [indx + 1] - filter->coeffs [indx]) ;
assert (data_index >= 0 && data_index < filter->b_len) ;
assert (data_index < filter->b_end) ;
right += icoeff * filter->buffer [data_index] ;
filter_index -= increment ;
data_index = data_index - 1 ;
}
while (filter_index > MAKE_INCREMENT_T (0)) ;
return (left + right) ;
} /* calc_output_single */
static SRC_ERROR
sinc_mono_vari_process (SRC_STATE *state, SRC_DATA *data)
{ SINC_FILTER *filter ;
double input_index, src_ratio, count, float_increment, terminate, rem ;
increment_t increment, start_filter_index ;
int half_filter_chan_len, samples_in_hand ;
if (state->private_data == NULL)
return SRC_ERR_NO_PRIVATE ;
filter = (SINC_FILTER*) state->private_data ;
/* If there is not a problem, this will be optimised out. */
if (sizeof (filter->buffer [0]) != sizeof (data->data_in [0]))
return SRC_ERR_SIZE_INCOMPATIBILITY ;
filter->in_count = data->input_frames * state->channels ;
filter->out_count = data->output_frames * state->channels ;
filter->in_used = filter->out_gen = 0 ;
src_ratio = state->last_ratio ;
if (is_bad_src_ratio (src_ratio))
return SRC_ERR_BAD_INTERNAL_STATE ;
/* Check the sample rate ratio wrt the buffer len. */
count = (filter->coeff_half_len + 2.0) / filter->index_inc ;
if (MIN (state->last_ratio, data->src_ratio) < 1.0)
count /= MIN (state->last_ratio, data->src_ratio) ;
/* Maximum coefficientson either side of center point. */
half_filter_chan_len = state->channels * (int) (psf_lrint (count) + 1) ;
input_index = state->last_position ;
rem = fmod_one (input_index) ;
filter->b_current = (filter->b_current + state->channels * psf_lrint (input_index - rem)) % filter->b_len ;
input_index = rem ;
terminate = 1.0 / src_ratio + 1e-20 ;
/* Main processing loop. */
while (filter->out_gen < filter->out_count)
{
/* Need to reload buffer? */
samples_in_hand = (filter->b_end - filter->b_current + filter->b_len) % filter->b_len ;
if (samples_in_hand <= half_filter_chan_len)
{ if ((state->error = prepare_data (filter, state->channels, data, half_filter_chan_len)) != 0)
return state->error ;
samples_in_hand = (filter->b_end - filter->b_current + filter->b_len) % filter->b_len ;
if (samples_in_hand <= half_filter_chan_len)
break ;
} ;
/* This is the termination condition. */
if (filter->b_real_end >= 0)
{ if (filter->b_current + input_index + terminate > filter->b_real_end)
break ;
} ;
if (filter->out_count > 0 && fabs (state->last_ratio - data->src_ratio) > 1e-10)
src_ratio = state->last_ratio + filter->out_gen * (data->src_ratio - state->last_ratio) / filter->out_count ;
float_increment = filter->index_inc * (src_ratio < 1.0 ? src_ratio : 1.0) ;
increment = double_to_fp (float_increment) ;
start_filter_index = double_to_fp (input_index * float_increment) ;
data->data_out [filter->out_gen] = (float) ((float_increment / filter->index_inc) *
calc_output_single (filter, increment, start_filter_index)) ;
filter->out_gen ++ ;
/* Figure out the next index. */
input_index += 1.0 / src_ratio ;
rem = fmod_one (input_index) ;
filter->b_current = (filter->b_current + state->channels * psf_lrint (input_index - rem)) % filter->b_len ;
input_index = rem ;
} ;
state->last_position = input_index ;
/* Save current ratio rather then target ratio. */
state->last_ratio = src_ratio ;
data->input_frames_used = filter->in_used / state->channels ;
data->output_frames_gen = filter->out_gen / state->channels ;
return SRC_ERR_NO_ERROR ;
} /* sinc_mono_vari_process */
static inline void
calc_output_stereo (SINC_FILTER *filter, int channels, increment_t increment, increment_t start_filter_index, double scale, float * output)
{ double fraction, left [2], right [2], icoeff ;
increment_t filter_index, max_filter_index ;
int data_index, coeff_count, indx ;
/* Convert input parameters into fixed point. */
max_filter_index = int_to_fp (filter->coeff_half_len) ;
/* First apply the left half of the filter. */
filter_index = start_filter_index ;
coeff_count = (max_filter_index - filter_index) / increment ;
filter_index = filter_index + coeff_count * increment ;
data_index = filter->b_current - channels * coeff_count ;
if (data_index < 0) /* Avoid underflow access to filter->buffer. */
{ int steps = int_div_ceil (-data_index, 2) ;
/* If the assert triggers we would have to take care not to underflow/overflow */
assert (steps <= int_div_ceil (filter_index, increment)) ;
filter_index -= increment * steps ;
data_index += steps * 2;
}
left [0] = left [1] = 0.0 ;
while (filter_index >= MAKE_INCREMENT_T (0))
{ fraction = fp_to_double (filter_index) ;
indx = fp_to_int (filter_index) ;
assert (indx >= 0 && indx + 1 < filter->coeff_half_len + 2) ;
icoeff = filter->coeffs [indx] + fraction * (filter->coeffs [indx + 1] - filter->coeffs [indx]) ;
assert (data_index >= 0 && data_index + 1 < filter->b_len) ;
assert (data_index + 1 < filter->b_end) ;
for (int ch = 0; ch < 2; ch++)
left [ch] += icoeff * filter->buffer [data_index + ch] ;
filter_index -= increment ;
data_index = data_index + 2 ;
} ;
/* Now apply the right half of the filter. */
filter_index = increment - start_filter_index ;
coeff_count = (max_filter_index - filter_index) / increment ;
filter_index = filter_index + coeff_count * increment ;
data_index = filter->b_current + channels * (1 + coeff_count) ;
right [0] = right [1] = 0.0 ;
do
{ fraction = fp_to_double (filter_index) ;
indx = fp_to_int (filter_index) ;
assert (indx >= 0 && indx + 1 < filter->coeff_half_len + 2) ;
icoeff = filter->coeffs [indx] + fraction * (filter->coeffs [indx + 1] - filter->coeffs [indx]) ;
assert (data_index >= 0 && data_index + 1 < filter->b_len) ;
assert (data_index + 1 < filter->b_end) ;
for (int ch = 0; ch < 2; ch++)
right [ch] += icoeff * filter->buffer [data_index + ch] ;
filter_index -= increment ;
data_index = data_index - 2 ;
}
while (filter_index > MAKE_INCREMENT_T (0)) ;
for (int ch = 0; ch < 2; ch++)
output [ch] = (float) (scale * (left [ch] + right [ch])) ;
} /* calc_output_stereo */
SRC_ERROR
sinc_stereo_vari_process (SRC_STATE *state, SRC_DATA *data)
{ SINC_FILTER *filter ;
double input_index, src_ratio, count, float_increment, terminate, rem ;
increment_t increment, start_filter_index ;
int half_filter_chan_len, samples_in_hand ;
if (state->private_data == NULL)
return SRC_ERR_NO_PRIVATE ;
filter = (SINC_FILTER*) state->private_data ;
/* If there is not a problem, this will be optimised out. */
if (sizeof (filter->buffer [0]) != sizeof (data->data_in [0]))
return SRC_ERR_SIZE_INCOMPATIBILITY ;
filter->in_count = data->input_frames * state->channels ;
filter->out_count = data->output_frames * state->channels ;
filter->in_used = filter->out_gen = 0 ;
src_ratio = state->last_ratio ;
if (is_bad_src_ratio (src_ratio))
return SRC_ERR_BAD_INTERNAL_STATE ;
/* Check the sample rate ratio wrt the buffer len. */
count = (filter->coeff_half_len + 2.0) / filter->index_inc ;
if (MIN (state->last_ratio, data->src_ratio) < 1.0)
count /= MIN (state->last_ratio, data->src_ratio) ;
/* Maximum coefficientson either side of center point. */
half_filter_chan_len = state->channels * (int) (psf_lrint (count) + 1) ;
input_index = state->last_position ;
rem = fmod_one (input_index) ;
filter->b_current = (filter->b_current + state->channels * psf_lrint (input_index - rem)) % filter->b_len ;
input_index = rem ;
terminate = 1.0 / src_ratio + 1e-20 ;
/* Main processing loop. */
while (filter->out_gen < filter->out_count)
{
/* Need to reload buffer? */
samples_in_hand = (filter->b_end - filter->b_current + filter->b_len) % filter->b_len ;
if (samples_in_hand <= half_filter_chan_len)
{ if ((state->error = prepare_data (filter, state->channels, data, half_filter_chan_len)) != 0)
return state->error ;
samples_in_hand = (filter->b_end - filter->b_current + filter->b_len) % filter->b_len ;
if (samples_in_hand <= half_filter_chan_len)
break ;
} ;
/* This is the termination condition. */
if (filter->b_real_end >= 0)
{ if (filter->b_current + input_index + terminate >= filter->b_real_end)
break ;
} ;
if (filter->out_count > 0 && fabs (state->last_ratio - data->src_ratio) > 1e-10)
src_ratio = state->last_ratio + filter->out_gen * (data->src_ratio - state->last_ratio) / filter->out_count ;
float_increment = filter->index_inc * (src_ratio < 1.0 ? src_ratio : 1.0) ;
increment = double_to_fp (float_increment) ;
start_filter_index = double_to_fp (input_index * float_increment) ;
calc_output_stereo (filter, state->channels, increment, start_filter_index, float_increment / filter->index_inc, data->data_out + filter->out_gen) ;
filter->out_gen += 2 ;
/* Figure out the next index. */
input_index += 1.0 / src_ratio ;
rem = fmod_one (input_index) ;
filter->b_current = (filter->b_current + state->channels * psf_lrint (input_index - rem)) % filter->b_len ;
input_index = rem ;
} ;
state->last_position = input_index ;
/* Save current ratio rather then target ratio. */
state->last_ratio = src_ratio ;
data->input_frames_used = filter->in_used / state->channels ;
data->output_frames_gen = filter->out_gen / state->channels ;
return SRC_ERR_NO_ERROR ;
} /* sinc_stereo_vari_process */
static inline void
calc_output_quad (SINC_FILTER *filter, int channels, increment_t increment, increment_t start_filter_index, double scale, float * output)
{ double fraction, left [4], right [4], icoeff ;
increment_t filter_index, max_filter_index ;
int data_index, coeff_count, indx ;
/* Convert input parameters into fixed point. */
max_filter_index = int_to_fp (filter->coeff_half_len) ;
/* First apply the left half of the filter. */
filter_index = start_filter_index ;
coeff_count = (max_filter_index - filter_index) / increment ;
filter_index = filter_index + coeff_count * increment ;
data_index = filter->b_current - channels * coeff_count ;
if (data_index < 0) /* Avoid underflow access to filter->buffer. */
{ int steps = int_div_ceil (-data_index, 4) ;
/* If the assert triggers we would have to take care not to underflow/overflow */
assert (steps <= int_div_ceil (filter_index, increment)) ;
filter_index -= increment * steps ;
data_index += steps * 4;
}
left [0] = left [1] = left [2] = left [3] = 0.0 ;
while (filter_index >= MAKE_INCREMENT_T (0))
{ fraction = fp_to_double (filter_index) ;
indx = fp_to_int (filter_index) ;
assert (indx >= 0 && indx + 1 < filter->coeff_half_len + 2) ;
icoeff = filter->coeffs [indx] + fraction * (filter->coeffs [indx + 1] - filter->coeffs [indx]) ;
assert (data_index >= 0 && data_index + 3 < filter->b_len) ;
assert (data_index + 3 < filter->b_end) ;
for (int ch = 0; ch < 4; ch++)
left [ch] += icoeff * filter->buffer [data_index + ch] ;
filter_index -= increment ;
data_index = data_index + 4 ;
} ;
/* Now apply the right half of the filter. */
filter_index = increment - start_filter_index ;
coeff_count = (max_filter_index - filter_index) / increment ;
filter_index = filter_index + coeff_count * increment ;
data_index = filter->b_current + channels * (1 + coeff_count) ;
right [0] = right [1] = right [2] = right [3] = 0.0 ;
do
{ fraction = fp_to_double (filter_index) ;
indx = fp_to_int (filter_index) ;
assert (indx >= 0 && indx + 1 < filter->coeff_half_len + 2) ;
icoeff = filter->coeffs [indx] + fraction * (filter->coeffs [indx + 1] - filter->coeffs [indx]) ;
assert (data_index >= 0 && data_index + 3 < filter->b_len) ;
assert (data_index + 3 < filter->b_end) ;
for (int ch = 0; ch < 4; ch++)
right [ch] += icoeff * filter->buffer [data_index + ch] ;
filter_index -= increment ;
data_index = data_index - 4 ;
}
while (filter_index > MAKE_INCREMENT_T (0)) ;
for (int ch = 0; ch < 4; ch++)
output [ch] = (float) (scale * (left [ch] + right [ch])) ;
} /* calc_output_quad */
SRC_ERROR
sinc_quad_vari_process (SRC_STATE *state, SRC_DATA *data)
{ SINC_FILTER *filter ;
double input_index, src_ratio, count, float_increment, terminate, rem ;
increment_t increment, start_filter_index ;
int half_filter_chan_len, samples_in_hand ;
if (state->private_data == NULL)
return SRC_ERR_NO_PRIVATE ;
filter = (SINC_FILTER*) state->private_data ;
/* If there is not a problem, this will be optimised out. */
if (sizeof (filter->buffer [0]) != sizeof (data->data_in [0]))
return SRC_ERR_SIZE_INCOMPATIBILITY ;
filter->in_count = data->input_frames * state->channels ;
filter->out_count = data->output_frames * state->channels ;
filter->in_used = filter->out_gen = 0 ;
src_ratio = state->last_ratio ;
if (is_bad_src_ratio (src_ratio))
return SRC_ERR_BAD_INTERNAL_STATE ;
/* Check the sample rate ratio wrt the buffer len. */
count = (filter->coeff_half_len + 2.0) / filter->index_inc ;
if (MIN (state->last_ratio, data->src_ratio) < 1.0)
count /= MIN (state->last_ratio, data->src_ratio) ;
/* Maximum coefficientson either side of center point. */
half_filter_chan_len = state->channels * (int) (psf_lrint (count) + 1) ;
input_index = state->last_position ;
rem = fmod_one (input_index) ;
filter->b_current = (filter->b_current + state->channels * psf_lrint (input_index - rem)) % filter->b_len ;
input_index = rem ;
terminate = 1.0 / src_ratio + 1e-20 ;
/* Main processing loop. */
while (filter->out_gen < filter->out_count)
{
/* Need to reload buffer? */
samples_in_hand = (filter->b_end - filter->b_current + filter->b_len) % filter->b_len ;
if (samples_in_hand <= half_filter_chan_len)
{ if ((state->error = prepare_data (filter, state->channels, data, half_filter_chan_len)) != 0)
return state->error ;
samples_in_hand = (filter->b_end - filter->b_current + filter->b_len) % filter->b_len ;
if (samples_in_hand <= half_filter_chan_len)
break ;
} ;
/* This is the termination condition. */
if (filter->b_real_end >= 0)
{ if (filter->b_current + input_index + terminate >= filter->b_real_end)
break ;
} ;
if (filter->out_count > 0 && fabs (state->last_ratio - data->src_ratio) > 1e-10)
src_ratio = state->last_ratio + filter->out_gen * (data->src_ratio - state->last_ratio) / filter->out_count ;
float_increment = filter->index_inc * (src_ratio < 1.0 ? src_ratio : 1.0) ;
increment = double_to_fp (float_increment) ;
start_filter_index = double_to_fp (input_index * float_increment) ;
calc_output_quad (filter, state->channels, increment, start_filter_index, float_increment / filter->index_inc, data->data_out + filter->out_gen) ;
filter->out_gen += 4 ;
/* Figure out the next index. */
input_index += 1.0 / src_ratio ;
rem = fmod_one (input_index) ;
filter->b_current = (filter->b_current + state->channels * psf_lrint (input_index - rem)) % filter->b_len ;
input_index = rem ;
} ;
state->last_position = input_index ;
/* Save current ratio rather then target ratio. */
state->last_ratio = src_ratio ;
data->input_frames_used = filter->in_used / state->channels ;
data->output_frames_gen = filter->out_gen / state->channels ;
return SRC_ERR_NO_ERROR ;
} /* sinc_quad_vari_process */
static inline void
calc_output_hex (SINC_FILTER *filter, int channels, increment_t increment, increment_t start_filter_index, double scale, float * output)
{ double fraction, left [6], right [6], icoeff ;
increment_t filter_index, max_filter_index ;
int data_index, coeff_count, indx ;
/* Convert input parameters into fixed point. */
max_filter_index = int_to_fp (filter->coeff_half_len) ;
/* First apply the left half of the filter. */
filter_index = start_filter_index ;
coeff_count = (max_filter_index - filter_index) / increment ;
filter_index = filter_index + coeff_count * increment ;
data_index = filter->b_current - channels * coeff_count ;
if (data_index < 0) /* Avoid underflow access to filter->buffer. */
{ int steps = int_div_ceil (-data_index, 6) ;
/* If the assert triggers we would have to take care not to underflow/overflow */
assert (steps <= int_div_ceil (filter_index, increment)) ;
filter_index -= increment * steps ;
data_index += steps * 6;
}
left [0] = left [1] = left [2] = left [3] = left [4] = left [5] = 0.0 ;
while (filter_index >= MAKE_INCREMENT_T (0))
{ fraction = fp_to_double (filter_index) ;
indx = fp_to_int (filter_index) ;
assert (indx >= 0 && indx + 1 < filter->coeff_half_len + 2) ;
icoeff = filter->coeffs [indx] + fraction * (filter->coeffs [indx + 1] - filter->coeffs [indx]) ;
assert (data_index >= 0 && data_index + 5 < filter->b_len) ;
assert (data_index + 5 < filter->b_end) ;
for (int ch = 0; ch < 6; ch++)
left [ch] += icoeff * filter->buffer [data_index + ch] ;
filter_index -= increment ;
data_index = data_index + 6 ;
} ;
/* Now apply the right half of the filter. */
filter_index = increment - start_filter_index ;
coeff_count = (max_filter_index - filter_index) / increment ;
filter_index = filter_index + coeff_count * increment ;
data_index = filter->b_current + channels * (1 + coeff_count) ;
right [0] = right [1] = right [2] = right [3] = right [4] = right [5] = 0.0 ;
do
{ fraction = fp_to_double (filter_index) ;
indx = fp_to_int (filter_index) ;
assert (indx >= 0 && indx + 1 < filter->coeff_half_len + 2) ;
icoeff = filter->coeffs [indx] + fraction * (filter->coeffs [indx + 1] - filter->coeffs [indx]) ;
assert (data_index >= 0 && data_index + 5 < filter->b_len) ;
assert (data_index + 5 < filter->b_end) ;
for (int ch = 0; ch < 6; ch++)
right [ch] += icoeff * filter->buffer [data_index + ch] ;
filter_index -= increment ;
data_index = data_index - 6 ;
}
while (filter_index > MAKE_INCREMENT_T (0)) ;
for (int ch = 0; ch < 6; ch++)
output [ch] = (float) (scale * (left [ch] + right [ch])) ;
} /* calc_output_hex */
SRC_ERROR
sinc_hex_vari_process (SRC_STATE *state, SRC_DATA *data)
{ SINC_FILTER *filter ;
double input_index, src_ratio, count, float_increment, terminate, rem ;
increment_t increment, start_filter_index ;
int half_filter_chan_len, samples_in_hand ;
if (state->private_data == NULL)
return SRC_ERR_NO_PRIVATE ;
filter = (SINC_FILTER*) state->private_data ;
/* If there is not a problem, this will be optimised out. */
if (sizeof (filter->buffer [0]) != sizeof (data->data_in [0]))
return SRC_ERR_SIZE_INCOMPATIBILITY ;
filter->in_count = data->input_frames * state->channels ;
filter->out_count = data->output_frames * state->channels ;
filter->in_used = filter->out_gen = 0 ;
src_ratio = state->last_ratio ;
if (is_bad_src_ratio (src_ratio))
return SRC_ERR_BAD_INTERNAL_STATE ;
/* Check the sample rate ratio wrt the buffer len. */
count = (filter->coeff_half_len + 2.0) / filter->index_inc ;
if (MIN (state->last_ratio, data->src_ratio) < 1.0)
count /= MIN (state->last_ratio, data->src_ratio) ;
/* Maximum coefficientson either side of center point. */
half_filter_chan_len = state->channels * (int) (psf_lrint (count) + 1) ;
input_index = state->last_position ;
rem = fmod_one (input_index) ;
filter->b_current = (filter->b_current + state->channels * psf_lrint (input_index - rem)) % filter->b_len ;
input_index = rem ;
terminate = 1.0 / src_ratio + 1e-20 ;
/* Main processing loop. */
while (filter->out_gen < filter->out_count)
{
/* Need to reload buffer? */
samples_in_hand = (filter->b_end - filter->b_current + filter->b_len) % filter->b_len ;
if (samples_in_hand <= half_filter_chan_len)
{ if ((state->error = prepare_data (filter, state->channels, data, half_filter_chan_len)) != 0)
return state->error ;
samples_in_hand = (filter->b_end - filter->b_current + filter->b_len) % filter->b_len ;
if (samples_in_hand <= half_filter_chan_len)
break ;
} ;
/* This is the termination condition. */
if (filter->b_real_end >= 0)
{ if (filter->b_current + input_index + terminate >= filter->b_real_end)
break ;
} ;
if (filter->out_count > 0 && fabs (state->last_ratio - data->src_ratio) > 1e-10)
src_ratio = state->last_ratio + filter->out_gen * (data->src_ratio - state->last_ratio) / filter->out_count ;
float_increment = filter->index_inc * (src_ratio < 1.0 ? src_ratio : 1.0) ;
increment = double_to_fp (float_increment) ;
start_filter_index = double_to_fp (input_index * float_increment) ;
calc_output_hex (filter, state->channels, increment, start_filter_index, float_increment / filter->index_inc, data->data_out + filter->out_gen) ;
filter->out_gen += 6 ;
/* Figure out the next index. */
input_index += 1.0 / src_ratio ;
rem = fmod_one (input_index) ;
filter->b_current = (filter->b_current + state->channels * psf_lrint (input_index - rem)) % filter->b_len ;
input_index = rem ;
} ;
state->last_position = input_index ;
/* Save current ratio rather then target ratio. */
state->last_ratio = src_ratio ;
data->input_frames_used = filter->in_used / state->channels ;
data->output_frames_gen = filter->out_gen / state->channels ;
return SRC_ERR_NO_ERROR ;
} /* sinc_hex_vari_process */
static inline void
calc_output_multi (SINC_FILTER *filter, increment_t increment, increment_t start_filter_index, int channels, double scale, float * output)
{ double fraction, icoeff ;
/* The following line is 1999 ISO Standard C. If your compiler complains, get a better compiler. */
double *left, *right ;
increment_t filter_index, max_filter_index ;
int data_index, coeff_count, indx ;
left = filter->left_calc ;
right = filter->right_calc ;
/* Convert input parameters into fixed point. */