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/*
* various filters for ACELP-based codecs
*
* Copyright (c) 2008 Vladimir Voroshilov
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <inttypes.h>
#include "avcodec.h"
#include "celp_filters.h"
void ff_celp_convolve_circ(int16_t* fc_out,
const int16_t* fc_in,
const int16_t* filter,
int len)
{
int i, k;
memset(fc_out, 0, len * sizeof(int16_t));
/* Since there are few pulses over an entire subframe (i.e. almost
all fc_in[i] are zero) it is faster to loop over fc_in first. */
for (i = 0; i < len; i++) {
if (fc_in[i]) {
for (k = 0; k < i; k++)
fc_out[k] += (fc_in[i] * filter[len + k - i]) >> 15;
for (k = i; k < len; k++)
fc_out[k] += (fc_in[i] * filter[ k - i]) >> 15;
}
}
}
void ff_celp_circ_addf(float *out, const float *in,
const float *lagged, int lag, float fac, int n)
{
int k;
for (k = 0; k < lag; k++)
out[k] = in[k] + fac * lagged[n + k - lag];
for (; k < n; k++)
out[k] = in[k] + fac * lagged[ k - lag];
}
int ff_celp_lp_synthesis_filter(int16_t *out,
const int16_t* filter_coeffs,
const int16_t* in,
int buffer_length,
int filter_length,
int stop_on_overflow,
int rounder)
{
int i,n;
// Avoids a +1 in the inner loop.
filter_length++;
for (n = 0; n < buffer_length; n++) {
int sum = rounder;
for (i = 1; i < filter_length; i++)
sum -= filter_coeffs[i-1] * out[n-i];
sum = (sum >> 12) + in[n];
if (sum + 0x8000 > 0xFFFFU) {
if (stop_on_overflow)
return 1;
sum = (sum >> 31) ^ 32767;
}
out[n] = sum;
}
return 0;
}
void ff_celp_lp_synthesis_filterf(float *out,
const float* filter_coeffs,
const float* in,
int buffer_length,
int filter_length)
{
int i,n;
// Avoids a +1 in the inner loop.
filter_length++;
for (n = 0; n < buffer_length; n++) {
out[n] = in[n];
for (i = 1; i < filter_length; i++)
out[n] -= filter_coeffs[i-1] * out[n-i];
}
}
void ff_celp_lp_zero_synthesis_filterf(float *out,
const float* filter_coeffs,
const float* in,
int buffer_length,
int filter_length)
{
int i,n;
// Avoids a +1 in the inner loop.
filter_length++;
for (n = 0; n < buffer_length; n++) {
out[n] = in[n];
for (i = 1; i < filter_length; i++)
out[n] += filter_coeffs[i-1] * in[n-i];
}
}
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