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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;
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;
#if 0 // Unoptimized code path for improved readability
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];
}
#else
float out0, out1, out2, out3;
float old_out0, old_out1, old_out2, old_out3;
float a,b,c;
a = filter_coeffs[0];
b = filter_coeffs[1];
c = filter_coeffs[2];
b -= filter_coeffs[0] * filter_coeffs[0];
c -= filter_coeffs[1] * filter_coeffs[0];
c -= filter_coeffs[0] * b;
old_out0 = out[-4];
old_out1 = out[-3];
old_out2 = out[-2];
old_out3 = out[-1];
for (n = 0; n <= buffer_length - 4; n+=4) {
float tmp0,tmp1,tmp2;
float val;
out0 = in[0];
out1 = in[1];
out2 = in[2];
out3 = in[3];
out0 -= filter_coeffs[2] * old_out1;
out1 -= filter_coeffs[2] * old_out2;
out2 -= filter_coeffs[2] * old_out3;
out0 -= filter_coeffs[1] * old_out2;
out1 -= filter_coeffs[1] * old_out3;
out0 -= filter_coeffs[0] * old_out3;
val = filter_coeffs[3];
out0 -= val * old_out0;
out1 -= val * old_out1;
out2 -= val * old_out2;
out3 -= val * old_out3;
old_out3 = out[-5];
for (i = 5; i <= filter_length; i += 2) {
val = filter_coeffs[i-1];
out0 -= val * old_out3;
out1 -= val * old_out0;
out2 -= val * old_out1;
out3 -= val * old_out2;
old_out2 = out[-i-1];
val = filter_coeffs[i];
out0 -= val * old_out2;
out1 -= val * old_out3;
out2 -= val * old_out0;
out3 -= val * old_out1;
FFSWAP(float, old_out0, old_out2);
old_out1 = old_out3;
old_out3 = out[-i-2];
}
tmp0 = out0;
tmp1 = out1;
tmp2 = out2;
out3 -= a * tmp2;
out2 -= a * tmp1;
out1 -= a * tmp0;
out3 -= b * tmp1;
out2 -= b * tmp0;
out3 -= c * tmp0;
out[0] = out0;
out[1] = out1;
out[2] = out2;
out[3] = out3;
old_out0 = out0;
old_out1 = out1;
old_out2 = out2;
old_out3 = out3;
out += 4;
in += 4;
}
out -= n;
in -= n;
for (; n < buffer_length; n++) {
out[n] = in[n];
for (i = 1; i <= filter_length; i++)
out[n] -= filter_coeffs[i-1] * out[n-i];
}
#endif
}
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;
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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