/* * 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 shift, 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]) >> shift; 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]; } }