| /* | |
| * various filters for CELP-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 | |
| */ | |
| typedef struct CELPFContext { | |
| /** | |
| * LP synthesis filter. | |
| * @param[out] out pointer to output buffer | |
| * - the array out[-filter_length, -1] must | |
| * contain the previous result of this filter | |
| * @param filter_coeffs filter coefficients. | |
| * @param in input signal | |
| * @param buffer_length amount of data to process | |
| * @param filter_length filter length (10 for 10th order LP filter). Must be | |
| * greater than 4 and even. | |
| * | |
| * @note Output buffer must contain filter_length samples of past | |
| * speech data before pointer. | |
| * | |
| * Routine applies 1/A(z) filter to given speech data. | |
| */ | |
| void (*celp_lp_synthesis_filterf)(float *out, const float *filter_coeffs, | |
| const float *in, int buffer_length, | |
| int filter_length); | |
| /** | |
| * LP zero synthesis filter. | |
| * @param[out] out pointer to output buffer | |
| * @param filter_coeffs filter coefficients. | |
| * @param in input signal | |
| * - the array in[-filter_length, -1] must | |
| * contain the previous input of this filter | |
| * @param buffer_length amount of data to process (should be a multiple of eight) | |
| * @param filter_length filter length (10 for 10th order LP filter; | |
| * should be a multiple of two) | |
| * | |
| * @note Output buffer must contain filter_length samples of past | |
| * speech data before pointer. | |
| * | |
| * Routine applies A(z) filter to given speech data. | |
| */ | |
| void (*celp_lp_zero_synthesis_filterf)(float *out, const float *filter_coeffs, | |
| const float *in, int buffer_length, | |
| int filter_length); | |
| }CELPFContext; | |
| /** | |
| * Initialize CELPFContext. | |
| */ | |
| void ff_celp_filter_init(CELPFContext *c); | |
| void ff_celp_filter_init_mips(CELPFContext *c); | |
| /** | |
| * Circularly convolve fixed vector with a phase dispersion impulse | |
| * response filter (D.6.2 of G.729 and 6.1.5 of AMR). | |
| * @param fc_out vector with filter applied | |
| * @param fc_in source vector | |
| * @param filter phase filter coefficients | |
| * | |
| * fc_out[n] = sum(i,0,len-1){ fc_in[i] * filter[(len + n - i)%len] } | |
| * | |
| * @note fc_in and fc_out should not overlap! | |
| */ | |
| void ff_celp_convolve_circ(int16_t *fc_out, const int16_t *fc_in, | |
| const int16_t *filter, int len); | |
| /** | |
| * Add an array to a rotated array. | |
| * | |
| * out[k] = in[k] + fac * lagged[k-lag] with wrap-around | |
| * | |
| * @param out result vector | |
| * @param in samples to be added unfiltered | |
| * @param lagged samples to be rotated, multiplied and added | |
| * @param lag lagged vector delay in the range [0, n] | |
| * @param fac scalefactor for lagged samples | |
| * @param n number of samples | |
| */ | |
| void ff_celp_circ_addf(float *out, const float *in, | |
| const float *lagged, int lag, float fac, int n); | |
| /** | |
| * LP synthesis filter. | |
| * @param[out] out pointer to output buffer | |
| * @param filter_coeffs filter coefficients (-0x8000 <= (3.12) < 0x8000) | |
| * @param in input signal | |
| * @param buffer_length amount of data to process | |
| * @param filter_length filter length (10 for 10th order LP filter) | |
| * @param stop_on_overflow 1 - return immediately if overflow occurs | |
| * 0 - ignore overflows | |
| * @param shift the result is shifted right by this value | |
| * @param rounder the amount to add for rounding (usually 0x800 or 0xfff) | |
| * | |
| * @return 1 if overflow occurred, 0 - otherwise | |
| * | |
| * @note Output buffer must contain filter_length samples of past | |
| * speech data before pointer. | |
| * | |
| * Routine applies 1/A(z) filter to given speech data. | |
| */ | |
| 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); | |
| /** | |
| * LP synthesis filter. | |
| * @param[out] out pointer to output buffer | |
| * - the array out[-filter_length, -1] must | |
| * contain the previous result of this filter | |
| * @param filter_coeffs filter coefficients. | |
| * @param in input signal | |
| * @param buffer_length amount of data to process | |
| * @param filter_length filter length (10 for 10th order LP filter). Must be | |
| * greater than 4 and even. | |
| * | |
| * @note Output buffer must contain filter_length samples of past | |
| * speech data before pointer. | |
| * | |
| * Routine applies 1/A(z) filter to given speech data. | |
| */ | |
| void ff_celp_lp_synthesis_filterf(float *out, const float *filter_coeffs, | |
| const float *in, int buffer_length, | |
| int filter_length); | |
| /** | |
| * LP zero synthesis filter. | |
| * @param[out] out pointer to output buffer | |
| * @param filter_coeffs filter coefficients. | |
| * @param in input signal | |
| * - the array in[-filter_length, -1] must | |
| * contain the previous input of this filter | |
| * @param buffer_length amount of data to process | |
| * @param filter_length filter length (10 for 10th order LP filter) | |
| * | |
| * @note Output buffer must contain filter_length samples of past | |
| * speech data before pointer. | |
| * | |
| * Routine applies A(z) filter to given speech data. | |
| */ | |
| void ff_celp_lp_zero_synthesis_filterf(float *out, const float *filter_coeffs, | |
| const float *in, int buffer_length, | |
| int filter_length); | |