1/* 2 * LSP computing for ACELP-based codecs 3 * 4 * Copyright (c) 2008 Vladimir Voroshilov 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23#ifndef AVCODEC_LSP_H 24#define AVCODEC_LSP_H 25 26#include <stdint.h> 27 28/** 29 (I.F) means fixed-point value with F fractional and I integer bits 30*/ 31 32/** 33 * \brief ensure a minimum distance between LSFs 34 * \param lsfq [in/out] LSF to check and adjust 35 * \param lsfq_min_distance minimum distance between LSFs 36 * \param lsfq_min minimum allowed LSF value 37 * \param lsfq_max maximum allowed LSF value 38 * \param lp_order LP filter order 39 */ 40void ff_acelp_reorder_lsf(int16_t* lsfq, int lsfq_min_distance, int lsfq_min, int lsfq_max, int lp_order); 41 42/** 43 * \brief Convert LSF to LSP 44 * \param lsp [out] LSP coefficients (-0x8000 <= (0.15) < 0x8000) 45 * \param lsf normalized LSF coefficients (0 <= (2.13) < 0x2000 * PI) 46 * \param lp_order LP filter order 47 * 48 * \remark It is safe to pass the same array into the lsf and lsp parameters. 49 */ 50void ff_acelp_lsf2lsp(int16_t *lsp, const int16_t *lsf, int lp_order); 51 52/** 53 * \brief LSP to LP conversion (3.2.6 of G.729) 54 * \param lp [out] decoded LP coefficients (-0x8000 <= (3.12) < 0x8000) 55 * \param lsp LSP coefficients (-0x8000 <= (0.15) < 0x8000) 56 * \param lp_half_order LP filter order, divided by 2 57 */ 58void ff_acelp_lsp2lpc(int16_t* lp, const int16_t* lsp, int lp_half_order); 59 60/** 61 * \brief Interpolate LSP for the first subframe and convert LSP -> LP for both subframes (3.2.5 and 3.2.6 of G.729) 62 * \param lp_1st [out] decoded LP coefficients for first subframe (-0x8000 <= (3.12) < 0x8000) 63 * \param lp_2nd [out] decoded LP coefficients for second subframe (-0x8000 <= (3.12) < 0x8000) 64 * \param lsp_2nd LSP coefficients of the second subframe (-0x8000 <= (0.15) < 0x8000) 65 * \param lsp_prev LSP coefficients from the second subframe of the previous frame (-0x8000 <= (0.15) < 0x8000) 66 * \param lp_order LP filter order 67 */ 68void ff_acelp_lp_decode(int16_t* lp_1st, int16_t* lp_2nd, const int16_t* lsp_2nd, const int16_t* lsp_prev, int lp_order); 69 70#endif /* AVCODEC_LSP_H */ 71