mirror of https://github.com/FFmpeg/FFmpeg.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
80 lines
3.0 KiB
80 lines
3.0 KiB
/* |
|
* LSP computing 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 |
|
*/ |
|
|
|
#ifndef AVCODEC_LSP_H |
|
#define AVCODEC_LSP_H |
|
|
|
#include <stdint.h> |
|
|
|
/** |
|
(I.F) means fixed-point value with F fractional and I integer bits |
|
*/ |
|
|
|
/** |
|
* \brief ensure a minimum distance between LSFs |
|
* \param lsfq [in/out] LSF to check and adjust |
|
* \param lsfq_min_distance minimum distance between LSFs |
|
* \param lsfq_min minimum allowed LSF value |
|
* \param lsfq_max maximum allowed LSF value |
|
* \param lp_order LP filter order |
|
*/ |
|
void ff_acelp_reorder_lsf(int16_t* lsfq, int lsfq_min_distance, int lsfq_min, int lsfq_max, int lp_order); |
|
|
|
/** |
|
* \brief Convert LSF to LSP |
|
* \param lsp [out] LSP coefficients (-0x8000 <= (0.15) < 0x8000) |
|
* \param lsf normalized LSF coefficients (0 <= (2.13) < 0x2000 * PI) |
|
* \param lp_order LP filter order |
|
* |
|
* \remark It is safe to pass the same array into the lsf and lsp parameters. |
|
*/ |
|
void ff_acelp_lsf2lsp(int16_t *lsp, const int16_t *lsf, int lp_order); |
|
|
|
/** |
|
* \brief LSP to LP conversion (3.2.6 of G.729) |
|
* \param lp [out] decoded LP coefficients (-0x8000 <= (3.12) < 0x8000) |
|
* \param lsp LSP coefficients (-0x8000 <= (0.15) < 0x8000) |
|
* \param lp_half_order LP filter order, divided by 2 |
|
*/ |
|
void ff_acelp_lsp2lpc(int16_t* lp, const int16_t* lsp, int lp_half_order); |
|
|
|
/** |
|
* \brief Interpolate LSP for the first subframe and convert LSP -> LP for both subframes (3.2.5 and 3.2.6 of G.729) |
|
* \param lp_1st [out] decoded LP coefficients for first subframe (-0x8000 <= (3.12) < 0x8000) |
|
* \param lp_2nd [out] decoded LP coefficients for second subframe (-0x8000 <= (3.12) < 0x8000) |
|
* \param lsp_2nd LSP coefficients of the second subframe (-0x8000 <= (0.15) < 0x8000) |
|
* \param lsp_prev LSP coefficients from the second subframe of the previous frame (-0x8000 <= (0.15) < 0x8000) |
|
* \param lp_order LP filter order |
|
*/ |
|
void 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); |
|
|
|
/** |
|
* Reconstructs LPC coefficients from the line spectral pair frequencies. |
|
* |
|
* @param lsp line spectral pairs in cosine domain |
|
* @param lpc linear predictive coding coefficients |
|
* |
|
* TIA/EIA/IS-733 2.4.3.3.5 |
|
*/ |
|
void ff_acelp_lspd2lpc(const double *lsp, float *lpc); |
|
|
|
#endif /* AVCODEC_LSP_H */
|
|
|