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/*
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* LSP computing for ACELP-based codecs
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*
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* Copyright (c) 2008 Vladimir Voroshilov
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef FFMPEG_ACELP_LPC_H
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#define FFMPEG_ACELP_LPC_H
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/**
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(I.F) means fixed-point value with F fractional and I integer bits
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*/
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/**
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* \brief ensure a minimum distance between LSFs
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* \param lsfq [in/out] LSF to check and adjust
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* \param lsfq_min_distance minimum distance between LSFs
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* \param lsfq_min minimum allowed LSF value
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* \param lsfq_max maximum allowed LSF value
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*/
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void ff_acelp_reorder_lsf(int16_t* lsfq, int lsfq_min_distance, int lsqf_min, int lsfq_max);
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/**
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* \brief Convert LSF to LSP
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* \param lsp [out] LSP coefficients (-0x8000 <= (0.15) < 0x8000)
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* \param lsf normalized LSF coefficients (0 <= (2.13) < 0x2000 * PI)
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*
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* \remark It is safe to pass the same array into the lsf and lsp parameters.
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*/
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void ff_acelp_lsf2lsp(int16_t *lsp, const int16_t *lsf);
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/**
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* \brief LSP to LP conversion (3.2.6 of G.729)
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* \param lp [out] decoded LP coefficients (-0x8000 <= (3.12) < 0x8000)
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* \param lsp LSP coefficients (-0x8000 <= (0.15) < 0x8000)
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*/
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void ff_acelp_lsp2lpc(int16_t* lp, const int16_t* lsp);
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/**
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* \brief Interpolate LSP for the first subframe and convert LSP -> LP for both subframes (3.2.5 and 3.2.6 of G.729)
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* \param lp_1st [out] decoded LP coefficients for first subframe (-0x8000 <= (3.12) < 0x8000)
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* \param lp_2nd [out] decoded LP coefficients for second subframe (-0x8000 <= (3.12) < 0x8000)
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* \param lsp_2nd LSP coefficients of the second subframe (-0x8000 <= (0.15) < 0x8000)
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* \param lsp_prev LSP coefficients from the second subframe of the previous frame (-0x8000 <= (0.15) < 0x8000)
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*/
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void ff_acelp_lp_decode(int16_t* lp_1st, int16_t* lp_2nd, const int16_t* lsp_2nd, const int16_t* lsp_prev);
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#endif // FFMPEG_ACELP_LPC_H
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