6222edb5fe2879c3022f5b56a5c8912c293fa7a2
[libav.git] / libavcodec / lsp.h
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 FFMPEG_LSP_H
24 #define FFMPEG_LSP_H
25 /**
26 (I.F) means fixed-point value with F fractional and I integer bits
27 */
28
29 /**
30 * \brief ensure a minimum distance between LSFs
31 * \param lsfq [in/out] LSF to check and adjust
32 * \param lsfq_min_distance minimum distance between LSFs
33 * \param lsfq_min minimum allowed LSF value
34 * \param lsfq_max maximum allowed LSF value
35 */
36 void ff_acelp_reorder_lsf(int16_t* lsfq, int lsfq_min_distance, int lsqf_min, int lsfq_max);
37
38 /**
39 * \brief Convert LSF to LSP
40 * \param lsp [out] LSP coefficients (-0x8000 <= (0.15) < 0x8000)
41 * \param lsf normalized LSF coefficients (0 <= (2.13) < 0x2000 * PI)
42 *
43 * \remark It is safe to pass the same array into the lsf and lsp parameters.
44 */
45 void ff_acelp_lsf2lsp(int16_t *lsp, const int16_t *lsf);
46
47 /**
48 * \brief LSP to LP conversion (3.2.6 of G.729)
49 * \param lp [out] decoded LP coefficients (-0x8000 <= (3.12) < 0x8000)
50 * \param lsp LSP coefficients (-0x8000 <= (0.15) < 0x8000)
51 */
52 void ff_acelp_lsp2lpc(int16_t* lp, const int16_t* lsp);
53
54 /**
55 * \brief Interpolate LSP for the first subframe and convert LSP -> LP for both subframes (3.2.5 and 3.2.6 of G.729)
56 * \param lp_1st [out] decoded LP coefficients for first subframe (-0x8000 <= (3.12) < 0x8000)
57 * \param lp_2nd [out] decoded LP coefficients for second subframe (-0x8000 <= (3.12) < 0x8000)
58 * \param lsp_2nd LSP coefficients of the second subframe (-0x8000 <= (0.15) < 0x8000)
59 * \param lsp_prev LSP coefficients from the second subframe of the previous frame (-0x8000 <= (0.15) < 0x8000)
60 */
61 void ff_acelp_lp_decode(int16_t* lp_1st, int16_t* lp_2nd, const int16_t* lsp_2nd, const int16_t* lsp_prev);
62
63 #endif /* FFMPEG_LSP_H */