Alexandre Lision | 7c6f4a6 | 2013-09-05 13:27:01 -0400 | [diff] [blame] | 1 | /* |
| 2 | ** Copyright (C) 2007-2011 Erik de Castro Lopo <erikd@mega-nerd.com> |
| 3 | ** Copyright (c) 2007 <robs@users.sourceforge.net> |
| 4 | ** |
| 5 | ** This library is free software; you can redistribute it and/or modify it |
| 6 | ** under the terms of the GNU Lesser General Public License as published by |
| 7 | ** the Free Software Foundation; either version 2 of the License, or (at |
| 8 | ** your option) any later version. |
| 9 | ** |
| 10 | ** This library is distributed in the hope that it will be useful, but |
| 11 | ** WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser |
| 13 | ** General Public License for more details. |
| 14 | ** |
| 15 | ** You should have received a copy of the GNU Lesser General Public License |
| 16 | ** along with this library. If not, write to the Free Software Foundation, |
| 17 | ** Fifth Floor, 51 Franklin Street, Boston, MA 02111-1301, USA. |
| 18 | */ |
| 19 | |
| 20 | /* ADPCM: IMA, OKI <==> 16-bit PCM. */ |
| 21 | |
| 22 | |
| 23 | #define IMA_OKI_ADPCM_CODE_LEN 256 |
| 24 | #define IMA_OKI_ADPCM_PCM_LEN (IMA_OKI_ADPCM_CODE_LEN *2) |
| 25 | |
| 26 | typedef struct |
| 27 | { |
| 28 | /* private: */ |
| 29 | int mask ; |
| 30 | int last_output ; |
| 31 | int step_index ; |
| 32 | int max_step_index ; |
| 33 | int const * steps ; |
| 34 | |
| 35 | /* public: */ |
| 36 | int errors ; |
| 37 | int code_count, pcm_count ; |
| 38 | |
| 39 | unsigned char codes [IMA_OKI_ADPCM_CODE_LEN] ; |
| 40 | short pcm [IMA_OKI_ADPCM_PCM_LEN] ; |
| 41 | } IMA_OKI_ADPCM ; |
| 42 | |
| 43 | typedef enum |
| 44 | { IMA_OKI_ADPCM_TYPE_IMA, |
| 45 | IMA_OKI_ADPCM_TYPE_OKI |
| 46 | } IMA_OKI_ADPCM_TYPE ; |
| 47 | |
| 48 | void ima_oki_adpcm_init (IMA_OKI_ADPCM * state, IMA_OKI_ADPCM_TYPE type) ; |
| 49 | |
| 50 | int adpcm_decode (IMA_OKI_ADPCM * state, int /* 0..15 */ code) ; |
| 51 | int adpcm_encode (IMA_OKI_ADPCM * state, int /* -32768..32767 */ sample) ; |
| 52 | |
| 53 | void ima_oki_adpcm_decode_block (IMA_OKI_ADPCM * state) ; |
| 54 | void ima_oki_adpcm_encode_block (IMA_OKI_ADPCM * state) ; |