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https://github.com/signalwire/freeswitch.git
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55 lines
1.7 KiB
C
55 lines
1.7 KiB
C
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/*
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** Copyright (c) 2007 <robs@users.sourceforge.net>
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** Copyright (C) 2007-2009 Erik de Castro Lopo <erikd@mega-nerd.com>
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**
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** This library is free software; you can redistribute it and/or modify it
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** under the terms of the GNU Lesser General Public License as published by
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** the Free Software Foundation; either version 2 of the License, or (at
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** your option) any later version.
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**
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** This library is distributed in the hope that it will be useful, but
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** WITHOUT ANY WARRANTY; without even the implied warranty of
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
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** 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 License
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** along with this library. If not, write to the Free Software Foundation,
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** Fifth Floor, 51 Franklin Street, Boston, MA 02111-1301, USA.
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*/
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/* ADPCM: IMA, OKI <==> 16-bit PCM. */
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#define IMA_OKI_ADPCM_CODE_LEN 256
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#define IMA_OKI_ADPCM_PCM_LEN (IMA_OKI_ADPCM_CODE_LEN *2)
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typedef struct
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{
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/* private: */
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int mask ;
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int last_output ;
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int step_index ;
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int max_step_index ;
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int const * steps ;
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/* public: */
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int errors ;
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int code_count, pcm_count ;
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unsigned char codes [IMA_OKI_ADPCM_CODE_LEN] ;
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short pcm [IMA_OKI_ADPCM_PCM_LEN] ;
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} IMA_OKI_ADPCM ;
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typedef enum
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{ IMA_OKI_ADPCM_TYPE_IMA,
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IMA_OKI_ADPCM_TYPE_OKI
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} IMA_OKI_ADPCM_TYPE ;
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void ima_oki_adpcm_init (IMA_OKI_ADPCM * state, IMA_OKI_ADPCM_TYPE type) ;
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int adpcm_decode (IMA_OKI_ADPCM * state, int /* 0..15 */ code) ;
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int adpcm_encode (IMA_OKI_ADPCM * state, int /* -32768..32767 */ sample) ;
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void ima_oki_adpcm_decode_block (IMA_OKI_ADPCM * state) ;
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void ima_oki_adpcm_encode_block (IMA_OKI_ADPCM * state) ;
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