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/*
* ADX ADPCM codecs
* Copyright (c) 2001,2003 BERO
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* SEGA CRI adx codecs.
*
* Reference documents:
* http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
* adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
*/
#ifndef AVCODEC_ADX_H
#define AVCODEC_ADX_H
#include <stdint.h>
#include "avcodec.h"
typedef struct {
int s1,s2;
} ADXChannelState;
typedef struct {
int channels;
ADXChannelState prev[2];
int header_parsed;
int eof;
int cutoff;
int coeff[2];
} ADXContext;
#define COEFF_BITS 12
#define BLOCK_SIZE 18
#define BLOCK_SAMPLES 32
/**
* Calculate LPC coefficients based on cutoff frequency and sample rate.
*
* @param cutoff cutoff frequency
* @param sample_rate sample rate
* @param bits number of bits used to quantize coefficients
* @param[out] coeff 2 quantized LPC coefficients
*/
void ff_adx_calculate_coeffs(int cutoff, int sample_rate, int bits, int *coeff);
/**
* Decode ADX stream header.
* Sets avctx->channels and avctx->sample_rate.
*
* @param avctx codec context
* @param buf header data
* @param bufsize data size, should be at least 24 bytes
* @param[out] header_size size of ADX header
* @param[out] coeff 2 LPC coefficients, can be NULL
* @return data offset or negative error code if header is invalid
*/
int ff_adx_decode_header(AVCodecContext *avctx, const uint8_t *buf, int bufsize,
int *header_size, int *coeff);
#endif /* AVCODEC_ADX_H */
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