81 lines
2.3 KiB
C
81 lines
2.3 KiB
C
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/*
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* ADX ADPCM codecs
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* Copyright (c) 2001,2003 BERO
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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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/**
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* @file
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* SEGA CRI adx codecs.
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*
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* Reference documents:
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* http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
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* adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
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*/
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#ifndef AVCODEC_ADX_H
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#define AVCODEC_ADX_H
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#include <stdint.h>
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#include "avcodec.h"
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typedef struct ADXChannelState {
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int s1,s2;
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} ADXChannelState;
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typedef struct ADXContext {
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int channels;
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ADXChannelState prev[2];
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int header_parsed;
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int eof;
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int cutoff;
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int coeff[2];
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} ADXContext;
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#define COEFF_BITS 12
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#define BLOCK_SIZE 18
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#define BLOCK_SAMPLES 32
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/**
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* Calculate LPC coefficients based on cutoff frequency and sample rate.
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*
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* @param cutoff cutoff frequency
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* @param sample_rate sample rate
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* @param bits number of bits used to quantize coefficients
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* @param[out] coeff 2 quantized LPC coefficients
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*/
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void ff_adx_calculate_coeffs(int cutoff, int sample_rate, int bits, int *coeff);
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/**
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* Decode ADX stream header.
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* Sets avctx->channels and avctx->sample_rate.
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*
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* @param avctx codec context
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* @param buf header data
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* @param bufsize data size, should be at least 24 bytes
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* @param[out] header_size size of ADX header
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* @param[out] coeff 2 LPC coefficients, can be NULL
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* @return data offset or negative error code if header is invalid
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*/
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int ff_adx_decode_header(AVCodecContext *avctx, const uint8_t *buf,
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int bufsize, int *header_size, int *coeff);
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#endif /* AVCODEC_ADX_H */
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