/* * ADX ADPCM codecs * Copyright (c) 2001,2003 BERO * * This file is part of FFmpeg. * * FFmpeg 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. * * FFmpeg 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 FFmpeg; 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 ADXChannelState { int s1,s2; } ADXChannelState; typedef struct ADXContext { 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 avpriv_adx_decode_header(AVCodecContext *avctx, const uint8_t *buf, int bufsize, int *header_size, int *coeff); #endif /* AVCODEC_ADX_H */