1 /* 2 * ADX ADPCM codecs 3 * Copyright (c) 2001,2003 BERO 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22 /** 23 * @file 24 * SEGA CRI adx codecs. 25 * 26 * Reference documents: 27 * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html 28 * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/ 29 */ 30 31 #ifndef AVCODEC_ADX_H 32 #define AVCODEC_ADX_H 33 34 #include <stdint.h> 35 36 #include "avcodec.h" 37 38 typedef struct ADXChannelState { 39 int s1,s2; 40 } ADXChannelState; 41 42 typedef struct ADXContext { 43 int channels; 44 ADXChannelState prev[2]; 45 int header_parsed; 46 int eof; 47 int cutoff; 48 int coeff[2]; 49 } ADXContext; 50 51 #define COEFF_BITS 12 52 53 #define BLOCK_SIZE 18 54 #define BLOCK_SAMPLES 32 55 56 /** 57 * Calculate LPC coefficients based on cutoff frequency and sample rate. 58 * 59 * @param cutoff cutoff frequency 60 * @param sample_rate sample rate 61 * @param bits number of bits used to quantize coefficients 62 * @param[out] coeff 2 quantized LPC coefficients 63 */ 64 void ff_adx_calculate_coeffs(int cutoff, int sample_rate, int bits, int *coeff); 65 66 /** 67 * Decode ADX stream header. 68 * Sets avctx->channels and avctx->sample_rate. 69 * 70 * @param avctx codec context 71 * @param buf header data 72 * @param bufsize data size, should be at least 24 bytes 73 * @param[out] header_size size of ADX header 74 * @param[out] coeff 2 LPC coefficients, can be NULL 75 * @return data offset or negative error code if header is invalid 76 */ 77 int ff_adx_decode_header(AVCodecContext *avctx, const uint8_t *buf, 78 int bufsize, int *header_size, int *coeff); 79 80 #endif /* AVCODEC_ADX_H */ 81