libavcodec/adx.h

   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 typedef struct ADXChannelState {
  35     int s1,s2;
  36 } ADXChannelState;
  37
  38 #define MAX_CHANNELS 6
  39
  40 typedef struct ADXContext {
  41     int channels;
  42     ADXChannelState prev[MAX_CHANNELS];
  43     int header_parsed;
  44     int eof;
  45     int cutoff;
  46     int coeff[2];
  47 } ADXContext;
  48
  49 #define COEFF_BITS  12
  50
  51 #define BLOCK_SIZE      18
  52 #define BLOCK_SAMPLES   32
  53
  54 /**
  55  * Calculate LPC coefficients based on cutoff frequency and sample rate.
  56  *
  57  * @param cutoff       cutoff frequency
  58  * @param sample_rate  sample rate
  59  * @param bits         number of bits used to quantize coefficients
  60  * @param[out] coeff   2 quantized LPC coefficients
  61  */
  62 void ff_adx_calculate_coeffs(int cutoff, int sample_rate, int bits, int *coeff);
  63
  64 #endif /* AVCODEC_ADX_H */