libavcodec/adxdec.c

   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 #include "avcodec.h"
  22 #include "adx.h"
  23
  24 /**
  25  * @file adx.c
  26  * SEGA CRI adx codecs.
  27  *
  28  * Reference documents:
  29  * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
  30  * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
  31  */
  32
  33 /* 18 bytes <-> 32 samples */
  34
  35 static void adx_decode(short *out,const unsigned char *in,PREV *prev)
  36 {
  37     int scale = AV_RB16(in);
  38     int i;
  39     int s0,s1,s2,d;
  40
  41 //    printf("%x ",scale);
  42
  43     in+=2;
  44     s1 = prev->s1;
  45     s2 = prev->s2;
  46     for(i=0;i<16;i++) {
  47         d = in[i];
  48         // d>>=4; if (d&8) d-=16;
  49         d = ((signed char)d >> 4);
  50         s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
  51         s2 = s1;
  52         s1 = av_clip_int16(s0);
  53         *out++=s1;
  54
  55         d = in[i];
  56         //d&=15; if (d&8) d-=16;
  57         d = ((signed char)(d<<4) >> 4);
  58         s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
  59         s2 = s1;
  60         s1 = av_clip_int16(s0);
  61         *out++=s1;
  62     }
  63     prev->s1 = s1;
  64     prev->s2 = s2;
  65
  66 }
  67
  68 static void adx_decode_stereo(short *out,const unsigned char *in,PREV *prev)
  69 {
  70     short tmp[32*2];
  71     int i;
  72
  73     adx_decode(tmp   ,in   ,prev);
  74     adx_decode(tmp+32,in+18,prev+1);
  75     for(i=0;i<32;i++) {
  76         out[i*2]   = tmp[i];
  77         out[i*2+1] = tmp[i+32];
  78     }
  79 }
  80
  81 /* return data offset or 0 */
  82 static int adx_decode_header(AVCodecContext *avctx,const unsigned char *buf,size_t bufsize)
  83 {
  84     int offset;
  85
  86     if (buf[0]!=0x80) return 0;
  87     offset = (AV_RB32(buf)^0x80000000)+4;
  88     if (bufsize<offset || memcmp(buf+offset-6,"(c)CRI",6)) return 0;
  89
  90     avctx->channels    = buf[7];
  91     avctx->sample_rate = AV_RB32(buf+8);
  92     avctx->bit_rate    = avctx->sample_rate*avctx->channels*18*8/32;
  93
  94     return offset;
  95 }
  96
  97 static int adx_decode_frame(AVCodecContext *avctx,
  98                 void *data, int *data_size,
  99                 const uint8_t *buf0, int buf_size)
 100 {
 101     ADXContext *c = avctx->priv_data;
 102     short *samples = data;
 103     const uint8_t *buf = buf0;
 104     int rest = buf_size;
 105
 106     if (!c->header_parsed) {
 107         int hdrsize = adx_decode_header(avctx,buf,rest);
 108         if (hdrsize==0) return -1;
 109         c->header_parsed = 1;
 110         buf  += hdrsize;
 111         rest -= hdrsize;
 112     }
 113
 114     /* 18 bytes of data are expanded into 32*2 bytes of audio,
 115        so guard against buffer overflows */
 116     if(rest/18 > *data_size/64)
 117         rest = (*data_size/64) * 18;
 118
 119     if (c->in_temp) {
 120         int copysize = 18*avctx->channels - c->in_temp;
 121         memcpy(c->dec_temp+c->in_temp,buf,copysize);
 122         rest -= copysize;
 123         buf  += copysize;
 124         if (avctx->channels==1) {
 125             adx_decode(samples,c->dec_temp,c->prev);
 126             samples += 32;
 127         } else {
 128             adx_decode_stereo(samples,c->dec_temp,c->prev);
 129             samples += 32*2;
 130         }
 131     }
 132     //
 133     if (avctx->channels==1) {
 134         while(rest>=18) {
 135             adx_decode(samples,buf,c->prev);
 136             rest-=18;
 137             buf+=18;
 138             samples+=32;
 139         }
 140     } else {
 141         while(rest>=18*2) {
 142             adx_decode_stereo(samples,buf,c->prev);
 143             rest-=18*2;
 144             buf+=18*2;
 145             samples+=32*2;
 146         }
 147     }
 148     //
 149     c->in_temp = rest;
 150     if (rest) {
 151         memcpy(c->dec_temp,buf,rest);
 152         buf+=rest;
 153     }
 154     *data_size = (uint8_t*)samples - (uint8_t*)data;
 155 //    printf("%d:%d ",buf-buf0,*data_size); fflush(stdout);
 156     return buf-buf0;
 157 }
 158
 159 AVCodec adpcm_adx_decoder = {
 160     "adpcm_adx",
 161     CODEC_TYPE_AUDIO,
 162     CODEC_ID_ADPCM_ADX,
 163     sizeof(ADXContext),
 164     NULL,
 165     NULL,
 166     NULL,
 167     adx_decode_frame,
 168     .long_name = "SEGA CRI ADX",
 169 };
 170