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 static av_cold int adx_decode_init(AVCodecContext *avctx)
  34 {
  35     avctx->sample_fmt = SAMPLE_FMT_S16;
  36     return 0;
  37 }
  38
  39 /* 18 bytes <-> 32 samples */
  40
  41 static void adx_decode(short *out,const unsigned char *in,PREV *prev)
  42 {
  43     int scale = AV_RB16(in);
  44     int i;
  45     int s0,s1,s2,d;
  46
  47 //    printf("%x ",scale);
  48
  49     in+=2;
  50     s1 = prev->s1;
  51     s2 = prev->s2;
  52     for(i=0;i<16;i++) {
  53         d = in[i];
  54         // d>>=4; if (d&8) d-=16;
  55         d = ((signed char)d >> 4);
  56         s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
  57         s2 = s1;
  58         s1 = av_clip_int16(s0);
  59         *out++=s1;
  60
  61         d = in[i];
  62         //d&=15; if (d&8) d-=16;
  63         d = ((signed char)(d<<4) >> 4);
  64         s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
  65         s2 = s1;
  66         s1 = av_clip_int16(s0);
  67         *out++=s1;
  68     }
  69     prev->s1 = s1;
  70     prev->s2 = s2;
  71
  72 }
  73
  74 static void adx_decode_stereo(short *out,const unsigned char *in,PREV *prev)
  75 {
  76     short tmp[32*2];
  77     int i;
  78
  79     adx_decode(tmp   ,in   ,prev);
  80     adx_decode(tmp+32,in+18,prev+1);
  81     for(i=0;i<32;i++) {
  82         out[i*2]   = tmp[i];
  83         out[i*2+1] = tmp[i+32];
  84     }
  85 }
  86
  87 /* return data offset or 0 */
  88 static int adx_decode_header(AVCodecContext *avctx,const unsigned char *buf,size_t bufsize)
  89 {
  90     int offset;
  91
  92     if (buf[0]!=0x80) return 0;
  93     offset = (AV_RB32(buf)^0x80000000)+4;
  94     if (bufsize<offset || memcmp(buf+offset-6,"(c)CRI",6)) return 0;
  95
  96     avctx->channels    = buf[7];
  97     avctx->sample_rate = AV_RB32(buf+8);
  98     avctx->bit_rate    = avctx->sample_rate*avctx->channels*18*8/32;
  99
 100     return offset;
 101 }
 102
 103 static int adx_decode_frame(AVCodecContext *avctx,
 104                 void *data, int *data_size,
 105                 const uint8_t *buf0, int buf_size)
 106 {
 107     ADXContext *c = avctx->priv_data;
 108     short *samples = data;
 109     const uint8_t *buf = buf0;
 110     int rest = buf_size;
 111
 112     if (!c->header_parsed) {
 113         int hdrsize = adx_decode_header(avctx,buf,rest);
 114         if (hdrsize==0) return -1;
 115         c->header_parsed = 1;
 116         buf  += hdrsize;
 117         rest -= hdrsize;
 118     }
 119
 120     /* 18 bytes of data are expanded into 32*2 bytes of audio,
 121        so guard against buffer overflows */
 122     if(rest/18 > *data_size/64)
 123         rest = (*data_size/64) * 18;
 124
 125     if (c->in_temp) {
 126         int copysize = 18*avctx->channels - c->in_temp;
 127         memcpy(c->dec_temp+c->in_temp,buf,copysize);
 128         rest -= copysize;
 129         buf  += copysize;
 130         if (avctx->channels==1) {
 131             adx_decode(samples,c->dec_temp,c->prev);
 132             samples += 32;
 133         } else {
 134             adx_decode_stereo(samples,c->dec_temp,c->prev);
 135             samples += 32*2;
 136         }
 137     }
 138     //
 139     if (avctx->channels==1) {
 140         while(rest>=18) {
 141             adx_decode(samples,buf,c->prev);
 142             rest-=18;
 143             buf+=18;
 144             samples+=32;
 145         }
 146     } else {
 147         while(rest>=18*2) {
 148             adx_decode_stereo(samples,buf,c->prev);
 149             rest-=18*2;
 150             buf+=18*2;
 151             samples+=32*2;
 152         }
 153     }
 154     //
 155     c->in_temp = rest;
 156     if (rest) {
 157         memcpy(c->dec_temp,buf,rest);
 158         buf+=rest;
 159     }
 160     *data_size = (uint8_t*)samples - (uint8_t*)data;
 161 //    printf("%d:%d ",buf-buf0,*data_size); fflush(stdout);
 162     return buf-buf0;
 163 }
 164
 165 AVCodec adpcm_adx_decoder = {
 166     "adpcm_adx",
 167     CODEC_TYPE_AUDIO,
 168     CODEC_ID_ADPCM_ADX,
 169     sizeof(ADXContext),
 170     adx_decode_init,
 171     NULL,
 172     NULL,
 173     adx_decode_frame,
 174     .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX"),
 175 };
 176