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
  22 #include "libavutil/intreadwrite.h"
  23 #include "avcodec.h"
  24 #include "adx.h"
  25
  26 /**
  27  * @file libavcodec/adxdec.c
  28  * SEGA CRI adx codecs.
  29  *
  30  * Reference documents:
  31  * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
  32  * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
  33  */
  34
  35 static av_cold int adx_decode_init(AVCodecContext *avctx)
  36 {
  37     avctx->sample_fmt = SAMPLE_FMT_S16;
  38     return 0;
  39 }
  40
  41 /* 18 bytes <-> 32 samples */
  42
  43 static void adx_decode(short *out,const unsigned char *in,PREV *prev)
  44 {
  45     int scale = AV_RB16(in);
  46     int i;
  47     int s0,s1,s2,d;
  48
  49 //    printf("%x ",scale);
  50
  51     in+=2;
  52     s1 = prev->s1;
  53     s2 = prev->s2;
  54     for(i=0;i<16;i++) {
  55         d = in[i];
  56         // d>>=4; if (d&8) d-=16;
  57         d = ((signed char)d >> 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         d = in[i];
  64         //d&=15; if (d&8) d-=16;
  65         d = ((signed char)(d<<4) >> 4);
  66         s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
  67         s2 = s1;
  68         s1 = av_clip_int16(s0);
  69         *out++=s1;
  70     }
  71     prev->s1 = s1;
  72     prev->s2 = s2;
  73
  74 }
  75
  76 static void adx_decode_stereo(short *out,const unsigned char *in,PREV *prev)
  77 {
  78     short tmp[32*2];
  79     int i;
  80
  81     adx_decode(tmp   ,in   ,prev);
  82     adx_decode(tmp+32,in+18,prev+1);
  83     for(i=0;i<32;i++) {
  84         out[i*2]   = tmp[i];
  85         out[i*2+1] = tmp[i+32];
  86     }
  87 }
  88
  89 /* return data offset or 0 */
  90 static int adx_decode_header(AVCodecContext *avctx,const unsigned char *buf,size_t bufsize)
  91 {
  92     int offset;
  93
  94     if (buf[0]!=0x80) return 0;
  95     offset = (AV_RB32(buf)^0x80000000)+4;
  96     if (bufsize<offset || memcmp(buf+offset-6,"(c)CRI",6)) return 0;
  97
  98     avctx->channels    = buf[7];
  99     avctx->sample_rate = AV_RB32(buf+8);
 100     avctx->bit_rate    = avctx->sample_rate*avctx->channels*18*8/32;
 101
 102     return offset;
 103 }
 104
 105 static int adx_decode_frame(AVCodecContext *avctx,
 106                 void *data, int *data_size,
 107                 AVPacket *avpkt)
 108 {
 109     const uint8_t *buf0 = avpkt->data;
 110     int buf_size = avpkt->size;
 111     ADXContext *c = avctx->priv_data;
 112     short *samples = data;
 113     const uint8_t *buf = buf0;
 114     int rest = buf_size;
 115
 116     if (!c->header_parsed) {
 117         int hdrsize = adx_decode_header(avctx,buf,rest);
 118         if (hdrsize==0) return -1;
 119         c->header_parsed = 1;
 120         buf  += hdrsize;
 121         rest -= hdrsize;
 122     }
 123
 124     /* 18 bytes of data are expanded into 32*2 bytes of audio,
 125        so guard against buffer overflows */
 126     if(rest/18 > *data_size/64)
 127         rest = (*data_size/64) * 18;
 128
 129     if (c->in_temp) {
 130         int copysize = 18*avctx->channels - c->in_temp;
 131         memcpy(c->dec_temp+c->in_temp,buf,copysize);
 132         rest -= copysize;
 133         buf  += copysize;
 134         if (avctx->channels==1) {
 135             adx_decode(samples,c->dec_temp,c->prev);
 136             samples += 32;
 137         } else {
 138             adx_decode_stereo(samples,c->dec_temp,c->prev);
 139             samples += 32*2;
 140         }
 141     }
 142     //
 143     if (avctx->channels==1) {
 144         while(rest>=18) {
 145             adx_decode(samples,buf,c->prev);
 146             rest-=18;
 147             buf+=18;
 148             samples+=32;
 149         }
 150     } else {
 151         while(rest>=18*2) {
 152             adx_decode_stereo(samples,buf,c->prev);
 153             rest-=18*2;
 154             buf+=18*2;
 155             samples+=32*2;
 156         }
 157     }
 158     //
 159     c->in_temp = rest;
 160     if (rest) {
 161         memcpy(c->dec_temp,buf,rest);
 162         buf+=rest;
 163     }
 164     *data_size = (uint8_t*)samples - (uint8_t*)data;
 165 //    printf("%d:%d ",buf-buf0,*data_size); fflush(stdout);
 166     return buf-buf0;
 167 }
 168
 169 AVCodec adpcm_adx_decoder = {
 170     "adpcm_adx",
 171     CODEC_TYPE_AUDIO,
 172     CODEC_ID_ADPCM_ADX,
 173     sizeof(ADXContext),
 174     adx_decode_init,
 175     NULL,
 176     NULL,
 177     adx_decode_frame,
 178     .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
 179 };
 180