libavcodec/ra288.c

   1 /*
   2  * RealAudio 2.0 (28.8K)
   3  * Copyright (c) 2003 the ffmpeg project
   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 "avcodec.h"
  23 #include "ra288.h"
  24
  25 typedef struct {
  26         float   history[8];
  27         float   output[40];
  28         float   pr1[36];
  29         float   pr2[10];
  30         int     phase, phasep;
  31
  32         float   st1a[111],st1b[37],st1[37];
  33         float   st2a[38],st2b[11],st2[11];
  34         float   sb[41];
  35         float   lhist[10];
  36 } Real288_internal;
  37
  38 static int ra288_decode_init(AVCodecContext * avctx)
  39 {
  40         Real288_internal *glob=avctx->priv_data;
  41         memset(glob,0,sizeof(Real288_internal));
  42         return 0;
  43 }
  44
  45 static void prodsum(float *tgt, float *src, int len, int n);
  46 static void co(int n, int i, int j, float *in, float *out, float *st1, float *st2, const float *table);
  47 static int pred(float *in, float *tgt, int n);
  48 static void colmult(float *tgt, float *m1, const float *m2, int n);
  49
  50
  51 /* initial decode */
  52 static void unpack(unsigned short *tgt, const unsigned char *src, unsigned int len)
  53 {
  54   int x,y,z;
  55   int n,temp;
  56   int buffer[len];
  57
  58   for (x=0;x<len;tgt[x++]=0)
  59     buffer[x]=9+(x&1);
  60
  61   for (x=y=z=0;x<len/*was 38*/;x++) {
  62     n=buffer[y]-z;
  63     temp=src[x];
  64     if (n<8) temp&=255>>(8-n);
  65     tgt[y]+=temp<<z;
  66     if (n<=8) {
  67       tgt[++y]+=src[x]>>n;
  68       z=8-n;
  69     } else z+=8;
  70   }
  71 }
  72
  73 static void update(Real288_internal *glob)
  74 {
  75   int x,y;
  76   float buffer1[40],temp1[37];
  77   float buffer2[8],temp2[11];
  78
  79   for (x=0,y=glob->phasep+5;x<40;buffer1[x++]=glob->output[(y++)%40]);
  80   co(36,40,35,buffer1,temp1,glob->st1a,glob->st1b,table1);
  81   if (pred(temp1,glob->st1,36))
  82     colmult(glob->pr1,glob->st1,table1a,36);
  83
  84   for (x=0,y=glob->phase+1;x<8;buffer2[x++]=glob->history[(y++)%8]);
  85   co(10,8,20,buffer2,temp2,glob->st2a,glob->st2b,table2);
  86   if (pred(temp2,glob->st2,10))
  87     colmult(glob->pr2,glob->st2,table2a,10);
  88 }
  89
  90 /* Decode and produce output */
  91 static void decode(Real288_internal *glob, unsigned int input)
  92 {
  93   unsigned int x,y;
  94   float f;
  95   double sum,sumsum;
  96   float *p1,*p2;
  97   float buffer[5];
  98   const float *table;
  99
 100   for (x=36;x--;glob->sb[x+5]=glob->sb[x]);
 101   for (x=5;x--;) {
 102     p1=glob->sb+x;p2=glob->pr1;
 103     for (sum=0,y=36;y--;sum-=(*(++p1))*(*(p2++)));
 104     glob->sb[x]=sum;
 105   }
 106
 107   f=amptable[input&7];
 108   table=codetable+(input>>3)*5;
 109
 110   /* convert log and do rms */
 111   for (sum=32,x=10;x--;sum-=glob->pr2[x]*glob->lhist[x]);
 112   if (sum<0) sum=0; else if (sum>60) sum=60;
 113
 114   sumsum=exp(sum*0.1151292546497)*f;    /* pow(10.0,sum/20)*f */
 115   for (sum=0,x=5;x--;) { buffer[x]=table[x]*sumsum; sum+=buffer[x]*buffer[x]; }
 116   if ((sum/=5)<1) sum=1;
 117
 118   /* shift and store */
 119   for (x=10;--x;glob->lhist[x]=glob->lhist[x-1]);
 120   *glob->lhist=glob->history[glob->phase]=10*log10(sum)-32;
 121
 122   for (x=1;x<5;x++) for (y=x;y--;buffer[x]-=glob->pr1[x-y-1]*buffer[y]);
 123
 124   /* output */
 125   for (x=0;x<5;x++) {
 126     f=glob->sb[4-x]+buffer[x];
 127     if (f>4095) f=4095; else if (f<-4095) f=-4095;
 128     glob->output[glob->phasep+x]=glob->sb[4-x]=f;
 129   }
 130 }
 131
 132 /* column multiply */
 133 static void colmult(float *tgt, float *m1, const float *m2, int n)
 134 {
 135   while (n--)
 136     *(tgt++)=(*(m1++))*(*(m2++));
 137 }
 138
 139 static int pred(float *in, float *tgt, int n)
 140 {
 141   int x,y;
 142   float *p1,*p2;
 143   double f0,f1,f2;
 144   float temp;
 145
 146   if (in[n]==0) return 0;
 147   if ((f0=*in)<=0) return 0;
 148
 149   for (x=1;;x++) {
 150     if (n<x) return 1;
 151
 152     p1=in+x;
 153     p2=tgt;
 154     f1=*(p1--);
 155     for (y=x;--y;f1+=(*(p1--))*(*(p2++)));
 156
 157     p1=tgt+x-1;
 158     p2=tgt;
 159     *(p1--)=f2=-f1/f0;
 160     for (y=x>>1;y--;) {
 161       temp=*p2+*p1*f2;
 162       *(p1--)+=*p2*f2;
 163       *(p2++)=temp;
 164     }
 165     if ((f0+=f1*f2)<0) return 0;
 166   }
 167 }
 168
 169 static void co(int n, int i, int j, float *in, float *out, float *st1, float *st2, const float *table)
 170 {
 171   int a,b,c;
 172   unsigned int x;
 173   float *fp;
 174   float buffer1[37];
 175   float buffer2[37];
 176   float work[111];
 177
 178   /* rotate and multiply */
 179   c=(b=(a=n+i)+j)-i;
 180   fp=st1+i;
 181   for (x=0;x<b;x++) {
 182     if (x==c) fp=in;
 183     work[x]=*(table++)*(*(st1++)=*(fp++));
 184   }
 185
 186   prodsum(buffer1,work+n,i,n);
 187   prodsum(buffer2,work+a,j,n);
 188
 189   for (x=0;x<=n;x++) {
 190     *st2=*st2*(0.5625)+buffer1[x];
 191     out[x]=*(st2++)+buffer2[x];
 192   }
 193   *out*=1.00390625; /* to prevent clipping */
 194 }
 195
 196 /* product sum (lsf) */
 197 static void prodsum(float *tgt, float *src, int len, int n)
 198 {
 199   unsigned int x;
 200   float *p1,*p2;
 201   double sum;
 202
 203   while (n>=0)
 204   {
 205     p1=(p2=src)-n;
 206     for (sum=0,x=len;x--;sum+=(*p1++)*(*p2++));
 207     tgt[n--]=sum;
 208   }
 209 }
 210
 211 static void * decode_block(AVCodecContext * avctx, const unsigned char *in, signed short int *out,unsigned len)
 212 {
 213   int x,y;
 214   Real288_internal *glob=avctx->priv_data;
 215   unsigned short int buffer[len];
 216
 217   unpack(buffer,in,len);
 218   for (x=0;x<32;x++)
 219   {
 220     glob->phasep=(glob->phase=x&7)*5;
 221     decode(glob,buffer[x]);
 222     for (y=0;y<5;*(out++)=8*glob->output[glob->phasep+(y++)]);
 223     if (glob->phase==3) update(glob);
 224   }
 225   return out;
 226 }
 227
 228 /* Decode a block (celp) */
 229 static int ra288_decode_frame(AVCodecContext * avctx,
 230             void *data, int *data_size,
 231             const uint8_t * buf, int buf_size)
 232 {
 233     void *datao;
 234
 235     if (buf_size < avctx->block_align)
 236     {
 237         av_log(avctx, AV_LOG_ERROR, "ffra288: Error! Input buffer is too small [%d<%d]\n",buf_size,avctx->block_align);
 238         return 0;
 239     }
 240
 241     datao = data;
 242     data = decode_block(avctx, buf, (signed short *)data, avctx->block_align);
 243
 244     *data_size = (char *)data - (char *)datao;
 245     return avctx->block_align;
 246 }
 247
 248 AVCodec ra_288_decoder =
 249 {
 250     "real_288",
 251     CODEC_TYPE_AUDIO,
 252     CODEC_ID_RA_288,
 253     sizeof(Real288_internal),
 254     ra288_decode_init,
 255     NULL,
 256     NULL,
 257     ra288_decode_frame,
 258     .long_name = "RealAudio 2.0 (28.8K)",
 259 };