libavcodec/ra144.c

   1 /*
   2  * Real Audio 1.0 (14.4K)
   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 "bitstream.h"
  24 #include "ra144.h"
  25
  26 #define NBLOCKS         4       /* number of segments within a block */
  27 #define BLOCKSIZE       40      /* (quarter) block size in 16-bit words (80 bytes) */
  28 #define HALFBLOCK       20      /* BLOCKSIZE/2 */
  29 #define BUFFERSIZE      146     /* for do_output */
  30
  31
  32 /* internal globals */
  33 typedef struct {
  34     unsigned int     oldval;
  35     unsigned int     gbuf1[4];
  36     unsigned short   gbuf2[120];
  37     unsigned int    *decptr;                /* decoder ptr */
  38     signed   short  *decsp;
  39
  40     /* the swapped buffers */
  41     unsigned int     swapbuffers[4][10];
  42     unsigned int    *swapbuf1;
  43     unsigned int    *swapbuf2;
  44     unsigned int    *swapbuf1alt;
  45     unsigned int    *swapbuf2alt;
  46
  47     unsigned int buffer[5];
  48     unsigned short int buffer_2[148];
  49
  50     unsigned short *sptr;
  51 } Real144_internal;
  52
  53 static int ra144_decode_init(AVCodecContext * avctx)
  54 {
  55     Real144_internal *glob = avctx->priv_data;
  56
  57     glob->swapbuf1    = glob->swapbuffers[0];
  58     glob->swapbuf2    = glob->swapbuffers[1];
  59     glob->swapbuf1alt = glob->swapbuffers[2];
  60     glob->swapbuf2alt = glob->swapbuffers[3];
  61
  62     return 0;
  63 }
  64
  65 /* lookup square roots in table */
  66 static int t_sqrt(unsigned int x)
  67 {
  68     int s = 0;
  69     while (x > 0xfff) {
  70         s++;
  71         x = x >> 2;
  72     }
  73
  74     return (ff_sqrt(x << 20) << s) << 2;
  75 }
  76
  77 /* do 'voice' */
  78 static void do_voice(const int *a1, int *a2)
  79 {
  80     int buffer[10];
  81     int *b1 = buffer;
  82     int *b2 = a2;
  83     int x, y;
  84
  85     for (x=0; x < 10; x++) {
  86         b1[x] = a1[x] << 4;
  87
  88         for (y=0; y < x; y++)
  89             b1[y] = ((a1[x] * b2[x-y-1]) >> 12) + b2[y];
  90
  91         FFSWAP(int *, b1, b2);
  92     }
  93
  94     for (x=0; x < 10; x++)
  95         a2[x] >>= 4;
  96 }
  97
  98 /* rotate block */
  99 static void rotate_block(const short *source, short *target, int offset)
 100 {
 101     int i=0, k=0;
 102     source += BUFFERSIZE - offset;
 103
 104     while (i<BLOCKSIZE) {
 105         target[i++] = source[k++];
 106
 107         if (k == offset)
 108             k = 0;
 109     }
 110 }
 111
 112 /* inverse root mean square */
 113 static int irms(const short *data, int factor)
 114 {
 115     unsigned int i, sum = 0;
 116
 117     for (i=0; i < BLOCKSIZE; i++)
 118         sum += data[i] * data[i];
 119
 120     if (sum == 0)
 121         return 0; /* OOPS - division by zero */
 122
 123     return (0x20000000 / (t_sqrt(sum) >> 8)) * factor;
 124 }
 125
 126 /* multiply/add wavetable */
 127 static void add_wav(int n, int f, int m1, int m2, int m3, const short *s1,
 128                     const short *s2, const short *s3, short *dest)
 129 {
 130     int a = 0;
 131     int b, c, i;
 132     const short *ptr, *ptr2;
 133
 134     ptr  = wavtable1 + n * 9;
 135     ptr2 = wavtable2 + n * 9;
 136
 137     if (f)
 138         a = (ptr[0] * m1) >> (ptr2[0] + 1);
 139
 140     b = (ptr[1] * m2) >> (ptr2[1] + 1);
 141     c = (ptr[2] * m3) >> (ptr2[2] + 1);
 142
 143     for (i=0; i < BLOCKSIZE; i++)
 144         dest[i] = ((*(s1++)) * a + (*(s2++)) * b + (*(s3++)) * c) >> 12;
 145 }
 146
 147
 148 static void final(const short *i1, const short *i2,
 149                   void *out, int *statbuf, int len)
 150 {
 151     int x, sum, i;
 152     int buffer[10];
 153     short *ptr;
 154     short *ptr2;
 155     unsigned short int work[50];
 156
 157     memcpy(work, statbuf,20);
 158     memcpy(work + 10, i2, len * 2);
 159
 160     for(i=0; i<10; i++)
 161         buffer[9-i] = i1[i];
 162
 163     ptr2 = (ptr = work) + len;
 164
 165     while (ptr < ptr2) {
 166         for(sum=0, x=0; x<=9; x++)
 167             sum += buffer[x] * (ptr[x]);
 168
 169         sum = sum >> 12;
 170         x = ptr[10] - sum;
 171
 172         if (x<-32768 || x>32767) {
 173             memset(out, 0, len * 2);
 174             memset(statbuf, 0, 20);
 175             return;
 176         }
 177
 178         ptr[10] = x;
 179         ptr++;
 180     }
 181     memcpy(out, ptr+10 - len, len * 2);
 182     memcpy(statbuf, ptr, 20);
 183 }
 184
 185 static unsigned int rms(const int *data, int f)
 186 {
 187     const int *c;
 188     int x;
 189     unsigned int res;
 190     int b;
 191
 192     c = data;
 193     b = 0;
 194     res = 0x10000;
 195     for (x=0; x<10; x++) {
 196         res = (((0x1000000 - (*c) * (*c)) >> 12) * res) >> 12;
 197
 198         if (res == 0)
 199             return 0;
 200
 201         if (res <= 0x3fff) {
 202             while (res <= 0x3fff) {
 203                 b++;
 204                 res <<= 2;
 205             }
 206         } else {
 207             if (res > 0x10000)
 208                 return 0; /* We're screwed, might as well go out with a bang. :P */
 209         }
 210         c++;
 211     }
 212
 213     if (res > 0)
 214         res = t_sqrt(res);
 215
 216     res >>= (b + 10);
 217     res = (res * f) >> 10;
 218     return res;
 219 }
 220
 221 /* do quarter-block output */
 222 static void do_output_subblock(Real144_internal *glob, const unsigned short  *gsp, unsigned int gval, signed short *output_buffer, GetBitContext *gb)
 223 {
 224     unsigned short int buffer_a[40];
 225     unsigned short int *block;
 226     int e, f, g;
 227     int a = get_bits(gb, 7);
 228     int d = get_bits(gb, 8);
 229     int b = get_bits(gb, 7);
 230     int c = get_bits(gb, 7);
 231
 232     if (a) {
 233         a += HALFBLOCK - 1;
 234         rotate_block(glob->buffer_2, buffer_a, a);
 235     }
 236
 237     e = ((ftable1[b] >> 4) * gval) >> 8;
 238     f = ((ftable2[c] >> 4) * gval) >> 8;
 239
 240     if (a)
 241         g = irms(buffer_a, gval) >> 12;
 242     else
 243         g = 0;
 244
 245     memmove(glob->buffer_2, glob->buffer_2 + BLOCKSIZE, (BUFFERSIZE - BLOCKSIZE) * 2);
 246     block = glob->buffer_2 + BUFFERSIZE - BLOCKSIZE;
 247
 248     add_wav(d, a, g, e, f, buffer_a, etable1[b],
 249             etable2[c], block);
 250
 251     final(gsp, block, output_buffer, glob->buffer, BLOCKSIZE);
 252 }
 253
 254 static void dec1(Real144_internal *glob, const int *data, const int *inp,
 255                  int n, int f)
 256 {
 257     short *ptr,*end;
 258
 259     *(glob->decptr++) = rms(data, f);
 260     end = (ptr = glob->decsp) + (n * 10);
 261
 262     while (ptr < end)
 263         *(ptr++) = *(inp++);
 264 }
 265
 266 static int eq(const short *in, int *target)
 267 {
 268     int retval;
 269     int a;
 270     int b;
 271     int c;
 272     unsigned int u;
 273     const short *sptr;
 274     int *ptr1, *ptr2, *ptr3;
 275     int *bp1, *bp2;
 276     int buffer1[10];
 277     int buffer2[10];
 278
 279     retval = 0;
 280     bp1 = buffer1;
 281     bp2 = buffer2;
 282     ptr2 = (ptr3 = buffer2) + 9;
 283     sptr = in;
 284
 285     while (ptr2 >= ptr3)
 286         *(ptr3++) = *(sptr++);
 287
 288     target += 9;
 289     a = bp2[9];
 290     *target = a;
 291
 292     if (a + 0x1000 > 0x1fff)
 293         return 0; /* We're screwed, might as well go out with a bang. :P */
 294
 295     c = 8;
 296     u = a;
 297
 298     while (c >= 0) {
 299         if (u == 0x1000)
 300             u++;
 301
 302         if (u == 0xfffff000)
 303             u--;
 304
 305         b = 0x1000-((u * u) >> 12);
 306
 307         if (b == 0)
 308             b++;
 309
 310         ptr2 = bp1;
 311         ptr1 = (ptr3 = bp2) + c;
 312
 313         for (u=0; u<=c; u++)
 314             *(ptr2++) = ((*(ptr3++) - (((*target) * (*(ptr1--))) >> 12)) * (0x1000000 / b)) >> 12;
 315
 316         *(--target) = u = bp1[(c--)];
 317
 318         if ((u + 0x1000) > 0x1fff)
 319             retval = 1;
 320
 321         FFSWAP(int *, bp1, bp2);
 322     }
 323     return retval;
 324 }
 325
 326 static void dec2(Real144_internal *glob, const int *data, const int *inp,
 327                  int n, int f, const int *inp2, int l)
 328 {
 329     unsigned const int *ptr1,*ptr2;
 330     int work[10];
 331     int a,b;
 332     int x;
 333     int result;
 334
 335     if(l + 1 < NBLOCKS / 2)
 336         a = NBLOCKS - (l + 1);
 337     else
 338         a = l + 1;
 339
 340     b = NBLOCKS - a;
 341
 342     if (l == 0) {
 343         glob->decsp = glob->sptr = glob->gbuf2;
 344         glob->decptr = glob->gbuf1;
 345     }
 346     ptr1 = inp;
 347     ptr2 = inp2;
 348
 349     for (x=0; x<10*n; x++)
 350         *(glob->sptr++) = (a * (*ptr1++) + b * (*ptr2++)) >> 2;
 351
 352     result = eq(glob->decsp, work);
 353
 354     if (result == 1) {
 355         dec1(glob, data, inp, n, f);
 356     } else {
 357         *(glob->decptr++) = rms(work, f);
 358     }
 359     glob->decsp += n * 10;
 360 }
 361
 362 /* Uncompress one block (20 bytes -> 160*2 bytes) */
 363 static int ra144_decode_frame(AVCodecContext * avctx,
 364             void *vdata, int *data_size,
 365             const uint8_t * buf, int buf_size)
 366 {
 367     static const uint8_t sizes[10] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2};
 368     unsigned int a, b, c;
 369     int i;
 370     signed short *shptr;
 371     int16_t *data = vdata;
 372     unsigned int val;
 373
 374     Real144_internal *glob = avctx->priv_data;
 375     GetBitContext gb;
 376
 377     if(buf_size == 0)
 378         return 0;
 379
 380     init_get_bits(&gb, buf, 20 * 8);
 381
 382     for (i=0; i<10; i++)
 383         // "<< 1"? Doesn't this make one value out of two of the table useless?
 384         glob->swapbuf1[i] = decodetable[i][get_bits(&gb, sizes[i]) << 1];
 385
 386     do_voice(glob->swapbuf1, glob->swapbuf2);
 387
 388     val = decodeval[get_bits(&gb, 5) << 1]; // Useless table entries?
 389     a = t_sqrt(val*glob->oldval) >> 12;
 390
 391     dec2(glob, glob->swapbuf1alt, glob->swapbuf2alt, 3, glob->oldval, glob->swapbuf2, 0);
 392     if (glob->oldval < val) {
 393         dec2(glob, glob->swapbuf1, glob->swapbuf2, 3, a, glob->swapbuf2alt, 1);
 394     } else {
 395         dec2(glob, glob->swapbuf1alt, glob->swapbuf2alt, 3, a, glob->swapbuf2, 1);
 396     }
 397     dec2(glob, glob->swapbuf1, glob->swapbuf2, 3, val, glob->swapbuf2alt, 2);
 398     dec1(glob, glob->swapbuf1, glob->swapbuf2, 3, val);
 399
 400     /* do output */
 401     for (b=0, c=0; c<4; c++) {
 402         unsigned int gval = glob->gbuf1[c];
 403         unsigned short *gsp = glob->gbuf2 + b;
 404         signed short output_buffer[40];
 405
 406         do_output_subblock(glob, gsp, gval, output_buffer, &gb);
 407
 408         shptr = output_buffer;
 409         while (shptr < output_buffer + BLOCKSIZE)
 410             *data++ = av_clip_int16(*(shptr++) << 2);
 411         b += 30;
 412     }
 413
 414     glob->oldval = val;
 415
 416     FFSWAP(unsigned int *, glob->swapbuf1alt, glob->swapbuf1);
 417     FFSWAP(unsigned int *, glob->swapbuf2alt, glob->swapbuf2);
 418
 419     *data_size = 2*160;
 420     return 20;
 421 }
 422
 423
 424 AVCodec ra_144_decoder =
 425 {
 426     "real_144",
 427     CODEC_TYPE_AUDIO,
 428     CODEC_ID_RA_144,
 429     sizeof(Real144_internal),
 430     ra144_decode_init,
 431     NULL,
 432     NULL,
 433     ra144_decode_frame,
 434     .long_name = "RealAudio 1.0 (14.4K)",
 435 };