libavcodec/wma.c

   1 /*
   2  * WMA compatible codec
   3  * Copyright (c) 2002-2007 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 "wma.h"
  24 #include "wmadata.h"
  25
  26 #undef NDEBUG
  27 #include <assert.h>
  28
  29 /* XXX: use same run/length optimization as mpeg decoders */
  30 //FIXME maybe split decode / encode or pass flag
  31 static void init_coef_vlc(VLC *vlc,
  32                           uint16_t **prun_table, uint16_t **plevel_table, uint16_t **pint_table,
  33                           const CoefVLCTable *vlc_table)
  34 {
  35     int n = vlc_table->n;
  36     const uint8_t *table_bits = vlc_table->huffbits;
  37     const uint32_t *table_codes = vlc_table->huffcodes;
  38     const uint16_t *levels_table = vlc_table->levels;
  39     uint16_t *run_table, *level_table, *int_table;
  40     int i, l, j, k, level;
  41
  42     init_vlc(vlc, VLCBITS, n, table_bits, 1, 1, table_codes, 4, 4, 0);
  43
  44     run_table = av_malloc(n * sizeof(uint16_t));
  45     level_table = av_malloc(n * sizeof(uint16_t));
  46     int_table = av_malloc(n * sizeof(uint16_t));
  47     i = 2;
  48     level = 1;
  49     k = 0;
  50     while (i < n) {
  51         int_table[k]= i;
  52         l = levels_table[k++];
  53         for(j=0;j<l;j++) {
  54             run_table[i] = j;
  55             level_table[i] = level;
  56             i++;
  57         }
  58         level++;
  59     }
  60     *prun_table = run_table;
  61     *plevel_table = level_table;
  62     *pint_table= int_table;
  63 }
  64
  65 int ff_wma_init(AVCodecContext * avctx, int flags2)
  66 {
  67     WMACodecContext *s = avctx->priv_data;
  68     int i;
  69     float *window;
  70     float bps1, high_freq;
  71     volatile float bps;
  72     int sample_rate1;
  73     int coef_vlc_table;
  74
  75     if(   avctx->sample_rate<=0 || avctx->sample_rate>50000
  76        || avctx->channels<=0 || avctx->channels>8
  77        || avctx->bit_rate<=0)
  78         return -1;
  79
  80     s->sample_rate = avctx->sample_rate;
  81     s->nb_channels = avctx->channels;
  82     s->bit_rate = avctx->bit_rate;
  83     s->block_align = avctx->block_align;
  84
  85     dsputil_init(&s->dsp, avctx);
  86
  87     if (avctx->codec->id == CODEC_ID_WMAV1) {
  88         s->version = 1;
  89     } else {
  90         s->version = 2;
  91     }
  92
  93     /* compute MDCT block size */
  94     if (s->sample_rate <= 16000) {
  95         s->frame_len_bits = 9;
  96     } else if (s->sample_rate <= 22050 ||
  97                (s->sample_rate <= 32000 && s->version == 1)) {
  98         s->frame_len_bits = 10;
  99     } else {
 100         s->frame_len_bits = 11;
 101     }
 102     s->frame_len = 1 << s->frame_len_bits;
 103     if (s->use_variable_block_len) {
 104         int nb_max, nb;
 105         nb = ((flags2 >> 3) & 3) + 1;
 106         if ((s->bit_rate / s->nb_channels) >= 32000)
 107             nb += 2;
 108         nb_max = s->frame_len_bits - BLOCK_MIN_BITS;
 109         if (nb > nb_max)
 110             nb = nb_max;
 111         s->nb_block_sizes = nb + 1;
 112     } else {
 113         s->nb_block_sizes = 1;
 114     }
 115
 116     /* init rate dependent parameters */
 117     s->use_noise_coding = 1;
 118     high_freq = s->sample_rate * 0.5;
 119
 120     /* if version 2, then the rates are normalized */
 121     sample_rate1 = s->sample_rate;
 122     if (s->version == 2) {
 123         if (sample_rate1 >= 44100)
 124             sample_rate1 = 44100;
 125         else if (sample_rate1 >= 22050)
 126             sample_rate1 = 22050;
 127         else if (sample_rate1 >= 16000)
 128             sample_rate1 = 16000;
 129         else if (sample_rate1 >= 11025)
 130             sample_rate1 = 11025;
 131         else if (sample_rate1 >= 8000)
 132             sample_rate1 = 8000;
 133     }
 134
 135     bps = (float)s->bit_rate / (float)(s->nb_channels * s->sample_rate);
 136     s->byte_offset_bits = av_log2((int)(bps * s->frame_len / 8.0 + 0.5)) + 2;
 137
 138     /* compute high frequency value and choose if noise coding should
 139        be activated */
 140     bps1 = bps;
 141     if (s->nb_channels == 2)
 142         bps1 = bps * 1.6;
 143     if (sample_rate1 == 44100) {
 144         if (bps1 >= 0.61)
 145             s->use_noise_coding = 0;
 146         else
 147             high_freq = high_freq * 0.4;
 148     } else if (sample_rate1 == 22050) {
 149         if (bps1 >= 1.16)
 150             s->use_noise_coding = 0;
 151         else if (bps1 >= 0.72)
 152             high_freq = high_freq * 0.7;
 153         else
 154             high_freq = high_freq * 0.6;
 155     } else if (sample_rate1 == 16000) {
 156         if (bps > 0.5)
 157             high_freq = high_freq * 0.5;
 158         else
 159             high_freq = high_freq * 0.3;
 160     } else if (sample_rate1 == 11025) {
 161         high_freq = high_freq * 0.7;
 162     } else if (sample_rate1 == 8000) {
 163         if (bps <= 0.625) {
 164             high_freq = high_freq * 0.5;
 165         } else if (bps > 0.75) {
 166             s->use_noise_coding = 0;
 167         } else {
 168             high_freq = high_freq * 0.65;
 169         }
 170     } else {
 171         if (bps >= 0.8) {
 172             high_freq = high_freq * 0.75;
 173         } else if (bps >= 0.6) {
 174             high_freq = high_freq * 0.6;
 175         } else {
 176             high_freq = high_freq * 0.5;
 177         }
 178     }
 179     dprintf(s->avctx, "flags2=0x%x\n", flags2);
 180     dprintf(s->avctx, "version=%d channels=%d sample_rate=%d bitrate=%d block_align=%d\n",
 181            s->version, s->nb_channels, s->sample_rate, s->bit_rate,
 182            s->block_align);
 183     dprintf(s->avctx, "bps=%f bps1=%f high_freq=%f bitoffset=%d\n",
 184            bps, bps1, high_freq, s->byte_offset_bits);
 185     dprintf(s->avctx, "use_noise_coding=%d use_exp_vlc=%d nb_block_sizes=%d\n",
 186            s->use_noise_coding, s->use_exp_vlc, s->nb_block_sizes);
 187
 188     /* compute the scale factor band sizes for each MDCT block size */
 189     {
 190         int a, b, pos, lpos, k, block_len, i, j, n;
 191         const uint8_t *table;
 192
 193         if (s->version == 1) {
 194             s->coefs_start = 3;
 195         } else {
 196             s->coefs_start = 0;
 197         }
 198         for(k = 0; k < s->nb_block_sizes; k++) {
 199             block_len = s->frame_len >> k;
 200
 201             if (s->version == 1) {
 202                 lpos = 0;
 203                 for(i=0;i<25;i++) {
 204                     a = wma_critical_freqs[i];
 205                     b = s->sample_rate;
 206                     pos = ((block_len * 2 * a)  + (b >> 1)) / b;
 207                     if (pos > block_len)
 208                         pos = block_len;
 209                     s->exponent_bands[0][i] = pos - lpos;
 210                     if (pos >= block_len) {
 211                         i++;
 212                         break;
 213                     }
 214                     lpos = pos;
 215                 }
 216                 s->exponent_sizes[0] = i;
 217             } else {
 218                 /* hardcoded tables */
 219                 table = NULL;
 220                 a = s->frame_len_bits - BLOCK_MIN_BITS - k;
 221                 if (a < 3) {
 222                     if (s->sample_rate >= 44100)
 223                         table = exponent_band_44100[a];
 224                     else if (s->sample_rate >= 32000)
 225                         table = exponent_band_32000[a];
 226                     else if (s->sample_rate >= 22050)
 227                         table = exponent_band_22050[a];
 228                 }
 229                 if (table) {
 230                     n = *table++;
 231                     for(i=0;i<n;i++)
 232                         s->exponent_bands[k][i] = table[i];
 233                     s->exponent_sizes[k] = n;
 234                 } else {
 235                     j = 0;
 236                     lpos = 0;
 237                     for(i=0;i<25;i++) {
 238                         a = wma_critical_freqs[i];
 239                         b = s->sample_rate;
 240                         pos = ((block_len * 2 * a)  + (b << 1)) / (4 * b);
 241                         pos <<= 2;
 242                         if (pos > block_len)
 243                             pos = block_len;
 244                         if (pos > lpos)
 245                             s->exponent_bands[k][j++] = pos - lpos;
 246                         if (pos >= block_len)
 247                             break;
 248                         lpos = pos;
 249                     }
 250                     s->exponent_sizes[k] = j;
 251                 }
 252             }
 253
 254             /* max number of coefs */
 255             s->coefs_end[k] = (s->frame_len - ((s->frame_len * 9) / 100)) >> k;
 256             /* high freq computation */
 257             s->high_band_start[k] = (int)((block_len * 2 * high_freq) /
 258                                           s->sample_rate + 0.5);
 259             n = s->exponent_sizes[k];
 260             j = 0;
 261             pos = 0;
 262             for(i=0;i<n;i++) {
 263                 int start, end;
 264                 start = pos;
 265                 pos += s->exponent_bands[k][i];
 266                 end = pos;
 267                 if (start < s->high_band_start[k])
 268                     start = s->high_band_start[k];
 269                 if (end > s->coefs_end[k])
 270                     end = s->coefs_end[k];
 271                 if (end > start)
 272                     s->exponent_high_bands[k][j++] = end - start;
 273             }
 274             s->exponent_high_sizes[k] = j;
 275 #if 0
 276             tprintf(s->avctx, "%5d: coefs_end=%d high_band_start=%d nb_high_bands=%d: ",
 277                   s->frame_len >> k,
 278                   s->coefs_end[k],
 279                   s->high_band_start[k],
 280                   s->exponent_high_sizes[k]);
 281             for(j=0;j<s->exponent_high_sizes[k];j++)
 282                 tprintf(s->avctx, " %d", s->exponent_high_bands[k][j]);
 283             tprintf(s->avctx, "\n");
 284 #endif
 285         }
 286     }
 287
 288 #ifdef TRACE
 289     {
 290         int i, j;
 291         for(i = 0; i < s->nb_block_sizes; i++) {
 292             tprintf(s->avctx, "%5d: n=%2d:",
 293                    s->frame_len >> i,
 294                    s->exponent_sizes[i]);
 295             for(j=0;j<s->exponent_sizes[i];j++)
 296                 tprintf(s->avctx, " %d", s->exponent_bands[i][j]);
 297             tprintf(s->avctx, "\n");
 298         }
 299     }
 300 #endif
 301
 302     /* init MDCT windows : simple sinus window */
 303     for(i = 0; i < s->nb_block_sizes; i++) {
 304         int n, j;
 305         float alpha;
 306         n = 1 << (s->frame_len_bits - i);
 307         window = av_malloc(sizeof(float) * n);
 308         alpha = M_PI / (2.0 * n);
 309         for(j=0;j<n;j++) {
 310             window[j] = sin((j + 0.5) * alpha);
 311         }
 312         s->windows[i] = window;
 313     }
 314
 315     s->reset_block_lengths = 1;
 316
 317     if (s->use_noise_coding) {
 318
 319         /* init the noise generator */
 320         if (s->use_exp_vlc)
 321             s->noise_mult = 0.02;
 322         else
 323             s->noise_mult = 0.04;
 324
 325 #ifdef TRACE
 326         for(i=0;i<NOISE_TAB_SIZE;i++)
 327             s->noise_table[i] = 1.0 * s->noise_mult;
 328 #else
 329         {
 330             unsigned int seed;
 331             float norm;
 332             seed = 1;
 333             norm = (1.0 / (float)(1LL << 31)) * sqrt(3) * s->noise_mult;
 334             for(i=0;i<NOISE_TAB_SIZE;i++) {
 335                 seed = seed * 314159 + 1;
 336                 s->noise_table[i] = (float)((int)seed) * norm;
 337             }
 338         }
 339 #endif
 340     }
 341
 342     /* choose the VLC tables for the coefficients */
 343     coef_vlc_table = 2;
 344     if (s->sample_rate >= 32000) {
 345         if (bps1 < 0.72)
 346             coef_vlc_table = 0;
 347         else if (bps1 < 1.16)
 348             coef_vlc_table = 1;
 349     }
 350     s->coef_vlcs[0]= &coef_vlcs[coef_vlc_table * 2    ];
 351     s->coef_vlcs[1]= &coef_vlcs[coef_vlc_table * 2 + 1];
 352     init_coef_vlc(&s->coef_vlc[0], &s->run_table[0], &s->level_table[0], &s->int_table[0],
 353                   s->coef_vlcs[0]);
 354     init_coef_vlc(&s->coef_vlc[1], &s->run_table[1], &s->level_table[1], &s->int_table[1],
 355                   s->coef_vlcs[1]);
 356
 357     return 0;
 358 }
 359
 360 int ff_wma_total_gain_to_bits(int total_gain){
 361          if (total_gain < 15) return 13;
 362     else if (total_gain < 32) return 12;
 363     else if (total_gain < 40) return 11;
 364     else if (total_gain < 45) return 10;
 365     else                      return  9;
 366 }
 367
 368 int ff_wma_end(AVCodecContext *avctx)
 369 {
 370     WMACodecContext *s = avctx->priv_data;
 371     int i;
 372
 373     for(i = 0; i < s->nb_block_sizes; i++)
 374         ff_mdct_end(&s->mdct_ctx[i]);
 375     for(i = 0; i < s->nb_block_sizes; i++)
 376         av_free(s->windows[i]);
 377
 378     if (s->use_exp_vlc) {
 379         free_vlc(&s->exp_vlc);
 380     }
 381     if (s->use_noise_coding) {
 382         free_vlc(&s->hgain_vlc);
 383     }
 384     for(i = 0;i < 2; i++) {
 385         free_vlc(&s->coef_vlc[i]);
 386         av_free(s->run_table[i]);
 387         av_free(s->level_table[i]);
 388         av_free(s->int_table[i]);
 389     }
 390
 391     return 0;
 392 }