libavcodec/wmadec.c

   1 /*
   2  * WMA compatible decoder
   3  * Copyright (c) 2002 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 /**
  23  * @file libavcodec/wmadec.c
  24  * WMA compatible decoder.
  25  * This decoder handles Microsoft Windows Media Audio data, versions 1 & 2.
  26  * WMA v1 is identified by audio format 0x160 in Microsoft media files
  27  * (ASF/AVI/WAV). WMA v2 is identified by audio format 0x161.
  28  *
  29  * To use this decoder, a calling application must supply the extra data
  30  * bytes provided with the WMA data. These are the extra, codec-specific
  31  * bytes at the end of a WAVEFORMATEX data structure. Transmit these bytes
  32  * to the decoder using the extradata[_size] fields in AVCodecContext. There
  33  * should be 4 extra bytes for v1 data and 6 extra bytes for v2 data.
  34  */
  35
  36 #include "avcodec.h"
  37 #include "wma.h"
  38
  39 #undef NDEBUG
  40 #include <assert.h>
  41
  42 #define EXPVLCBITS 8
  43 #define EXPMAX ((19+EXPVLCBITS-1)/EXPVLCBITS)
  44
  45 #define HGAINVLCBITS 9
  46 #define HGAINMAX ((13+HGAINVLCBITS-1)/HGAINVLCBITS)
  47
  48 static void wma_lsp_to_curve_init(WMACodecContext *s, int frame_len);
  49
  50 #ifdef TRACE
  51 static void dump_shorts(WMACodecContext *s, const char *name, const short *tab, int n)
  52 {
  53     int i;
  54
  55     tprintf(s->avctx, "%s[%d]:\n", name, n);
  56     for(i=0;i<n;i++) {
  57         if ((i & 7) == 0)
  58             tprintf(s->avctx, "%4d: ", i);
  59         tprintf(s->avctx, " %5d.0", tab[i]);
  60         if ((i & 7) == 7)
  61             tprintf(s->avctx, "\n");
  62     }
  63 }
  64
  65 static void dump_floats(WMACodecContext *s, const char *name, int prec, const float *tab, int n)
  66 {
  67     int i;
  68
  69     tprintf(s->avctx, "%s[%d]:\n", name, n);
  70     for(i=0;i<n;i++) {
  71         if ((i & 7) == 0)
  72             tprintf(s->avctx, "%4d: ", i);
  73         tprintf(s->avctx, " %8.*f", prec, tab[i]);
  74         if ((i & 7) == 7)
  75             tprintf(s->avctx, "\n");
  76     }
  77     if ((i & 7) != 0)
  78         tprintf(s->avctx, "\n");
  79 }
  80 #endif
  81
  82 static int wma_decode_init(AVCodecContext * avctx)
  83 {
  84     WMACodecContext *s = avctx->priv_data;
  85     int i, flags2;
  86     uint8_t *extradata;
  87
  88     s->avctx = avctx;
  89
  90     /* extract flag infos */
  91     flags2 = 0;
  92     extradata = avctx->extradata;
  93     if (avctx->codec->id == CODEC_ID_WMAV1 && avctx->extradata_size >= 4) {
  94         flags2 = AV_RL16(extradata+2);
  95     } else if (avctx->codec->id == CODEC_ID_WMAV2 && avctx->extradata_size >= 6) {
  96         flags2 = AV_RL16(extradata+4);
  97     }
  98 // for(i=0; i<avctx->extradata_size; i++)
  99 //     av_log(NULL, AV_LOG_ERROR, "%02X ", extradata[i]);
 100
 101     s->use_exp_vlc = flags2 & 0x0001;
 102     s->use_bit_reservoir = flags2 & 0x0002;
 103     s->use_variable_block_len = flags2 & 0x0004;
 104
 105     if(ff_wma_init(avctx, flags2)<0)
 106         return -1;
 107
 108     /* init MDCT */
 109     for(i = 0; i < s->nb_block_sizes; i++)
 110         ff_mdct_init(&s->mdct_ctx[i], s->frame_len_bits - i + 1, 1, 1.0);
 111
 112     if (s->use_noise_coding) {
 113         init_vlc(&s->hgain_vlc, HGAINVLCBITS, sizeof(ff_wma_hgain_huffbits),
 114                  ff_wma_hgain_huffbits, 1, 1,
 115                  ff_wma_hgain_huffcodes, 2, 2, 0);
 116     }
 117
 118     if (s->use_exp_vlc) {
 119         init_vlc(&s->exp_vlc, EXPVLCBITS, sizeof(ff_wma_scale_huffbits), //FIXME move out of context
 120                  ff_wma_scale_huffbits, 1, 1,
 121                  ff_wma_scale_huffcodes, 4, 4, 0);
 122     } else {
 123         wma_lsp_to_curve_init(s, s->frame_len);
 124     }
 125
 126     avctx->sample_fmt = SAMPLE_FMT_S16;
 127     return 0;
 128 }
 129
 130 /**
 131  * compute x^-0.25 with an exponent and mantissa table. We use linear
 132  * interpolation to reduce the mantissa table size at a small speed
 133  * expense (linear interpolation approximately doubles the number of
 134  * bits of precision).
 135  */
 136 static inline float pow_m1_4(WMACodecContext *s, float x)
 137 {
 138     union {
 139         float f;
 140         unsigned int v;
 141     } u, t;
 142     unsigned int e, m;
 143     float a, b;
 144
 145     u.f = x;
 146     e = u.v >> 23;
 147     m = (u.v >> (23 - LSP_POW_BITS)) & ((1 << LSP_POW_BITS) - 1);
 148     /* build interpolation scale: 1 <= t < 2. */
 149     t.v = ((u.v << LSP_POW_BITS) & ((1 << 23) - 1)) | (127 << 23);
 150     a = s->lsp_pow_m_table1[m];
 151     b = s->lsp_pow_m_table2[m];
 152     return s->lsp_pow_e_table[e] * (a + b * t.f);
 153 }
 154
 155 static void wma_lsp_to_curve_init(WMACodecContext *s, int frame_len)
 156 {
 157     float wdel, a, b;
 158     int i, e, m;
 159
 160     wdel = M_PI / frame_len;
 161     for(i=0;i<frame_len;i++)
 162         s->lsp_cos_table[i] = 2.0f * cos(wdel * i);
 163
 164     /* tables for x^-0.25 computation */
 165     for(i=0;i<256;i++) {
 166         e = i - 126;
 167         s->lsp_pow_e_table[i] = pow(2.0, e * -0.25);
 168     }
 169
 170     /* NOTE: these two tables are needed to avoid two operations in
 171        pow_m1_4 */
 172     b = 1.0;
 173     for(i=(1 << LSP_POW_BITS) - 1;i>=0;i--) {
 174         m = (1 << LSP_POW_BITS) + i;
 175         a = (float)m * (0.5 / (1 << LSP_POW_BITS));
 176         a = pow(a, -0.25);
 177         s->lsp_pow_m_table1[i] = 2 * a - b;
 178         s->lsp_pow_m_table2[i] = b - a;
 179         b = a;
 180     }
 181 #if 0
 182     for(i=1;i<20;i++) {
 183         float v, r1, r2;
 184         v = 5.0 / i;
 185         r1 = pow_m1_4(s, v);
 186         r2 = pow(v,-0.25);
 187         printf("%f^-0.25=%f e=%f\n", v, r1, r2 - r1);
 188     }
 189 #endif
 190 }
 191
 192 /**
 193  * NOTE: We use the same code as Vorbis here
 194  * @todo optimize it further with SSE/3Dnow
 195  */
 196 static void wma_lsp_to_curve(WMACodecContext *s,
 197                              float *out, float *val_max_ptr,
 198                              int n, float *lsp)
 199 {
 200     int i, j;
 201     float p, q, w, v, val_max;
 202
 203     val_max = 0;
 204     for(i=0;i<n;i++) {
 205         p = 0.5f;
 206         q = 0.5f;
 207         w = s->lsp_cos_table[i];
 208         for(j=1;j<NB_LSP_COEFS;j+=2){
 209             q *= w - lsp[j - 1];
 210             p *= w - lsp[j];
 211         }
 212         p *= p * (2.0f - w);
 213         q *= q * (2.0f + w);
 214         v = p + q;
 215         v = pow_m1_4(s, v);
 216         if (v > val_max)
 217             val_max = v;
 218         out[i] = v;
 219     }
 220     *val_max_ptr = val_max;
 221 }
 222
 223 /**
 224  * decode exponents coded with LSP coefficients (same idea as Vorbis)
 225  */
 226 static void decode_exp_lsp(WMACodecContext *s, int ch)
 227 {
 228     float lsp_coefs[NB_LSP_COEFS];
 229     int val, i;
 230
 231     for(i = 0; i < NB_LSP_COEFS; i++) {
 232         if (i == 0 || i >= 8)
 233             val = get_bits(&s->gb, 3);
 234         else
 235             val = get_bits(&s->gb, 4);
 236         lsp_coefs[i] = ff_wma_lsp_codebook[i][val];
 237     }
 238
 239     wma_lsp_to_curve(s, s->exponents[ch], &s->max_exponent[ch],
 240                      s->block_len, lsp_coefs);
 241 }
 242
 243 /**
 244  * decode exponents coded with VLC codes
 245  */
 246 static int decode_exp_vlc(WMACodecContext *s, int ch)
 247 {
 248     int last_exp, n, code;
 249     const uint16_t *ptr;
 250     float v, *q, max_scale, *q_end;
 251
 252     ptr = s->exponent_bands[s->frame_len_bits - s->block_len_bits];
 253     q = s->exponents[ch];
 254     q_end = q + s->block_len;
 255     max_scale = 0;
 256     if (s->version == 1) {
 257         last_exp = get_bits(&s->gb, 5) + 10;
 258         /* XXX: use a table */
 259         v = pow(10, last_exp * (1.0 / 16.0));
 260         max_scale = v;
 261         n = *ptr++;
 262         do {
 263             *q++ = v;
 264         } while (--n);
 265     }else
 266         last_exp = 36;
 267
 268     while (q < q_end) {
 269         code = get_vlc2(&s->gb, s->exp_vlc.table, EXPVLCBITS, EXPMAX);
 270         if (code < 0)
 271             return -1;
 272         /* NOTE: this offset is the same as MPEG4 AAC ! */
 273         last_exp += code - 60;
 274         /* XXX: use a table */
 275         v = pow(10, last_exp * (1.0 / 16.0));
 276         if (v > max_scale)
 277             max_scale = v;
 278         n = *ptr++;
 279         do {
 280             *q++ = v;
 281         } while (--n);
 282     }
 283     s->max_exponent[ch] = max_scale;
 284     return 0;
 285 }
 286
 287
 288 /**
 289  * Apply MDCT window and add into output.
 290  *
 291  * We ensure that when the windows overlap their squared sum
 292  * is always 1 (MDCT reconstruction rule).
 293  */
 294 static void wma_window(WMACodecContext *s, float *out)
 295 {
 296     float *in = s->output;
 297     int block_len, bsize, n;
 298
 299     /* left part */
 300     if (s->block_len_bits <= s->prev_block_len_bits) {
 301         block_len = s->block_len;
 302         bsize = s->frame_len_bits - s->block_len_bits;
 303
 304         s->dsp.vector_fmul_add_add(out, in, s->windows[bsize],
 305                                    out, 0, block_len, 1);
 306
 307     } else {
 308         block_len = 1 << s->prev_block_len_bits;
 309         n = (s->block_len - block_len) / 2;
 310         bsize = s->frame_len_bits - s->prev_block_len_bits;
 311
 312         s->dsp.vector_fmul_add_add(out+n, in+n, s->windows[bsize],
 313                                    out+n, 0, block_len, 1);
 314
 315         memcpy(out+n+block_len, in+n+block_len, n*sizeof(float));
 316     }
 317
 318     out += s->block_len;
 319     in += s->block_len;
 320
 321     /* right part */
 322     if (s->block_len_bits <= s->next_block_len_bits) {
 323         block_len = s->block_len;
 324         bsize = s->frame_len_bits - s->block_len_bits;
 325
 326         s->dsp.vector_fmul_reverse(out, in, s->windows[bsize], block_len);
 327
 328     } else {
 329         block_len = 1 << s->next_block_len_bits;
 330         n = (s->block_len - block_len) / 2;
 331         bsize = s->frame_len_bits - s->next_block_len_bits;
 332
 333         memcpy(out, in, n*sizeof(float));
 334
 335         s->dsp.vector_fmul_reverse(out+n, in+n, s->windows[bsize], block_len);
 336
 337         memset(out+n+block_len, 0, n*sizeof(float));
 338     }
 339 }
 340
 341
 342 /**
 343  * @return 0 if OK. 1 if last block of frame. return -1 if
 344  * unrecorrable error.
 345  */
 346 static int wma_decode_block(WMACodecContext *s)
 347 {
 348     int n, v, a, ch, bsize;
 349     int coef_nb_bits, total_gain;
 350     int nb_coefs[MAX_CHANNELS];
 351     float mdct_norm;
 352
 353 #ifdef TRACE
 354     tprintf(s->avctx, "***decode_block: %d:%d\n", s->frame_count - 1, s->block_num);
 355 #endif
 356
 357     /* compute current block length */
 358     if (s->use_variable_block_len) {
 359         n = av_log2(s->nb_block_sizes - 1) + 1;
 360
 361         if (s->reset_block_lengths) {
 362             s->reset_block_lengths = 0;
 363             v = get_bits(&s->gb, n);
 364             if (v >= s->nb_block_sizes)
 365                 return -1;
 366             s->prev_block_len_bits = s->frame_len_bits - v;
 367             v = get_bits(&s->gb, n);
 368             if (v >= s->nb_block_sizes)
 369                 return -1;
 370             s->block_len_bits = s->frame_len_bits - v;
 371         } else {
 372             /* update block lengths */
 373             s->prev_block_len_bits = s->block_len_bits;
 374             s->block_len_bits = s->next_block_len_bits;
 375         }
 376         v = get_bits(&s->gb, n);
 377         if (v >= s->nb_block_sizes)
 378             return -1;
 379         s->next_block_len_bits = s->frame_len_bits - v;
 380     } else {
 381         /* fixed block len */
 382         s->next_block_len_bits = s->frame_len_bits;
 383         s->prev_block_len_bits = s->frame_len_bits;
 384         s->block_len_bits = s->frame_len_bits;
 385     }
 386
 387     /* now check if the block length is coherent with the frame length */
 388     s->block_len = 1 << s->block_len_bits;
 389     if ((s->block_pos + s->block_len) > s->frame_len)
 390         return -1;
 391
 392     if (s->nb_channels == 2) {
 393         s->ms_stereo = get_bits1(&s->gb);
 394     }
 395     v = 0;
 396     for(ch = 0; ch < s->nb_channels; ch++) {
 397         a = get_bits1(&s->gb);
 398         s->channel_coded[ch] = a;
 399         v |= a;
 400     }
 401
 402     bsize = s->frame_len_bits - s->block_len_bits;
 403
 404     /* if no channel coded, no need to go further */
 405     /* XXX: fix potential framing problems */
 406     if (!v)
 407         goto next;
 408
 409     /* read total gain and extract corresponding number of bits for
 410        coef escape coding */
 411     total_gain = 1;
 412     for(;;) {
 413         a = get_bits(&s->gb, 7);
 414         total_gain += a;
 415         if (a != 127)
 416             break;
 417     }
 418
 419     coef_nb_bits= ff_wma_total_gain_to_bits(total_gain);
 420
 421     /* compute number of coefficients */
 422     n = s->coefs_end[bsize] - s->coefs_start;
 423     for(ch = 0; ch < s->nb_channels; ch++)
 424         nb_coefs[ch] = n;
 425
 426     /* complex coding */
 427     if (s->use_noise_coding) {
 428
 429         for(ch = 0; ch < s->nb_channels; ch++) {
 430             if (s->channel_coded[ch]) {
 431                 int i, n, a;
 432                 n = s->exponent_high_sizes[bsize];
 433                 for(i=0;i<n;i++) {
 434                     a = get_bits1(&s->gb);
 435                     s->high_band_coded[ch][i] = a;
 436                     /* if noise coding, the coefficients are not transmitted */
 437                     if (a)
 438                         nb_coefs[ch] -= s->exponent_high_bands[bsize][i];
 439                 }
 440             }
 441         }
 442         for(ch = 0; ch < s->nb_channels; ch++) {
 443             if (s->channel_coded[ch]) {
 444                 int i, n, val, code;
 445
 446                 n = s->exponent_high_sizes[bsize];
 447                 val = (int)0x80000000;
 448                 for(i=0;i<n;i++) {
 449                     if (s->high_band_coded[ch][i]) {
 450                         if (val == (int)0x80000000) {
 451                             val = get_bits(&s->gb, 7) - 19;
 452                         } else {
 453                             code = get_vlc2(&s->gb, s->hgain_vlc.table, HGAINVLCBITS, HGAINMAX);
 454                             if (code < 0)
 455                                 return -1;
 456                             val += code - 18;
 457                         }
 458                         s->high_band_values[ch][i] = val;
 459                     }
 460                 }
 461             }
 462         }
 463     }
 464
 465     /* exponents can be reused in short blocks. */
 466     if ((s->block_len_bits == s->frame_len_bits) ||
 467         get_bits1(&s->gb)) {
 468         for(ch = 0; ch < s->nb_channels; ch++) {
 469             if (s->channel_coded[ch]) {
 470                 if (s->use_exp_vlc) {
 471                     if (decode_exp_vlc(s, ch) < 0)
 472                         return -1;
 473                 } else {
 474                     decode_exp_lsp(s, ch);
 475                 }
 476                 s->exponents_bsize[ch] = bsize;
 477             }
 478         }
 479     }
 480
 481     /* parse spectral coefficients : just RLE encoding */
 482     for(ch = 0; ch < s->nb_channels; ch++) {
 483         if (s->channel_coded[ch]) {
 484             int tindex;
 485             WMACoef* ptr = &s->coefs1[ch][0];
 486
 487             /* special VLC tables are used for ms stereo because
 488                there is potentially less energy there */
 489             tindex = (ch == 1 && s->ms_stereo);
 490             memset(ptr, 0, s->block_len * sizeof(WMACoef));
 491             ff_wma_run_level_decode(s->avctx, &s->gb, &s->coef_vlc[tindex],
 492                   s->level_table[tindex], s->run_table[tindex],
 493                   0, ptr, 0, nb_coefs[ch],
 494                   s->block_len, s->frame_len_bits, coef_nb_bits);
 495         }
 496         if (s->version == 1 && s->nb_channels >= 2) {
 497             align_get_bits(&s->gb);
 498         }
 499     }
 500
 501     /* normalize */
 502     {
 503         int n4 = s->block_len / 2;
 504         mdct_norm = 1.0 / (float)n4;
 505         if (s->version == 1) {
 506             mdct_norm *= sqrt(n4);
 507         }
 508     }
 509
 510     /* finally compute the MDCT coefficients */
 511     for(ch = 0; ch < s->nb_channels; ch++) {
 512         if (s->channel_coded[ch]) {
 513             WMACoef *coefs1;
 514             float *coefs, *exponents, mult, mult1, noise;
 515             int i, j, n, n1, last_high_band, esize;
 516             float exp_power[HIGH_BAND_MAX_SIZE];
 517
 518             coefs1 = s->coefs1[ch];
 519             exponents = s->exponents[ch];
 520             esize = s->exponents_bsize[ch];
 521             mult = pow(10, total_gain * 0.05) / s->max_exponent[ch];
 522             mult *= mdct_norm;
 523             coefs = s->coefs[ch];
 524             if (s->use_noise_coding) {
 525                 mult1 = mult;
 526                 /* very low freqs : noise */
 527                 for(i = 0;i < s->coefs_start; i++) {
 528                     *coefs++ = s->noise_table[s->noise_index] *
 529                       exponents[i<<bsize>>esize] * mult1;
 530                     s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
 531                 }
 532
 533                 n1 = s->exponent_high_sizes[bsize];
 534
 535                 /* compute power of high bands */
 536                 exponents = s->exponents[ch] +
 537                     (s->high_band_start[bsize]<<bsize);
 538                 last_high_band = 0; /* avoid warning */
 539                 for(j=0;j<n1;j++) {
 540                     n = s->exponent_high_bands[s->frame_len_bits -
 541                                               s->block_len_bits][j];
 542                     if (s->high_band_coded[ch][j]) {
 543                         float e2, v;
 544                         e2 = 0;
 545                         for(i = 0;i < n; i++) {
 546                             v = exponents[i<<bsize>>esize];
 547                             e2 += v * v;
 548                         }
 549                         exp_power[j] = e2 / n;
 550                         last_high_band = j;
 551                         tprintf(s->avctx, "%d: power=%f (%d)\n", j, exp_power[j], n);
 552                     }
 553                     exponents += n<<bsize;
 554                 }
 555
 556                 /* main freqs and high freqs */
 557                 exponents = s->exponents[ch] + (s->coefs_start<<bsize);
 558                 for(j=-1;j<n1;j++) {
 559                     if (j < 0) {
 560                         n = s->high_band_start[bsize] -
 561                             s->coefs_start;
 562                     } else {
 563                         n = s->exponent_high_bands[s->frame_len_bits -
 564                                                   s->block_len_bits][j];
 565                     }
 566                     if (j >= 0 && s->high_band_coded[ch][j]) {
 567                         /* use noise with specified power */
 568                         mult1 = sqrt(exp_power[j] / exp_power[last_high_band]);
 569                         /* XXX: use a table */
 570                         mult1 = mult1 * pow(10, s->high_band_values[ch][j] * 0.05);
 571                         mult1 = mult1 / (s->max_exponent[ch] * s->noise_mult);
 572                         mult1 *= mdct_norm;
 573                         for(i = 0;i < n; i++) {
 574                             noise = s->noise_table[s->noise_index];
 575                             s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
 576                             *coefs++ =  noise *
 577                                 exponents[i<<bsize>>esize] * mult1;
 578                         }
 579                         exponents += n<<bsize;
 580                     } else {
 581                         /* coded values + small noise */
 582                         for(i = 0;i < n; i++) {
 583                             noise = s->noise_table[s->noise_index];
 584                             s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
 585                             *coefs++ = ((*coefs1++) + noise) *
 586                                 exponents[i<<bsize>>esize] * mult;
 587                         }
 588                         exponents += n<<bsize;
 589                     }
 590                 }
 591
 592                 /* very high freqs : noise */
 593                 n = s->block_len - s->coefs_end[bsize];
 594                 mult1 = mult * exponents[((-1<<bsize))>>esize];
 595                 for(i = 0; i < n; i++) {
 596                     *coefs++ = s->noise_table[s->noise_index] * mult1;
 597                     s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
 598                 }
 599             } else {
 600                 /* XXX: optimize more */
 601                 for(i = 0;i < s->coefs_start; i++)
 602                     *coefs++ = 0.0;
 603                 n = nb_coefs[ch];
 604                 for(i = 0;i < n; i++) {
 605                     *coefs++ = coefs1[i] * exponents[i<<bsize>>esize] * mult;
 606                 }
 607                 n = s->block_len - s->coefs_end[bsize];
 608                 for(i = 0;i < n; i++)
 609                     *coefs++ = 0.0;
 610             }
 611         }
 612     }
 613
 614 #ifdef TRACE
 615     for(ch = 0; ch < s->nb_channels; ch++) {
 616         if (s->channel_coded[ch]) {
 617             dump_floats(s, "exponents", 3, s->exponents[ch], s->block_len);
 618             dump_floats(s, "coefs", 1, s->coefs[ch], s->block_len);
 619         }
 620     }
 621 #endif
 622
 623     if (s->ms_stereo && s->channel_coded[1]) {
 624         /* nominal case for ms stereo: we do it before mdct */
 625         /* no need to optimize this case because it should almost
 626            never happen */
 627         if (!s->channel_coded[0]) {
 628             tprintf(s->avctx, "rare ms-stereo case happened\n");
 629             memset(s->coefs[0], 0, sizeof(float) * s->block_len);
 630             s->channel_coded[0] = 1;
 631         }
 632
 633         s->dsp.butterflies_float(s->coefs[0], s->coefs[1], s->block_len);
 634     }
 635
 636 next:
 637     for(ch = 0; ch < s->nb_channels; ch++) {
 638         int n4, index;
 639
 640         n4 = s->block_len / 2;
 641         if(s->channel_coded[ch]){
 642             ff_imdct_calc(&s->mdct_ctx[bsize], s->output, s->coefs[ch]);
 643         }else if(!(s->ms_stereo && ch==1))
 644             memset(s->output, 0, sizeof(s->output));
 645
 646         /* multiply by the window and add in the frame */
 647         index = (s->frame_len / 2) + s->block_pos - n4;
 648         wma_window(s, &s->frame_out[ch][index]);
 649     }
 650
 651     /* update block number */
 652     s->block_num++;
 653     s->block_pos += s->block_len;
 654     if (s->block_pos >= s->frame_len)
 655         return 1;
 656     else
 657         return 0;
 658 }
 659
 660 /* decode a frame of frame_len samples */
 661 static int wma_decode_frame(WMACodecContext *s, int16_t *samples)
 662 {
 663     int ret, i, n, ch, incr;
 664     int16_t *ptr;
 665     float *iptr;
 666
 667 #ifdef TRACE
 668     tprintf(s->avctx, "***decode_frame: %d size=%d\n", s->frame_count++, s->frame_len);
 669 #endif
 670
 671     /* read each block */
 672     s->block_num = 0;
 673     s->block_pos = 0;
 674     for(;;) {
 675         ret = wma_decode_block(s);
 676         if (ret < 0)
 677             return -1;
 678         if (ret)
 679             break;
 680     }
 681
 682     /* convert frame to integer */
 683     n = s->frame_len;
 684     incr = s->nb_channels;
 685     for(ch = 0; ch < s->nb_channels; ch++) {
 686         ptr = samples + ch;
 687         iptr = s->frame_out[ch];
 688
 689         for(i=0;i<n;i++) {
 690             *ptr = av_clip_int16(lrintf(*iptr++));
 691             ptr += incr;
 692         }
 693         /* prepare for next block */
 694         memmove(&s->frame_out[ch][0], &s->frame_out[ch][s->frame_len],
 695                 s->frame_len * sizeof(float));
 696     }
 697
 698 #ifdef TRACE
 699     dump_shorts(s, "samples", samples, n * s->nb_channels);
 700 #endif
 701     return 0;
 702 }
 703
 704 static int wma_decode_superframe(AVCodecContext *avctx,
 705                                  void *data, int *data_size,
 706                                  AVPacket *avpkt)
 707 {
 708     const uint8_t *buf = avpkt->data;
 709     int buf_size = avpkt->size;
 710     WMACodecContext *s = avctx->priv_data;
 711     int nb_frames, bit_offset, i, pos, len;
 712     uint8_t *q;
 713     int16_t *samples;
 714
 715     tprintf(avctx, "***decode_superframe:\n");
 716
 717     if(buf_size==0){
 718         s->last_superframe_len = 0;
 719         return 0;
 720     }
 721     if (buf_size < s->block_align)
 722         return 0;
 723     buf_size = s->block_align;
 724
 725     samples = data;
 726
 727     init_get_bits(&s->gb, buf, buf_size*8);
 728
 729     if (s->use_bit_reservoir) {
 730         /* read super frame header */
 731         skip_bits(&s->gb, 4); /* super frame index */
 732         nb_frames = get_bits(&s->gb, 4) - 1;
 733
 734         if((nb_frames+1) * s->nb_channels * s->frame_len * sizeof(int16_t) > *data_size){
 735             av_log(s->avctx, AV_LOG_ERROR, "Insufficient output space\n");
 736             goto fail;
 737         }
 738
 739         bit_offset = get_bits(&s->gb, s->byte_offset_bits + 3);
 740
 741         if (s->last_superframe_len > 0) {
 742             //        printf("skip=%d\n", s->last_bitoffset);
 743             /* add bit_offset bits to last frame */
 744             if ((s->last_superframe_len + ((bit_offset + 7) >> 3)) >
 745                 MAX_CODED_SUPERFRAME_SIZE)
 746                 goto fail;
 747             q = s->last_superframe + s->last_superframe_len;
 748             len = bit_offset;
 749             while (len > 7) {
 750                 *q++ = (get_bits)(&s->gb, 8);
 751                 len -= 8;
 752             }
 753             if (len > 0) {
 754                 *q++ = (get_bits)(&s->gb, len) << (8 - len);
 755             }
 756
 757             /* XXX: bit_offset bits into last frame */
 758             init_get_bits(&s->gb, s->last_superframe, MAX_CODED_SUPERFRAME_SIZE*8);
 759             /* skip unused bits */
 760             if (s->last_bitoffset > 0)
 761                 skip_bits(&s->gb, s->last_bitoffset);
 762             /* this frame is stored in the last superframe and in the
 763                current one */
 764             if (wma_decode_frame(s, samples) < 0)
 765                 goto fail;
 766             samples += s->nb_channels * s->frame_len;
 767         }
 768
 769         /* read each frame starting from bit_offset */
 770         pos = bit_offset + 4 + 4 + s->byte_offset_bits + 3;
 771         init_get_bits(&s->gb, buf + (pos >> 3), (MAX_CODED_SUPERFRAME_SIZE - (pos >> 3))*8);
 772         len = pos & 7;
 773         if (len > 0)
 774             skip_bits(&s->gb, len);
 775
 776         s->reset_block_lengths = 1;
 777         for(i=0;i<nb_frames;i++) {
 778             if (wma_decode_frame(s, samples) < 0)
 779                 goto fail;
 780             samples += s->nb_channels * s->frame_len;
 781         }
 782
 783         /* we copy the end of the frame in the last frame buffer */
 784         pos = get_bits_count(&s->gb) + ((bit_offset + 4 + 4 + s->byte_offset_bits + 3) & ~7);
 785         s->last_bitoffset = pos & 7;
 786         pos >>= 3;
 787         len = buf_size - pos;
 788         if (len > MAX_CODED_SUPERFRAME_SIZE || len < 0) {
 789             goto fail;
 790         }
 791         s->last_superframe_len = len;
 792         memcpy(s->last_superframe, buf + pos, len);
 793     } else {
 794         if(s->nb_channels * s->frame_len * sizeof(int16_t) > *data_size){
 795             av_log(s->avctx, AV_LOG_ERROR, "Insufficient output space\n");
 796             goto fail;
 797         }
 798         /* single frame decode */
 799         if (wma_decode_frame(s, samples) < 0)
 800             goto fail;
 801         samples += s->nb_channels * s->frame_len;
 802     }
 803
 804 //av_log(NULL, AV_LOG_ERROR, "%d %d %d %d outbytes:%d eaten:%d\n", s->frame_len_bits, s->block_len_bits, s->frame_len, s->block_len,        (int8_t *)samples - (int8_t *)data, s->block_align);
 805
 806     *data_size = (int8_t *)samples - (int8_t *)data;
 807     return s->block_align;
 808  fail:
 809     /* when error, we reset the bit reservoir */
 810     s->last_superframe_len = 0;
 811     return -1;
 812 }
 813
 814 AVCodec wmav1_decoder =
 815 {
 816     "wmav1",
 817     CODEC_TYPE_AUDIO,
 818     CODEC_ID_WMAV1,
 819     sizeof(WMACodecContext),
 820     wma_decode_init,
 821     NULL,
 822     ff_wma_end,
 823     wma_decode_superframe,
 824     .long_name = NULL_IF_CONFIG_SMALL("Windows Media Audio 1"),
 825 };
 826
 827 AVCodec wmav2_decoder =
 828 {
 829     "wmav2",
 830     CODEC_TYPE_AUDIO,
 831     CODEC_ID_WMAV2,
 832     sizeof(WMACodecContext),
 833     wma_decode_init,
 834     NULL,
 835     ff_wma_end,
 836     wma_decode_superframe,
 837     .long_name = NULL_IF_CONFIG_SMALL("Windows Media Audio 2"),
 838 };