wma.c
Go to the documentation of this file.
1 /*
2  * WMA compatible codec
3  * Copyright (c) 2002-2007 The Libav Project
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; 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 "sinewin.h"
24 #include "wma.h"
25 #include "wmadata.h"
26 
27 #undef NDEBUG
28 #include <assert.h>
29 
30 /* XXX: use same run/length optimization as mpeg decoders */
31 //FIXME maybe split decode / encode or pass flag
32 static void init_coef_vlc(VLC *vlc, uint16_t **prun_table,
33  float **plevel_table, uint16_t **pint_table,
34  const CoefVLCTable *vlc_table)
35 {
36  int n = vlc_table->n;
37  const uint8_t *table_bits = vlc_table->huffbits;
38  const uint32_t *table_codes = vlc_table->huffcodes;
39  const uint16_t *levels_table = vlc_table->levels;
40  uint16_t *run_table, *level_table, *int_table;
41  float *flevel_table;
42  int i, l, j, k, level;
43 
44  init_vlc(vlc, VLCBITS, n, table_bits, 1, 1, table_codes, 4, 4, 0);
45 
46  run_table = av_malloc(n * sizeof(uint16_t));
47  level_table = av_malloc(n * sizeof(uint16_t));
48  flevel_table= av_malloc(n * sizeof(*flevel_table));
49  int_table = av_malloc(n * sizeof(uint16_t));
50  i = 2;
51  level = 1;
52  k = 0;
53  while (i < n) {
54  int_table[k] = i;
55  l = levels_table[k++];
56  for (j = 0; j < l; j++) {
57  run_table[i] = j;
58  level_table[i] = level;
59  flevel_table[i]= level;
60  i++;
61  }
62  level++;
63  }
64  *prun_table = run_table;
65  *plevel_table = flevel_table;
66  *pint_table = int_table;
67  av_free(level_table);
68 }
69 
77 int av_cold ff_wma_get_frame_len_bits(int sample_rate, int version,
78  unsigned int decode_flags)
79 {
80 
81  int frame_len_bits;
82 
83  if (sample_rate <= 16000) {
84  frame_len_bits = 9;
85  } else if (sample_rate <= 22050 ||
86  (sample_rate <= 32000 && version == 1)) {
87  frame_len_bits = 10;
88  } else if (sample_rate <= 48000 || version < 3) {
89  frame_len_bits = 11;
90  } else if (sample_rate <= 96000) {
91  frame_len_bits = 12;
92  } else {
93  frame_len_bits = 13;
94  }
95 
96  if (version == 3) {
97  int tmp = decode_flags & 0x6;
98  if (tmp == 0x2) {
99  ++frame_len_bits;
100  } else if (tmp == 0x4) {
101  --frame_len_bits;
102  } else if (tmp == 0x6) {
103  frame_len_bits -= 2;
104  }
105  }
106 
107  return frame_len_bits;
108 }
109 
110 int ff_wma_init(AVCodecContext *avctx, int flags2)
111 {
112  WMACodecContext *s = avctx->priv_data;
113  int i;
114  float bps1, high_freq;
115  volatile float bps;
116  int sample_rate1;
117  int coef_vlc_table;
118 
119  if ( avctx->sample_rate <= 0 || avctx->sample_rate > 50000
120  || avctx->channels <= 0 || avctx->channels > 8
121  || avctx->bit_rate <= 0)
122  return -1;
123 
124  s->sample_rate = avctx->sample_rate;
125  s->nb_channels = avctx->channels;
126  s->bit_rate = avctx->bit_rate;
127  s->block_align = avctx->block_align;
128 
129  dsputil_init(&s->dsp, avctx);
130  ff_fmt_convert_init(&s->fmt_conv, avctx);
131 
132  if (avctx->codec->id == CODEC_ID_WMAV1) {
133  s->version = 1;
134  } else {
135  s->version = 2;
136  }
137 
138  /* compute MDCT block size */
143 
144  s->frame_len = 1 << s->frame_len_bits;
145  if (s->use_variable_block_len) {
146  int nb_max, nb;
147  nb = ((flags2 >> 3) & 3) + 1;
148  if ((s->bit_rate / s->nb_channels) >= 32000)
149  nb += 2;
150  nb_max = s->frame_len_bits - BLOCK_MIN_BITS;
151  if (nb > nb_max)
152  nb = nb_max;
153  s->nb_block_sizes = nb + 1;
154  } else {
155  s->nb_block_sizes = 1;
156  }
157 
158  /* init rate dependent parameters */
159  s->use_noise_coding = 1;
160  high_freq = s->sample_rate * 0.5;
161 
162  /* if version 2, then the rates are normalized */
163  sample_rate1 = s->sample_rate;
164  if (s->version == 2) {
165  if (sample_rate1 >= 44100) {
166  sample_rate1 = 44100;
167  } else if (sample_rate1 >= 22050) {
168  sample_rate1 = 22050;
169  } else if (sample_rate1 >= 16000) {
170  sample_rate1 = 16000;
171  } else if (sample_rate1 >= 11025) {
172  sample_rate1 = 11025;
173  } else if (sample_rate1 >= 8000) {
174  sample_rate1 = 8000;
175  }
176  }
177 
178  bps = (float)s->bit_rate / (float)(s->nb_channels * s->sample_rate);
179  s->byte_offset_bits = av_log2((int)(bps * s->frame_len / 8.0 + 0.5)) + 2;
180 
181  /* compute high frequency value and choose if noise coding should
182  be activated */
183  bps1 = bps;
184  if (s->nb_channels == 2)
185  bps1 = bps * 1.6;
186  if (sample_rate1 == 44100) {
187  if (bps1 >= 0.61) {
188  s->use_noise_coding = 0;
189  } else {
190  high_freq = high_freq * 0.4;
191  }
192  } else if (sample_rate1 == 22050) {
193  if (bps1 >= 1.16) {
194  s->use_noise_coding = 0;
195  } else if (bps1 >= 0.72) {
196  high_freq = high_freq * 0.7;
197  } else {
198  high_freq = high_freq * 0.6;
199  }
200  } else if (sample_rate1 == 16000) {
201  if (bps > 0.5) {
202  high_freq = high_freq * 0.5;
203  } else {
204  high_freq = high_freq * 0.3;
205  }
206  } else if (sample_rate1 == 11025) {
207  high_freq = high_freq * 0.7;
208  } else if (sample_rate1 == 8000) {
209  if (bps <= 0.625) {
210  high_freq = high_freq * 0.5;
211  } else if (bps > 0.75) {
212  s->use_noise_coding = 0;
213  } else {
214  high_freq = high_freq * 0.65;
215  }
216  } else {
217  if (bps >= 0.8) {
218  high_freq = high_freq * 0.75;
219  } else if (bps >= 0.6) {
220  high_freq = high_freq * 0.6;
221  } else {
222  high_freq = high_freq * 0.5;
223  }
224  }
225  av_dlog(s->avctx, "flags2=0x%x\n", flags2);
226  av_dlog(s->avctx, "version=%d channels=%d sample_rate=%d bitrate=%d block_align=%d\n",
227  s->version, s->nb_channels, s->sample_rate, s->bit_rate,
228  s->block_align);
229  av_dlog(s->avctx, "bps=%f bps1=%f high_freq=%f bitoffset=%d\n",
230  bps, bps1, high_freq, s->byte_offset_bits);
231  av_dlog(s->avctx, "use_noise_coding=%d use_exp_vlc=%d nb_block_sizes=%d\n",
233 
234  /* compute the scale factor band sizes for each MDCT block size */
235  {
236  int a, b, pos, lpos, k, block_len, i, j, n;
237  const uint8_t *table;
238 
239  if (s->version == 1) {
240  s->coefs_start = 3;
241  } else {
242  s->coefs_start = 0;
243  }
244  for (k = 0; k < s->nb_block_sizes; k++) {
245  block_len = s->frame_len >> k;
246 
247  if (s->version == 1) {
248  lpos = 0;
249  for (i = 0; i < 25; i++) {
250  a = ff_wma_critical_freqs[i];
251  b = s->sample_rate;
252  pos = ((block_len * 2 * a) + (b >> 1)) / b;
253  if (pos > block_len)
254  pos = block_len;
255  s->exponent_bands[0][i] = pos - lpos;
256  if (pos >= block_len) {
257  i++;
258  break;
259  }
260  lpos = pos;
261  }
262  s->exponent_sizes[0] = i;
263  } else {
264  /* hardcoded tables */
265  table = NULL;
266  a = s->frame_len_bits - BLOCK_MIN_BITS - k;
267  if (a < 3) {
268  if (s->sample_rate >= 44100) {
269  table = exponent_band_44100[a];
270  } else if (s->sample_rate >= 32000) {
271  table = exponent_band_32000[a];
272  } else if (s->sample_rate >= 22050) {
273  table = exponent_band_22050[a];
274  }
275  }
276  if (table) {
277  n = *table++;
278  for (i = 0; i < n; i++)
279  s->exponent_bands[k][i] = table[i];
280  s->exponent_sizes[k] = n;
281  } else {
282  j = 0;
283  lpos = 0;
284  for (i = 0; i < 25; i++) {
285  a = ff_wma_critical_freqs[i];
286  b = s->sample_rate;
287  pos = ((block_len * 2 * a) + (b << 1)) / (4 * b);
288  pos <<= 2;
289  if (pos > block_len)
290  pos = block_len;
291  if (pos > lpos)
292  s->exponent_bands[k][j++] = pos - lpos;
293  if (pos >= block_len)
294  break;
295  lpos = pos;
296  }
297  s->exponent_sizes[k] = j;
298  }
299  }
300 
301  /* max number of coefs */
302  s->coefs_end[k] = (s->frame_len - ((s->frame_len * 9) / 100)) >> k;
303  /* high freq computation */
304  s->high_band_start[k] = (int)((block_len * 2 * high_freq) /
305  s->sample_rate + 0.5);
306  n = s->exponent_sizes[k];
307  j = 0;
308  pos = 0;
309  for (i = 0; i < n; i++) {
310  int start, end;
311  start = pos;
312  pos += s->exponent_bands[k][i];
313  end = pos;
314  if (start < s->high_band_start[k])
315  start = s->high_band_start[k];
316  if (end > s->coefs_end[k])
317  end = s->coefs_end[k];
318  if (end > start)
319  s->exponent_high_bands[k][j++] = end - start;
320  }
321  s->exponent_high_sizes[k] = j;
322 #if 0
323  tprintf(s->avctx, "%5d: coefs_end=%d high_band_start=%d nb_high_bands=%d: ",
324  s->frame_len >> k,
325  s->coefs_end[k],
326  s->high_band_start[k],
327  s->exponent_high_sizes[k]);
328  for (j = 0; j < s->exponent_high_sizes[k]; j++)
329  tprintf(s->avctx, " %d", s->exponent_high_bands[k][j]);
330  tprintf(s->avctx, "\n");
331 #endif
332  }
333  }
334 
335 #ifdef TRACE
336  {
337  int i, j;
338  for (i = 0; i < s->nb_block_sizes; i++) {
339  tprintf(s->avctx, "%5d: n=%2d:",
340  s->frame_len >> i,
341  s->exponent_sizes[i]);
342  for (j = 0; j < s->exponent_sizes[i]; j++)
343  tprintf(s->avctx, " %d", s->exponent_bands[i][j]);
344  tprintf(s->avctx, "\n");
345  }
346  }
347 #endif
348 
349  /* init MDCT windows : simple sinus window */
350  for (i = 0; i < s->nb_block_sizes; i++) {
352  s->windows[i] = ff_sine_windows[s->frame_len_bits - i];
353  }
354 
355  s->reset_block_lengths = 1;
356 
357  if (s->use_noise_coding) {
358 
359  /* init the noise generator */
360  if (s->use_exp_vlc) {
361  s->noise_mult = 0.02;
362  } else {
363  s->noise_mult = 0.04;
364  }
365 
366 #ifdef TRACE
367  for (i = 0; i < NOISE_TAB_SIZE; i++)
368  s->noise_table[i] = 1.0 * s->noise_mult;
369 #else
370  {
371  unsigned int seed;
372  float norm;
373  seed = 1;
374  norm = (1.0 / (float)(1LL << 31)) * sqrt(3) * s->noise_mult;
375  for (i = 0; i < NOISE_TAB_SIZE; i++) {
376  seed = seed * 314159 + 1;
377  s->noise_table[i] = (float)((int)seed) * norm;
378  }
379  }
380 #endif
381  }
382 
383  /* choose the VLC tables for the coefficients */
384  coef_vlc_table = 2;
385  if (s->sample_rate >= 32000) {
386  if (bps1 < 0.72) {
387  coef_vlc_table = 0;
388  } else if (bps1 < 1.16) {
389  coef_vlc_table = 1;
390  }
391  }
392  s->coef_vlcs[0]= &coef_vlcs[coef_vlc_table * 2 ];
393  s->coef_vlcs[1]= &coef_vlcs[coef_vlc_table * 2 + 1];
394  init_coef_vlc(&s->coef_vlc[0], &s->run_table[0], &s->level_table[0], &s->int_table[0],
395  s->coef_vlcs[0]);
396  init_coef_vlc(&s->coef_vlc[1], &s->run_table[1], &s->level_table[1], &s->int_table[1],
397  s->coef_vlcs[1]);
398 
399  return 0;
400 }
401 
402 int ff_wma_total_gain_to_bits(int total_gain)
403 {
404  if (total_gain < 15) return 13;
405  else if (total_gain < 32) return 12;
406  else if (total_gain < 40) return 11;
407  else if (total_gain < 45) return 10;
408  else return 9;
409 }
410 
412 {
413  WMACodecContext *s = avctx->priv_data;
414  int i;
415 
416  for (i = 0; i < s->nb_block_sizes; i++)
417  ff_mdct_end(&s->mdct_ctx[i]);
418 
419  if (s->use_exp_vlc) {
420  ff_free_vlc(&s->exp_vlc);
421  }
422  if (s->use_noise_coding) {
423  ff_free_vlc(&s->hgain_vlc);
424  }
425  for (i = 0; i < 2; i++) {
426  ff_free_vlc(&s->coef_vlc[i]);
427  av_free(s->run_table[i]);
428  av_free(s->level_table[i]);
429  av_free(s->int_table[i]);
430  }
431 
432  return 0;
433 }
434 
441 {
443  int n_bits = 8;
445  if (get_bits1(gb)) {
446  n_bits += 8;
447  if (get_bits1(gb)) {
448  n_bits += 8;
449  if (get_bits1(gb)) {
450  n_bits += 7;
451  }
452  }
453  }
454  return get_bits_long(gb, n_bits);
455 }
456 
474  VLC *vlc,
475  const float *level_table, const uint16_t *run_table,
476  int version, WMACoef *ptr, int offset,
477  int num_coefs, int block_len, int frame_len_bits,
478  int coef_nb_bits)
479 {
480  int code, level, sign;
481  const uint32_t *ilvl = (const uint32_t*)level_table;
482  uint32_t *iptr = (uint32_t*)ptr;
483  const unsigned int coef_mask = block_len - 1;
484  for (; offset < num_coefs; offset++) {
485  code = get_vlc2(gb, vlc->table, VLCBITS, VLCMAX);
486  if (code > 1) {
488  offset += run_table[code];
489  sign = get_bits1(gb) - 1;
490  iptr[offset & coef_mask] = ilvl[code] ^ sign<<31;
491  } else if (code == 1) {
493  break;
494  } else {
496  if (!version) {
497  level = get_bits(gb, coef_nb_bits);
500  offset += get_bits(gb, frame_len_bits);
501  } else {
502  level = ff_wma_get_large_val(gb);
504  if (get_bits1(gb)) {
505  if (get_bits1(gb)) {
506  if (get_bits1(gb)) {
507  av_log(avctx,AV_LOG_ERROR,
508  "broken escape sequence\n");
509  return -1;
510  } else
511  offset += get_bits(gb, frame_len_bits) + 4;
512  } else
513  offset += get_bits(gb, 2) + 1;
514  }
515  }
516  sign = get_bits1(gb) - 1;
517  ptr[offset & coef_mask] = (level^sign) - sign;
518  }
519  }
521  if (offset > num_coefs) {
522  av_log(avctx, AV_LOG_ERROR, "overflow in spectral RLE, ignoring\n");
523  return -1;
524  }
525 
526  return 0;
527 }
528