imc.c
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1 /*
2  * IMC compatible decoder
3  * Copyright (c) 2002-2004 Maxim Poliakovski
4  * Copyright (c) 2006 Benjamin Larsson
5  * Copyright (c) 2006 Konstantin Shishkov
6  *
7  * This file is part of Libav.
8  *
9  * Libav is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * Libav is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with Libav; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
34 #include <math.h>
35 #include <stddef.h>
36 #include <stdio.h>
37 
39 #include "libavutil/float_dsp.h"
40 #include "avcodec.h"
41 #include "get_bits.h"
42 #include "dsputil.h"
43 #include "fft.h"
44 #include "internal.h"
45 #include "sinewin.h"
46 
47 #include "imcdata.h"
48 
49 #define IMC_BLOCK_SIZE 64
50 #define IMC_FRAME_ID 0x21
51 #define BANDS 32
52 #define COEFFS 256
53 
54 typedef struct IMCChannel {
55  float old_floor[BANDS];
56  float flcoeffs1[BANDS];
57  float flcoeffs2[BANDS];
58  float flcoeffs3[BANDS];
59  float flcoeffs4[BANDS];
60  float flcoeffs5[BANDS];
61  float flcoeffs6[BANDS];
62  float CWdecoded[COEFFS];
63 
75 
77 
79 } IMCChannel;
80 
81 typedef struct {
83 
84  IMCChannel chctx[2];
85 
88  float mdct_sine_window[COEFFS];
89  float post_cos[COEFFS];
90  float post_sin[COEFFS];
91  float pre_coef1[COEFFS];
92  float pre_coef2[COEFFS];
94 
95  float sqrt_tab[30];
97 
102  float *out_samples;
103 
104  int8_t cyclTab[32], cyclTab2[32];
105  float weights1[31], weights2[31];
106 } IMCContext;
107 
108 static VLC huffman_vlc[4][4];
109 
110 #define VLC_TABLES_SIZE 9512
111 
112 static const int vlc_offsets[17] = {
113  0, 640, 1156, 1732, 2308, 2852, 3396, 3924,
114  4452, 5220, 5860, 6628, 7268, 7908, 8424, 8936, VLC_TABLES_SIZE
115 };
116 
118 
119 static inline double freq2bark(double freq)
120 {
121  return 3.5 * atan((freq / 7500.0) * (freq / 7500.0)) + 13.0 * atan(freq * 0.00076);
122 }
123 
124 static av_cold void iac_generate_tabs(IMCContext *q, int sampling_rate)
125 {
126  double freqmin[32], freqmid[32], freqmax[32];
127  double scale = sampling_rate / (256.0 * 2.0 * 2.0);
128  double nyquist_freq = sampling_rate * 0.5;
129  double freq, bark, prev_bark = 0, tf, tb;
130  int i, j;
131 
132  for (i = 0; i < 32; i++) {
133  freq = (band_tab[i] + band_tab[i + 1] - 1) * scale;
134  bark = freq2bark(freq);
135 
136  if (i > 0) {
137  tb = bark - prev_bark;
138  q->weights1[i - 1] = pow(10.0, -1.0 * tb);
139  q->weights2[i - 1] = pow(10.0, -2.7 * tb);
140  }
141  prev_bark = bark;
142 
143  freqmid[i] = freq;
144 
145  tf = freq;
146  while (tf < nyquist_freq) {
147  tf += 0.5;
148  tb = freq2bark(tf);
149  if (tb > bark + 0.5)
150  break;
151  }
152  freqmax[i] = tf;
153 
154  tf = freq;
155  while (tf > 0.0) {
156  tf -= 0.5;
157  tb = freq2bark(tf);
158  if (tb <= bark - 0.5)
159  break;
160  }
161  freqmin[i] = tf;
162  }
163 
164  for (i = 0; i < 32; i++) {
165  freq = freqmax[i];
166  for (j = 31; j > 0 && freq <= freqmid[j]; j--);
167  q->cyclTab[i] = j + 1;
168 
169  freq = freqmin[i];
170  for (j = 0; j < 32 && freq >= freqmid[j]; j++);
171  q->cyclTab2[i] = j - 1;
172  }
173 }
174 
176 {
177  int i, j, ret;
178  IMCContext *q = avctx->priv_data;
179  double r1, r2;
180 
181  if (avctx->codec_id == AV_CODEC_ID_IMC)
182  avctx->channels = 1;
183 
184  if (avctx->channels > 2) {
185  av_log_ask_for_sample(avctx, "Number of channels is not supported\n");
186  return AVERROR_PATCHWELCOME;
187  }
188 
189  for (j = 0; j < avctx->channels; j++) {
190  q->chctx[j].decoder_reset = 1;
191 
192  for (i = 0; i < BANDS; i++)
193  q->chctx[j].old_floor[i] = 1.0;
194 
195  for (i = 0; i < COEFFS / 2; i++)
196  q->chctx[j].last_fft_im[i] = 0;
197  }
198 
199  /* Build mdct window, a simple sine window normalized with sqrt(2) */
201  for (i = 0; i < COEFFS; i++)
202  q->mdct_sine_window[i] *= sqrt(2.0);
203  for (i = 0; i < COEFFS / 2; i++) {
204  q->post_cos[i] = (1.0f / 32768) * cos(i / 256.0 * M_PI);
205  q->post_sin[i] = (1.0f / 32768) * sin(i / 256.0 * M_PI);
206 
207  r1 = sin((i * 4.0 + 1.0) / 1024.0 * M_PI);
208  r2 = cos((i * 4.0 + 1.0) / 1024.0 * M_PI);
209 
210  if (i & 0x1) {
211  q->pre_coef1[i] = (r1 + r2) * sqrt(2.0);
212  q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0);
213  } else {
214  q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0);
215  q->pre_coef2[i] = (r1 - r2) * sqrt(2.0);
216  }
217  }
218 
219  /* Generate a square root table */
220 
221  for (i = 0; i < 30; i++)
222  q->sqrt_tab[i] = sqrt(i);
223 
224  /* initialize the VLC tables */
225  for (i = 0; i < 4 ; i++) {
226  for (j = 0; j < 4; j++) {
227  huffman_vlc[i][j].table = &vlc_tables[vlc_offsets[i * 4 + j]];
228  huffman_vlc[i][j].table_allocated = vlc_offsets[i * 4 + j + 1] - vlc_offsets[i * 4 + j];
229  init_vlc(&huffman_vlc[i][j], 9, imc_huffman_sizes[i],
230  imc_huffman_lens[i][j], 1, 1,
232  }
233  }
234 
235  if (avctx->codec_id == AV_CODEC_ID_IAC) {
236  iac_generate_tabs(q, avctx->sample_rate);
237  } else {
238  memcpy(q->cyclTab, cyclTab, sizeof(cyclTab));
239  memcpy(q->cyclTab2, cyclTab2, sizeof(cyclTab2));
240  memcpy(q->weights1, imc_weights1, sizeof(imc_weights1));
241  memcpy(q->weights2, imc_weights2, sizeof(imc_weights2));
242  }
243 
244  if ((ret = ff_fft_init(&q->fft, 7, 1))) {
245  av_log(avctx, AV_LOG_INFO, "FFT init failed\n");
246  return ret;
247  }
248  ff_dsputil_init(&q->dsp, avctx);
251  avctx->channel_layout = avctx->channels == 1 ? AV_CH_LAYOUT_MONO
253 
255  avctx->coded_frame = &q->frame;
256 
257  return 0;
258 }
259 
260 static void imc_calculate_coeffs(IMCContext *q, float *flcoeffs1,
261  float *flcoeffs2, int *bandWidthT,
262  float *flcoeffs3, float *flcoeffs5)
263 {
264  float workT1[BANDS];
265  float workT2[BANDS];
266  float workT3[BANDS];
267  float snr_limit = 1.e-30;
268  float accum = 0.0;
269  int i, cnt2;
270 
271  for (i = 0; i < BANDS; i++) {
272  flcoeffs5[i] = workT2[i] = 0.0;
273  if (bandWidthT[i]) {
274  workT1[i] = flcoeffs1[i] * flcoeffs1[i];
275  flcoeffs3[i] = 2.0 * flcoeffs2[i];
276  } else {
277  workT1[i] = 0.0;
278  flcoeffs3[i] = -30000.0;
279  }
280  workT3[i] = bandWidthT[i] * workT1[i] * 0.01;
281  if (workT3[i] <= snr_limit)
282  workT3[i] = 0.0;
283  }
284 
285  for (i = 0; i < BANDS; i++) {
286  for (cnt2 = i; cnt2 < q->cyclTab[i]; cnt2++)
287  flcoeffs5[cnt2] = flcoeffs5[cnt2] + workT3[i];
288  workT2[cnt2 - 1] = workT2[cnt2 - 1] + workT3[i];
289  }
290 
291  for (i = 1; i < BANDS; i++) {
292  accum = (workT2[i - 1] + accum) * q->weights1[i - 1];
293  flcoeffs5[i] += accum;
294  }
295 
296  for (i = 0; i < BANDS; i++)
297  workT2[i] = 0.0;
298 
299  for (i = 0; i < BANDS; i++) {
300  for (cnt2 = i - 1; cnt2 > q->cyclTab2[i]; cnt2--)
301  flcoeffs5[cnt2] += workT3[i];
302  workT2[cnt2+1] += workT3[i];
303  }
304 
305  accum = 0.0;
306 
307  for (i = BANDS-2; i >= 0; i--) {
308  accum = (workT2[i+1] + accum) * q->weights2[i];
309  flcoeffs5[i] += accum;
310  // there is missing code here, but it seems to never be triggered
311  }
312 }
313 
314 
315 static void imc_read_level_coeffs(IMCContext *q, int stream_format_code,
316  int *levlCoeffs)
317 {
318  int i;
319  VLC *hufftab[4];
320  int start = 0;
321  const uint8_t *cb_sel;
322  int s;
323 
324  s = stream_format_code >> 1;
325  hufftab[0] = &huffman_vlc[s][0];
326  hufftab[1] = &huffman_vlc[s][1];
327  hufftab[2] = &huffman_vlc[s][2];
328  hufftab[3] = &huffman_vlc[s][3];
329  cb_sel = imc_cb_select[s];
330 
331  if (stream_format_code & 4)
332  start = 1;
333  if (start)
334  levlCoeffs[0] = get_bits(&q->gb, 7);
335  for (i = start; i < BANDS; i++) {
336  levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table,
337  hufftab[cb_sel[i]]->bits, 2);
338  if (levlCoeffs[i] == 17)
339  levlCoeffs[i] += get_bits(&q->gb, 4);
340  }
341 }
342 
343 static void imc_decode_level_coefficients(IMCContext *q, int *levlCoeffBuf,
344  float *flcoeffs1, float *flcoeffs2)
345 {
346  int i, level;
347  float tmp, tmp2;
348  // maybe some frequency division thingy
349 
350  flcoeffs1[0] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
351  flcoeffs2[0] = log2f(flcoeffs1[0]);
352  tmp = flcoeffs1[0];
353  tmp2 = flcoeffs2[0];
354 
355  for (i = 1; i < BANDS; i++) {
356  level = levlCoeffBuf[i];
357  if (level == 16) {
358  flcoeffs1[i] = 1.0;
359  flcoeffs2[i] = 0.0;
360  } else {
361  if (level < 17)
362  level -= 7;
363  else if (level <= 24)
364  level -= 32;
365  else
366  level -= 16;
367 
368  tmp *= imc_exp_tab[15 + level];
369  tmp2 += 0.83048 * level; // 0.83048 = log2(10) * 0.25
370  flcoeffs1[i] = tmp;
371  flcoeffs2[i] = tmp2;
372  }
373  }
374 }
375 
376 
377 static void imc_decode_level_coefficients2(IMCContext *q, int *levlCoeffBuf,
378  float *old_floor, float *flcoeffs1,
379  float *flcoeffs2)
380 {
381  int i;
382  /* FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors
383  * and flcoeffs2 old scale factors
384  * might be incomplete due to a missing table that is in the binary code
385  */
386  for (i = 0; i < BANDS; i++) {
387  flcoeffs1[i] = 0;
388  if (levlCoeffBuf[i] < 16) {
389  flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i];
390  flcoeffs2[i] = (levlCoeffBuf[i] - 7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25
391  } else {
392  flcoeffs1[i] = old_floor[i];
393  }
394  }
395 }
396 
400 static int bit_allocation(IMCContext *q, IMCChannel *chctx,
401  int stream_format_code, int freebits, int flag)
402 {
403  int i, j;
404  const float limit = -1.e20;
405  float highest = 0.0;
406  int indx;
407  int t1 = 0;
408  int t2 = 1;
409  float summa = 0.0;
410  int iacc = 0;
411  int summer = 0;
412  int rres, cwlen;
413  float lowest = 1.e10;
414  int low_indx = 0;
415  float workT[32];
416  int flg;
417  int found_indx = 0;
418 
419  for (i = 0; i < BANDS; i++)
420  highest = FFMAX(highest, chctx->flcoeffs1[i]);
421 
422  for (i = 0; i < BANDS - 1; i++)
423  chctx->flcoeffs4[i] = chctx->flcoeffs3[i] - log2f(chctx->flcoeffs5[i]);
424  chctx->flcoeffs4[BANDS - 1] = limit;
425 
426  highest = highest * 0.25;
427 
428  for (i = 0; i < BANDS; i++) {
429  indx = -1;
430  if ((band_tab[i + 1] - band_tab[i]) == chctx->bandWidthT[i])
431  indx = 0;
432 
433  if ((band_tab[i + 1] - band_tab[i]) > chctx->bandWidthT[i])
434  indx = 1;
435 
436  if (((band_tab[i + 1] - band_tab[i]) / 2) >= chctx->bandWidthT[i])
437  indx = 2;
438 
439  if (indx == -1)
440  return AVERROR_INVALIDDATA;
441 
442  chctx->flcoeffs4[i] += xTab[(indx * 2 + (chctx->flcoeffs1[i] < highest)) * 2 + flag];
443  }
444 
445  if (stream_format_code & 0x2) {
446  chctx->flcoeffs4[0] = limit;
447  chctx->flcoeffs4[1] = limit;
448  chctx->flcoeffs4[2] = limit;
449  chctx->flcoeffs4[3] = limit;
450  }
451 
452  for (i = (stream_format_code & 0x2) ? 4 : 0; i < BANDS - 1; i++) {
453  iacc += chctx->bandWidthT[i];
454  summa += chctx->bandWidthT[i] * chctx->flcoeffs4[i];
455  }
456 
457  if (!iacc)
458  return AVERROR_INVALIDDATA;
459 
460  chctx->bandWidthT[BANDS - 1] = 0;
461  summa = (summa * 0.5 - freebits) / iacc;
462 
463 
464  for (i = 0; i < BANDS / 2; i++) {
465  rres = summer - freebits;
466  if ((rres >= -8) && (rres <= 8))
467  break;
468 
469  summer = 0;
470  iacc = 0;
471 
472  for (j = (stream_format_code & 0x2) ? 4 : 0; j < BANDS; j++) {
473  cwlen = av_clipf(((chctx->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6);
474 
475  chctx->bitsBandT[j] = cwlen;
476  summer += chctx->bandWidthT[j] * cwlen;
477 
478  if (cwlen > 0)
479  iacc += chctx->bandWidthT[j];
480  }
481 
482  flg = t2;
483  t2 = 1;
484  if (freebits < summer)
485  t2 = -1;
486  if (i == 0)
487  flg = t2;
488  if (flg != t2)
489  t1++;
490 
491  summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa;
492  }
493 
494  for (i = (stream_format_code & 0x2) ? 4 : 0; i < BANDS; i++) {
495  for (j = band_tab[i]; j < band_tab[i + 1]; j++)
496  chctx->CWlengthT[j] = chctx->bitsBandT[i];
497  }
498 
499  if (freebits > summer) {
500  for (i = 0; i < BANDS; i++) {
501  workT[i] = (chctx->bitsBandT[i] == 6) ? -1.e20
502  : (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] - 0.415);
503  }
504 
505  highest = 0.0;
506 
507  do {
508  if (highest <= -1.e20)
509  break;
510 
511  found_indx = 0;
512  highest = -1.e20;
513 
514  for (i = 0; i < BANDS; i++) {
515  if (workT[i] > highest) {
516  highest = workT[i];
517  found_indx = i;
518  }
519  }
520 
521  if (highest > -1.e20) {
522  workT[found_indx] -= 2.0;
523  if (++chctx->bitsBandT[found_indx] == 6)
524  workT[found_indx] = -1.e20;
525 
526  for (j = band_tab[found_indx]; j < band_tab[found_indx + 1] && (freebits > summer); j++) {
527  chctx->CWlengthT[j]++;
528  summer++;
529  }
530  }
531  } while (freebits > summer);
532  }
533  if (freebits < summer) {
534  for (i = 0; i < BANDS; i++) {
535  workT[i] = chctx->bitsBandT[i] ? (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] + 1.585)
536  : 1.e20;
537  }
538  if (stream_format_code & 0x2) {
539  workT[0] = 1.e20;
540  workT[1] = 1.e20;
541  workT[2] = 1.e20;
542  workT[3] = 1.e20;
543  }
544  while (freebits < summer) {
545  lowest = 1.e10;
546  low_indx = 0;
547  for (i = 0; i < BANDS; i++) {
548  if (workT[i] < lowest) {
549  lowest = workT[i];
550  low_indx = i;
551  }
552  }
553  // if (lowest >= 1.e10)
554  // break;
555  workT[low_indx] = lowest + 2.0;
556 
557  if (!--chctx->bitsBandT[low_indx])
558  workT[low_indx] = 1.e20;
559 
560  for (j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++) {
561  if (chctx->CWlengthT[j] > 0) {
562  chctx->CWlengthT[j]--;
563  summer--;
564  }
565  }
566  }
567  }
568  return 0;
569 }
570 
571 static void imc_get_skip_coeff(IMCContext *q, IMCChannel *chctx)
572 {
573  int i, j;
574 
575  memset(chctx->skipFlagBits, 0, sizeof(chctx->skipFlagBits));
576  memset(chctx->skipFlagCount, 0, sizeof(chctx->skipFlagCount));
577  for (i = 0; i < BANDS; i++) {
578  if (!chctx->bandFlagsBuf[i] || !chctx->bandWidthT[i])
579  continue;
580 
581  if (!chctx->skipFlagRaw[i]) {
582  chctx->skipFlagBits[i] = band_tab[i + 1] - band_tab[i];
583 
584  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
585  chctx->skipFlags[j] = get_bits1(&q->gb);
586  if (chctx->skipFlags[j])
587  chctx->skipFlagCount[i]++;
588  }
589  } else {
590  for (j = band_tab[i]; j < band_tab[i + 1] - 1; j += 2) {
591  if (!get_bits1(&q->gb)) { // 0
592  chctx->skipFlagBits[i]++;
593  chctx->skipFlags[j] = 1;
594  chctx->skipFlags[j + 1] = 1;
595  chctx->skipFlagCount[i] += 2;
596  } else {
597  if (get_bits1(&q->gb)) { // 11
598  chctx->skipFlagBits[i] += 2;
599  chctx->skipFlags[j] = 0;
600  chctx->skipFlags[j + 1] = 1;
601  chctx->skipFlagCount[i]++;
602  } else {
603  chctx->skipFlagBits[i] += 3;
604  chctx->skipFlags[j + 1] = 0;
605  if (!get_bits1(&q->gb)) { // 100
606  chctx->skipFlags[j] = 1;
607  chctx->skipFlagCount[i]++;
608  } else { // 101
609  chctx->skipFlags[j] = 0;
610  }
611  }
612  }
613  }
614 
615  if (j < band_tab[i + 1]) {
616  chctx->skipFlagBits[i]++;
617  if ((chctx->skipFlags[j] = get_bits1(&q->gb)))
618  chctx->skipFlagCount[i]++;
619  }
620  }
621  }
622 }
623 
628  int summer)
629 {
630  float workT[32];
631  int corrected = 0;
632  int i, j;
633  float highest = 0;
634  int found_indx = 0;
635 
636  for (i = 0; i < BANDS; i++) {
637  workT[i] = (chctx->bitsBandT[i] == 6) ? -1.e20
638  : (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] - 0.415);
639  }
640 
641  while (corrected < summer) {
642  if (highest <= -1.e20)
643  break;
644 
645  highest = -1.e20;
646 
647  for (i = 0; i < BANDS; i++) {
648  if (workT[i] > highest) {
649  highest = workT[i];
650  found_indx = i;
651  }
652  }
653 
654  if (highest > -1.e20) {
655  workT[found_indx] -= 2.0;
656  if (++(chctx->bitsBandT[found_indx]) == 6)
657  workT[found_indx] = -1.e20;
658 
659  for (j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) {
660  if (!chctx->skipFlags[j] && (chctx->CWlengthT[j] < 6)) {
661  chctx->CWlengthT[j]++;
662  corrected++;
663  }
664  }
665  }
666  }
667 }
668 
669 static void imc_imdct256(IMCContext *q, IMCChannel *chctx, int channels)
670 {
671  int i;
672  float re, im;
673  float *dst1 = q->out_samples;
674  float *dst2 = q->out_samples + (COEFFS - 1);
675 
676  /* prerotation */
677  for (i = 0; i < COEFFS / 2; i++) {
678  q->samples[i].re = -(q->pre_coef1[i] * chctx->CWdecoded[COEFFS - 1 - i * 2]) -
679  (q->pre_coef2[i] * chctx->CWdecoded[i * 2]);
680  q->samples[i].im = (q->pre_coef2[i] * chctx->CWdecoded[COEFFS - 1 - i * 2]) -
681  (q->pre_coef1[i] * chctx->CWdecoded[i * 2]);
682  }
683 
684  /* FFT */
685  q->fft.fft_permute(&q->fft, q->samples);
686  q->fft.fft_calc(&q->fft, q->samples);
687 
688  /* postrotation, window and reorder */
689  for (i = 0; i < COEFFS / 2; i++) {
690  re = ( q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]);
691  im = (-q->samples[i].im * q->post_cos[i]) - ( q->samples[i].re * q->post_sin[i]);
692  *dst1 = (q->mdct_sine_window[COEFFS - 1 - i * 2] * chctx->last_fft_im[i])
693  + (q->mdct_sine_window[i * 2] * re);
694  *dst2 = (q->mdct_sine_window[i * 2] * chctx->last_fft_im[i])
695  - (q->mdct_sine_window[COEFFS - 1 - i * 2] * re);
696  dst1 += 2;
697  dst2 -= 2;
698  chctx->last_fft_im[i] = im;
699  }
700 }
701 
703  int stream_format_code)
704 {
705  int i, j;
706  int middle_value, cw_len, max_size;
707  const float *quantizer;
708 
709  for (i = 0; i < BANDS; i++) {
710  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
711  chctx->CWdecoded[j] = 0;
712  cw_len = chctx->CWlengthT[j];
713 
714  if (cw_len <= 0 || chctx->skipFlags[j])
715  continue;
716 
717  max_size = 1 << cw_len;
718  middle_value = max_size >> 1;
719 
720  if (chctx->codewords[j] >= max_size || chctx->codewords[j] < 0)
721  return AVERROR_INVALIDDATA;
722 
723  if (cw_len >= 4) {
724  quantizer = imc_quantizer2[(stream_format_code & 2) >> 1];
725  if (chctx->codewords[j] >= middle_value)
726  chctx->CWdecoded[j] = quantizer[chctx->codewords[j] - 8] * chctx->flcoeffs6[i];
727  else
728  chctx->CWdecoded[j] = -quantizer[max_size - chctx->codewords[j] - 8 - 1] * chctx->flcoeffs6[i];
729  }else{
730  quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (chctx->bandFlagsBuf[i] << 1)];
731  if (chctx->codewords[j] >= middle_value)
732  chctx->CWdecoded[j] = quantizer[chctx->codewords[j] - 1] * chctx->flcoeffs6[i];
733  else
734  chctx->CWdecoded[j] = -quantizer[max_size - 2 - chctx->codewords[j]] * chctx->flcoeffs6[i];
735  }
736  }
737  }
738  return 0;
739 }
740 
741 
742 static int imc_get_coeffs(IMCContext *q, IMCChannel *chctx)
743 {
744  int i, j, cw_len, cw;
745 
746  for (i = 0; i < BANDS; i++) {
747  if (!chctx->sumLenArr[i])
748  continue;
749  if (chctx->bandFlagsBuf[i] || chctx->bandWidthT[i]) {
750  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
751  cw_len = chctx->CWlengthT[j];
752  cw = 0;
753 
754  if (get_bits_count(&q->gb) + cw_len > 512) {
755  av_dlog(NULL, "Band %i coeff %i cw_len %i\n", i, j, cw_len);
756  return AVERROR_INVALIDDATA;
757  }
758 
759  if (cw_len && (!chctx->bandFlagsBuf[i] || !chctx->skipFlags[j]))
760  cw = get_bits(&q->gb, cw_len);
761 
762  chctx->codewords[j] = cw;
763  }
764  }
765  }
766  return 0;
767 }
768 
769 static int imc_decode_block(AVCodecContext *avctx, IMCContext *q, int ch)
770 {
771  int stream_format_code;
772  int imc_hdr, i, j, ret;
773  int flag;
774  int bits, summer;
775  int counter, bitscount;
776  IMCChannel *chctx = q->chctx + ch;
777 
778 
779  /* Check the frame header */
780  imc_hdr = get_bits(&q->gb, 9);
781  if (imc_hdr & 0x18) {
782  av_log(avctx, AV_LOG_ERROR, "frame header check failed!\n");
783  av_log(avctx, AV_LOG_ERROR, "got %X.\n", imc_hdr);
784  return AVERROR_INVALIDDATA;
785  }
786  stream_format_code = get_bits(&q->gb, 3);
787 
788  if (stream_format_code & 1) {
789  av_log_ask_for_sample(avctx, "Stream format %X is not supported\n",
790  stream_format_code);
791  return AVERROR_PATCHWELCOME;
792  }
793 
794  if (stream_format_code & 0x04)
795  chctx->decoder_reset = 1;
796 
797  if (chctx->decoder_reset) {
798  for (i = 0; i < BANDS; i++)
799  chctx->old_floor[i] = 1.0;
800  for (i = 0; i < COEFFS; i++)
801  chctx->CWdecoded[i] = 0;
802  chctx->decoder_reset = 0;
803  }
804 
805  flag = get_bits1(&q->gb);
806  imc_read_level_coeffs(q, stream_format_code, chctx->levlCoeffBuf);
807 
808  if (stream_format_code & 0x4)
810  chctx->flcoeffs1, chctx->flcoeffs2);
811  else
813  chctx->flcoeffs1, chctx->flcoeffs2);
814 
815  memcpy(chctx->old_floor, chctx->flcoeffs1, 32 * sizeof(float));
816 
817  counter = 0;
818  for (i = 0; i < BANDS; i++) {
819  if (chctx->levlCoeffBuf[i] == 16) {
820  chctx->bandWidthT[i] = 0;
821  counter++;
822  } else
823  chctx->bandWidthT[i] = band_tab[i + 1] - band_tab[i];
824  }
825  memset(chctx->bandFlagsBuf, 0, BANDS * sizeof(int));
826  for (i = 0; i < BANDS - 1; i++) {
827  if (chctx->bandWidthT[i])
828  chctx->bandFlagsBuf[i] = get_bits1(&q->gb);
829  }
830 
831  imc_calculate_coeffs(q, chctx->flcoeffs1, chctx->flcoeffs2, chctx->bandWidthT, chctx->flcoeffs3, chctx->flcoeffs5);
832 
833  bitscount = 0;
834  /* first 4 bands will be assigned 5 bits per coefficient */
835  if (stream_format_code & 0x2) {
836  bitscount += 15;
837 
838  chctx->bitsBandT[0] = 5;
839  chctx->CWlengthT[0] = 5;
840  chctx->CWlengthT[1] = 5;
841  chctx->CWlengthT[2] = 5;
842  for (i = 1; i < 4; i++) {
843  bits = (chctx->levlCoeffBuf[i] == 16) ? 0 : 5;
844  chctx->bitsBandT[i] = bits;
845  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
846  chctx->CWlengthT[j] = bits;
847  bitscount += bits;
848  }
849  }
850  }
851  if (avctx->codec_id == AV_CODEC_ID_IAC) {
852  bitscount += !!chctx->bandWidthT[BANDS - 1];
853  if (!(stream_format_code & 0x2))
854  bitscount += 16;
855  }
856 
857  if ((ret = bit_allocation(q, chctx, stream_format_code,
858  512 - bitscount - get_bits_count(&q->gb),
859  flag)) < 0) {
860  av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n");
861  chctx->decoder_reset = 1;
862  return ret;
863  }
864 
865  for (i = 0; i < BANDS; i++) {
866  chctx->sumLenArr[i] = 0;
867  chctx->skipFlagRaw[i] = 0;
868  for (j = band_tab[i]; j < band_tab[i + 1]; j++)
869  chctx->sumLenArr[i] += chctx->CWlengthT[j];
870  if (chctx->bandFlagsBuf[i])
871  if ((((band_tab[i + 1] - band_tab[i]) * 1.5) > chctx->sumLenArr[i]) && (chctx->sumLenArr[i] > 0))
872  chctx->skipFlagRaw[i] = 1;
873  }
874 
875  imc_get_skip_coeff(q, chctx);
876 
877  for (i = 0; i < BANDS; i++) {
878  chctx->flcoeffs6[i] = chctx->flcoeffs1[i];
879  /* band has flag set and at least one coded coefficient */
880  if (chctx->bandFlagsBuf[i] && (band_tab[i + 1] - band_tab[i]) != chctx->skipFlagCount[i]) {
881  chctx->flcoeffs6[i] *= q->sqrt_tab[ band_tab[i + 1] - band_tab[i]] /
882  q->sqrt_tab[(band_tab[i + 1] - band_tab[i] - chctx->skipFlagCount[i])];
883  }
884  }
885 
886  /* calculate bits left, bits needed and adjust bit allocation */
887  bits = summer = 0;
888 
889  for (i = 0; i < BANDS; i++) {
890  if (chctx->bandFlagsBuf[i]) {
891  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
892  if (chctx->skipFlags[j]) {
893  summer += chctx->CWlengthT[j];
894  chctx->CWlengthT[j] = 0;
895  }
896  }
897  bits += chctx->skipFlagBits[i];
898  summer -= chctx->skipFlagBits[i];
899  }
900  }
901  imc_adjust_bit_allocation(q, chctx, summer);
902 
903  for (i = 0; i < BANDS; i++) {
904  chctx->sumLenArr[i] = 0;
905 
906  for (j = band_tab[i]; j < band_tab[i + 1]; j++)
907  if (!chctx->skipFlags[j])
908  chctx->sumLenArr[i] += chctx->CWlengthT[j];
909  }
910 
911  memset(chctx->codewords, 0, sizeof(chctx->codewords));
912 
913  if (imc_get_coeffs(q, chctx) < 0) {
914  av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n");
915  chctx->decoder_reset = 1;
916  return AVERROR_INVALIDDATA;
917  }
918 
919  if (inverse_quant_coeff(q, chctx, stream_format_code) < 0) {
920  av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n");
921  chctx->decoder_reset = 1;
922  return AVERROR_INVALIDDATA;
923  }
924 
925  memset(chctx->skipFlags, 0, sizeof(chctx->skipFlags));
926 
927  imc_imdct256(q, chctx, avctx->channels);
928 
929  return 0;
930 }
931 
932 static int imc_decode_frame(AVCodecContext *avctx, void *data,
933  int *got_frame_ptr, AVPacket *avpkt)
934 {
935  const uint8_t *buf = avpkt->data;
936  int buf_size = avpkt->size;
937  int ret, i;
938 
939  IMCContext *q = avctx->priv_data;
940 
941  LOCAL_ALIGNED_16(uint16_t, buf16, [IMC_BLOCK_SIZE / 2]);
942 
943  if (buf_size < IMC_BLOCK_SIZE * avctx->channels) {
944  av_log(avctx, AV_LOG_ERROR, "frame too small!\n");
945  return AVERROR_INVALIDDATA;
946  }
947 
948  /* get output buffer */
949  q->frame.nb_samples = COEFFS;
950  if ((ret = ff_get_buffer(avctx, &q->frame)) < 0) {
951  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
952  return ret;
953  }
954 
955  for (i = 0; i < avctx->channels; i++) {
956  q->out_samples = (float *)q->frame.extended_data[i];
957 
958  q->dsp.bswap16_buf(buf16, (const uint16_t*)buf, IMC_BLOCK_SIZE / 2);
959 
960  init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8);
961 
962  buf += IMC_BLOCK_SIZE;
963 
964  if ((ret = imc_decode_block(avctx, q, i)) < 0)
965  return ret;
966  }
967 
968  if (avctx->channels == 2) {
969  q->fdsp.butterflies_float((float *)q->frame.extended_data[0],
970  (float *)q->frame.extended_data[1], COEFFS);
971  }
972 
973  *got_frame_ptr = 1;
974  *(AVFrame *)data = q->frame;
975 
976  return IMC_BLOCK_SIZE * avctx->channels;
977 }
978 
979 
981 {
982  IMCContext *q = avctx->priv_data;
983 
984  ff_fft_end(&q->fft);
985 
986  return 0;
987 }
988 
989 
991  .name = "imc",
992  .type = AVMEDIA_TYPE_AUDIO,
993  .id = AV_CODEC_ID_IMC,
994  .priv_data_size = sizeof(IMCContext),
998  .capabilities = CODEC_CAP_DR1,
999  .long_name = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"),
1000  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
1002 };
1003 
1005  .name = "iac",
1006  .type = AVMEDIA_TYPE_AUDIO,
1007  .id = AV_CODEC_ID_IAC,
1008  .priv_data_size = sizeof(IMCContext),
1009  .init = imc_decode_init,
1012  .capabilities = CODEC_CAP_DR1,
1013  .long_name = NULL_IF_CONFIG_SMALL("IAC (Indeo Audio Coder)"),
1014  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
1016 };