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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 FFmpeg.
8  *
9  * FFmpeg 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  * FFmpeg 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 FFmpeg; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
24 /**
25  * @file
26  * IMC - Intel Music Coder
27  * A mdct based codec using a 256 points large transform
28  * divided into 32 bands with some mix of scale factors.
29  * Only mono is supported.
30  *
31  */
32 
33 
34 #include <math.h>
35 #include <stddef.h>
36 #include <stdio.h>
37 
39 #include "libavutil/float_dsp.h"
40 #include "libavutil/internal.h"
41 #include "libavutil/libm.h"
42 #include "avcodec.h"
43 #include "bswapdsp.h"
44 #include "get_bits.h"
45 #include "fft.h"
46 #include "internal.h"
47 #include "sinewin.h"
48 
49 #include "imcdata.h"
50 
51 #define IMC_BLOCK_SIZE 64
52 #define IMC_FRAME_ID 0x21
53 #define BANDS 32
54 #define COEFFS 256
55 
56 typedef struct IMCChannel {
57  float old_floor[BANDS];
58  float flcoeffs1[BANDS];
59  float flcoeffs2[BANDS];
60  float flcoeffs3[BANDS];
61  float flcoeffs4[BANDS];
62  float flcoeffs5[BANDS];
63  float flcoeffs6[BANDS];
64  float CWdecoded[COEFFS];
65 
66  int bandWidthT[BANDS]; ///< codewords per band
67  int bitsBandT[BANDS]; ///< how many bits per codeword in band
68  int CWlengthT[COEFFS]; ///< how many bits in each codeword
70  int bandFlagsBuf[BANDS]; ///< flags for each band
71  int sumLenArr[BANDS]; ///< bits for all coeffs in band
72  int skipFlagRaw[BANDS]; ///< skip flags are stored in raw form or not
73  int skipFlagBits[BANDS]; ///< bits used to code skip flags
74  int skipFlagCount[BANDS]; ///< skipped coeffients per band
75  int skipFlags[COEFFS]; ///< skip coefficient decoding or not
76  int codewords[COEFFS]; ///< raw codewords read from bitstream
77 
79 
81 } IMCChannel;
82 
83 typedef struct {
84  IMCChannel chctx[2];
85 
86  /** MDCT tables */
87  //@{
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];
93  //@}
94 
95  float sqrt_tab[30];
97 
101  DECLARE_ALIGNED(32, FFTComplex, samples)[COEFFS / 2];
102  float *out_samples;
103 
105 
106  int8_t cyclTab[32], cyclTab2[32];
107  float weights1[31], weights2[31];
108 } IMCContext;
109 
110 static VLC huffman_vlc[4][4];
111 
112 #define VLC_TABLES_SIZE 9512
113 
114 static const int vlc_offsets[17] = {
115  0, 640, 1156, 1732, 2308, 2852, 3396, 3924,
116  4452, 5220, 5860, 6628, 7268, 7908, 8424, 8936, VLC_TABLES_SIZE
117 };
118 
120 
121 static inline double freq2bark(double freq)
122 {
123  return 3.5 * atan((freq / 7500.0) * (freq / 7500.0)) + 13.0 * atan(freq * 0.00076);
124 }
125 
126 static av_cold void iac_generate_tabs(IMCContext *q, int sampling_rate)
127 {
128  double freqmin[32], freqmid[32], freqmax[32];
129  double scale = sampling_rate / (256.0 * 2.0 * 2.0);
130  double nyquist_freq = sampling_rate * 0.5;
131  double freq, bark, prev_bark = 0, tf, tb;
132  int i, j;
133 
134  for (i = 0; i < 32; i++) {
135  freq = (band_tab[i] + band_tab[i + 1] - 1) * scale;
136  bark = freq2bark(freq);
137 
138  if (i > 0) {
139  tb = bark - prev_bark;
140  q->weights1[i - 1] = pow(10.0, -1.0 * tb);
141  q->weights2[i - 1] = pow(10.0, -2.7 * tb);
142  }
143  prev_bark = bark;
144 
145  freqmid[i] = freq;
146 
147  tf = freq;
148  while (tf < nyquist_freq) {
149  tf += 0.5;
150  tb = freq2bark(tf);
151  if (tb > bark + 0.5)
152  break;
153  }
154  freqmax[i] = tf;
155 
156  tf = freq;
157  while (tf > 0.0) {
158  tf -= 0.5;
159  tb = freq2bark(tf);
160  if (tb <= bark - 0.5)
161  break;
162  }
163  freqmin[i] = tf;
164  }
165 
166  for (i = 0; i < 32; i++) {
167  freq = freqmax[i];
168  for (j = 31; j > 0 && freq <= freqmid[j]; j--);
169  q->cyclTab[i] = j + 1;
170 
171  freq = freqmin[i];
172  for (j = 0; j < 32 && freq >= freqmid[j]; j++);
173  q->cyclTab2[i] = j - 1;
174  }
175 }
176 
178 {
179  int i, j, ret;
180  IMCContext *q = avctx->priv_data;
181  double r1, r2;
182 
183  if (avctx->codec_id == AV_CODEC_ID_IAC && avctx->sample_rate > 96000) {
184  av_log(avctx, AV_LOG_ERROR,
185  "Strange sample rate of %i, file likely corrupt or "
186  "needing a new table derivation method.\n",
187  avctx->sample_rate);
188  return AVERROR_PATCHWELCOME;
189  }
190 
191  if (avctx->codec_id == AV_CODEC_ID_IMC)
192  avctx->channels = 1;
193 
194  if (avctx->channels > 2) {
195  avpriv_request_sample(avctx, "Number of channels > 2");
196  return AVERROR_PATCHWELCOME;
197  }
198 
199  for (j = 0; j < avctx->channels; j++) {
200  q->chctx[j].decoder_reset = 1;
201 
202  for (i = 0; i < BANDS; i++)
203  q->chctx[j].old_floor[i] = 1.0;
204 
205  for (i = 0; i < COEFFS / 2; i++)
206  q->chctx[j].last_fft_im[i] = 0;
207  }
208 
209  /* Build mdct window, a simple sine window normalized with sqrt(2) */
211  for (i = 0; i < COEFFS; i++)
212  q->mdct_sine_window[i] *= sqrt(2.0);
213  for (i = 0; i < COEFFS / 2; i++) {
214  q->post_cos[i] = (1.0f / 32768) * cos(i / 256.0 * M_PI);
215  q->post_sin[i] = (1.0f / 32768) * sin(i / 256.0 * M_PI);
216 
217  r1 = sin((i * 4.0 + 1.0) / 1024.0 * M_PI);
218  r2 = cos((i * 4.0 + 1.0) / 1024.0 * M_PI);
219 
220  if (i & 0x1) {
221  q->pre_coef1[i] = (r1 + r2) * sqrt(2.0);
222  q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0);
223  } else {
224  q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0);
225  q->pre_coef2[i] = (r1 - r2) * sqrt(2.0);
226  }
227  }
228 
229  /* Generate a square root table */
230 
231  for (i = 0; i < 30; i++)
232  q->sqrt_tab[i] = sqrt(i);
233 
234  /* initialize the VLC tables */
235  for (i = 0; i < 4 ; i++) {
236  for (j = 0; j < 4; j++) {
237  huffman_vlc[i][j].table = &vlc_tables[vlc_offsets[i * 4 + j]];
238  huffman_vlc[i][j].table_allocated = vlc_offsets[i * 4 + j + 1] - vlc_offsets[i * 4 + j];
239  init_vlc(&huffman_vlc[i][j], 9, imc_huffman_sizes[i],
240  imc_huffman_lens[i][j], 1, 1,
242  }
243  }
244 
245  if (avctx->codec_id == AV_CODEC_ID_IAC) {
246  iac_generate_tabs(q, avctx->sample_rate);
247  } else {
248  memcpy(q->cyclTab, cyclTab, sizeof(cyclTab));
249  memcpy(q->cyclTab2, cyclTab2, sizeof(cyclTab2));
250  memcpy(q->weights1, imc_weights1, sizeof(imc_weights1));
251  memcpy(q->weights2, imc_weights2, sizeof(imc_weights2));
252  }
253 
254  if ((ret = ff_fft_init(&q->fft, 7, 1))) {
255  av_log(avctx, AV_LOG_INFO, "FFT init failed\n");
256  return ret;
257  }
258  ff_bswapdsp_init(&q->bdsp);
261  avctx->channel_layout = avctx->channels == 1 ? AV_CH_LAYOUT_MONO
263 
264  return 0;
265 }
266 
267 static void imc_calculate_coeffs(IMCContext *q, float *flcoeffs1,
268  float *flcoeffs2, int *bandWidthT,
269  float *flcoeffs3, float *flcoeffs5)
270 {
271  float workT1[BANDS];
272  float workT2[BANDS];
273  float workT3[BANDS];
274  float snr_limit = 1.e-30;
275  float accum = 0.0;
276  int i, cnt2;
277 
278  for (i = 0; i < BANDS; i++) {
279  flcoeffs5[i] = workT2[i] = 0.0;
280  if (bandWidthT[i]) {
281  workT1[i] = flcoeffs1[i] * flcoeffs1[i];
282  flcoeffs3[i] = 2.0 * flcoeffs2[i];
283  } else {
284  workT1[i] = 0.0;
285  flcoeffs3[i] = -30000.0;
286  }
287  workT3[i] = bandWidthT[i] * workT1[i] * 0.01;
288  if (workT3[i] <= snr_limit)
289  workT3[i] = 0.0;
290  }
291 
292  for (i = 0; i < BANDS; i++) {
293  for (cnt2 = i; cnt2 < q->cyclTab[i]; cnt2++)
294  flcoeffs5[cnt2] = flcoeffs5[cnt2] + workT3[i];
295  workT2[cnt2 - 1] = workT2[cnt2 - 1] + workT3[i];
296  }
297 
298  for (i = 1; i < BANDS; i++) {
299  accum = (workT2[i - 1] + accum) * q->weights1[i - 1];
300  flcoeffs5[i] += accum;
301  }
302 
303  for (i = 0; i < BANDS; i++)
304  workT2[i] = 0.0;
305 
306  for (i = 0; i < BANDS; i++) {
307  for (cnt2 = i - 1; cnt2 > q->cyclTab2[i]; cnt2--)
308  flcoeffs5[cnt2] += workT3[i];
309  workT2[cnt2+1] += workT3[i];
310  }
311 
312  accum = 0.0;
313 
314  for (i = BANDS-2; i >= 0; i--) {
315  accum = (workT2[i+1] + accum) * q->weights2[i];
316  flcoeffs5[i] += accum;
317  // there is missing code here, but it seems to never be triggered
318  }
319 }
320 
321 
322 static void imc_read_level_coeffs(IMCContext *q, int stream_format_code,
323  int *levlCoeffs)
324 {
325  int i;
326  VLC *hufftab[4];
327  int start = 0;
328  const uint8_t *cb_sel;
329  int s;
330 
331  s = stream_format_code >> 1;
332  hufftab[0] = &huffman_vlc[s][0];
333  hufftab[1] = &huffman_vlc[s][1];
334  hufftab[2] = &huffman_vlc[s][2];
335  hufftab[3] = &huffman_vlc[s][3];
336  cb_sel = imc_cb_select[s];
337 
338  if (stream_format_code & 4)
339  start = 1;
340  if (start)
341  levlCoeffs[0] = get_bits(&q->gb, 7);
342  for (i = start; i < BANDS; i++) {
343  levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table,
344  hufftab[cb_sel[i]]->bits, 2);
345  if (levlCoeffs[i] == 17)
346  levlCoeffs[i] += get_bits(&q->gb, 4);
347  }
348 }
349 
350 static void imc_read_level_coeffs_raw(IMCContext *q, int stream_format_code,
351  int *levlCoeffs)
352 {
353  int i;
354 
355  q->coef0_pos = get_bits(&q->gb, 5);
356  levlCoeffs[0] = get_bits(&q->gb, 7);
357  for (i = 1; i < BANDS; i++)
358  levlCoeffs[i] = get_bits(&q->gb, 4);
359 }
360 
361 static void imc_decode_level_coefficients(IMCContext *q, int *levlCoeffBuf,
362  float *flcoeffs1, float *flcoeffs2)
363 {
364  int i, level;
365  float tmp, tmp2;
366  // maybe some frequency division thingy
367 
368  flcoeffs1[0] = 20000.0 / exp2 (levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
369  flcoeffs2[0] = log2f(flcoeffs1[0]);
370  tmp = flcoeffs1[0];
371  tmp2 = flcoeffs2[0];
372 
373  for (i = 1; i < BANDS; i++) {
374  level = levlCoeffBuf[i];
375  if (level == 16) {
376  flcoeffs1[i] = 1.0;
377  flcoeffs2[i] = 0.0;
378  } else {
379  if (level < 17)
380  level -= 7;
381  else if (level <= 24)
382  level -= 32;
383  else
384  level -= 16;
385 
386  tmp *= imc_exp_tab[15 + level];
387  tmp2 += 0.83048 * level; // 0.83048 = log2(10) * 0.25
388  flcoeffs1[i] = tmp;
389  flcoeffs2[i] = tmp2;
390  }
391  }
392 }
393 
394 
395 static void imc_decode_level_coefficients2(IMCContext *q, int *levlCoeffBuf,
396  float *old_floor, float *flcoeffs1,
397  float *flcoeffs2)
398 {
399  int i;
400  /* FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors
401  * and flcoeffs2 old scale factors
402  * might be incomplete due to a missing table that is in the binary code
403  */
404  for (i = 0; i < BANDS; i++) {
405  flcoeffs1[i] = 0;
406  if (levlCoeffBuf[i] < 16) {
407  flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i];
408  flcoeffs2[i] = (levlCoeffBuf[i] - 7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25
409  } else {
410  flcoeffs1[i] = old_floor[i];
411  }
412  }
413 }
414 
415 static void imc_decode_level_coefficients_raw(IMCContext *q, int *levlCoeffBuf,
416  float *flcoeffs1, float *flcoeffs2)
417 {
418  int i, level, pos;
419  float tmp, tmp2;
420 
421  pos = q->coef0_pos;
422  flcoeffs1[pos] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
423  flcoeffs2[pos] = log2f(flcoeffs1[0]);
424  tmp = flcoeffs1[pos];
425  tmp2 = flcoeffs2[pos];
426 
427  levlCoeffBuf++;
428  for (i = 0; i < BANDS; i++) {
429  if (i == pos)
430  continue;
431  level = *levlCoeffBuf++;
432  flcoeffs1[i] = tmp * powf(10.0, -level * 0.4375); //todo tab
433  flcoeffs2[i] = tmp2 - 1.4533435415 * level; // 1.4533435415 = log2(10) * 0.4375
434  }
435 }
436 
437 /**
438  * Perform bit allocation depending on bits available
439  */
440 static int bit_allocation(IMCContext *q, IMCChannel *chctx,
441  int stream_format_code, int freebits, int flag)
442 {
443  int i, j;
444  const float limit = -1.e20;
445  float highest = 0.0;
446  int indx;
447  int t1 = 0;
448  int t2 = 1;
449  float summa = 0.0;
450  int iacc = 0;
451  int summer = 0;
452  int rres, cwlen;
453  float lowest = 1.e10;
454  int low_indx = 0;
455  float workT[32];
456  int flg;
457  int found_indx = 0;
458 
459  for (i = 0; i < BANDS; i++)
460  highest = FFMAX(highest, chctx->flcoeffs1[i]);
461 
462  for (i = 0; i < BANDS - 1; i++) {
463  if (chctx->flcoeffs5[i] <= 0) {
464  av_log(NULL, AV_LOG_ERROR, "flcoeffs5 %f invalid\n", chctx->flcoeffs5[i]);
465  return AVERROR_INVALIDDATA;
466  }
467  chctx->flcoeffs4[i] = chctx->flcoeffs3[i] - log2f(chctx->flcoeffs5[i]);
468  }
469  chctx->flcoeffs4[BANDS - 1] = limit;
470 
471  highest = highest * 0.25;
472 
473  for (i = 0; i < BANDS; i++) {
474  indx = -1;
475  if ((band_tab[i + 1] - band_tab[i]) == chctx->bandWidthT[i])
476  indx = 0;
477 
478  if ((band_tab[i + 1] - band_tab[i]) > chctx->bandWidthT[i])
479  indx = 1;
480 
481  if (((band_tab[i + 1] - band_tab[i]) / 2) >= chctx->bandWidthT[i])
482  indx = 2;
483 
484  if (indx == -1)
485  return AVERROR_INVALIDDATA;
486 
487  chctx->flcoeffs4[i] += xTab[(indx * 2 + (chctx->flcoeffs1[i] < highest)) * 2 + flag];
488  }
489 
490  if (stream_format_code & 0x2) {
491  chctx->flcoeffs4[0] = limit;
492  chctx->flcoeffs4[1] = limit;
493  chctx->flcoeffs4[2] = limit;
494  chctx->flcoeffs4[3] = limit;
495  }
496 
497  for (i = (stream_format_code & 0x2) ? 4 : 0; i < BANDS - 1; i++) {
498  iacc += chctx->bandWidthT[i];
499  summa += chctx->bandWidthT[i] * chctx->flcoeffs4[i];
500  }
501 
502  if (!iacc)
503  return AVERROR_INVALIDDATA;
504 
505  chctx->bandWidthT[BANDS - 1] = 0;
506  summa = (summa * 0.5 - freebits) / iacc;
507 
508 
509  for (i = 0; i < BANDS / 2; i++) {
510  rres = summer - freebits;
511  if ((rres >= -8) && (rres <= 8))
512  break;
513 
514  summer = 0;
515  iacc = 0;
516 
517  for (j = (stream_format_code & 0x2) ? 4 : 0; j < BANDS; j++) {
518  cwlen = av_clipf(((chctx->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6);
519 
520  chctx->bitsBandT[j] = cwlen;
521  summer += chctx->bandWidthT[j] * cwlen;
522 
523  if (cwlen > 0)
524  iacc += chctx->bandWidthT[j];
525  }
526 
527  flg = t2;
528  t2 = 1;
529  if (freebits < summer)
530  t2 = -1;
531  if (i == 0)
532  flg = t2;
533  if (flg != t2)
534  t1++;
535 
536  summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa;
537  }
538 
539  for (i = (stream_format_code & 0x2) ? 4 : 0; i < BANDS; i++) {
540  for (j = band_tab[i]; j < band_tab[i + 1]; j++)
541  chctx->CWlengthT[j] = chctx->bitsBandT[i];
542  }
543 
544  if (freebits > summer) {
545  for (i = 0; i < BANDS; i++) {
546  workT[i] = (chctx->bitsBandT[i] == 6) ? -1.e20
547  : (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] - 0.415);
548  }
549 
550  highest = 0.0;
551 
552  do {
553  if (highest <= -1.e20)
554  break;
555 
556  found_indx = 0;
557  highest = -1.e20;
558 
559  for (i = 0; i < BANDS; i++) {
560  if (workT[i] > highest) {
561  highest = workT[i];
562  found_indx = i;
563  }
564  }
565 
566  if (highest > -1.e20) {
567  workT[found_indx] -= 2.0;
568  if (++chctx->bitsBandT[found_indx] == 6)
569  workT[found_indx] = -1.e20;
570 
571  for (j = band_tab[found_indx]; j < band_tab[found_indx + 1] && (freebits > summer); j++) {
572  chctx->CWlengthT[j]++;
573  summer++;
574  }
575  }
576  } while (freebits > summer);
577  }
578  if (freebits < summer) {
579  for (i = 0; i < BANDS; i++) {
580  workT[i] = chctx->bitsBandT[i] ? (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] + 1.585)
581  : 1.e20;
582  }
583  if (stream_format_code & 0x2) {
584  workT[0] = 1.e20;
585  workT[1] = 1.e20;
586  workT[2] = 1.e20;
587  workT[3] = 1.e20;
588  }
589  while (freebits < summer) {
590  lowest = 1.e10;
591  low_indx = 0;
592  for (i = 0; i < BANDS; i++) {
593  if (workT[i] < lowest) {
594  lowest = workT[i];
595  low_indx = i;
596  }
597  }
598  // if (lowest >= 1.e10)
599  // break;
600  workT[low_indx] = lowest + 2.0;
601 
602  if (!--chctx->bitsBandT[low_indx])
603  workT[low_indx] = 1.e20;
604 
605  for (j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++) {
606  if (chctx->CWlengthT[j] > 0) {
607  chctx->CWlengthT[j]--;
608  summer--;
609  }
610  }
611  }
612  }
613  return 0;
614 }
615 
616 static void imc_get_skip_coeff(IMCContext *q, IMCChannel *chctx)
617 {
618  int i, j;
619 
620  memset(chctx->skipFlagBits, 0, sizeof(chctx->skipFlagBits));
621  memset(chctx->skipFlagCount, 0, sizeof(chctx->skipFlagCount));
622  for (i = 0; i < BANDS; i++) {
623  if (!chctx->bandFlagsBuf[i] || !chctx->bandWidthT[i])
624  continue;
625 
626  if (!chctx->skipFlagRaw[i]) {
627  chctx->skipFlagBits[i] = band_tab[i + 1] - band_tab[i];
628 
629  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
630  chctx->skipFlags[j] = get_bits1(&q->gb);
631  if (chctx->skipFlags[j])
632  chctx->skipFlagCount[i]++;
633  }
634  } else {
635  for (j = band_tab[i]; j < band_tab[i + 1] - 1; j += 2) {
636  if (!get_bits1(&q->gb)) { // 0
637  chctx->skipFlagBits[i]++;
638  chctx->skipFlags[j] = 1;
639  chctx->skipFlags[j + 1] = 1;
640  chctx->skipFlagCount[i] += 2;
641  } else {
642  if (get_bits1(&q->gb)) { // 11
643  chctx->skipFlagBits[i] += 2;
644  chctx->skipFlags[j] = 0;
645  chctx->skipFlags[j + 1] = 1;
646  chctx->skipFlagCount[i]++;
647  } else {
648  chctx->skipFlagBits[i] += 3;
649  chctx->skipFlags[j + 1] = 0;
650  if (!get_bits1(&q->gb)) { // 100
651  chctx->skipFlags[j] = 1;
652  chctx->skipFlagCount[i]++;
653  } else { // 101
654  chctx->skipFlags[j] = 0;
655  }
656  }
657  }
658  }
659 
660  if (j < band_tab[i + 1]) {
661  chctx->skipFlagBits[i]++;
662  if ((chctx->skipFlags[j] = get_bits1(&q->gb)))
663  chctx->skipFlagCount[i]++;
664  }
665  }
666  }
667 }
668 
669 /**
670  * Increase highest' band coefficient sizes as some bits won't be used
671  */
673  int summer)
674 {
675  float workT[32];
676  int corrected = 0;
677  int i, j;
678  float highest = 0;
679  int found_indx = 0;
680 
681  for (i = 0; i < BANDS; i++) {
682  workT[i] = (chctx->bitsBandT[i] == 6) ? -1.e20
683  : (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] - 0.415);
684  }
685 
686  while (corrected < summer) {
687  if (highest <= -1.e20)
688  break;
689 
690  highest = -1.e20;
691 
692  for (i = 0; i < BANDS; i++) {
693  if (workT[i] > highest) {
694  highest = workT[i];
695  found_indx = i;
696  }
697  }
698 
699  if (highest > -1.e20) {
700  workT[found_indx] -= 2.0;
701  if (++(chctx->bitsBandT[found_indx]) == 6)
702  workT[found_indx] = -1.e20;
703 
704  for (j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) {
705  if (!chctx->skipFlags[j] && (chctx->CWlengthT[j] < 6)) {
706  chctx->CWlengthT[j]++;
707  corrected++;
708  }
709  }
710  }
711  }
712 }
713 
714 static void imc_imdct256(IMCContext *q, IMCChannel *chctx, int channels)
715 {
716  int i;
717  float re, im;
718  float *dst1 = q->out_samples;
719  float *dst2 = q->out_samples + (COEFFS - 1);
720 
721  /* prerotation */
722  for (i = 0; i < COEFFS / 2; i++) {
723  q->samples[i].re = -(q->pre_coef1[i] * chctx->CWdecoded[COEFFS - 1 - i * 2]) -
724  (q->pre_coef2[i] * chctx->CWdecoded[i * 2]);
725  q->samples[i].im = (q->pre_coef2[i] * chctx->CWdecoded[COEFFS - 1 - i * 2]) -
726  (q->pre_coef1[i] * chctx->CWdecoded[i * 2]);
727  }
728 
729  /* FFT */
730  q->fft.fft_permute(&q->fft, q->samples);
731  q->fft.fft_calc(&q->fft, q->samples);
732 
733  /* postrotation, window and reorder */
734  for (i = 0; i < COEFFS / 2; i++) {
735  re = ( q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]);
736  im = (-q->samples[i].im * q->post_cos[i]) - ( q->samples[i].re * q->post_sin[i]);
737  *dst1 = (q->mdct_sine_window[COEFFS - 1 - i * 2] * chctx->last_fft_im[i])
738  + (q->mdct_sine_window[i * 2] * re);
739  *dst2 = (q->mdct_sine_window[i * 2] * chctx->last_fft_im[i])
740  - (q->mdct_sine_window[COEFFS - 1 - i * 2] * re);
741  dst1 += 2;
742  dst2 -= 2;
743  chctx->last_fft_im[i] = im;
744  }
745 }
746 
748  int stream_format_code)
749 {
750  int i, j;
751  int middle_value, cw_len, max_size;
752  const float *quantizer;
753 
754  for (i = 0; i < BANDS; i++) {
755  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
756  chctx->CWdecoded[j] = 0;
757  cw_len = chctx->CWlengthT[j];
758 
759  if (cw_len <= 0 || chctx->skipFlags[j])
760  continue;
761 
762  max_size = 1 << cw_len;
763  middle_value = max_size >> 1;
764 
765  if (chctx->codewords[j] >= max_size || chctx->codewords[j] < 0)
766  return AVERROR_INVALIDDATA;
767 
768  if (cw_len >= 4) {
769  quantizer = imc_quantizer2[(stream_format_code & 2) >> 1];
770  if (chctx->codewords[j] >= middle_value)
771  chctx->CWdecoded[j] = quantizer[chctx->codewords[j] - 8] * chctx->flcoeffs6[i];
772  else
773  chctx->CWdecoded[j] = -quantizer[max_size - chctx->codewords[j] - 8 - 1] * chctx->flcoeffs6[i];
774  }else{
775  quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (chctx->bandFlagsBuf[i] << 1)];
776  if (chctx->codewords[j] >= middle_value)
777  chctx->CWdecoded[j] = quantizer[chctx->codewords[j] - 1] * chctx->flcoeffs6[i];
778  else
779  chctx->CWdecoded[j] = -quantizer[max_size - 2 - chctx->codewords[j]] * chctx->flcoeffs6[i];
780  }
781  }
782  }
783  return 0;
784 }
785 
786 
787 static int imc_get_coeffs(IMCContext *q, IMCChannel *chctx)
788 {
789  int i, j, cw_len, cw;
790 
791  for (i = 0; i < BANDS; i++) {
792  if (!chctx->sumLenArr[i])
793  continue;
794  if (chctx->bandFlagsBuf[i] || chctx->bandWidthT[i]) {
795  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
796  cw_len = chctx->CWlengthT[j];
797  cw = 0;
798 
799  if (get_bits_count(&q->gb) + cw_len > 512) {
800  av_dlog(NULL, "Band %i coeff %i cw_len %i\n", i, j, cw_len);
801  return AVERROR_INVALIDDATA;
802  }
803 
804  if (cw_len && (!chctx->bandFlagsBuf[i] || !chctx->skipFlags[j]))
805  cw = get_bits(&q->gb, cw_len);
806 
807  chctx->codewords[j] = cw;
808  }
809  }
810  }
811  return 0;
812 }
813 
815 {
816  int i, j;
817  int bits, summer;
818 
819  for (i = 0; i < BANDS; i++) {
820  chctx->sumLenArr[i] = 0;
821  chctx->skipFlagRaw[i] = 0;
822  for (j = band_tab[i]; j < band_tab[i + 1]; j++)
823  chctx->sumLenArr[i] += chctx->CWlengthT[j];
824  if (chctx->bandFlagsBuf[i])
825  if ((((band_tab[i + 1] - band_tab[i]) * 1.5) > chctx->sumLenArr[i]) && (chctx->sumLenArr[i] > 0))
826  chctx->skipFlagRaw[i] = 1;
827  }
828 
829  imc_get_skip_coeff(q, chctx);
830 
831  for (i = 0; i < BANDS; i++) {
832  chctx->flcoeffs6[i] = chctx->flcoeffs1[i];
833  /* band has flag set and at least one coded coefficient */
834  if (chctx->bandFlagsBuf[i] && (band_tab[i + 1] - band_tab[i]) != chctx->skipFlagCount[i]) {
835  chctx->flcoeffs6[i] *= q->sqrt_tab[ band_tab[i + 1] - band_tab[i]] /
836  q->sqrt_tab[(band_tab[i + 1] - band_tab[i] - chctx->skipFlagCount[i])];
837  }
838  }
839 
840  /* calculate bits left, bits needed and adjust bit allocation */
841  bits = summer = 0;
842 
843  for (i = 0; i < BANDS; i++) {
844  if (chctx->bandFlagsBuf[i]) {
845  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
846  if (chctx->skipFlags[j]) {
847  summer += chctx->CWlengthT[j];
848  chctx->CWlengthT[j] = 0;
849  }
850  }
851  bits += chctx->skipFlagBits[i];
852  summer -= chctx->skipFlagBits[i];
853  }
854  }
855  imc_adjust_bit_allocation(q, chctx, summer);
856 }
857 
858 static int imc_decode_block(AVCodecContext *avctx, IMCContext *q, int ch)
859 {
860  int stream_format_code;
861  int imc_hdr, i, j, ret;
862  int flag;
863  int bits;
864  int counter, bitscount;
865  IMCChannel *chctx = q->chctx + ch;
866 
867 
868  /* Check the frame header */
869  imc_hdr = get_bits(&q->gb, 9);
870  if (imc_hdr & 0x18) {
871  av_log(avctx, AV_LOG_ERROR, "frame header check failed!\n");
872  av_log(avctx, AV_LOG_ERROR, "got %X.\n", imc_hdr);
873  return AVERROR_INVALIDDATA;
874  }
875  stream_format_code = get_bits(&q->gb, 3);
876 
877  if (stream_format_code & 0x04)
878  chctx->decoder_reset = 1;
879 
880  if (chctx->decoder_reset) {
881  for (i = 0; i < BANDS; i++)
882  chctx->old_floor[i] = 1.0;
883  for (i = 0; i < COEFFS; i++)
884  chctx->CWdecoded[i] = 0;
885  chctx->decoder_reset = 0;
886  }
887 
888  flag = get_bits1(&q->gb);
889  if (stream_format_code & 0x1)
890  imc_read_level_coeffs_raw(q, stream_format_code, chctx->levlCoeffBuf);
891  else
892  imc_read_level_coeffs(q, stream_format_code, chctx->levlCoeffBuf);
893 
894  if (stream_format_code & 0x1)
896  chctx->flcoeffs1, chctx->flcoeffs2);
897  else if (stream_format_code & 0x4)
899  chctx->flcoeffs1, chctx->flcoeffs2);
900  else
902  chctx->flcoeffs1, chctx->flcoeffs2);
903 
904  for(i=0; i<BANDS; i++) {
905  if(chctx->flcoeffs1[i] > INT_MAX) {
906  av_log(avctx, AV_LOG_ERROR, "scalefactor out of range\n");
907  return AVERROR_INVALIDDATA;
908  }
909  }
910 
911  memcpy(chctx->old_floor, chctx->flcoeffs1, 32 * sizeof(float));
912 
913  counter = 0;
914  if (stream_format_code & 0x1) {
915  for (i = 0; i < BANDS; i++) {
916  chctx->bandWidthT[i] = band_tab[i + 1] - band_tab[i];
917  chctx->bandFlagsBuf[i] = 0;
918  chctx->flcoeffs3[i] = chctx->flcoeffs2[i] * 2;
919  chctx->flcoeffs5[i] = 1.0;
920  }
921  } else {
922  for (i = 0; i < BANDS; i++) {
923  if (chctx->levlCoeffBuf[i] == 16) {
924  chctx->bandWidthT[i] = 0;
925  counter++;
926  } else
927  chctx->bandWidthT[i] = band_tab[i + 1] - band_tab[i];
928  }
929 
930  memset(chctx->bandFlagsBuf, 0, BANDS * sizeof(int));
931  for (i = 0; i < BANDS - 1; i++)
932  if (chctx->bandWidthT[i])
933  chctx->bandFlagsBuf[i] = get_bits1(&q->gb);
934 
935  imc_calculate_coeffs(q, chctx->flcoeffs1, chctx->flcoeffs2,
936  chctx->bandWidthT, chctx->flcoeffs3,
937  chctx->flcoeffs5);
938  }
939 
940  bitscount = 0;
941  /* first 4 bands will be assigned 5 bits per coefficient */
942  if (stream_format_code & 0x2) {
943  bitscount += 15;
944 
945  chctx->bitsBandT[0] = 5;
946  chctx->CWlengthT[0] = 5;
947  chctx->CWlengthT[1] = 5;
948  chctx->CWlengthT[2] = 5;
949  for (i = 1; i < 4; i++) {
950  if (stream_format_code & 0x1)
951  bits = 5;
952  else
953  bits = (chctx->levlCoeffBuf[i] == 16) ? 0 : 5;
954  chctx->bitsBandT[i] = bits;
955  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
956  chctx->CWlengthT[j] = bits;
957  bitscount += bits;
958  }
959  }
960  }
961  if (avctx->codec_id == AV_CODEC_ID_IAC) {
962  bitscount += !!chctx->bandWidthT[BANDS - 1];
963  if (!(stream_format_code & 0x2))
964  bitscount += 16;
965  }
966 
967  if ((ret = bit_allocation(q, chctx, stream_format_code,
968  512 - bitscount - get_bits_count(&q->gb),
969  flag)) < 0) {
970  av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n");
971  chctx->decoder_reset = 1;
972  return ret;
973  }
974 
975  if (stream_format_code & 0x1) {
976  for (i = 0; i < BANDS; i++)
977  chctx->skipFlags[i] = 0;
978  } else {
979  imc_refine_bit_allocation(q, chctx);
980  }
981 
982  for (i = 0; i < BANDS; i++) {
983  chctx->sumLenArr[i] = 0;
984 
985  for (j = band_tab[i]; j < band_tab[i + 1]; j++)
986  if (!chctx->skipFlags[j])
987  chctx->sumLenArr[i] += chctx->CWlengthT[j];
988  }
989 
990  memset(chctx->codewords, 0, sizeof(chctx->codewords));
991 
992  if (imc_get_coeffs(q, chctx) < 0) {
993  av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n");
994  chctx->decoder_reset = 1;
995  return AVERROR_INVALIDDATA;
996  }
997 
998  if (inverse_quant_coeff(q, chctx, stream_format_code) < 0) {
999  av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n");
1000  chctx->decoder_reset = 1;
1001  return AVERROR_INVALIDDATA;
1002  }
1003 
1004  memset(chctx->skipFlags, 0, sizeof(chctx->skipFlags));
1005 
1006  imc_imdct256(q, chctx, avctx->channels);
1007 
1008  return 0;
1009 }
1010 
1011 static int imc_decode_frame(AVCodecContext *avctx, void *data,
1012  int *got_frame_ptr, AVPacket *avpkt)
1013 {
1014  AVFrame *frame = data;
1015  const uint8_t *buf = avpkt->data;
1016  int buf_size = avpkt->size;
1017  int ret, i;
1018 
1019  IMCContext *q = avctx->priv_data;
1020 
1021  LOCAL_ALIGNED_16(uint16_t, buf16, [IMC_BLOCK_SIZE / 2 + FF_INPUT_BUFFER_PADDING_SIZE/2]);
1022 
1023  if (buf_size < IMC_BLOCK_SIZE * avctx->channels) {
1024  av_log(avctx, AV_LOG_ERROR, "frame too small!\n");
1025  return AVERROR_INVALIDDATA;
1026  }
1027 
1028  /* get output buffer */
1029  frame->nb_samples = COEFFS;
1030  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
1031  return ret;
1032 
1033  for (i = 0; i < avctx->channels; i++) {
1034  q->out_samples = (float *)frame->extended_data[i];
1035 
1036  q->bdsp.bswap16_buf(buf16, (const uint16_t *) buf, IMC_BLOCK_SIZE / 2);
1037 
1038  init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8);
1039 
1040  buf += IMC_BLOCK_SIZE;
1041 
1042  if ((ret = imc_decode_block(avctx, q, i)) < 0)
1043  return ret;
1044  }
1045 
1046  if (avctx->channels == 2) {
1047  q->fdsp.butterflies_float((float *)frame->extended_data[0],
1048  (float *)frame->extended_data[1], COEFFS);
1049  }
1050 
1051  *got_frame_ptr = 1;
1052 
1053  return IMC_BLOCK_SIZE * avctx->channels;
1054 }
1055 
1056 
1058 {
1059  IMCContext *q = avctx->priv_data;
1060 
1061  ff_fft_end(&q->fft);
1062 
1063  return 0;
1064 }
1065 
1066 static av_cold void flush(AVCodecContext *avctx)
1067 {
1068  IMCContext *q = avctx->priv_data;
1069 
1070  q->chctx[0].decoder_reset =
1071  q->chctx[1].decoder_reset = 1;
1072 }
1073 
1074 #if CONFIG_IMC_DECODER
1075 AVCodec ff_imc_decoder = {
1076  .name = "imc",
1077  .long_name = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"),
1078  .type = AVMEDIA_TYPE_AUDIO,
1079  .id = AV_CODEC_ID_IMC,
1080  .priv_data_size = sizeof(IMCContext),
1081  .init = imc_decode_init,
1084  .flush = flush,
1085  .capabilities = CODEC_CAP_DR1,
1086  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
1088 };
1089 #endif
1090 #if CONFIG_IAC_DECODER
1091 AVCodec ff_iac_decoder = {
1092  .name = "iac",
1093  .long_name = NULL_IF_CONFIG_SMALL("IAC (Indeo Audio Coder)"),
1094  .type = AVMEDIA_TYPE_AUDIO,
1095  .id = AV_CODEC_ID_IAC,
1096  .priv_data_size = sizeof(IMCContext),
1097  .init = imc_decode_init,
1100  .flush = flush,
1101  .capabilities = CODEC_CAP_DR1,
1102  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
1104 };
1105 #endif