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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);
260  if (!q->fdsp) {
261  ff_fft_end(&q->fft);
262 
263  return AVERROR(ENOMEM);
264  }
265 
267  avctx->channel_layout = avctx->channels == 1 ? AV_CH_LAYOUT_MONO
269 
270  return 0;
271 }
272 
273 static void imc_calculate_coeffs(IMCContext *q, float *flcoeffs1,
274  float *flcoeffs2, int *bandWidthT,
275  float *flcoeffs3, float *flcoeffs5)
276 {
277  float workT1[BANDS];
278  float workT2[BANDS];
279  float workT3[BANDS];
280  float snr_limit = 1.e-30;
281  float accum = 0.0;
282  int i, cnt2;
283 
284  for (i = 0; i < BANDS; i++) {
285  flcoeffs5[i] = workT2[i] = 0.0;
286  if (bandWidthT[i]) {
287  workT1[i] = flcoeffs1[i] * flcoeffs1[i];
288  flcoeffs3[i] = 2.0 * flcoeffs2[i];
289  } else {
290  workT1[i] = 0.0;
291  flcoeffs3[i] = -30000.0;
292  }
293  workT3[i] = bandWidthT[i] * workT1[i] * 0.01;
294  if (workT3[i] <= snr_limit)
295  workT3[i] = 0.0;
296  }
297 
298  for (i = 0; i < BANDS; i++) {
299  for (cnt2 = i; cnt2 < q->cyclTab[i]; cnt2++)
300  flcoeffs5[cnt2] = flcoeffs5[cnt2] + workT3[i];
301  workT2[cnt2 - 1] = workT2[cnt2 - 1] + workT3[i];
302  }
303 
304  for (i = 1; i < BANDS; i++) {
305  accum = (workT2[i - 1] + accum) * q->weights1[i - 1];
306  flcoeffs5[i] += accum;
307  }
308 
309  for (i = 0; i < BANDS; i++)
310  workT2[i] = 0.0;
311 
312  for (i = 0; i < BANDS; i++) {
313  for (cnt2 = i - 1; cnt2 > q->cyclTab2[i]; cnt2--)
314  flcoeffs5[cnt2] += workT3[i];
315  workT2[cnt2+1] += workT3[i];
316  }
317 
318  accum = 0.0;
319 
320  for (i = BANDS-2; i >= 0; i--) {
321  accum = (workT2[i+1] + accum) * q->weights2[i];
322  flcoeffs5[i] += accum;
323  // there is missing code here, but it seems to never be triggered
324  }
325 }
326 
327 
328 static void imc_read_level_coeffs(IMCContext *q, int stream_format_code,
329  int *levlCoeffs)
330 {
331  int i;
332  VLC *hufftab[4];
333  int start = 0;
334  const uint8_t *cb_sel;
335  int s;
336 
337  s = stream_format_code >> 1;
338  hufftab[0] = &huffman_vlc[s][0];
339  hufftab[1] = &huffman_vlc[s][1];
340  hufftab[2] = &huffman_vlc[s][2];
341  hufftab[3] = &huffman_vlc[s][3];
342  cb_sel = imc_cb_select[s];
343 
344  if (stream_format_code & 4)
345  start = 1;
346  if (start)
347  levlCoeffs[0] = get_bits(&q->gb, 7);
348  for (i = start; i < BANDS; i++) {
349  levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table,
350  hufftab[cb_sel[i]]->bits, 2);
351  if (levlCoeffs[i] == 17)
352  levlCoeffs[i] += get_bits(&q->gb, 4);
353  }
354 }
355 
356 static void imc_read_level_coeffs_raw(IMCContext *q, int stream_format_code,
357  int *levlCoeffs)
358 {
359  int i;
360 
361  q->coef0_pos = get_bits(&q->gb, 5);
362  levlCoeffs[0] = get_bits(&q->gb, 7);
363  for (i = 1; i < BANDS; i++)
364  levlCoeffs[i] = get_bits(&q->gb, 4);
365 }
366 
367 static void imc_decode_level_coefficients(IMCContext *q, int *levlCoeffBuf,
368  float *flcoeffs1, float *flcoeffs2)
369 {
370  int i, level;
371  float tmp, tmp2;
372  // maybe some frequency division thingy
373 
374  flcoeffs1[0] = 20000.0 / exp2 (levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
375  flcoeffs2[0] = log2f(flcoeffs1[0]);
376  tmp = flcoeffs1[0];
377  tmp2 = flcoeffs2[0];
378 
379  for (i = 1; i < BANDS; i++) {
380  level = levlCoeffBuf[i];
381  if (level == 16) {
382  flcoeffs1[i] = 1.0;
383  flcoeffs2[i] = 0.0;
384  } else {
385  if (level < 17)
386  level -= 7;
387  else if (level <= 24)
388  level -= 32;
389  else
390  level -= 16;
391 
392  tmp *= imc_exp_tab[15 + level];
393  tmp2 += 0.83048 * level; // 0.83048 = log2(10) * 0.25
394  flcoeffs1[i] = tmp;
395  flcoeffs2[i] = tmp2;
396  }
397  }
398 }
399 
400 
401 static void imc_decode_level_coefficients2(IMCContext *q, int *levlCoeffBuf,
402  float *old_floor, float *flcoeffs1,
403  float *flcoeffs2)
404 {
405  int i;
406  /* FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors
407  * and flcoeffs2 old scale factors
408  * might be incomplete due to a missing table that is in the binary code
409  */
410  for (i = 0; i < BANDS; i++) {
411  flcoeffs1[i] = 0;
412  if (levlCoeffBuf[i] < 16) {
413  flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i];
414  flcoeffs2[i] = (levlCoeffBuf[i] - 7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25
415  } else {
416  flcoeffs1[i] = old_floor[i];
417  }
418  }
419 }
420 
421 static void imc_decode_level_coefficients_raw(IMCContext *q, int *levlCoeffBuf,
422  float *flcoeffs1, float *flcoeffs2)
423 {
424  int i, level, pos;
425  float tmp, tmp2;
426 
427  pos = q->coef0_pos;
428  flcoeffs1[pos] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
429  flcoeffs2[pos] = log2f(flcoeffs1[0]);
430  tmp = flcoeffs1[pos];
431  tmp2 = flcoeffs2[pos];
432 
433  levlCoeffBuf++;
434  for (i = 0; i < BANDS; i++) {
435  if (i == pos)
436  continue;
437  level = *levlCoeffBuf++;
438  flcoeffs1[i] = tmp * powf(10.0, -level * 0.4375); //todo tab
439  flcoeffs2[i] = tmp2 - 1.4533435415 * level; // 1.4533435415 = log2(10) * 0.4375
440  }
441 }
442 
443 /**
444  * Perform bit allocation depending on bits available
445  */
446 static int bit_allocation(IMCContext *q, IMCChannel *chctx,
447  int stream_format_code, int freebits, int flag)
448 {
449  int i, j;
450  const float limit = -1.e20;
451  float highest = 0.0;
452  int indx;
453  int t1 = 0;
454  int t2 = 1;
455  float summa = 0.0;
456  int iacc = 0;
457  int summer = 0;
458  int rres, cwlen;
459  float lowest = 1.e10;
460  int low_indx = 0;
461  float workT[32];
462  int flg;
463  int found_indx = 0;
464 
465  for (i = 0; i < BANDS; i++)
466  highest = FFMAX(highest, chctx->flcoeffs1[i]);
467 
468  for (i = 0; i < BANDS - 1; i++) {
469  if (chctx->flcoeffs5[i] <= 0) {
470  av_log(NULL, AV_LOG_ERROR, "flcoeffs5 %f invalid\n", chctx->flcoeffs5[i]);
471  return AVERROR_INVALIDDATA;
472  }
473  chctx->flcoeffs4[i] = chctx->flcoeffs3[i] - log2f(chctx->flcoeffs5[i]);
474  }
475  chctx->flcoeffs4[BANDS - 1] = limit;
476 
477  highest = highest * 0.25;
478 
479  for (i = 0; i < BANDS; i++) {
480  indx = -1;
481  if ((band_tab[i + 1] - band_tab[i]) == chctx->bandWidthT[i])
482  indx = 0;
483 
484  if ((band_tab[i + 1] - band_tab[i]) > chctx->bandWidthT[i])
485  indx = 1;
486 
487  if (((band_tab[i + 1] - band_tab[i]) / 2) >= chctx->bandWidthT[i])
488  indx = 2;
489 
490  if (indx == -1)
491  return AVERROR_INVALIDDATA;
492 
493  chctx->flcoeffs4[i] += xTab[(indx * 2 + (chctx->flcoeffs1[i] < highest)) * 2 + flag];
494  }
495 
496  if (stream_format_code & 0x2) {
497  chctx->flcoeffs4[0] = limit;
498  chctx->flcoeffs4[1] = limit;
499  chctx->flcoeffs4[2] = limit;
500  chctx->flcoeffs4[3] = limit;
501  }
502 
503  for (i = (stream_format_code & 0x2) ? 4 : 0; i < BANDS - 1; i++) {
504  iacc += chctx->bandWidthT[i];
505  summa += chctx->bandWidthT[i] * chctx->flcoeffs4[i];
506  }
507 
508  if (!iacc)
509  return AVERROR_INVALIDDATA;
510 
511  chctx->bandWidthT[BANDS - 1] = 0;
512  summa = (summa * 0.5 - freebits) / iacc;
513 
514 
515  for (i = 0; i < BANDS / 2; i++) {
516  rres = summer - freebits;
517  if ((rres >= -8) && (rres <= 8))
518  break;
519 
520  summer = 0;
521  iacc = 0;
522 
523  for (j = (stream_format_code & 0x2) ? 4 : 0; j < BANDS; j++) {
524  cwlen = av_clipf(((chctx->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6);
525 
526  chctx->bitsBandT[j] = cwlen;
527  summer += chctx->bandWidthT[j] * cwlen;
528 
529  if (cwlen > 0)
530  iacc += chctx->bandWidthT[j];
531  }
532 
533  flg = t2;
534  t2 = 1;
535  if (freebits < summer)
536  t2 = -1;
537  if (i == 0)
538  flg = t2;
539  if (flg != t2)
540  t1++;
541 
542  summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa;
543  }
544 
545  for (i = (stream_format_code & 0x2) ? 4 : 0; i < BANDS; i++) {
546  for (j = band_tab[i]; j < band_tab[i + 1]; j++)
547  chctx->CWlengthT[j] = chctx->bitsBandT[i];
548  }
549 
550  if (freebits > summer) {
551  for (i = 0; i < BANDS; i++) {
552  workT[i] = (chctx->bitsBandT[i] == 6) ? -1.e20
553  : (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] - 0.415);
554  }
555 
556  highest = 0.0;
557 
558  do {
559  if (highest <= -1.e20)
560  break;
561 
562  found_indx = 0;
563  highest = -1.e20;
564 
565  for (i = 0; i < BANDS; i++) {
566  if (workT[i] > highest) {
567  highest = workT[i];
568  found_indx = i;
569  }
570  }
571 
572  if (highest > -1.e20) {
573  workT[found_indx] -= 2.0;
574  if (++chctx->bitsBandT[found_indx] == 6)
575  workT[found_indx] = -1.e20;
576 
577  for (j = band_tab[found_indx]; j < band_tab[found_indx + 1] && (freebits > summer); j++) {
578  chctx->CWlengthT[j]++;
579  summer++;
580  }
581  }
582  } while (freebits > summer);
583  }
584  if (freebits < summer) {
585  for (i = 0; i < BANDS; i++) {
586  workT[i] = chctx->bitsBandT[i] ? (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] + 1.585)
587  : 1.e20;
588  }
589  if (stream_format_code & 0x2) {
590  workT[0] = 1.e20;
591  workT[1] = 1.e20;
592  workT[2] = 1.e20;
593  workT[3] = 1.e20;
594  }
595  while (freebits < summer) {
596  lowest = 1.e10;
597  low_indx = 0;
598  for (i = 0; i < BANDS; i++) {
599  if (workT[i] < lowest) {
600  lowest = workT[i];
601  low_indx = i;
602  }
603  }
604  // if (lowest >= 1.e10)
605  // break;
606  workT[low_indx] = lowest + 2.0;
607 
608  if (!--chctx->bitsBandT[low_indx])
609  workT[low_indx] = 1.e20;
610 
611  for (j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++) {
612  if (chctx->CWlengthT[j] > 0) {
613  chctx->CWlengthT[j]--;
614  summer--;
615  }
616  }
617  }
618  }
619  return 0;
620 }
621 
622 static void imc_get_skip_coeff(IMCContext *q, IMCChannel *chctx)
623 {
624  int i, j;
625 
626  memset(chctx->skipFlagBits, 0, sizeof(chctx->skipFlagBits));
627  memset(chctx->skipFlagCount, 0, sizeof(chctx->skipFlagCount));
628  for (i = 0; i < BANDS; i++) {
629  if (!chctx->bandFlagsBuf[i] || !chctx->bandWidthT[i])
630  continue;
631 
632  if (!chctx->skipFlagRaw[i]) {
633  chctx->skipFlagBits[i] = band_tab[i + 1] - band_tab[i];
634 
635  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
636  chctx->skipFlags[j] = get_bits1(&q->gb);
637  if (chctx->skipFlags[j])
638  chctx->skipFlagCount[i]++;
639  }
640  } else {
641  for (j = band_tab[i]; j < band_tab[i + 1] - 1; j += 2) {
642  if (!get_bits1(&q->gb)) { // 0
643  chctx->skipFlagBits[i]++;
644  chctx->skipFlags[j] = 1;
645  chctx->skipFlags[j + 1] = 1;
646  chctx->skipFlagCount[i] += 2;
647  } else {
648  if (get_bits1(&q->gb)) { // 11
649  chctx->skipFlagBits[i] += 2;
650  chctx->skipFlags[j] = 0;
651  chctx->skipFlags[j + 1] = 1;
652  chctx->skipFlagCount[i]++;
653  } else {
654  chctx->skipFlagBits[i] += 3;
655  chctx->skipFlags[j + 1] = 0;
656  if (!get_bits1(&q->gb)) { // 100
657  chctx->skipFlags[j] = 1;
658  chctx->skipFlagCount[i]++;
659  } else { // 101
660  chctx->skipFlags[j] = 0;
661  }
662  }
663  }
664  }
665 
666  if (j < band_tab[i + 1]) {
667  chctx->skipFlagBits[i]++;
668  if ((chctx->skipFlags[j] = get_bits1(&q->gb)))
669  chctx->skipFlagCount[i]++;
670  }
671  }
672  }
673 }
674 
675 /**
676  * Increase highest' band coefficient sizes as some bits won't be used
677  */
679  int summer)
680 {
681  float workT[32];
682  int corrected = 0;
683  int i, j;
684  float highest = 0;
685  int found_indx = 0;
686 
687  for (i = 0; i < BANDS; i++) {
688  workT[i] = (chctx->bitsBandT[i] == 6) ? -1.e20
689  : (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] - 0.415);
690  }
691 
692  while (corrected < summer) {
693  if (highest <= -1.e20)
694  break;
695 
696  highest = -1.e20;
697 
698  for (i = 0; i < BANDS; i++) {
699  if (workT[i] > highest) {
700  highest = workT[i];
701  found_indx = i;
702  }
703  }
704 
705  if (highest > -1.e20) {
706  workT[found_indx] -= 2.0;
707  if (++(chctx->bitsBandT[found_indx]) == 6)
708  workT[found_indx] = -1.e20;
709 
710  for (j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) {
711  if (!chctx->skipFlags[j] && (chctx->CWlengthT[j] < 6)) {
712  chctx->CWlengthT[j]++;
713  corrected++;
714  }
715  }
716  }
717  }
718 }
719 
720 static void imc_imdct256(IMCContext *q, IMCChannel *chctx, int channels)
721 {
722  int i;
723  float re, im;
724  float *dst1 = q->out_samples;
725  float *dst2 = q->out_samples + (COEFFS - 1);
726 
727  /* prerotation */
728  for (i = 0; i < COEFFS / 2; i++) {
729  q->samples[i].re = -(q->pre_coef1[i] * chctx->CWdecoded[COEFFS - 1 - i * 2]) -
730  (q->pre_coef2[i] * chctx->CWdecoded[i * 2]);
731  q->samples[i].im = (q->pre_coef2[i] * chctx->CWdecoded[COEFFS - 1 - i * 2]) -
732  (q->pre_coef1[i] * chctx->CWdecoded[i * 2]);
733  }
734 
735  /* FFT */
736  q->fft.fft_permute(&q->fft, q->samples);
737  q->fft.fft_calc(&q->fft, q->samples);
738 
739  /* postrotation, window and reorder */
740  for (i = 0; i < COEFFS / 2; i++) {
741  re = ( q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]);
742  im = (-q->samples[i].im * q->post_cos[i]) - ( q->samples[i].re * q->post_sin[i]);
743  *dst1 = (q->mdct_sine_window[COEFFS - 1 - i * 2] * chctx->last_fft_im[i])
744  + (q->mdct_sine_window[i * 2] * re);
745  *dst2 = (q->mdct_sine_window[i * 2] * chctx->last_fft_im[i])
746  - (q->mdct_sine_window[COEFFS - 1 - i * 2] * re);
747  dst1 += 2;
748  dst2 -= 2;
749  chctx->last_fft_im[i] = im;
750  }
751 }
752 
754  int stream_format_code)
755 {
756  int i, j;
757  int middle_value, cw_len, max_size;
758  const float *quantizer;
759 
760  for (i = 0; i < BANDS; i++) {
761  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
762  chctx->CWdecoded[j] = 0;
763  cw_len = chctx->CWlengthT[j];
764 
765  if (cw_len <= 0 || chctx->skipFlags[j])
766  continue;
767 
768  max_size = 1 << cw_len;
769  middle_value = max_size >> 1;
770 
771  if (chctx->codewords[j] >= max_size || chctx->codewords[j] < 0)
772  return AVERROR_INVALIDDATA;
773 
774  if (cw_len >= 4) {
775  quantizer = imc_quantizer2[(stream_format_code & 2) >> 1];
776  if (chctx->codewords[j] >= middle_value)
777  chctx->CWdecoded[j] = quantizer[chctx->codewords[j] - 8] * chctx->flcoeffs6[i];
778  else
779  chctx->CWdecoded[j] = -quantizer[max_size - chctx->codewords[j] - 8 - 1] * chctx->flcoeffs6[i];
780  }else{
781  quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (chctx->bandFlagsBuf[i] << 1)];
782  if (chctx->codewords[j] >= middle_value)
783  chctx->CWdecoded[j] = quantizer[chctx->codewords[j] - 1] * chctx->flcoeffs6[i];
784  else
785  chctx->CWdecoded[j] = -quantizer[max_size - 2 - chctx->codewords[j]] * chctx->flcoeffs6[i];
786  }
787  }
788  }
789  return 0;
790 }
791 
792 
793 static void imc_get_coeffs(AVCodecContext *avctx,
794  IMCContext *q, IMCChannel *chctx)
795 {
796  int i, j, cw_len, cw;
797 
798  for (i = 0; i < BANDS; i++) {
799  if (!chctx->sumLenArr[i])
800  continue;
801  if (chctx->bandFlagsBuf[i] || chctx->bandWidthT[i]) {
802  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
803  cw_len = chctx->CWlengthT[j];
804  cw = 0;
805 
806  if (cw_len && (!chctx->bandFlagsBuf[i] || !chctx->skipFlags[j])) {
807  if (get_bits_count(&q->gb) + cw_len > 512) {
808  av_log(avctx, AV_LOG_WARNING,
809  "Potential problem on band %i, coefficient %i"
810  ": cw_len=%i\n", i, j, cw_len);
811  } else
812  cw = get_bits(&q->gb, cw_len);
813  }
814 
815  chctx->codewords[j] = cw;
816  }
817  }
818  }
819 }
820 
822 {
823  int i, j;
824  int bits, summer;
825 
826  for (i = 0; i < BANDS; i++) {
827  chctx->sumLenArr[i] = 0;
828  chctx->skipFlagRaw[i] = 0;
829  for (j = band_tab[i]; j < band_tab[i + 1]; j++)
830  chctx->sumLenArr[i] += chctx->CWlengthT[j];
831  if (chctx->bandFlagsBuf[i])
832  if ((((band_tab[i + 1] - band_tab[i]) * 1.5) > chctx->sumLenArr[i]) && (chctx->sumLenArr[i] > 0))
833  chctx->skipFlagRaw[i] = 1;
834  }
835 
836  imc_get_skip_coeff(q, chctx);
837 
838  for (i = 0; i < BANDS; i++) {
839  chctx->flcoeffs6[i] = chctx->flcoeffs1[i];
840  /* band has flag set and at least one coded coefficient */
841  if (chctx->bandFlagsBuf[i] && (band_tab[i + 1] - band_tab[i]) != chctx->skipFlagCount[i]) {
842  chctx->flcoeffs6[i] *= q->sqrt_tab[ band_tab[i + 1] - band_tab[i]] /
843  q->sqrt_tab[(band_tab[i + 1] - band_tab[i] - chctx->skipFlagCount[i])];
844  }
845  }
846 
847  /* calculate bits left, bits needed and adjust bit allocation */
848  bits = summer = 0;
849 
850  for (i = 0; i < BANDS; i++) {
851  if (chctx->bandFlagsBuf[i]) {
852  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
853  if (chctx->skipFlags[j]) {
854  summer += chctx->CWlengthT[j];
855  chctx->CWlengthT[j] = 0;
856  }
857  }
858  bits += chctx->skipFlagBits[i];
859  summer -= chctx->skipFlagBits[i];
860  }
861  }
862  imc_adjust_bit_allocation(q, chctx, summer);
863 }
864 
865 static int imc_decode_block(AVCodecContext *avctx, IMCContext *q, int ch)
866 {
867  int stream_format_code;
868  int imc_hdr, i, j, ret;
869  int flag;
870  int bits;
871  int counter, bitscount;
872  IMCChannel *chctx = q->chctx + ch;
873 
874 
875  /* Check the frame header */
876  imc_hdr = get_bits(&q->gb, 9);
877  if (imc_hdr & 0x18) {
878  av_log(avctx, AV_LOG_ERROR, "frame header check failed!\n");
879  av_log(avctx, AV_LOG_ERROR, "got %X.\n", imc_hdr);
880  return AVERROR_INVALIDDATA;
881  }
882  stream_format_code = get_bits(&q->gb, 3);
883 
884  if (stream_format_code & 0x04)
885  chctx->decoder_reset = 1;
886 
887  if (chctx->decoder_reset) {
888  for (i = 0; i < BANDS; i++)
889  chctx->old_floor[i] = 1.0;
890  for (i = 0; i < COEFFS; i++)
891  chctx->CWdecoded[i] = 0;
892  chctx->decoder_reset = 0;
893  }
894 
895  flag = get_bits1(&q->gb);
896  if (stream_format_code & 0x1)
897  imc_read_level_coeffs_raw(q, stream_format_code, chctx->levlCoeffBuf);
898  else
899  imc_read_level_coeffs(q, stream_format_code, chctx->levlCoeffBuf);
900 
901  if (stream_format_code & 0x1)
903  chctx->flcoeffs1, chctx->flcoeffs2);
904  else if (stream_format_code & 0x4)
906  chctx->flcoeffs1, chctx->flcoeffs2);
907  else
909  chctx->flcoeffs1, chctx->flcoeffs2);
910 
911  for(i=0; i<BANDS; i++) {
912  if(chctx->flcoeffs1[i] > INT_MAX) {
913  av_log(avctx, AV_LOG_ERROR, "scalefactor out of range\n");
914  return AVERROR_INVALIDDATA;
915  }
916  }
917 
918  memcpy(chctx->old_floor, chctx->flcoeffs1, 32 * sizeof(float));
919 
920  counter = 0;
921  if (stream_format_code & 0x1) {
922  for (i = 0; i < BANDS; i++) {
923  chctx->bandWidthT[i] = band_tab[i + 1] - band_tab[i];
924  chctx->bandFlagsBuf[i] = 0;
925  chctx->flcoeffs3[i] = chctx->flcoeffs2[i] * 2;
926  chctx->flcoeffs5[i] = 1.0;
927  }
928  } else {
929  for (i = 0; i < BANDS; i++) {
930  if (chctx->levlCoeffBuf[i] == 16) {
931  chctx->bandWidthT[i] = 0;
932  counter++;
933  } else
934  chctx->bandWidthT[i] = band_tab[i + 1] - band_tab[i];
935  }
936 
937  memset(chctx->bandFlagsBuf, 0, BANDS * sizeof(int));
938  for (i = 0; i < BANDS - 1; i++)
939  if (chctx->bandWidthT[i])
940  chctx->bandFlagsBuf[i] = get_bits1(&q->gb);
941 
942  imc_calculate_coeffs(q, chctx->flcoeffs1, chctx->flcoeffs2,
943  chctx->bandWidthT, chctx->flcoeffs3,
944  chctx->flcoeffs5);
945  }
946 
947  bitscount = 0;
948  /* first 4 bands will be assigned 5 bits per coefficient */
949  if (stream_format_code & 0x2) {
950  bitscount += 15;
951 
952  chctx->bitsBandT[0] = 5;
953  chctx->CWlengthT[0] = 5;
954  chctx->CWlengthT[1] = 5;
955  chctx->CWlengthT[2] = 5;
956  for (i = 1; i < 4; i++) {
957  if (stream_format_code & 0x1)
958  bits = 5;
959  else
960  bits = (chctx->levlCoeffBuf[i] == 16) ? 0 : 5;
961  chctx->bitsBandT[i] = bits;
962  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
963  chctx->CWlengthT[j] = bits;
964  bitscount += bits;
965  }
966  }
967  }
968  if (avctx->codec_id == AV_CODEC_ID_IAC) {
969  bitscount += !!chctx->bandWidthT[BANDS - 1];
970  if (!(stream_format_code & 0x2))
971  bitscount += 16;
972  }
973 
974  if ((ret = bit_allocation(q, chctx, stream_format_code,
975  512 - bitscount - get_bits_count(&q->gb),
976  flag)) < 0) {
977  av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n");
978  chctx->decoder_reset = 1;
979  return ret;
980  }
981 
982  if (stream_format_code & 0x1) {
983  for (i = 0; i < BANDS; i++)
984  chctx->skipFlags[i] = 0;
985  } else {
986  imc_refine_bit_allocation(q, chctx);
987  }
988 
989  for (i = 0; i < BANDS; i++) {
990  chctx->sumLenArr[i] = 0;
991 
992  for (j = band_tab[i]; j < band_tab[i + 1]; j++)
993  if (!chctx->skipFlags[j])
994  chctx->sumLenArr[i] += chctx->CWlengthT[j];
995  }
996 
997  memset(chctx->codewords, 0, sizeof(chctx->codewords));
998 
999  imc_get_coeffs(avctx, q, chctx);
1000 
1001  if (inverse_quant_coeff(q, chctx, stream_format_code) < 0) {
1002  av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n");
1003  chctx->decoder_reset = 1;
1004  return AVERROR_INVALIDDATA;
1005  }
1006 
1007  memset(chctx->skipFlags, 0, sizeof(chctx->skipFlags));
1008 
1009  imc_imdct256(q, chctx, avctx->channels);
1010 
1011  return 0;
1012 }
1013 
1014 static int imc_decode_frame(AVCodecContext *avctx, void *data,
1015  int *got_frame_ptr, AVPacket *avpkt)
1016 {
1017  AVFrame *frame = data;
1018  const uint8_t *buf = avpkt->data;
1019  int buf_size = avpkt->size;
1020  int ret, i;
1021 
1022  IMCContext *q = avctx->priv_data;
1023 
1024  LOCAL_ALIGNED_16(uint16_t, buf16, [IMC_BLOCK_SIZE / 2 + FF_INPUT_BUFFER_PADDING_SIZE/2]);
1025 
1026  if (buf_size < IMC_BLOCK_SIZE * avctx->channels) {
1027  av_log(avctx, AV_LOG_ERROR, "frame too small!\n");
1028  return AVERROR_INVALIDDATA;
1029  }
1030 
1031  /* get output buffer */
1032  frame->nb_samples = COEFFS;
1033  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
1034  return ret;
1035 
1036  for (i = 0; i < avctx->channels; i++) {
1037  q->out_samples = (float *)frame->extended_data[i];
1038 
1039  q->bdsp.bswap16_buf(buf16, (const uint16_t *) buf, IMC_BLOCK_SIZE / 2);
1040 
1041  init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8);
1042 
1043  buf += IMC_BLOCK_SIZE;
1044 
1045  if ((ret = imc_decode_block(avctx, q, i)) < 0)
1046  return ret;
1047  }
1048 
1049  if (avctx->channels == 2) {
1050  q->fdsp->butterflies_float((float *)frame->extended_data[0],
1051  (float *)frame->extended_data[1], COEFFS);
1052  }
1053 
1054  *got_frame_ptr = 1;
1055 
1056  return IMC_BLOCK_SIZE * avctx->channels;
1057 }
1058 
1060 {
1061  IMCContext *q = avctx->priv_data;
1062 
1063  ff_fft_end(&q->fft);
1064  av_freep(&q->fdsp);
1065 
1066  return 0;
1067 }
1068 
1069 static av_cold void flush(AVCodecContext *avctx)
1070 {
1071  IMCContext *q = avctx->priv_data;
1072 
1073  q->chctx[0].decoder_reset =
1074  q->chctx[1].decoder_reset = 1;
1075 }
1076 
1077 #if CONFIG_IMC_DECODER
1078 AVCodec ff_imc_decoder = {
1079  .name = "imc",
1080  .long_name = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"),
1081  .type = AVMEDIA_TYPE_AUDIO,
1082  .id = AV_CODEC_ID_IMC,
1083  .priv_data_size = sizeof(IMCContext),
1084  .init = imc_decode_init,
1087  .flush = flush,
1088  .capabilities = CODEC_CAP_DR1,
1089  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
1091 };
1092 #endif
1093 #if CONFIG_IAC_DECODER
1094 AVCodec ff_iac_decoder = {
1095  .name = "iac",
1096  .long_name = NULL_IF_CONFIG_SMALL("IAC (Indeo Audio Coder)"),
1097  .type = AVMEDIA_TYPE_AUDIO,
1098  .id = AV_CODEC_ID_IAC,
1099  .priv_data_size = sizeof(IMCContext),
1100  .init = imc_decode_init,
1103  .flush = flush,
1104  .capabilities = CODEC_CAP_DR1,
1105  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
1107 };
1108 #endif