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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 "get_bits.h"
44 #include "dsputil.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_IMC)
184  avctx->channels = 1;
185 
186  if (avctx->channels > 2) {
187  avpriv_request_sample(avctx, "Number of channels > 2");
188  return AVERROR_PATCHWELCOME;
189  }
190 
191  for (j = 0; j < avctx->channels; j++) {
192  q->chctx[j].decoder_reset = 1;
193 
194  for (i = 0; i < BANDS; i++)
195  q->chctx[j].old_floor[i] = 1.0;
196 
197  for (i = 0; i < COEFFS / 2; i++)
198  q->chctx[j].last_fft_im[i] = 0;
199  }
200 
201  /* Build mdct window, a simple sine window normalized with sqrt(2) */
203  for (i = 0; i < COEFFS; i++)
204  q->mdct_sine_window[i] *= sqrt(2.0);
205  for (i = 0; i < COEFFS / 2; i++) {
206  q->post_cos[i] = (1.0f / 32768) * cos(i / 256.0 * M_PI);
207  q->post_sin[i] = (1.0f / 32768) * sin(i / 256.0 * M_PI);
208 
209  r1 = sin((i * 4.0 + 1.0) / 1024.0 * M_PI);
210  r2 = cos((i * 4.0 + 1.0) / 1024.0 * M_PI);
211 
212  if (i & 0x1) {
213  q->pre_coef1[i] = (r1 + r2) * sqrt(2.0);
214  q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0);
215  } else {
216  q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0);
217  q->pre_coef2[i] = (r1 - r2) * sqrt(2.0);
218  }
219  }
220 
221  /* Generate a square root table */
222 
223  for (i = 0; i < 30; i++)
224  q->sqrt_tab[i] = sqrt(i);
225 
226  /* initialize the VLC tables */
227  for (i = 0; i < 4 ; i++) {
228  for (j = 0; j < 4; j++) {
229  huffman_vlc[i][j].table = &vlc_tables[vlc_offsets[i * 4 + j]];
230  huffman_vlc[i][j].table_allocated = vlc_offsets[i * 4 + j + 1] - vlc_offsets[i * 4 + j];
231  init_vlc(&huffman_vlc[i][j], 9, imc_huffman_sizes[i],
232  imc_huffman_lens[i][j], 1, 1,
234  }
235  }
236 
237  if (avctx->codec_id == AV_CODEC_ID_IAC) {
238  iac_generate_tabs(q, avctx->sample_rate);
239  } else {
240  memcpy(q->cyclTab, cyclTab, sizeof(cyclTab));
241  memcpy(q->cyclTab2, cyclTab2, sizeof(cyclTab2));
242  memcpy(q->weights1, imc_weights1, sizeof(imc_weights1));
243  memcpy(q->weights2, imc_weights2, sizeof(imc_weights2));
244  }
245 
246  if ((ret = ff_fft_init(&q->fft, 7, 1))) {
247  av_log(avctx, AV_LOG_INFO, "FFT init failed\n");
248  return ret;
249  }
250  ff_dsputil_init(&q->dsp, avctx);
253  avctx->channel_layout = avctx->channels == 1 ? AV_CH_LAYOUT_MONO
255 
256  return 0;
257 }
258 
259 static void imc_calculate_coeffs(IMCContext *q, float *flcoeffs1,
260  float *flcoeffs2, int *bandWidthT,
261  float *flcoeffs3, float *flcoeffs5)
262 {
263  float workT1[BANDS];
264  float workT2[BANDS];
265  float workT3[BANDS];
266  float snr_limit = 1.e-30;
267  float accum = 0.0;
268  int i, cnt2;
269 
270  for (i = 0; i < BANDS; i++) {
271  flcoeffs5[i] = workT2[i] = 0.0;
272  if (bandWidthT[i]) {
273  workT1[i] = flcoeffs1[i] * flcoeffs1[i];
274  flcoeffs3[i] = 2.0 * flcoeffs2[i];
275  } else {
276  workT1[i] = 0.0;
277  flcoeffs3[i] = -30000.0;
278  }
279  workT3[i] = bandWidthT[i] * workT1[i] * 0.01;
280  if (workT3[i] <= snr_limit)
281  workT3[i] = 0.0;
282  }
283 
284  for (i = 0; i < BANDS; i++) {
285  for (cnt2 = i; cnt2 < q->cyclTab[i]; cnt2++)
286  flcoeffs5[cnt2] = flcoeffs5[cnt2] + workT3[i];
287  workT2[cnt2 - 1] = workT2[cnt2 - 1] + workT3[i];
288  }
289 
290  for (i = 1; i < BANDS; i++) {
291  accum = (workT2[i - 1] + accum) * q->weights1[i - 1];
292  flcoeffs5[i] += accum;
293  }
294 
295  for (i = 0; i < BANDS; i++)
296  workT2[i] = 0.0;
297 
298  for (i = 0; i < BANDS; i++) {
299  for (cnt2 = i - 1; cnt2 > q->cyclTab2[i]; cnt2--)
300  flcoeffs5[cnt2] += workT3[i];
301  workT2[cnt2+1] += workT3[i];
302  }
303 
304  accum = 0.0;
305 
306  for (i = BANDS-2; i >= 0; i--) {
307  accum = (workT2[i+1] + accum) * q->weights2[i];
308  flcoeffs5[i] += accum;
309  // there is missing code here, but it seems to never be triggered
310  }
311 }
312 
313 
314 static void imc_read_level_coeffs(IMCContext *q, int stream_format_code,
315  int *levlCoeffs)
316 {
317  int i;
318  VLC *hufftab[4];
319  int start = 0;
320  const uint8_t *cb_sel;
321  int s;
322 
323  s = stream_format_code >> 1;
324  hufftab[0] = &huffman_vlc[s][0];
325  hufftab[1] = &huffman_vlc[s][1];
326  hufftab[2] = &huffman_vlc[s][2];
327  hufftab[3] = &huffman_vlc[s][3];
328  cb_sel = imc_cb_select[s];
329 
330  if (stream_format_code & 4)
331  start = 1;
332  if (start)
333  levlCoeffs[0] = get_bits(&q->gb, 7);
334  for (i = start; i < BANDS; i++) {
335  levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table,
336  hufftab[cb_sel[i]]->bits, 2);
337  if (levlCoeffs[i] == 17)
338  levlCoeffs[i] += get_bits(&q->gb, 4);
339  }
340 }
341 
342 static void imc_read_level_coeffs_raw(IMCContext *q, int stream_format_code,
343  int *levlCoeffs)
344 {
345  int i;
346 
347  q->coef0_pos = get_bits(&q->gb, 5);
348  levlCoeffs[0] = get_bits(&q->gb, 7);
349  for (i = 1; i < BANDS; i++)
350  levlCoeffs[i] = get_bits(&q->gb, 4);
351 }
352 
353 static void imc_decode_level_coefficients(IMCContext *q, int *levlCoeffBuf,
354  float *flcoeffs1, float *flcoeffs2)
355 {
356  int i, level;
357  float tmp, tmp2;
358  // maybe some frequency division thingy
359 
360  flcoeffs1[0] = 20000.0 / exp2 (levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
361  flcoeffs2[0] = log2f(flcoeffs1[0]);
362  tmp = flcoeffs1[0];
363  tmp2 = flcoeffs2[0];
364 
365  for (i = 1; i < BANDS; i++) {
366  level = levlCoeffBuf[i];
367  if (level == 16) {
368  flcoeffs1[i] = 1.0;
369  flcoeffs2[i] = 0.0;
370  } else {
371  if (level < 17)
372  level -= 7;
373  else if (level <= 24)
374  level -= 32;
375  else
376  level -= 16;
377 
378  tmp *= imc_exp_tab[15 + level];
379  tmp2 += 0.83048 * level; // 0.83048 = log2(10) * 0.25
380  flcoeffs1[i] = tmp;
381  flcoeffs2[i] = tmp2;
382  }
383  }
384 }
385 
386 
387 static void imc_decode_level_coefficients2(IMCContext *q, int *levlCoeffBuf,
388  float *old_floor, float *flcoeffs1,
389  float *flcoeffs2)
390 {
391  int i;
392  /* FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors
393  * and flcoeffs2 old scale factors
394  * might be incomplete due to a missing table that is in the binary code
395  */
396  for (i = 0; i < BANDS; i++) {
397  flcoeffs1[i] = 0;
398  if (levlCoeffBuf[i] < 16) {
399  flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i];
400  flcoeffs2[i] = (levlCoeffBuf[i] - 7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25
401  } else {
402  flcoeffs1[i] = old_floor[i];
403  }
404  }
405 }
406 
407 static void imc_decode_level_coefficients_raw(IMCContext *q, int *levlCoeffBuf,
408  float *flcoeffs1, float *flcoeffs2)
409 {
410  int i, level, pos;
411  float tmp, tmp2;
412 
413  pos = q->coef0_pos;
414  flcoeffs1[pos] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
415  flcoeffs2[pos] = log2f(flcoeffs1[0]);
416  tmp = flcoeffs1[pos];
417  tmp2 = flcoeffs2[pos];
418 
419  levlCoeffBuf++;
420  for (i = 0; i < BANDS; i++) {
421  if (i == pos)
422  continue;
423  level = *levlCoeffBuf++;
424  flcoeffs1[i] = tmp * powf(10.0, -level * 0.4375); //todo tab
425  flcoeffs2[i] = tmp2 - 1.4533435415 * level; // 1.4533435415 = log2(10) * 0.4375
426  }
427 }
428 
429 /**
430  * Perform bit allocation depending on bits available
431  */
432 static int bit_allocation(IMCContext *q, IMCChannel *chctx,
433  int stream_format_code, int freebits, int flag)
434 {
435  int i, j;
436  const float limit = -1.e20;
437  float highest = 0.0;
438  int indx;
439  int t1 = 0;
440  int t2 = 1;
441  float summa = 0.0;
442  int iacc = 0;
443  int summer = 0;
444  int rres, cwlen;
445  float lowest = 1.e10;
446  int low_indx = 0;
447  float workT[32];
448  int flg;
449  int found_indx = 0;
450 
451  for (i = 0; i < BANDS; i++)
452  highest = FFMAX(highest, chctx->flcoeffs1[i]);
453 
454  for (i = 0; i < BANDS - 1; i++) {
455  if (chctx->flcoeffs5[i] <= 0) {
456  av_log(NULL, AV_LOG_ERROR, "flcoeffs5 %f invalid\n", chctx->flcoeffs5[i]);
457  return AVERROR_INVALIDDATA;
458  }
459  chctx->flcoeffs4[i] = chctx->flcoeffs3[i] - log2f(chctx->flcoeffs5[i]);
460  }
461  chctx->flcoeffs4[BANDS - 1] = limit;
462 
463  highest = highest * 0.25;
464 
465  for (i = 0; i < BANDS; i++) {
466  indx = -1;
467  if ((band_tab[i + 1] - band_tab[i]) == chctx->bandWidthT[i])
468  indx = 0;
469 
470  if ((band_tab[i + 1] - band_tab[i]) > chctx->bandWidthT[i])
471  indx = 1;
472 
473  if (((band_tab[i + 1] - band_tab[i]) / 2) >= chctx->bandWidthT[i])
474  indx = 2;
475 
476  if (indx == -1)
477  return AVERROR_INVALIDDATA;
478 
479  chctx->flcoeffs4[i] += xTab[(indx * 2 + (chctx->flcoeffs1[i] < highest)) * 2 + flag];
480  }
481 
482  if (stream_format_code & 0x2) {
483  chctx->flcoeffs4[0] = limit;
484  chctx->flcoeffs4[1] = limit;
485  chctx->flcoeffs4[2] = limit;
486  chctx->flcoeffs4[3] = limit;
487  }
488 
489  for (i = (stream_format_code & 0x2) ? 4 : 0; i < BANDS - 1; i++) {
490  iacc += chctx->bandWidthT[i];
491  summa += chctx->bandWidthT[i] * chctx->flcoeffs4[i];
492  }
493 
494  if (!iacc)
495  return AVERROR_INVALIDDATA;
496 
497  chctx->bandWidthT[BANDS - 1] = 0;
498  summa = (summa * 0.5 - freebits) / iacc;
499 
500 
501  for (i = 0; i < BANDS / 2; i++) {
502  rres = summer - freebits;
503  if ((rres >= -8) && (rres <= 8))
504  break;
505 
506  summer = 0;
507  iacc = 0;
508 
509  for (j = (stream_format_code & 0x2) ? 4 : 0; j < BANDS; j++) {
510  cwlen = av_clipf(((chctx->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6);
511 
512  chctx->bitsBandT[j] = cwlen;
513  summer += chctx->bandWidthT[j] * cwlen;
514 
515  if (cwlen > 0)
516  iacc += chctx->bandWidthT[j];
517  }
518 
519  flg = t2;
520  t2 = 1;
521  if (freebits < summer)
522  t2 = -1;
523  if (i == 0)
524  flg = t2;
525  if (flg != t2)
526  t1++;
527 
528  summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa;
529  }
530 
531  for (i = (stream_format_code & 0x2) ? 4 : 0; i < BANDS; i++) {
532  for (j = band_tab[i]; j < band_tab[i + 1]; j++)
533  chctx->CWlengthT[j] = chctx->bitsBandT[i];
534  }
535 
536  if (freebits > summer) {
537  for (i = 0; i < BANDS; i++) {
538  workT[i] = (chctx->bitsBandT[i] == 6) ? -1.e20
539  : (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] - 0.415);
540  }
541 
542  highest = 0.0;
543 
544  do {
545  if (highest <= -1.e20)
546  break;
547 
548  found_indx = 0;
549  highest = -1.e20;
550 
551  for (i = 0; i < BANDS; i++) {
552  if (workT[i] > highest) {
553  highest = workT[i];
554  found_indx = i;
555  }
556  }
557 
558  if (highest > -1.e20) {
559  workT[found_indx] -= 2.0;
560  if (++chctx->bitsBandT[found_indx] == 6)
561  workT[found_indx] = -1.e20;
562 
563  for (j = band_tab[found_indx]; j < band_tab[found_indx + 1] && (freebits > summer); j++) {
564  chctx->CWlengthT[j]++;
565  summer++;
566  }
567  }
568  } while (freebits > summer);
569  }
570  if (freebits < summer) {
571  for (i = 0; i < BANDS; i++) {
572  workT[i] = chctx->bitsBandT[i] ? (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] + 1.585)
573  : 1.e20;
574  }
575  if (stream_format_code & 0x2) {
576  workT[0] = 1.e20;
577  workT[1] = 1.e20;
578  workT[2] = 1.e20;
579  workT[3] = 1.e20;
580  }
581  while (freebits < summer) {
582  lowest = 1.e10;
583  low_indx = 0;
584  for (i = 0; i < BANDS; i++) {
585  if (workT[i] < lowest) {
586  lowest = workT[i];
587  low_indx = i;
588  }
589  }
590  // if (lowest >= 1.e10)
591  // break;
592  workT[low_indx] = lowest + 2.0;
593 
594  if (!--chctx->bitsBandT[low_indx])
595  workT[low_indx] = 1.e20;
596 
597  for (j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++) {
598  if (chctx->CWlengthT[j] > 0) {
599  chctx->CWlengthT[j]--;
600  summer--;
601  }
602  }
603  }
604  }
605  return 0;
606 }
607 
608 static void imc_get_skip_coeff(IMCContext *q, IMCChannel *chctx)
609 {
610  int i, j;
611 
612  memset(chctx->skipFlagBits, 0, sizeof(chctx->skipFlagBits));
613  memset(chctx->skipFlagCount, 0, sizeof(chctx->skipFlagCount));
614  for (i = 0; i < BANDS; i++) {
615  if (!chctx->bandFlagsBuf[i] || !chctx->bandWidthT[i])
616  continue;
617 
618  if (!chctx->skipFlagRaw[i]) {
619  chctx->skipFlagBits[i] = band_tab[i + 1] - band_tab[i];
620 
621  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
622  chctx->skipFlags[j] = get_bits1(&q->gb);
623  if (chctx->skipFlags[j])
624  chctx->skipFlagCount[i]++;
625  }
626  } else {
627  for (j = band_tab[i]; j < band_tab[i + 1] - 1; j += 2) {
628  if (!get_bits1(&q->gb)) { // 0
629  chctx->skipFlagBits[i]++;
630  chctx->skipFlags[j] = 1;
631  chctx->skipFlags[j + 1] = 1;
632  chctx->skipFlagCount[i] += 2;
633  } else {
634  if (get_bits1(&q->gb)) { // 11
635  chctx->skipFlagBits[i] += 2;
636  chctx->skipFlags[j] = 0;
637  chctx->skipFlags[j + 1] = 1;
638  chctx->skipFlagCount[i]++;
639  } else {
640  chctx->skipFlagBits[i] += 3;
641  chctx->skipFlags[j + 1] = 0;
642  if (!get_bits1(&q->gb)) { // 100
643  chctx->skipFlags[j] = 1;
644  chctx->skipFlagCount[i]++;
645  } else { // 101
646  chctx->skipFlags[j] = 0;
647  }
648  }
649  }
650  }
651 
652  if (j < band_tab[i + 1]) {
653  chctx->skipFlagBits[i]++;
654  if ((chctx->skipFlags[j] = get_bits1(&q->gb)))
655  chctx->skipFlagCount[i]++;
656  }
657  }
658  }
659 }
660 
661 /**
662  * Increase highest' band coefficient sizes as some bits won't be used
663  */
665  int summer)
666 {
667  float workT[32];
668  int corrected = 0;
669  int i, j;
670  float highest = 0;
671  int found_indx = 0;
672 
673  for (i = 0; i < BANDS; i++) {
674  workT[i] = (chctx->bitsBandT[i] == 6) ? -1.e20
675  : (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] - 0.415);
676  }
677 
678  while (corrected < summer) {
679  if (highest <= -1.e20)
680  break;
681 
682  highest = -1.e20;
683 
684  for (i = 0; i < BANDS; i++) {
685  if (workT[i] > highest) {
686  highest = workT[i];
687  found_indx = i;
688  }
689  }
690 
691  if (highest > -1.e20) {
692  workT[found_indx] -= 2.0;
693  if (++(chctx->bitsBandT[found_indx]) == 6)
694  workT[found_indx] = -1.e20;
695 
696  for (j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) {
697  if (!chctx->skipFlags[j] && (chctx->CWlengthT[j] < 6)) {
698  chctx->CWlengthT[j]++;
699  corrected++;
700  }
701  }
702  }
703  }
704 }
705 
706 static void imc_imdct256(IMCContext *q, IMCChannel *chctx, int channels)
707 {
708  int i;
709  float re, im;
710  float *dst1 = q->out_samples;
711  float *dst2 = q->out_samples + (COEFFS - 1);
712 
713  /* prerotation */
714  for (i = 0; i < COEFFS / 2; i++) {
715  q->samples[i].re = -(q->pre_coef1[i] * chctx->CWdecoded[COEFFS - 1 - i * 2]) -
716  (q->pre_coef2[i] * chctx->CWdecoded[i * 2]);
717  q->samples[i].im = (q->pre_coef2[i] * chctx->CWdecoded[COEFFS - 1 - i * 2]) -
718  (q->pre_coef1[i] * chctx->CWdecoded[i * 2]);
719  }
720 
721  /* FFT */
722  q->fft.fft_permute(&q->fft, q->samples);
723  q->fft.fft_calc(&q->fft, q->samples);
724 
725  /* postrotation, window and reorder */
726  for (i = 0; i < COEFFS / 2; i++) {
727  re = ( q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]);
728  im = (-q->samples[i].im * q->post_cos[i]) - ( q->samples[i].re * q->post_sin[i]);
729  *dst1 = (q->mdct_sine_window[COEFFS - 1 - i * 2] * chctx->last_fft_im[i])
730  + (q->mdct_sine_window[i * 2] * re);
731  *dst2 = (q->mdct_sine_window[i * 2] * chctx->last_fft_im[i])
732  - (q->mdct_sine_window[COEFFS - 1 - i * 2] * re);
733  dst1 += 2;
734  dst2 -= 2;
735  chctx->last_fft_im[i] = im;
736  }
737 }
738 
740  int stream_format_code)
741 {
742  int i, j;
743  int middle_value, cw_len, max_size;
744  const float *quantizer;
745 
746  for (i = 0; i < BANDS; i++) {
747  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
748  chctx->CWdecoded[j] = 0;
749  cw_len = chctx->CWlengthT[j];
750 
751  if (cw_len <= 0 || chctx->skipFlags[j])
752  continue;
753 
754  max_size = 1 << cw_len;
755  middle_value = max_size >> 1;
756 
757  if (chctx->codewords[j] >= max_size || chctx->codewords[j] < 0)
758  return AVERROR_INVALIDDATA;
759 
760  if (cw_len >= 4) {
761  quantizer = imc_quantizer2[(stream_format_code & 2) >> 1];
762  if (chctx->codewords[j] >= middle_value)
763  chctx->CWdecoded[j] = quantizer[chctx->codewords[j] - 8] * chctx->flcoeffs6[i];
764  else
765  chctx->CWdecoded[j] = -quantizer[max_size - chctx->codewords[j] - 8 - 1] * chctx->flcoeffs6[i];
766  }else{
767  quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (chctx->bandFlagsBuf[i] << 1)];
768  if (chctx->codewords[j] >= middle_value)
769  chctx->CWdecoded[j] = quantizer[chctx->codewords[j] - 1] * chctx->flcoeffs6[i];
770  else
771  chctx->CWdecoded[j] = -quantizer[max_size - 2 - chctx->codewords[j]] * chctx->flcoeffs6[i];
772  }
773  }
774  }
775  return 0;
776 }
777 
778 
779 static int imc_get_coeffs(IMCContext *q, IMCChannel *chctx)
780 {
781  int i, j, cw_len, cw;
782 
783  for (i = 0; i < BANDS; i++) {
784  if (!chctx->sumLenArr[i])
785  continue;
786  if (chctx->bandFlagsBuf[i] || chctx->bandWidthT[i]) {
787  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
788  cw_len = chctx->CWlengthT[j];
789  cw = 0;
790 
791  if (get_bits_count(&q->gb) + cw_len > 512) {
792  av_dlog(NULL, "Band %i coeff %i cw_len %i\n", i, j, cw_len);
793  return AVERROR_INVALIDDATA;
794  }
795 
796  if (cw_len && (!chctx->bandFlagsBuf[i] || !chctx->skipFlags[j]))
797  cw = get_bits(&q->gb, cw_len);
798 
799  chctx->codewords[j] = cw;
800  }
801  }
802  }
803  return 0;
804 }
805 
807 {
808  int i, j;
809  int bits, summer;
810 
811  for (i = 0; i < BANDS; i++) {
812  chctx->sumLenArr[i] = 0;
813  chctx->skipFlagRaw[i] = 0;
814  for (j = band_tab[i]; j < band_tab[i + 1]; j++)
815  chctx->sumLenArr[i] += chctx->CWlengthT[j];
816  if (chctx->bandFlagsBuf[i])
817  if ((((band_tab[i + 1] - band_tab[i]) * 1.5) > chctx->sumLenArr[i]) && (chctx->sumLenArr[i] > 0))
818  chctx->skipFlagRaw[i] = 1;
819  }
820 
821  imc_get_skip_coeff(q, chctx);
822 
823  for (i = 0; i < BANDS; i++) {
824  chctx->flcoeffs6[i] = chctx->flcoeffs1[i];
825  /* band has flag set and at least one coded coefficient */
826  if (chctx->bandFlagsBuf[i] && (band_tab[i + 1] - band_tab[i]) != chctx->skipFlagCount[i]) {
827  chctx->flcoeffs6[i] *= q->sqrt_tab[ band_tab[i + 1] - band_tab[i]] /
828  q->sqrt_tab[(band_tab[i + 1] - band_tab[i] - chctx->skipFlagCount[i])];
829  }
830  }
831 
832  /* calculate bits left, bits needed and adjust bit allocation */
833  bits = summer = 0;
834 
835  for (i = 0; i < BANDS; i++) {
836  if (chctx->bandFlagsBuf[i]) {
837  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
838  if (chctx->skipFlags[j]) {
839  summer += chctx->CWlengthT[j];
840  chctx->CWlengthT[j] = 0;
841  }
842  }
843  bits += chctx->skipFlagBits[i];
844  summer -= chctx->skipFlagBits[i];
845  }
846  }
847  imc_adjust_bit_allocation(q, chctx, summer);
848 }
849 
850 static int imc_decode_block(AVCodecContext *avctx, IMCContext *q, int ch)
851 {
852  int stream_format_code;
853  int imc_hdr, i, j, ret;
854  int flag;
855  int bits;
856  int counter, bitscount;
857  IMCChannel *chctx = q->chctx + ch;
858 
859 
860  /* Check the frame header */
861  imc_hdr = get_bits(&q->gb, 9);
862  if (imc_hdr & 0x18) {
863  av_log(avctx, AV_LOG_ERROR, "frame header check failed!\n");
864  av_log(avctx, AV_LOG_ERROR, "got %X.\n", imc_hdr);
865  return AVERROR_INVALIDDATA;
866  }
867  stream_format_code = get_bits(&q->gb, 3);
868 
869  if (stream_format_code & 0x04)
870  chctx->decoder_reset = 1;
871 
872  if (chctx->decoder_reset) {
873  for (i = 0; i < BANDS; i++)
874  chctx->old_floor[i] = 1.0;
875  for (i = 0; i < COEFFS; i++)
876  chctx->CWdecoded[i] = 0;
877  chctx->decoder_reset = 0;
878  }
879 
880  flag = get_bits1(&q->gb);
881  if (stream_format_code & 0x1)
883  chctx->flcoeffs1, chctx->flcoeffs2);
884  else if (stream_format_code & 0x1)
885  imc_read_level_coeffs_raw(q, stream_format_code, chctx->levlCoeffBuf);
886  else
887  imc_read_level_coeffs(q, stream_format_code, chctx->levlCoeffBuf);
888 
889  if (stream_format_code & 0x4)
891  chctx->flcoeffs1, chctx->flcoeffs2);
892  else
894  chctx->flcoeffs1, chctx->flcoeffs2);
895 
896  for(i=0; i<BANDS; i++) {
897  if(chctx->flcoeffs1[i] > INT_MAX) {
898  av_log(avctx, AV_LOG_ERROR, "scalefactor out of range\n");
899  return AVERROR_INVALIDDATA;
900  }
901  }
902 
903  memcpy(chctx->old_floor, chctx->flcoeffs1, 32 * sizeof(float));
904 
905  counter = 0;
906  if (stream_format_code & 0x1) {
907  for (i = 0; i < BANDS; i++) {
908  chctx->bandWidthT[i] = band_tab[i + 1] - band_tab[i];
909  chctx->bandFlagsBuf[i] = 0;
910  chctx->flcoeffs3[i] = chctx->flcoeffs2[i] * 2;
911  chctx->flcoeffs5[i] = 1.0;
912  }
913  } else {
914  for (i = 0; i < BANDS; i++) {
915  if (chctx->levlCoeffBuf[i] == 16) {
916  chctx->bandWidthT[i] = 0;
917  counter++;
918  } else
919  chctx->bandWidthT[i] = band_tab[i + 1] - band_tab[i];
920  }
921 
922  memset(chctx->bandFlagsBuf, 0, BANDS * sizeof(int));
923  for (i = 0; i < BANDS - 1; i++)
924  if (chctx->bandWidthT[i])
925  chctx->bandFlagsBuf[i] = get_bits1(&q->gb);
926 
927  imc_calculate_coeffs(q, chctx->flcoeffs1, chctx->flcoeffs2,
928  chctx->bandWidthT, chctx->flcoeffs3,
929  chctx->flcoeffs5);
930  }
931 
932  bitscount = 0;
933  /* first 4 bands will be assigned 5 bits per coefficient */
934  if (stream_format_code & 0x2) {
935  bitscount += 15;
936 
937  chctx->bitsBandT[0] = 5;
938  chctx->CWlengthT[0] = 5;
939  chctx->CWlengthT[1] = 5;
940  chctx->CWlengthT[2] = 5;
941  for (i = 1; i < 4; i++) {
942  if (stream_format_code & 0x1)
943  bits = 5;
944  else
945  bits = (chctx->levlCoeffBuf[i] == 16) ? 0 : 5;
946  chctx->bitsBandT[i] = bits;
947  for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
948  chctx->CWlengthT[j] = bits;
949  bitscount += bits;
950  }
951  }
952  }
953  if (avctx->codec_id == AV_CODEC_ID_IAC) {
954  bitscount += !!chctx->bandWidthT[BANDS - 1];
955  if (!(stream_format_code & 0x2))
956  bitscount += 16;
957  }
958 
959  if ((ret = bit_allocation(q, chctx, stream_format_code,
960  512 - bitscount - get_bits_count(&q->gb),
961  flag)) < 0) {
962  av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n");
963  chctx->decoder_reset = 1;
964  return ret;
965  }
966 
967  if (stream_format_code & 0x1) {
968  for (i = 0; i < BANDS; i++)
969  chctx->skipFlags[i] = 0;
970  } else {
971  imc_refine_bit_allocation(q, chctx);
972  }
973 
974  for (i = 0; i < BANDS; i++) {
975  chctx->sumLenArr[i] = 0;
976 
977  for (j = band_tab[i]; j < band_tab[i + 1]; j++)
978  if (!chctx->skipFlags[j])
979  chctx->sumLenArr[i] += chctx->CWlengthT[j];
980  }
981 
982  memset(chctx->codewords, 0, sizeof(chctx->codewords));
983 
984  if (imc_get_coeffs(q, chctx) < 0) {
985  av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n");
986  chctx->decoder_reset = 1;
987  return AVERROR_INVALIDDATA;
988  }
989 
990  if (inverse_quant_coeff(q, chctx, stream_format_code) < 0) {
991  av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n");
992  chctx->decoder_reset = 1;
993  return AVERROR_INVALIDDATA;
994  }
995 
996  memset(chctx->skipFlags, 0, sizeof(chctx->skipFlags));
997 
998  imc_imdct256(q, chctx, avctx->channels);
999 
1000  return 0;
1001 }
1002 
1003 static int imc_decode_frame(AVCodecContext *avctx, void *data,
1004  int *got_frame_ptr, AVPacket *avpkt)
1005 {
1006  AVFrame *frame = data;
1007  const uint8_t *buf = avpkt->data;
1008  int buf_size = avpkt->size;
1009  int ret, i;
1010 
1011  IMCContext *q = avctx->priv_data;
1012 
1013  LOCAL_ALIGNED_16(uint16_t, buf16, [IMC_BLOCK_SIZE / 2]);
1014 
1015  if (buf_size < IMC_BLOCK_SIZE * avctx->channels) {
1016  av_log(avctx, AV_LOG_ERROR, "frame too small!\n");
1017  return AVERROR_INVALIDDATA;
1018  }
1019 
1020  /* get output buffer */
1021  frame->nb_samples = COEFFS;
1022  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
1023  return ret;
1024 
1025  for (i = 0; i < avctx->channels; i++) {
1026  q->out_samples = (float *)frame->extended_data[i];
1027 
1028  q->dsp.bswap16_buf(buf16, (const uint16_t*)buf, IMC_BLOCK_SIZE / 2);
1029 
1030  init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8);
1031 
1032  buf += IMC_BLOCK_SIZE;
1033 
1034  if ((ret = imc_decode_block(avctx, q, i)) < 0)
1035  return ret;
1036  }
1037 
1038  if (avctx->channels == 2) {
1039  q->fdsp.butterflies_float((float *)frame->extended_data[0],
1040  (float *)frame->extended_data[1], COEFFS);
1041  }
1042 
1043  *got_frame_ptr = 1;
1044 
1045  return IMC_BLOCK_SIZE * avctx->channels;
1046 }
1047 
1048 
1050 {
1051  IMCContext *q = avctx->priv_data;
1052 
1053  ff_fft_end(&q->fft);
1054 
1055  return 0;
1056 }
1057 
1058 static av_cold void flush(AVCodecContext *avctx)
1059 {
1060  IMCContext *q = avctx->priv_data;
1061 
1062  q->chctx[0].decoder_reset =
1063  q->chctx[1].decoder_reset = 1;
1064 }
1065 
1066 #if CONFIG_IMC_DECODER
1067 AVCodec ff_imc_decoder = {
1068  .name = "imc",
1069  .long_name = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"),
1070  .type = AVMEDIA_TYPE_AUDIO,
1071  .id = AV_CODEC_ID_IMC,
1072  .priv_data_size = sizeof(IMCContext),
1073  .init = imc_decode_init,
1076  .flush = flush,
1077  .capabilities = CODEC_CAP_DR1,
1078  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
1080 };
1081 #endif
1082 #if CONFIG_IAC_DECODER
1083 AVCodec ff_iac_decoder = {
1084  .name = "iac",
1085  .long_name = NULL_IF_CONFIG_SMALL("IAC (Indeo Audio Coder)"),
1086  .type = AVMEDIA_TYPE_AUDIO,
1087  .id = AV_CODEC_ID_IAC,
1088  .priv_data_size = sizeof(IMCContext),
1089  .init = imc_decode_init,
1092  .flush = flush,
1093  .capabilities = CODEC_CAP_DR1,
1094  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
1096 };
1097 #endif