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 
38 #include "avcodec.h"
39 #include "get_bits.h"
40 #include "dsputil.h"
41 #include "fft.h"
42 #include "libavutil/audioconvert.h"
43 #include "sinewin.h"
44 
45 #include "imcdata.h"
46 
47 #define IMC_BLOCK_SIZE 64
48 #define IMC_FRAME_ID 0x21
49 #define BANDS 32
50 #define COEFFS 256
51 
52 typedef struct {
54 
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 
66  float mdct_sine_window[COEFFS];
67  float post_cos[COEFFS];
68  float post_sin[COEFFS];
69  float pre_coef1[COEFFS];
70  float pre_coef2[COEFFS];
71  float last_fft_im[COEFFS];
73 
74  int bandWidthT[BANDS];
75  int bitsBandT[BANDS];
76  int CWlengthT[COEFFS];
77  int levlCoeffBuf[BANDS];
78  int bandFlagsBuf[BANDS];
79  int sumLenArr[BANDS];
80  int skipFlagRaw[BANDS];
81  int skipFlagBits[BANDS];
82  int skipFlagCount[BANDS];
83  int skipFlags[COEFFS];
84  int codewords[COEFFS];
85  float sqrt_tab[30];
88  float one_div_log2;
89 
93  float *out_samples;
94 } IMCContext;
95 
96 static VLC huffman_vlc[4][4];
97 
98 #define VLC_TABLES_SIZE 9512
99 
100 static const int vlc_offsets[17] = {
101  0, 640, 1156, 1732, 2308, 2852, 3396, 3924,
102  4452, 5220, 5860, 6628, 7268, 7908, 8424, 8936, VLC_TABLES_SIZE};
103 
105 
107 {
108  int i, j, ret;
109  IMCContext *q = avctx->priv_data;
110  double r1, r2;
111 
112  if (avctx->channels != 1) {
113  av_log_ask_for_sample(avctx, "Number of channels is not supported\n");
114  return AVERROR_PATCHWELCOME;
115  }
116 
117  q->decoder_reset = 1;
118 
119  for(i = 0; i < BANDS; i++)
120  q->old_floor[i] = 1.0;
121 
122  /* Build mdct window, a simple sine window normalized with sqrt(2) */
124  for(i = 0; i < COEFFS; i++)
125  q->mdct_sine_window[i] *= sqrt(2.0);
126  for(i = 0; i < COEFFS/2; i++){
127  q->post_cos[i] = (1.0f / 32768) * cos(i / 256.0 * M_PI);
128  q->post_sin[i] = (1.0f / 32768) * sin(i / 256.0 * M_PI);
129 
130  r1 = sin((i * 4.0 + 1.0) / 1024.0 * M_PI);
131  r2 = cos((i * 4.0 + 1.0) / 1024.0 * M_PI);
132 
133  if (i & 0x1)
134  {
135  q->pre_coef1[i] = (r1 + r2) * sqrt(2.0);
136  q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0);
137  }
138  else
139  {
140  q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0);
141  q->pre_coef2[i] = (r1 - r2) * sqrt(2.0);
142  }
143 
144  q->last_fft_im[i] = 0;
145  }
146 
147  /* Generate a square root table */
148 
149  for(i = 0; i < 30; i++) {
150  q->sqrt_tab[i] = sqrt(i);
151  }
152 
153  /* initialize the VLC tables */
154  for(i = 0; i < 4 ; i++) {
155  for(j = 0; j < 4; j++) {
156  huffman_vlc[i][j].table = &vlc_tables[vlc_offsets[i * 4 + j]];
157  huffman_vlc[i][j].table_allocated = vlc_offsets[i * 4 + j + 1] - vlc_offsets[i * 4 + j];
158  init_vlc(&huffman_vlc[i][j], 9, imc_huffman_sizes[i],
159  imc_huffman_lens[i][j], 1, 1,
161  }
162  }
163  q->one_div_log2 = 1/log(2);
164 
165  if ((ret = ff_fft_init(&q->fft, 7, 1))) {
166  av_log(avctx, AV_LOG_INFO, "FFT init failed\n");
167  return ret;
168  }
169  dsputil_init(&q->dsp, avctx);
170  avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
172 
174  avctx->coded_frame = &q->frame;
175 
176  return 0;
177 }
178 
179 static void imc_calculate_coeffs(IMCContext* q, float* flcoeffs1, float* flcoeffs2, int* bandWidthT,
180  float* flcoeffs3, float* flcoeffs5)
181 {
182  float workT1[BANDS];
183  float workT2[BANDS];
184  float workT3[BANDS];
185  float snr_limit = 1.e-30;
186  float accum = 0.0;
187  int i, cnt2;
188 
189  for(i = 0; i < BANDS; i++) {
190  flcoeffs5[i] = workT2[i] = 0.0;
191  if (bandWidthT[i]){
192  workT1[i] = flcoeffs1[i] * flcoeffs1[i];
193  flcoeffs3[i] = 2.0 * flcoeffs2[i];
194  } else {
195  workT1[i] = 0.0;
196  flcoeffs3[i] = -30000.0;
197  }
198  workT3[i] = bandWidthT[i] * workT1[i] * 0.01;
199  if (workT3[i] <= snr_limit)
200  workT3[i] = 0.0;
201  }
202 
203  for(i = 0; i < BANDS; i++) {
204  for(cnt2 = i; cnt2 < cyclTab[i]; cnt2++)
205  flcoeffs5[cnt2] = flcoeffs5[cnt2] + workT3[i];
206  workT2[cnt2-1] = workT2[cnt2-1] + workT3[i];
207  }
208 
209  for(i = 1; i < BANDS; i++) {
210  accum = (workT2[i-1] + accum) * imc_weights1[i-1];
211  flcoeffs5[i] += accum;
212  }
213 
214  for(i = 0; i < BANDS; i++)
215  workT2[i] = 0.0;
216 
217  for(i = 0; i < BANDS; i++) {
218  for(cnt2 = i-1; cnt2 > cyclTab2[i]; cnt2--)
219  flcoeffs5[cnt2] += workT3[i];
220  workT2[cnt2+1] += workT3[i];
221  }
222 
223  accum = 0.0;
224 
225  for(i = BANDS-2; i >= 0; i--) {
226  accum = (workT2[i+1] + accum) * imc_weights2[i];
227  flcoeffs5[i] += accum;
228  //there is missing code here, but it seems to never be triggered
229  }
230 }
231 
232 
233 static void imc_read_level_coeffs(IMCContext* q, int stream_format_code, int* levlCoeffs)
234 {
235  int i;
236  VLC *hufftab[4];
237  int start = 0;
238  const uint8_t *cb_sel;
239  int s;
240 
241  s = stream_format_code >> 1;
242  hufftab[0] = &huffman_vlc[s][0];
243  hufftab[1] = &huffman_vlc[s][1];
244  hufftab[2] = &huffman_vlc[s][2];
245  hufftab[3] = &huffman_vlc[s][3];
246  cb_sel = imc_cb_select[s];
247 
248  if(stream_format_code & 4)
249  start = 1;
250  if(start)
251  levlCoeffs[0] = get_bits(&q->gb, 7);
252  for(i = start; i < BANDS; i++){
253  levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table, hufftab[cb_sel[i]]->bits, 2);
254  if(levlCoeffs[i] == 17)
255  levlCoeffs[i] += get_bits(&q->gb, 4);
256  }
257 }
258 
259 static void imc_decode_level_coefficients(IMCContext* q, int* levlCoeffBuf, float* flcoeffs1,
260  float* flcoeffs2)
261 {
262  int i, level;
263  float tmp, tmp2;
264  //maybe some frequency division thingy
265 
266  flcoeffs1[0] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
267  flcoeffs2[0] = log(flcoeffs1[0])/log(2);
268  tmp = flcoeffs1[0];
269  tmp2 = flcoeffs2[0];
270 
271  for(i = 1; i < BANDS; i++) {
272  level = levlCoeffBuf[i];
273  if (level == 16) {
274  flcoeffs1[i] = 1.0;
275  flcoeffs2[i] = 0.0;
276  } else {
277  if (level < 17)
278  level -=7;
279  else if (level <= 24)
280  level -=32;
281  else
282  level -=16;
283 
284  tmp *= imc_exp_tab[15 + level];
285  tmp2 += 0.83048 * level; // 0.83048 = log2(10) * 0.25
286  flcoeffs1[i] = tmp;
287  flcoeffs2[i] = tmp2;
288  }
289  }
290 }
291 
292 
293 static void imc_decode_level_coefficients2(IMCContext* q, int* levlCoeffBuf, float* old_floor, float* flcoeffs1,
294  float* flcoeffs2) {
295  int i;
296  //FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors
297  // and flcoeffs2 old scale factors
298  // might be incomplete due to a missing table that is in the binary code
299  for(i = 0; i < BANDS; i++) {
300  flcoeffs1[i] = 0;
301  if(levlCoeffBuf[i] < 16) {
302  flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i];
303  flcoeffs2[i] = (levlCoeffBuf[i]-7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25
304  } else {
305  flcoeffs1[i] = old_floor[i];
306  }
307  }
308 }
309 
313 static int bit_allocation (IMCContext* q, int stream_format_code, int freebits, int flag) {
314  int i, j;
315  const float limit = -1.e20;
316  float highest = 0.0;
317  int indx;
318  int t1 = 0;
319  int t2 = 1;
320  float summa = 0.0;
321  int iacc = 0;
322  int summer = 0;
323  int rres, cwlen;
324  float lowest = 1.e10;
325  int low_indx = 0;
326  float workT[32];
327  int flg;
328  int found_indx = 0;
329 
330  for(i = 0; i < BANDS; i++)
331  highest = FFMAX(highest, q->flcoeffs1[i]);
332 
333  for(i = 0; i < BANDS-1; i++) {
334  q->flcoeffs4[i] = q->flcoeffs3[i] - log(q->flcoeffs5[i])/log(2);
335  }
336  q->flcoeffs4[BANDS - 1] = limit;
337 
338  highest = highest * 0.25;
339 
340  for(i = 0; i < BANDS; i++) {
341  indx = -1;
342  if ((band_tab[i+1] - band_tab[i]) == q->bandWidthT[i])
343  indx = 0;
344 
345  if ((band_tab[i+1] - band_tab[i]) > q->bandWidthT[i])
346  indx = 1;
347 
348  if (((band_tab[i+1] - band_tab[i])/2) >= q->bandWidthT[i])
349  indx = 2;
350 
351  if (indx == -1)
352  return AVERROR_INVALIDDATA;
353 
354  q->flcoeffs4[i] = q->flcoeffs4[i] + xTab[(indx*2 + (q->flcoeffs1[i] < highest)) * 2 + flag];
355  }
356 
357  if (stream_format_code & 0x2) {
358  q->flcoeffs4[0] = limit;
359  q->flcoeffs4[1] = limit;
360  q->flcoeffs4[2] = limit;
361  q->flcoeffs4[3] = limit;
362  }
363 
364  for(i = (stream_format_code & 0x2)?4:0; i < BANDS-1; i++) {
365  iacc += q->bandWidthT[i];
366  summa += q->bandWidthT[i] * q->flcoeffs4[i];
367  }
368  q->bandWidthT[BANDS-1] = 0;
369  summa = (summa * 0.5 - freebits) / iacc;
370 
371 
372  for(i = 0; i < BANDS/2; i++) {
373  rres = summer - freebits;
374  if((rres >= -8) && (rres <= 8)) break;
375 
376  summer = 0;
377  iacc = 0;
378 
379  for(j = (stream_format_code & 0x2)?4:0; j < BANDS; j++) {
380  cwlen = av_clipf(((q->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6);
381 
382  q->bitsBandT[j] = cwlen;
383  summer += q->bandWidthT[j] * cwlen;
384 
385  if (cwlen > 0)
386  iacc += q->bandWidthT[j];
387  }
388 
389  flg = t2;
390  t2 = 1;
391  if (freebits < summer)
392  t2 = -1;
393  if (i == 0)
394  flg = t2;
395  if(flg != t2)
396  t1++;
397 
398  summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa;
399  }
400 
401  for(i = (stream_format_code & 0x2)?4:0; i < BANDS; i++) {
402  for(j = band_tab[i]; j < band_tab[i+1]; j++)
403  q->CWlengthT[j] = q->bitsBandT[i];
404  }
405 
406  if (freebits > summer) {
407  for(i = 0; i < BANDS; i++) {
408  workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415);
409  }
410 
411  highest = 0.0;
412 
413  do{
414  if (highest <= -1.e20)
415  break;
416 
417  found_indx = 0;
418  highest = -1.e20;
419 
420  for(i = 0; i < BANDS; i++) {
421  if (workT[i] > highest) {
422  highest = workT[i];
423  found_indx = i;
424  }
425  }
426 
427  if (highest > -1.e20) {
428  workT[found_indx] -= 2.0;
429  if (++(q->bitsBandT[found_indx]) == 6)
430  workT[found_indx] = -1.e20;
431 
432  for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (freebits > summer); j++){
433  q->CWlengthT[j]++;
434  summer++;
435  }
436  }
437  }while (freebits > summer);
438  }
439  if (freebits < summer) {
440  for(i = 0; i < BANDS; i++) {
441  workT[i] = q->bitsBandT[i] ? (q->bitsBandT[i] * -2 + q->flcoeffs4[i] + 1.585) : 1.e20;
442  }
443  if (stream_format_code & 0x2) {
444  workT[0] = 1.e20;
445  workT[1] = 1.e20;
446  workT[2] = 1.e20;
447  workT[3] = 1.e20;
448  }
449  while (freebits < summer){
450  lowest = 1.e10;
451  low_indx = 0;
452  for(i = 0; i < BANDS; i++) {
453  if (workT[i] < lowest) {
454  lowest = workT[i];
455  low_indx = i;
456  }
457  }
458  //if(lowest >= 1.e10) break;
459  workT[low_indx] = lowest + 2.0;
460 
461  if (!(--q->bitsBandT[low_indx]))
462  workT[low_indx] = 1.e20;
463 
464  for(j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++){
465  if(q->CWlengthT[j] > 0){
466  q->CWlengthT[j]--;
467  summer--;
468  }
469  }
470  }
471  }
472  return 0;
473 }
474 
476  int i, j;
477 
478  memset(q->skipFlagBits, 0, sizeof(q->skipFlagBits));
479  memset(q->skipFlagCount, 0, sizeof(q->skipFlagCount));
480  for(i = 0; i < BANDS; i++) {
481  if (!q->bandFlagsBuf[i] || !q->bandWidthT[i])
482  continue;
483 
484  if (!q->skipFlagRaw[i]) {
485  q->skipFlagBits[i] = band_tab[i+1] - band_tab[i];
486 
487  for(j = band_tab[i]; j < band_tab[i+1]; j++) {
488  if ((q->skipFlags[j] = get_bits1(&q->gb)))
489  q->skipFlagCount[i]++;
490  }
491  } else {
492  for(j = band_tab[i]; j < (band_tab[i+1]-1); j += 2) {
493  if(!get_bits1(&q->gb)){//0
494  q->skipFlagBits[i]++;
495  q->skipFlags[j]=1;
496  q->skipFlags[j+1]=1;
497  q->skipFlagCount[i] += 2;
498  }else{
499  if(get_bits1(&q->gb)){//11
500  q->skipFlagBits[i] +=2;
501  q->skipFlags[j]=0;
502  q->skipFlags[j+1]=1;
503  q->skipFlagCount[i]++;
504  }else{
505  q->skipFlagBits[i] +=3;
506  q->skipFlags[j+1]=0;
507  if(!get_bits1(&q->gb)){//100
508  q->skipFlags[j]=1;
509  q->skipFlagCount[i]++;
510  }else{//101
511  q->skipFlags[j]=0;
512  }
513  }
514  }
515  }
516 
517  if (j < band_tab[i+1]) {
518  q->skipFlagBits[i]++;
519  if ((q->skipFlags[j] = get_bits1(&q->gb)))
520  q->skipFlagCount[i]++;
521  }
522  }
523  }
524 }
525 
529 static void imc_adjust_bit_allocation (IMCContext* q, int summer) {
530  float workT[32];
531  int corrected = 0;
532  int i, j;
533  float highest = 0;
534  int found_indx=0;
535 
536  for(i = 0; i < BANDS; i++) {
537  workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415);
538  }
539 
540  while (corrected < summer) {
541  if(highest <= -1.e20)
542  break;
543 
544  highest = -1.e20;
545 
546  for(i = 0; i < BANDS; i++) {
547  if (workT[i] > highest) {
548  highest = workT[i];
549  found_indx = i;
550  }
551  }
552 
553  if (highest > -1.e20) {
554  workT[found_indx] -= 2.0;
555  if (++(q->bitsBandT[found_indx]) == 6)
556  workT[found_indx] = -1.e20;
557 
558  for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) {
559  if (!q->skipFlags[j] && (q->CWlengthT[j] < 6)) {
560  q->CWlengthT[j]++;
561  corrected++;
562  }
563  }
564  }
565  }
566 }
567 
568 static void imc_imdct256(IMCContext *q) {
569  int i;
570  float re, im;
571 
572  /* prerotation */
573  for(i=0; i < COEFFS/2; i++){
574  q->samples[i].re = -(q->pre_coef1[i] * q->CWdecoded[COEFFS-1-i*2]) -
575  (q->pre_coef2[i] * q->CWdecoded[i*2]);
576  q->samples[i].im = (q->pre_coef2[i] * q->CWdecoded[COEFFS-1-i*2]) -
577  (q->pre_coef1[i] * q->CWdecoded[i*2]);
578  }
579 
580  /* FFT */
581  q->fft.fft_permute(&q->fft, q->samples);
582  q->fft.fft_calc (&q->fft, q->samples);
583 
584  /* postrotation, window and reorder */
585  for(i = 0; i < COEFFS/2; i++){
586  re = (q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]);
587  im = (-q->samples[i].im * q->post_cos[i]) - (q->samples[i].re * q->post_sin[i]);
588  q->out_samples[i*2] = (q->mdct_sine_window[COEFFS-1-i*2] * q->last_fft_im[i]) + (q->mdct_sine_window[i*2] * re);
589  q->out_samples[COEFFS-1-i*2] = (q->mdct_sine_window[i*2] * q->last_fft_im[i]) - (q->mdct_sine_window[COEFFS-1-i*2] * re);
590  q->last_fft_im[i] = im;
591  }
592 }
593 
594 static int inverse_quant_coeff (IMCContext* q, int stream_format_code) {
595  int i, j;
596  int middle_value, cw_len, max_size;
597  const float* quantizer;
598 
599  for(i = 0; i < BANDS; i++) {
600  for(j = band_tab[i]; j < band_tab[i+1]; j++) {
601  q->CWdecoded[j] = 0;
602  cw_len = q->CWlengthT[j];
603 
604  if (cw_len <= 0 || q->skipFlags[j])
605  continue;
606 
607  max_size = 1 << cw_len;
608  middle_value = max_size >> 1;
609 
610  if (q->codewords[j] >= max_size || q->codewords[j] < 0)
611  return AVERROR_INVALIDDATA;
612 
613  if (cw_len >= 4){
614  quantizer = imc_quantizer2[(stream_format_code & 2) >> 1];
615  if (q->codewords[j] >= middle_value)
616  q->CWdecoded[j] = quantizer[q->codewords[j] - 8] * q->flcoeffs6[i];
617  else
618  q->CWdecoded[j] = -quantizer[max_size - q->codewords[j] - 8 - 1] * q->flcoeffs6[i];
619  }else{
620  quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (q->bandFlagsBuf[i] << 1)];
621  if (q->codewords[j] >= middle_value)
622  q->CWdecoded[j] = quantizer[q->codewords[j] - 1] * q->flcoeffs6[i];
623  else
624  q->CWdecoded[j] = -quantizer[max_size - 2 - q->codewords[j]] * q->flcoeffs6[i];
625  }
626  }
627  }
628  return 0;
629 }
630 
631 
632 static int imc_get_coeffs (IMCContext* q) {
633  int i, j, cw_len, cw;
634 
635  for(i = 0; i < BANDS; i++) {
636  if(!q->sumLenArr[i]) continue;
637  if (q->bandFlagsBuf[i] || q->bandWidthT[i]) {
638  for(j = band_tab[i]; j < band_tab[i+1]; j++) {
639  cw_len = q->CWlengthT[j];
640  cw = 0;
641 
642  if (get_bits_count(&q->gb) + cw_len > 512){
643 //av_log(NULL,0,"Band %i coeff %i cw_len %i\n",i,j,cw_len);
644  return AVERROR_INVALIDDATA;
645  }
646 
647  if(cw_len && (!q->bandFlagsBuf[i] || !q->skipFlags[j]))
648  cw = get_bits(&q->gb, cw_len);
649 
650  q->codewords[j] = cw;
651  }
652  }
653  }
654  return 0;
655 }
656 
657 static int imc_decode_frame(AVCodecContext * avctx, void *data,
658  int *got_frame_ptr, AVPacket *avpkt)
659 {
660  const uint8_t *buf = avpkt->data;
661  int buf_size = avpkt->size;
662 
663  IMCContext *q = avctx->priv_data;
664 
665  int stream_format_code;
666  int imc_hdr, i, j, ret;
667  int flag;
668  int bits, summer;
669  int counter, bitscount;
670  LOCAL_ALIGNED_16(uint16_t, buf16, [IMC_BLOCK_SIZE / 2]);
671 
672  if (buf_size < IMC_BLOCK_SIZE) {
673  av_log(avctx, AV_LOG_ERROR, "imc frame too small!\n");
674  return AVERROR_INVALIDDATA;
675  }
676 
677  /* get output buffer */
678  q->frame.nb_samples = COEFFS;
679  if ((ret = avctx->get_buffer(avctx, &q->frame)) < 0) {
680  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
681  return ret;
682  }
683  q->out_samples = (float *)q->frame.data[0];
684 
685  q->dsp.bswap16_buf(buf16, (const uint16_t*)buf, IMC_BLOCK_SIZE / 2);
686 
687  init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8);
688 
689  /* Check the frame header */
690  imc_hdr = get_bits(&q->gb, 9);
691  if (imc_hdr != IMC_FRAME_ID) {
692  av_log(avctx, AV_LOG_ERROR, "imc frame header check failed!\n");
693  av_log(avctx, AV_LOG_ERROR, "got %x instead of 0x21.\n", imc_hdr);
694  return AVERROR_INVALIDDATA;
695  }
696  stream_format_code = get_bits(&q->gb, 3);
697 
698  if(stream_format_code & 1){
699  av_log(avctx, AV_LOG_ERROR, "Stream code format %X is not supported\n", stream_format_code);
700  return AVERROR_INVALIDDATA;
701  }
702 
703 // av_log(avctx, AV_LOG_DEBUG, "stream_format_code = %d\n", stream_format_code);
704 
705  if (stream_format_code & 0x04)
706  q->decoder_reset = 1;
707 
708  if(q->decoder_reset) {
709  memset(q->out_samples, 0, sizeof(q->out_samples));
710  for(i = 0; i < BANDS; i++)q->old_floor[i] = 1.0;
711  for(i = 0; i < COEFFS; i++)q->CWdecoded[i] = 0;
712  q->decoder_reset = 0;
713  }
714 
715  flag = get_bits1(&q->gb);
716  imc_read_level_coeffs(q, stream_format_code, q->levlCoeffBuf);
717 
718  if (stream_format_code & 0x4)
720  else
722 
723  memcpy(q->old_floor, q->flcoeffs1, 32 * sizeof(float));
724 
725  counter = 0;
726  for (i=0 ; i<BANDS ; i++) {
727  if (q->levlCoeffBuf[i] == 16) {
728  q->bandWidthT[i] = 0;
729  counter++;
730  } else
731  q->bandWidthT[i] = band_tab[i+1] - band_tab[i];
732  }
733  memset(q->bandFlagsBuf, 0, BANDS * sizeof(int));
734  for(i = 0; i < BANDS-1; i++) {
735  if (q->bandWidthT[i])
736  q->bandFlagsBuf[i] = get_bits1(&q->gb);
737  }
738 
740 
741  bitscount = 0;
742  /* first 4 bands will be assigned 5 bits per coefficient */
743  if (stream_format_code & 0x2) {
744  bitscount += 15;
745 
746  q->bitsBandT[0] = 5;
747  q->CWlengthT[0] = 5;
748  q->CWlengthT[1] = 5;
749  q->CWlengthT[2] = 5;
750  for(i = 1; i < 4; i++){
751  bits = (q->levlCoeffBuf[i] == 16) ? 0 : 5;
752  q->bitsBandT[i] = bits;
753  for(j = band_tab[i]; j < band_tab[i+1]; j++) {
754  q->CWlengthT[j] = bits;
755  bitscount += bits;
756  }
757  }
758  }
759 
760  if((ret = bit_allocation (q, stream_format_code,
761  512 - bitscount - get_bits_count(&q->gb), flag)) < 0) {
762  av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n");
763  q->decoder_reset = 1;
764  return ret;
765  }
766 
767  for(i = 0; i < BANDS; i++) {
768  q->sumLenArr[i] = 0;
769  q->skipFlagRaw[i] = 0;
770  for(j = band_tab[i]; j < band_tab[i+1]; j++)
771  q->sumLenArr[i] += q->CWlengthT[j];
772  if (q->bandFlagsBuf[i])
773  if( (((band_tab[i+1] - band_tab[i]) * 1.5) > q->sumLenArr[i]) && (q->sumLenArr[i] > 0))
774  q->skipFlagRaw[i] = 1;
775  }
776 
778 
779  for(i = 0; i < BANDS; i++) {
780  q->flcoeffs6[i] = q->flcoeffs1[i];
781  /* band has flag set and at least one coded coefficient */
782  if (q->bandFlagsBuf[i] && (band_tab[i+1] - band_tab[i]) != q->skipFlagCount[i]){
783  q->flcoeffs6[i] *= q->sqrt_tab[band_tab[i+1] - band_tab[i]] /
784  q->sqrt_tab[(band_tab[i+1] - band_tab[i] - q->skipFlagCount[i])];
785  }
786  }
787 
788  /* calculate bits left, bits needed and adjust bit allocation */
789  bits = summer = 0;
790 
791  for(i = 0; i < BANDS; i++) {
792  if (q->bandFlagsBuf[i]) {
793  for(j = band_tab[i]; j < band_tab[i+1]; j++) {
794  if(q->skipFlags[j]) {
795  summer += q->CWlengthT[j];
796  q->CWlengthT[j] = 0;
797  }
798  }
799  bits += q->skipFlagBits[i];
800  summer -= q->skipFlagBits[i];
801  }
802  }
803  imc_adjust_bit_allocation(q, summer);
804 
805  for(i = 0; i < BANDS; i++) {
806  q->sumLenArr[i] = 0;
807 
808  for(j = band_tab[i]; j < band_tab[i+1]; j++)
809  if (!q->skipFlags[j])
810  q->sumLenArr[i] += q->CWlengthT[j];
811  }
812 
813  memset(q->codewords, 0, sizeof(q->codewords));
814 
815  if(imc_get_coeffs(q) < 0) {
816  av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n");
817  q->decoder_reset = 1;
818  return AVERROR_INVALIDDATA;
819  }
820 
821  if(inverse_quant_coeff(q, stream_format_code) < 0) {
822  av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n");
823  q->decoder_reset = 1;
824  return AVERROR_INVALIDDATA;
825  }
826 
827  memset(q->skipFlags, 0, sizeof(q->skipFlags));
828 
829  imc_imdct256(q);
830 
831  *got_frame_ptr = 1;
832  *(AVFrame *)data = q->frame;
833 
834  return IMC_BLOCK_SIZE;
835 }
836 
837 
839 {
840  IMCContext *q = avctx->priv_data;
841 
842  ff_fft_end(&q->fft);
843 
844  return 0;
845 }
846 
847 
849  .name = "imc",
850  .type = AVMEDIA_TYPE_AUDIO,
851  .id = CODEC_ID_IMC,
852  .priv_data_size = sizeof(IMCContext),
856  .capabilities = CODEC_CAP_DR1,
857  .long_name = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"),
858 };