FFmpeg: libavcodec/mpc8.c Source File

FFmpeg
mpc8.c
Go to the documentation of this file.
1 /*
2  * Musepack SV8 decoder
3  * Copyright (c) 2007 Konstantin Shishkov
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * MPEG Audio Layer 1/2 -like codec with frames of 1152 samples
25  * divided into 32 subbands.
26  */
27 
28 #include "libavutil/channel_layout.h"
29 #include "libavutil/lfg.h"
30 #include "avcodec.h"
31 #include "get_bits.h"
32 #include "dsputil.h"
33 #include "internal.h"
34 #include "mpegaudiodsp.h"
35 
36 #include "mpc.h"
37 #include "mpc8data.h"
38 #include "mpc8huff.h"
39 
40  static VLC band_vlc, scfi_vlc[2], dscf_vlc[2], res_vlc[2];
41  static VLC q1_vlc, q2_vlc[2], q3_vlc[2], quant_vlc[4][2], q9up_vlc;
42 
43  static const int q3_offsets[2] = { MPC8_Q3_OFFSET, MPC8_Q4_OFFSET };
44  static const int quant_offsets[6] = { MPC8_Q5_OFFSET, MPC8_Q6_OFFSET, MPC8_Q7_OFFSET, MPC8_Q8_OFFSET };
45 
46  static inline int mpc8_dec_base(GetBitContext *gb, int k, int n)
47 {
48  int len = mpc8_cnk_len[k-1][n-1] - 1;
49  int code = len ? get_bits_long(gb, len) : 0;
50 
51  if (code >= mpc8_cnk_lost[k-1][n-1])
52  code = ((code << 1) | get_bits1(gb)) - mpc8_cnk_lost[k-1][n-1];
53 
54  return code;
55 }
56 
57  static inline int mpc8_dec_enum(GetBitContext *gb, int k, int n)
58 {
59  int bits = 0;
60  const uint32_t * C = mpc8_cnk[k-1];
61  int code = mpc8_dec_base(gb, k, n);
62 
63  do {
64  n--;
65  if (code >= C[n]) {
66  bits |= 1 << n;
67  code -= C[n];
68  C -= 32;
69  k--;
70  }
71  } while(k > 0);
72 
73  return bits;
74 }
75 
76  static inline int mpc8_get_mod_golomb(GetBitContext *gb, int m)
77 {
78  if(mpc8_cnk_len[0][m] < 1) return 0;
79  return mpc8_dec_base(gb, 1, m+1);
80 }
81 
82  static int mpc8_get_mask(GetBitContext *gb, int size, int t)
83 {
84  int mask = 0;
85 
86  if(t && t != size)
87  mask = mpc8_dec_enum(gb, FFMIN(t, size - t), size);
88  if((t << 1) > size) mask = ~mask;
89 
90  return mask;
91 }
92 
93  static const uint16_t vlc_offsets[13] = {
94  0, 640, 1184, 1748, 2298, 2426, 2554, 3066, 3578, 4106, 4618, 5196, 5708
95 };
96 
97  static av_cold int mpc8_decode_init(AVCodecContext * avctx)
98 {
99  int i;
100  MPCContext *c = avctx->priv_data;
101  GetBitContext gb;
102  static int vlc_initialized = 0;
103  int channels;
104 
105  static VLC_TYPE band_table[542][2];
106  static VLC_TYPE q1_table[520][2];
107  static VLC_TYPE q9up_table[524][2];
108  static VLC_TYPE scfi0_table[1 << MPC8_SCFI0_BITS][2];
109  static VLC_TYPE scfi1_table[1 << MPC8_SCFI1_BITS][2];
110  static VLC_TYPE dscf0_table[560][2];
111  static VLC_TYPE dscf1_table[598][2];
112  static VLC_TYPE q3_0_table[512][2];
113  static VLC_TYPE q3_1_table[516][2];
114  static VLC_TYPE codes_table[5708][2];
115 
116  if(avctx->extradata_size < 2){
117  av_log(avctx, AV_LOG_ERROR, "Too small extradata size (%i)!\n", avctx->extradata_size);
118  return -1;
119  }
120  memset(c->oldDSCF, 0, sizeof(c->oldDSCF));
121  av_lfg_init(&c->rnd, 0xDEADBEEF);
122  ff_dsputil_init(&c->dsp, avctx);
123  ff_mpadsp_init(&c->mpadsp);
124 
125  ff_mpc_init();
126 
127  init_get_bits(&gb, avctx->extradata, 16);
128 
129  skip_bits(&gb, 3);//sample rate
130  c->maxbands = get_bits(&gb, 5) + 1;
131  if (c->maxbands >= BANDS) {
132  av_log(avctx,AV_LOG_ERROR, "maxbands %d too high\n", c->maxbands);
133  return AVERROR_INVALIDDATA;
134  }
135  channels = get_bits(&gb, 4) + 1;
136  if (channels > 2) {
137  avpriv_request_sample(avctx, "Multichannel MPC SV8");
138  return AVERROR_PATCHWELCOME;
139  }
140  c->MSS = get_bits1(&gb);
141  c->frames = 1 << (get_bits(&gb, 3) * 2);
142 
143  avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
144  avctx->channel_layout = (channels==2) ? AV_CH_LAYOUT_STEREO : AV_CH_LAYOUT_MONO;
145  avctx->channels = channels;
146 
147  if(vlc_initialized) return 0;
148  av_log(avctx, AV_LOG_DEBUG, "Initing VLC\n");
149 
150  band_vlc.table = band_table;
151  band_vlc.table_allocated = 542;
152  init_vlc(&band_vlc, MPC8_BANDS_BITS, MPC8_BANDS_SIZE,
153  mpc8_bands_bits, 1, 1,
154  mpc8_bands_codes, 1, 1, INIT_VLC_USE_NEW_STATIC);
155 
156  q1_vlc.table = q1_table;
157  q1_vlc.table_allocated = 520;
158  init_vlc(&q1_vlc, MPC8_Q1_BITS, MPC8_Q1_SIZE,
159  mpc8_q1_bits, 1, 1,
160  mpc8_q1_codes, 1, 1, INIT_VLC_USE_NEW_STATIC);
161  q9up_vlc.table = q9up_table;
162  q9up_vlc.table_allocated = 524;
163  init_vlc(&q9up_vlc, MPC8_Q9UP_BITS, MPC8_Q9UP_SIZE,
164  mpc8_q9up_bits, 1, 1,
165  mpc8_q9up_codes, 1, 1, INIT_VLC_USE_NEW_STATIC);
166 
167  scfi_vlc[0].table = scfi0_table;
168  scfi_vlc[0].table_allocated = 1 << MPC8_SCFI0_BITS;
169  init_vlc(&scfi_vlc[0], MPC8_SCFI0_BITS, MPC8_SCFI0_SIZE,
170  mpc8_scfi0_bits, 1, 1,
171  mpc8_scfi0_codes, 1, 1, INIT_VLC_USE_NEW_STATIC);
172  scfi_vlc[1].table = scfi1_table;
173  scfi_vlc[1].table_allocated = 1 << MPC8_SCFI1_BITS;
174  init_vlc(&scfi_vlc[1], MPC8_SCFI1_BITS, MPC8_SCFI1_SIZE,
175  mpc8_scfi1_bits, 1, 1,
176  mpc8_scfi1_codes, 1, 1, INIT_VLC_USE_NEW_STATIC);
177 
178  dscf_vlc[0].table = dscf0_table;
179  dscf_vlc[0].table_allocated = 560;
180  init_vlc(&dscf_vlc[0], MPC8_DSCF0_BITS, MPC8_DSCF0_SIZE,
181  mpc8_dscf0_bits, 1, 1,
182  mpc8_dscf0_codes, 1, 1, INIT_VLC_USE_NEW_STATIC);
183  dscf_vlc[1].table = dscf1_table;
184  dscf_vlc[1].table_allocated = 598;
185  init_vlc(&dscf_vlc[1], MPC8_DSCF1_BITS, MPC8_DSCF1_SIZE,
186  mpc8_dscf1_bits, 1, 1,
187  mpc8_dscf1_codes, 1, 1, INIT_VLC_USE_NEW_STATIC);
188 
189  q3_vlc[0].table = q3_0_table;
190  q3_vlc[0].table_allocated = 512;
191  ff_init_vlc_sparse(&q3_vlc[0], MPC8_Q3_BITS, MPC8_Q3_SIZE,
192  mpc8_q3_bits, 1, 1,
193  mpc8_q3_codes, 1, 1,
194  mpc8_q3_syms, 1, 1, INIT_VLC_USE_NEW_STATIC);
195  q3_vlc[1].table = q3_1_table;
196  q3_vlc[1].table_allocated = 516;
197  ff_init_vlc_sparse(&q3_vlc[1], MPC8_Q4_BITS, MPC8_Q4_SIZE,
198  mpc8_q4_bits, 1, 1,
199  mpc8_q4_codes, 1, 1,
200  mpc8_q4_syms, 1, 1, INIT_VLC_USE_NEW_STATIC);
201 
202  for(i = 0; i < 2; i++){
203  res_vlc[i].table = &codes_table[vlc_offsets[0+i]];
204  res_vlc[i].table_allocated = vlc_offsets[1+i] - vlc_offsets[0+i];
205  init_vlc(&res_vlc[i], MPC8_RES_BITS, MPC8_RES_SIZE,
206  &mpc8_res_bits[i], 1, 1,
207  &mpc8_res_codes[i], 1, 1, INIT_VLC_USE_NEW_STATIC);
208 
209  q2_vlc[i].table = &codes_table[vlc_offsets[2+i]];
210  q2_vlc[i].table_allocated = vlc_offsets[3+i] - vlc_offsets[2+i];
211  init_vlc(&q2_vlc[i], MPC8_Q2_BITS, MPC8_Q2_SIZE,
212  &mpc8_q2_bits[i], 1, 1,
213  &mpc8_q2_codes[i], 1, 1, INIT_VLC_USE_NEW_STATIC);
214 
215  quant_vlc[0][i].table = &codes_table[vlc_offsets[4+i]];
216  quant_vlc[0][i].table_allocated = vlc_offsets[5+i] - vlc_offsets[4+i];
217  init_vlc(&quant_vlc[0][i], MPC8_Q5_BITS, MPC8_Q5_SIZE,
218  &mpc8_q5_bits[i], 1, 1,
219  &mpc8_q5_codes[i], 1, 1, INIT_VLC_USE_NEW_STATIC);
220  quant_vlc[1][i].table = &codes_table[vlc_offsets[6+i]];
221  quant_vlc[1][i].table_allocated = vlc_offsets[7+i] - vlc_offsets[6+i];
222  init_vlc(&quant_vlc[1][i], MPC8_Q6_BITS, MPC8_Q6_SIZE,
223  &mpc8_q6_bits[i], 1, 1,
224  &mpc8_q6_codes[i], 1, 1, INIT_VLC_USE_NEW_STATIC);
225  quant_vlc[2][i].table = &codes_table[vlc_offsets[8+i]];
226  quant_vlc[2][i].table_allocated = vlc_offsets[9+i] - vlc_offsets[8+i];
227  init_vlc(&quant_vlc[2][i], MPC8_Q7_BITS, MPC8_Q7_SIZE,
228  &mpc8_q7_bits[i], 1, 1,
229  &mpc8_q7_codes[i], 1, 1, INIT_VLC_USE_NEW_STATIC);
230  quant_vlc[3][i].table = &codes_table[vlc_offsets[10+i]];
231  quant_vlc[3][i].table_allocated = vlc_offsets[11+i] - vlc_offsets[10+i];
232  init_vlc(&quant_vlc[3][i], MPC8_Q8_BITS, MPC8_Q8_SIZE,
233  &mpc8_q8_bits[i], 1, 1,
234  &mpc8_q8_codes[i], 1, 1, INIT_VLC_USE_NEW_STATIC);
235  }
236  vlc_initialized = 1;
237 
238  return 0;
239 }
240 
241  static int mpc8_decode_frame(AVCodecContext * avctx, void *data,
242  int *got_frame_ptr, AVPacket *avpkt)
243 {
244  AVFrame *frame = data;
245  const uint8_t *buf = avpkt->data;
246  int buf_size = avpkt->size;
247  MPCContext *c = avctx->priv_data;
248  GetBitContext gb2, *gb = &gb2;
249  int i, j, k, ch, cnt, res, t;
250  Band *bands = c->bands;
251  int off;
252  int maxband, keyframe;
253  int last[2];
254 
255  /* get output buffer */
256  frame->nb_samples = MPC_FRAME_SIZE;
257  if ((res = ff_get_buffer(avctx, frame, 0)) < 0)
258  return res;
259 
260  keyframe = c->cur_frame == 0;
261 
262  if(keyframe){
263  memset(c->Q, 0, sizeof(c->Q));
264  c->last_bits_used = 0;
265  }
266  init_get_bits(gb, buf, buf_size * 8);
267  skip_bits(gb, c->last_bits_used & 7);
268 
269  if(keyframe)
270  maxband = mpc8_get_mod_golomb(gb, c->maxbands + 1);
271  else{
272  maxband = c->last_max_band + get_vlc2(gb, band_vlc.table, MPC8_BANDS_BITS, 2);
273  if(maxband > 32) maxband -= 33;
274  }
275 
276  if(maxband > c->maxbands + 1) {
277  av_log(avctx, AV_LOG_ERROR, "maxband %d too large\n",maxband);
278  return AVERROR_INVALIDDATA;
279  }
280  c->last_max_band = maxband;
281 
282  /* read subband indexes */
283  if(maxband){
284  last[0] = last[1] = 0;
285  for(i = maxband - 1; i >= 0; i--){
286  for(ch = 0; ch < 2; ch++){
287  last[ch] = get_vlc2(gb, res_vlc[last[ch] > 2].table, MPC8_RES_BITS, 2) + last[ch];
288  if(last[ch] > 15) last[ch] -= 17;
289  bands[i].res[ch] = last[ch];
290  }
291  }
292  if(c->MSS){
293  int mask;
294 
295  cnt = 0;
296  for(i = 0; i < maxband; i++)
297  if(bands[i].res[0] || bands[i].res[1])
298  cnt++;
299  t = mpc8_get_mod_golomb(gb, cnt);
300  mask = mpc8_get_mask(gb, cnt, t);
301  for(i = maxband - 1; i >= 0; i--)
302  if(bands[i].res[0] || bands[i].res[1]){
303  bands[i].msf = mask & 1;
304  mask >>= 1;
305  }
306  }
307  }
308  for(i = maxband; i < c->maxbands; i++)
309  bands[i].res[0] = bands[i].res[1] = 0;
310 
311  if(keyframe){
312  for(i = 0; i < 32; i++)
313  c->oldDSCF[0][i] = c->oldDSCF[1][i] = 1;
314  }
315 
316  for(i = 0; i < maxband; i++){
317  if(bands[i].res[0] || bands[i].res[1]){
318  cnt = !!bands[i].res[0] + !!bands[i].res[1] - 1;
319  if(cnt >= 0){
320  t = get_vlc2(gb, scfi_vlc[cnt].table, scfi_vlc[cnt].bits, 1);
321  if(bands[i].res[0]) bands[i].scfi[0] = t >> (2 * cnt);
322  if(bands[i].res[1]) bands[i].scfi[1] = t & 3;
323  }
324  }
325  }
326 
327  for(i = 0; i < maxband; i++){
328  for(ch = 0; ch < 2; ch++){
329  if(!bands[i].res[ch]) continue;
330 
331  if(c->oldDSCF[ch][i]){
332  bands[i].scf_idx[ch][0] = get_bits(gb, 7) - 6;
333  c->oldDSCF[ch][i] = 0;
334  }else{
335  t = get_vlc2(gb, dscf_vlc[1].table, MPC8_DSCF1_BITS, 2);
336  if(t == 64)
337  t += get_bits(gb, 6);
338  bands[i].scf_idx[ch][0] = ((bands[i].scf_idx[ch][2] + t - 25) & 0x7F) - 6;
339  }
340  for(j = 0; j < 2; j++){
341  if((bands[i].scfi[ch] << j) & 2)
342  bands[i].scf_idx[ch][j + 1] = bands[i].scf_idx[ch][j];
343  else{
344  t = get_vlc2(gb, dscf_vlc[0].table, MPC8_DSCF0_BITS, 2);
345  if(t == 31)
346  t = 64 + get_bits(gb, 6);
347  bands[i].scf_idx[ch][j + 1] = ((bands[i].scf_idx[ch][j] + t - 25) & 0x7F) - 6;
348  }
349  }
350  }
351  }
352 
353  for(i = 0, off = 0; i < maxband; i++, off += SAMPLES_PER_BAND){
354  for(ch = 0; ch < 2; ch++){
355  res = bands[i].res[ch];
356  switch(res){
357  case -1:
358  for(j = 0; j < SAMPLES_PER_BAND; j++)
359  c->Q[ch][off + j] = (av_lfg_get(&c->rnd) & 0x3FC) - 510;
360  break;
361  case 0:
362  break;
363  case 1:
364  for(j = 0; j < SAMPLES_PER_BAND; j += SAMPLES_PER_BAND / 2){
365  cnt = get_vlc2(gb, q1_vlc.table, MPC8_Q1_BITS, 2);
366  t = mpc8_get_mask(gb, 18, cnt);
367  for(k = 0; k < SAMPLES_PER_BAND / 2; k++, t <<= 1)
368  c->Q[ch][off + j + k] = (t & 0x20000) ? (get_bits1(gb) << 1) - 1 : 0;
369  }
370  break;
371  case 2:
372  cnt = 6;//2*mpc8_thres[res]
373  for(j = 0; j < SAMPLES_PER_BAND; j += 3){
374  t = get_vlc2(gb, q2_vlc[cnt > 3].table, MPC8_Q2_BITS, 2);
375  c->Q[ch][off + j + 0] = mpc8_idx50[t];
376  c->Q[ch][off + j + 1] = mpc8_idx51[t];
377  c->Q[ch][off + j + 2] = mpc8_idx52[t];
378  cnt = (cnt >> 1) + mpc8_huffq2[t];
379  }
380  break;
381  case 3:
382  case 4:
383  for(j = 0; j < SAMPLES_PER_BAND; j += 2){
384  t = get_vlc2(gb, q3_vlc[res - 3].table, MPC8_Q3_BITS, 2) + q3_offsets[res - 3];
385  c->Q[ch][off + j + 1] = t >> 4;
386  c->Q[ch][off + j + 0] = (t & 8) ? (t & 0xF) - 16 : (t & 0xF);
387  }
388  break;
389  case 5:
390  case 6:
391  case 7:
392  case 8:
393  cnt = 2 * mpc8_thres[res];
394  for(j = 0; j < SAMPLES_PER_BAND; j++){
395  t = get_vlc2(gb, quant_vlc[res - 5][cnt > mpc8_thres[res]].table, quant_vlc[res - 5][cnt > mpc8_thres[res]].bits, 2) + quant_offsets[res - 5];
396  c->Q[ch][off + j] = t;
397  cnt = (cnt >> 1) + FFABS(c->Q[ch][off + j]);
398  }
399  break;
400  default:
401  for(j = 0; j < SAMPLES_PER_BAND; j++){
402  c->Q[ch][off + j] = get_vlc2(gb, q9up_vlc.table, MPC8_Q9UP_BITS, 2);
403  if(res != 9){
404  c->Q[ch][off + j] <<= res - 9;
405  c->Q[ch][off + j] |= get_bits(gb, res - 9);
406  }
407  c->Q[ch][off + j] -= (1 << (res - 2)) - 1;
408  }
409  }
410  }
411  }
412 
413  ff_mpc_dequantize_and_synth(c, maxband - 1,
414  (int16_t **)frame->extended_data,
415  avctx->channels);
416 
417  c->cur_frame++;
418 
419  c->last_bits_used = get_bits_count(gb);
420  if(get_bits_left(gb) < 8) // we have only padding left
421  c->last_bits_used = buf_size << 3;
422  if(c->cur_frame >= c->frames)
423  c->cur_frame = 0;
424 
425  *got_frame_ptr = 1;
426 
427  return c->cur_frame ? c->last_bits_used >> 3 : buf_size;
428 }
429 
430  static av_cold void mpc8_decode_flush(AVCodecContext *avctx)
431 {
432  MPCContext *c = avctx->priv_data;
433  c->cur_frame = 0;
434 }
435 
436  AVCodec ff_mpc8_decoder = {
437  .name = "mpc8",
438  .long_name = NULL_IF_CONFIG_SMALL("Musepack SV8"),
439  .type = AVMEDIA_TYPE_AUDIO,
440  .id = AV_CODEC_ID_MUSEPACK8,
441  .priv_data_size = sizeof(MPCContext),
442  .init = mpc8_decode_init,
443  .decode = mpc8_decode_frame,
444  .flush = mpc8_decode_flush,
445  .capabilities = CODEC_CAP_DR1,
446  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
447  AV_SAMPLE_FMT_NONE },
448 };
Generated on Sat Jan 25 2014 19:51:51 for FFmpeg by   doxygen 1.8.2

AltStyle によって変換されたページ (->オリジナル) /