FFmpeg
msmpeg4dec.c
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1 /*
2  * MSMPEG4 backend for encoder and decoder
3  * Copyright (c) 2001 Fabrice Bellard
4  * Copyright (c) 2002-2013 Michael Niedermayer <michaelni@gmx.at>
5  *
6  * msmpeg4v1 & v2 stuff by Michael Niedermayer <michaelni@gmx.at>
7  *
8  * This file is part of FFmpeg.
9  *
10  * FFmpeg is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU Lesser General Public
12  * License as published by the Free Software Foundation; either
13  * version 2.1 of the License, or (at your option) any later version.
14  *
15  * FFmpeg is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18  * Lesser General Public License for more details.
19  *
20  * You should have received a copy of the GNU Lesser General Public
21  * License along with FFmpeg; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23  */
24 
25 #include "libavutil/thread.h"
26 
27 #include "avcodec.h"
28 #include "codec_internal.h"
29 #include "mpegutils.h"
30 #include "mpegvideo.h"
31 #include "msmpeg4.h"
32 #include "msmpeg4dec.h"
33 #include "libavutil/imgutils.h"
34 #include "h263.h"
35 #include "h263data.h"
36 #include "h263dec.h"
37 #include "mpeg4videodec.h"
38 #include "msmpeg4data.h"
39 #include "msmpeg4_vc1_data.h"
40 
41 #define V2_INTRA_CBPC_VLC_BITS 3
42 #define V2_MB_TYPE_VLC_BITS 7
43 #define MV_VLC_BITS 9
44 #define TEX_VLC_BITS 9
45 
46 #define DEFAULT_INTER_INDEX 3
47 
48 static inline int msmpeg4v1_pred_dc(MpegEncContext * s, int n,
49  int32_t **dc_val_ptr)
50 {
51  int i;
52 
53  if (n < 4) {
54  i= 0;
55  } else {
56  i= n-3;
57  }
58 
59  *dc_val_ptr= &s->last_dc[i];
60  return s->last_dc[i];
61 }
62 
63 /****************************************/
64 /* decoding stuff */
65 
67 static VLCElem v2_dc_lum_vlc[1472];
70 static VLCElem v2_mb_type_vlc[128];
72 
73 /* This is identical to H.263 except that its range is multiplied by 2. */
74 static int msmpeg4v2_decode_motion(MpegEncContext * s, int pred, int f_code)
75 {
76  int code, val, sign, shift;
77 
79  ff_dlog(s, "MV code %d at %d %d pred: %d\n", code, s->mb_x,s->mb_y, pred);
80  if (code < 0)
81  return 0xffff;
82 
83  if (code == 0)
84  return pred;
85  sign = get_bits1(&s->gb);
86  shift = f_code - 1;
87  val = code;
88  if (shift) {
89  val = (val - 1) << shift;
90  val |= get_bits(&s->gb, shift);
91  val++;
92  }
93  if (sign)
94  val = -val;
95 
96  val += pred;
97  if (val <= -64)
98  val += 64;
99  else if (val >= 64)
100  val -= 64;
101 
102  return val;
103 }
104 
105 static int msmpeg4v12_decode_mb(MpegEncContext *s, int16_t block[6][64])
106 {
107  int cbp, code, i;
108  uint32_t * const mb_type_ptr = &s->current_picture.mb_type[s->mb_x + s->mb_y*s->mb_stride];
109 
110  if (s->pict_type == AV_PICTURE_TYPE_P) {
111  if (s->use_skip_mb_code) {
112  if (get_bits1(&s->gb)) {
113  /* skip mb */
114  s->mb_intra = 0;
115  for(i=0;i<6;i++)
116  s->block_last_index[i] = -1;
117  s->mv_dir = MV_DIR_FORWARD;
118  s->mv_type = MV_TYPE_16X16;
119  s->mv[0][0][0] = 0;
120  s->mv[0][0][1] = 0;
121  s->mb_skipped = 1;
122  *mb_type_ptr = MB_TYPE_SKIP | MB_TYPE_L0 | MB_TYPE_16x16;
123  return 0;
124  }
125  }
126 
127  if(s->msmpeg4_version==2)
129  else
131  if(code<0 || code>7){
132  av_log(s->avctx, AV_LOG_ERROR, "cbpc %d invalid at %d %d\n", code, s->mb_x, s->mb_y);
133  return -1;
134  }
135 
136  s->mb_intra = code >>2;
137 
138  cbp = code & 0x3;
139  } else {
140  s->mb_intra = 1;
141  if(s->msmpeg4_version==2)
143  else
145  if(cbp<0 || cbp>3){
146  av_log(s->avctx, AV_LOG_ERROR, "cbpc %d invalid at %d %d\n", cbp, s->mb_x, s->mb_y);
147  return -1;
148  }
149  }
150 
151  if (!s->mb_intra) {
152  int mx, my, cbpy;
153 
154  cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc, CBPY_VLC_BITS, 1);
155  if(cbpy<0){
156  av_log(s->avctx, AV_LOG_ERROR, "cbpy %d invalid at %d %d\n", cbp, s->mb_x, s->mb_y);
157  return -1;
158  }
159 
160  cbp|= cbpy<<2;
161  if(s->msmpeg4_version==1 || (cbp&3) != 3) cbp^= 0x3C;
162 
163  ff_h263_pred_motion(s, 0, 0, &mx, &my);
164  mx= msmpeg4v2_decode_motion(s, mx, 1);
165  my= msmpeg4v2_decode_motion(s, my, 1);
166 
167  s->mv_dir = MV_DIR_FORWARD;
168  s->mv_type = MV_TYPE_16X16;
169  s->mv[0][0][0] = mx;
170  s->mv[0][0][1] = my;
171  *mb_type_ptr = MB_TYPE_L0 | MB_TYPE_16x16;
172  } else {
173  int v;
174  if(s->msmpeg4_version==2){
175  s->ac_pred = get_bits1(&s->gb);
176  v = get_vlc2(&s->gb, ff_h263_cbpy_vlc, CBPY_VLC_BITS, 1);
177  if (v < 0) {
178  av_log(s->avctx, AV_LOG_ERROR, "cbpy vlc invalid\n");
179  return -1;
180  }
181  cbp|= v<<2;
182  } else{
183  s->ac_pred = 0;
184  v = get_vlc2(&s->gb, ff_h263_cbpy_vlc, CBPY_VLC_BITS, 1);
185  if (v < 0) {
186  av_log(s->avctx, AV_LOG_ERROR, "cbpy vlc invalid\n");
187  return -1;
188  }
189  cbp|= v<<2;
190  if(s->pict_type==AV_PICTURE_TYPE_P) cbp^=0x3C;
191  }
192  *mb_type_ptr = MB_TYPE_INTRA;
193  }
194 
195  s->bdsp.clear_blocks(s->block[0]);
196  for (i = 0; i < 6; i++) {
197  if (ff_msmpeg4_decode_block(s, block[i], i, (cbp >> (5 - i)) & 1, NULL) < 0)
198  {
199  av_log(s->avctx, AV_LOG_ERROR, "\nerror while decoding block: %d x %d (%d)\n", s->mb_x, s->mb_y, i);
200  return -1;
201  }
202  }
203  return 0;
204 }
205 
206 static int msmpeg4v34_decode_mb(MpegEncContext *s, int16_t block[6][64])
207 {
208  int cbp, code, i;
209  uint8_t *coded_val;
210  uint32_t * const mb_type_ptr = &s->current_picture.mb_type[s->mb_x + s->mb_y*s->mb_stride];
211 
212  if (get_bits_left(&s->gb) <= 0)
213  return AVERROR_INVALIDDATA;
214 
215  if (s->pict_type == AV_PICTURE_TYPE_P) {
216  if (s->use_skip_mb_code) {
217  if (get_bits1(&s->gb)) {
218  /* skip mb */
219  s->mb_intra = 0;
220  for(i=0;i<6;i++)
221  s->block_last_index[i] = -1;
222  s->mv_dir = MV_DIR_FORWARD;
223  s->mv_type = MV_TYPE_16X16;
224  s->mv[0][0][0] = 0;
225  s->mv[0][0][1] = 0;
226  s->mb_skipped = 1;
227  *mb_type_ptr = MB_TYPE_SKIP | MB_TYPE_L0 | MB_TYPE_16x16;
228 
229  return 0;
230  }
231  }
232 
234  //s->mb_intra = (code & 0x40) ? 0 : 1;
235  s->mb_intra = (~code & 0x40) >> 6;
236 
237  cbp = code & 0x3f;
238  } else {
239  s->mb_intra = 1;
241  /* predict coded block pattern */
242  cbp = 0;
243  for(i=0;i<6;i++) {
244  int val = ((code >> (5 - i)) & 1);
245  if (i < 4) {
246  int pred = ff_msmpeg4_coded_block_pred(s, i, &coded_val);
247  val = val ^ pred;
248  *coded_val = val;
249  }
250  cbp |= val << (5 - i);
251  }
252  }
253 
254  if (!s->mb_intra) {
255  int mx, my;
256  if(s->per_mb_rl_table && cbp){
257  s->rl_table_index = decode012(&s->gb);
258  s->rl_chroma_table_index = s->rl_table_index;
259  }
260  ff_h263_pred_motion(s, 0, 0, &mx, &my);
261  ff_msmpeg4_decode_motion(s, &mx, &my);
262  s->mv_dir = MV_DIR_FORWARD;
263  s->mv_type = MV_TYPE_16X16;
264  s->mv[0][0][0] = mx;
265  s->mv[0][0][1] = my;
266  *mb_type_ptr = MB_TYPE_L0 | MB_TYPE_16x16;
267  } else {
268  ff_dlog(s, "I at %d %d %d %06X\n", s->mb_x, s->mb_y,
269  ((cbp & 3) ? 1 : 0) +((cbp & 0x3C)? 2 : 0),
270  show_bits(&s->gb, 24));
271  s->ac_pred = get_bits1(&s->gb);
272  *mb_type_ptr = MB_TYPE_INTRA;
273  if(s->inter_intra_pred){
274  s->h263_aic_dir= get_vlc2(&s->gb, ff_inter_intra_vlc, INTER_INTRA_VLC_BITS, 1);
275  ff_dlog(s, "%d%d %d %d/",
276  s->ac_pred, s->h263_aic_dir, s->mb_x, s->mb_y);
277  }
278  if(s->per_mb_rl_table && cbp){
279  s->rl_table_index = decode012(&s->gb);
280  s->rl_chroma_table_index = s->rl_table_index;
281  }
282  }
283 
284  s->bdsp.clear_blocks(s->block[0]);
285  for (i = 0; i < 6; i++) {
286  if (ff_msmpeg4_decode_block(s, block[i], i, (cbp >> (5 - i)) & 1, NULL) < 0)
287  {
288  av_log(s->avctx, AV_LOG_ERROR, "\nerror while decoding block: %d x %d (%d)\n", s->mb_x, s->mb_y, i);
289  return -1;
290  }
291  }
292 
293  return 0;
294 }
295 
296 /* init all vlc decoding tables */
298 {
299  static VLCElem vlc_buf[3714 + 2694 + 1636 + 2648 + 1532 + 2488];
300  VLCInitState state = VLC_INIT_STATE(vlc_buf);
301  MVTable *mv;
302 
304  INIT_FIRST_VLC_RL(ff_rl_table[1], 1104);
306  VLC_INIT_RL(ff_rl_table[3], 940);
307  VLC_INIT_RL(ff_rl_table[4], 962);
308  /* ff_rl_table[5] coincides with ff_h263_rl_inter which has just been
309  * initialized in ff_h263_decode_init() earlier. So just copy the VLCs. */
312 
314  &ff_v2_dc_lum_table[0][1], 8, 4,
315  &ff_v2_dc_lum_table[0][0], 8, 4, 0);
317  &ff_v2_dc_chroma_table[0][1], 8, 4,
318  &ff_v2_dc_chroma_table[0][0], 8, 4, 0);
319 
321  &ff_v2_intra_cbpc[0][1], 2, 1,
322  &ff_v2_intra_cbpc[0][0], 2, 1, 0);
324  &ff_v2_mb_type[0][1], 2, 1,
325  &ff_v2_mb_type[0][0], 2, 1, 0);
326 
327  mv = &ff_mv_tables[0];
330  mv->table_mv_bits, 1, 1,
331  mv->table_mv_code, 2, 2,
332  NULL, 0, 0, 0);
333  mv = &ff_mv_tables[1];
336  mv->table_mv_bits, 1, 1,
337  mv->table_mv_code, 2, 2,
338  NULL, 0, 0, 0);
339 
340  for (unsigned i = 0; i < 4; i++) {
343  &ff_wmv2_inter_table[i][0][1], 8, 4,
344  &ff_wmv2_inter_table[i][0][0], 8, 4,
345  NULL, 0, 0, 0);
346  }
347 
349  &ff_table_inter_intra[0][1], 2, 1,
350  &ff_table_inter_intra[0][0], 2, 1, 0);
352 }
353 
355 {
356  static AVOnce init_static_once = AV_ONCE_INIT;
357  MpegEncContext *s = avctx->priv_data;
358  int ret;
359 
360  if ((ret = av_image_check_size(avctx->width, avctx->height, 0, avctx)) < 0)
361  return ret;
362 
363  if (ff_h263_decode_init(avctx) < 0)
364  return -1;
365 
367 
368  switch(s->msmpeg4_version){
369  case 1:
370  case 2:
371  s->decode_mb= msmpeg4v12_decode_mb;
372  break;
373  case 3:
374  case 4:
375  s->decode_mb= msmpeg4v34_decode_mb;
376  break;
377  case 5:
378  break;
379  }
380 
381  s->slice_height= s->mb_height; //to avoid 1/0 if the first frame is not a keyframe
382 
383  ff_thread_once(&init_static_once, msmpeg4_decode_init_static);
384 
385  return 0;
386 }
387 
389 {
390  int code;
391 
392  // at minimum one bit per macroblock is required at least in a valid frame,
393  // we discard frames much smaller than this. Frames smaller than 1/8 of the
394  // smallest "black/skip" frame generally contain not much recoverable content
395  // while at the same time they have the highest computational requirements
396  // per byte
397  if (get_bits_left(&s->gb) * 8LL < (s->width+15)/16 * ((s->height+15)/16))
398  return AVERROR_INVALIDDATA;
399 
400  if(s->msmpeg4_version==1){
401  int start_code = get_bits_long(&s->gb, 32);
402  if(start_code!=0x00000100){
403  av_log(s->avctx, AV_LOG_ERROR, "invalid startcode\n");
404  return -1;
405  }
406 
407  skip_bits(&s->gb, 5); // frame number */
408  }
409 
410  s->pict_type = get_bits(&s->gb, 2) + 1;
411  if (s->pict_type != AV_PICTURE_TYPE_I &&
412  s->pict_type != AV_PICTURE_TYPE_P){
413  av_log(s->avctx, AV_LOG_ERROR, "invalid picture type\n");
414  return -1;
415  }
416  s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
417  if(s->qscale==0){
418  av_log(s->avctx, AV_LOG_ERROR, "invalid qscale\n");
419  return -1;
420  }
421 
422  if (s->pict_type == AV_PICTURE_TYPE_I) {
423  code = get_bits(&s->gb, 5);
424  if(s->msmpeg4_version==1){
425  if(code==0 || code>s->mb_height){
426  av_log(s->avctx, AV_LOG_ERROR, "invalid slice height %d\n", code);
427  return -1;
428  }
429 
430  s->slice_height = code;
431  }else{
432  /* 0x17: one slice, 0x18: two slices, ... */
433  if (code < 0x17){
434  av_log(s->avctx, AV_LOG_ERROR, "error, slice code was %X\n", code);
435  return -1;
436  }
437 
438  s->slice_height = s->mb_height / (code - 0x16);
439  }
440 
441  switch(s->msmpeg4_version){
442  case 1:
443  case 2:
444  s->rl_chroma_table_index = 2;
445  s->rl_table_index = 2;
446 
447  s->dc_table_index = 0; //not used
448  break;
449  case 3:
450  s->rl_chroma_table_index = decode012(&s->gb);
451  s->rl_table_index = decode012(&s->gb);
452 
453  s->dc_table_index = get_bits1(&s->gb);
454  break;
455  case 4:
456  ff_msmpeg4_decode_ext_header(s, (2+5+5+17+7)/8);
457 
458  if(s->bit_rate > MBAC_BITRATE) s->per_mb_rl_table= get_bits1(&s->gb);
459  else s->per_mb_rl_table= 0;
460 
461  if(!s->per_mb_rl_table){
462  s->rl_chroma_table_index = decode012(&s->gb);
463  s->rl_table_index = decode012(&s->gb);
464  }
465 
466  s->dc_table_index = get_bits1(&s->gb);
467  s->inter_intra_pred= 0;
468  break;
469  }
470  s->no_rounding = 1;
471  if(s->avctx->debug&FF_DEBUG_PICT_INFO)
472  av_log(s->avctx, AV_LOG_DEBUG, "qscale:%d rlc:%d rl:%d dc:%d mbrl:%d slice:%d \n",
473  s->qscale,
474  s->rl_chroma_table_index,
475  s->rl_table_index,
476  s->dc_table_index,
477  s->per_mb_rl_table,
478  s->slice_height);
479  } else {
480  switch(s->msmpeg4_version){
481  case 1:
482  case 2:
483  if(s->msmpeg4_version==1)
484  s->use_skip_mb_code = 1;
485  else
486  s->use_skip_mb_code = get_bits1(&s->gb);
487  s->rl_table_index = 2;
488  s->rl_chroma_table_index = s->rl_table_index;
489  s->dc_table_index = 0; //not used
490  s->mv_table_index = 0;
491  break;
492  case 3:
493  s->use_skip_mb_code = get_bits1(&s->gb);
494  s->rl_table_index = decode012(&s->gb);
495  s->rl_chroma_table_index = s->rl_table_index;
496 
497  s->dc_table_index = get_bits1(&s->gb);
498 
499  s->mv_table_index = get_bits1(&s->gb);
500  break;
501  case 4:
502  s->use_skip_mb_code = get_bits1(&s->gb);
503 
504  if(s->bit_rate > MBAC_BITRATE) s->per_mb_rl_table= get_bits1(&s->gb);
505  else s->per_mb_rl_table= 0;
506 
507  if(!s->per_mb_rl_table){
508  s->rl_table_index = decode012(&s->gb);
509  s->rl_chroma_table_index = s->rl_table_index;
510  }
511 
512  s->dc_table_index = get_bits1(&s->gb);
513 
514  s->mv_table_index = get_bits1(&s->gb);
515  s->inter_intra_pred= (s->width*s->height < 320*240 && s->bit_rate<=II_BITRATE);
516  break;
517  }
518 
519  if(s->avctx->debug&FF_DEBUG_PICT_INFO)
520  av_log(s->avctx, AV_LOG_DEBUG, "skip:%d rl:%d rlc:%d dc:%d mv:%d mbrl:%d qp:%d \n",
521  s->use_skip_mb_code,
522  s->rl_table_index,
523  s->rl_chroma_table_index,
524  s->dc_table_index,
525  s->mv_table_index,
526  s->per_mb_rl_table,
527  s->qscale);
528 
529  if(s->flipflop_rounding){
530  s->no_rounding ^= 1;
531  }else{
532  s->no_rounding = 0;
533  }
534  }
535  ff_dlog(s->avctx, "%d %"PRId64" %d %d %d\n", s->pict_type, s->bit_rate,
536  s->inter_intra_pred, s->width, s->height);
537 
538  s->esc3_level_length= 0;
539  s->esc3_run_length= 0;
540 
541  return 0;
542 }
543 
545 {
546  int left= buf_size*8 - get_bits_count(&s->gb);
547  int length= s->msmpeg4_version>=3 ? 17 : 16;
548  /* the alt_bitstream reader could read over the end so we need to check it */
549  if(left>=length && left<length+8)
550  {
551  skip_bits(&s->gb, 5); /* fps */
552  s->bit_rate= get_bits(&s->gb, 11)*1024;
553  if(s->msmpeg4_version>=3)
554  s->flipflop_rounding= get_bits1(&s->gb);
555  else
556  s->flipflop_rounding= 0;
557  }
558  else if(left<length+8)
559  {
560  s->flipflop_rounding= 0;
561  if(s->msmpeg4_version != 2)
562  av_log(s->avctx, AV_LOG_ERROR, "ext header missing, %d left\n", left);
563  }
564  else
565  {
566  av_log(s->avctx, AV_LOG_ERROR, "I-frame too long, ignoring ext header\n");
567  }
568 
569  return 0;
570 }
571 
572 static int msmpeg4_decode_dc(MpegEncContext * s, int n, int *dir_ptr)
573 {
574  int level, pred;
575 
576  if(s->msmpeg4_version<=2){
577  if (n < 4) {
579  } else {
581  }
582  if (level < 0) {
583  av_log(s->avctx, AV_LOG_ERROR, "illegal dc vlc\n");
584  *dir_ptr = 0;
585  return -1;
586  }
587  level-=256;
588  } else {
589  level = get_vlc2(&s->gb, ff_msmp4_dc_vlc[s->dc_table_index][n >= 4],
590  MSMP4_DC_VLC_BITS, 3);
591 
592  if (level == DC_MAX) {
593  level = get_bits(&s->gb, 8);
594  if (get_bits1(&s->gb))
595  level = -level;
596  } else if (level != 0) {
597  if (get_bits1(&s->gb))
598  level = -level;
599  }
600  }
601 
602  if(s->msmpeg4_version==1){
603  int32_t *dc_val;
604  pred = msmpeg4v1_pred_dc(s, n, &dc_val);
605  level += pred;
606 
607  /* update predictor */
608  *dc_val= level;
609  }else{
610  int16_t *dc_val;
611  pred = ff_msmpeg4_pred_dc(s, n, &dc_val, dir_ptr);
612  level += pred;
613 
614  /* update predictor */
615  if (n < 4) {
616  *dc_val = level * s->y_dc_scale;
617  } else {
618  *dc_val = level * s->c_dc_scale;
619  }
620  }
621 
622  return level;
623 }
624 
626  int n, int coded, const uint8_t *scan_table)
627 {
628  int level, i, last, run, run_diff;
629  int av_uninit(dc_pred_dir);
630  RLTable *rl;
632  int qmul, qadd;
633 
634  if (s->mb_intra) {
635  qmul=1;
636  qadd=0;
637 
638  /* DC coef */
639  level = msmpeg4_decode_dc(s, n, &dc_pred_dir);
640 
641  if (level < 0){
642  av_log(s->avctx, AV_LOG_ERROR, "dc overflow- block: %d qscale: %d//\n", n, s->qscale);
643  if(s->inter_intra_pred) level=0;
644  }
645  if (n < 4) {
646  rl = &ff_rl_table[s->rl_table_index];
647  if(level > 256*s->y_dc_scale){
648  av_log(s->avctx, AV_LOG_ERROR, "dc overflow+ L qscale: %d//\n", s->qscale);
649  if(!s->inter_intra_pred) return -1;
650  }
651  } else {
652  rl = &ff_rl_table[3 + s->rl_chroma_table_index];
653  if(level > 256*s->c_dc_scale){
654  av_log(s->avctx, AV_LOG_ERROR, "dc overflow+ C qscale: %d//\n", s->qscale);
655  if(!s->inter_intra_pred) return -1;
656  }
657  }
658  block[0] = level;
659 
660  run_diff = s->msmpeg4_version >= 4;
661  i = 0;
662  if (!coded) {
663  goto not_coded;
664  }
665  if (s->ac_pred) {
666  if (dc_pred_dir == 0)
667  scan_table = s->permutated_intra_v_scantable; /* left */
668  else
669  scan_table = s->permutated_intra_h_scantable; /* top */
670  } else {
671  scan_table = s->intra_scantable.permutated;
672  }
673  rl_vlc= rl->rl_vlc[0];
674  } else {
675  qmul = s->qscale << 1;
676  qadd = (s->qscale - 1) | 1;
677  i = -1;
678  rl = &ff_rl_table[3 + s->rl_table_index];
679 
680  if(s->msmpeg4_version==2)
681  run_diff = 0;
682  else
683  run_diff = 1;
684 
685  if (!coded) {
686  s->block_last_index[n] = i;
687  return 0;
688  }
689  if(!scan_table)
690  scan_table = s->inter_scantable.permutated;
691  rl_vlc= rl->rl_vlc[s->qscale];
692  }
693  {
694  OPEN_READER(re, &s->gb);
695  for(;;) {
696  UPDATE_CACHE(re, &s->gb);
697  GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 0);
698  if (level==0) {
699  int cache;
700  cache= GET_CACHE(re, &s->gb);
701  /* escape */
702  if (s->msmpeg4_version==1 || (cache&0x80000000)==0) {
703  if (s->msmpeg4_version==1 || (cache&0x40000000)==0) {
704  /* third escape */
705  if(s->msmpeg4_version!=1) LAST_SKIP_BITS(re, &s->gb, 2);
706  UPDATE_CACHE(re, &s->gb);
707  if(s->msmpeg4_version<=3){
708  last= SHOW_UBITS(re, &s->gb, 1); SKIP_CACHE(re, &s->gb, 1);
709  run= SHOW_UBITS(re, &s->gb, 6); SKIP_CACHE(re, &s->gb, 6);
710  level= SHOW_SBITS(re, &s->gb, 8);
711  SKIP_COUNTER(re, &s->gb, 1+6+8);
712  }else{
713  int sign;
714  last= SHOW_UBITS(re, &s->gb, 1); SKIP_BITS(re, &s->gb, 1);
715  if(!s->esc3_level_length){
716  int ll;
717  ff_dlog(s->avctx, "ESC-3 %X at %d %d\n",
718  show_bits(&s->gb, 24), s->mb_x, s->mb_y);
719  if(s->qscale<8){
720  ll= SHOW_UBITS(re, &s->gb, 3); SKIP_BITS(re, &s->gb, 3);
721  if(ll==0){
722  ll= 8+SHOW_UBITS(re, &s->gb, 1); SKIP_BITS(re, &s->gb, 1);
723  }
724  }else{
725  ll=2;
726  while(ll<8 && SHOW_UBITS(re, &s->gb, 1)==0){
727  ll++;
728  SKIP_BITS(re, &s->gb, 1);
729  }
730  if(ll<8) SKIP_BITS(re, &s->gb, 1);
731  }
732 
733  s->esc3_level_length= ll;
734  s->esc3_run_length= SHOW_UBITS(re, &s->gb, 2) + 3; SKIP_BITS(re, &s->gb, 2);
735  UPDATE_CACHE(re, &s->gb);
736  }
737  run= SHOW_UBITS(re, &s->gb, s->esc3_run_length);
738  SKIP_BITS(re, &s->gb, s->esc3_run_length);
739 
740  sign= SHOW_UBITS(re, &s->gb, 1);
741  SKIP_BITS(re, &s->gb, 1);
742 
743  level= SHOW_UBITS(re, &s->gb, s->esc3_level_length);
744  SKIP_BITS(re, &s->gb, s->esc3_level_length);
745  if(sign) level= -level;
746  }
747 
748  //level = level * qmul + (level>0) * qadd - (level<=0) * qadd ;
749  if (level>0) level= level * qmul + qadd;
750  else level= level * qmul - qadd;
751  i+= run + 1;
752  if(last) i+=192;
753  } else {
754  /* second escape */
755  SKIP_BITS(re, &s->gb, 2);
756  GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
757  i+= run + rl->max_run[run>>7][level/qmul] + run_diff; //FIXME opt indexing
758  level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
759  LAST_SKIP_BITS(re, &s->gb, 1);
760  }
761  } else {
762  /* first escape */
763  SKIP_BITS(re, &s->gb, 1);
764  GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
765  i+= run;
766  level = level + rl->max_level[run>>7][(run-1)&63] * qmul;//FIXME opt indexing
767  level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
768  LAST_SKIP_BITS(re, &s->gb, 1);
769  }
770  } else {
771  i+= run;
772  level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
773  LAST_SKIP_BITS(re, &s->gb, 1);
774  }
775  if (i > 62){
776  i-= 192;
777  if(i&(~63)){
778  const int left= get_bits_left(&s->gb);
779  if (((i + 192 == 64 && level / qmul == -1) ||
780  !(s->avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))) &&
781  left >= 0) {
782  av_log(s->avctx, AV_LOG_ERROR, "ignoring overflow at %d %d\n", s->mb_x, s->mb_y);
783  i = 63;
784  break;
785  }else{
786  av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
787  return -1;
788  }
789  }
790 
791  block[scan_table[i]] = level;
792  break;
793  }
794 
795  block[scan_table[i]] = level;
796  }
797  CLOSE_READER(re, &s->gb);
798  }
799  not_coded:
800  if (s->mb_intra) {
801  ff_mpeg4_pred_ac(s, block, n, dc_pred_dir);
802  if (s->ac_pred) {
803  i = 63; /* XXX: not optimal */
804  }
805  }
806  if(s->msmpeg4_version>=4 && i>0) i=63; //FIXME/XXX optimize
807  s->block_last_index[n] = i;
808 
809  return 0;
810 }
811 
812 void ff_msmpeg4_decode_motion(MpegEncContext *s, int *mx_ptr, int *my_ptr)
813 {
814  MVTable *mv;
815  int code, mx, my;
816 
817  mv = &ff_mv_tables[s->mv_table_index];
818 
819  code = get_vlc2(&s->gb, mv->vlc, MV_VLC_BITS, 2);
821  mx = get_bits(&s->gb, 6);
822  my = get_bits(&s->gb, 6);
823  } else {
824  mx = mv->table_mvx[code];
825  my = mv->table_mvy[code];
826  }
827 
828  mx += *mx_ptr - 32;
829  my += *my_ptr - 32;
830  /* WARNING : they do not do exactly modulo encoding */
831  if (mx <= -64)
832  mx += 64;
833  else if (mx >= 64)
834  mx -= 64;
835 
836  if (my <= -64)
837  my += 64;
838  else if (my >= 64)
839  my -= 64;
840  *mx_ptr = mx;
841  *my_ptr = my;
842 }
843 
845  .p.name = "msmpeg4v1",
846  CODEC_LONG_NAME("MPEG-4 part 2 Microsoft variant version 1"),
847  .p.type = AVMEDIA_TYPE_VIDEO,
848  .p.id = AV_CODEC_ID_MSMPEG4V1,
849  .priv_data_size = sizeof(MpegEncContext),
851  .close = ff_h263_decode_end,
854  .caps_internal = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
855  .p.max_lowres = 3,
856 };
857 
859  .p.name = "msmpeg4v2",
860  CODEC_LONG_NAME("MPEG-4 part 2 Microsoft variant version 2"),
861  .p.type = AVMEDIA_TYPE_VIDEO,
862  .p.id = AV_CODEC_ID_MSMPEG4V2,
863  .priv_data_size = sizeof(MpegEncContext),
865  .close = ff_h263_decode_end,
868  .caps_internal = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
869  .p.max_lowres = 3,
870 };
871 
873  .p.name = "msmpeg4",
874  CODEC_LONG_NAME("MPEG-4 part 2 Microsoft variant version 3"),
875  .p.type = AVMEDIA_TYPE_VIDEO,
876  .p.id = AV_CODEC_ID_MSMPEG4V3,
877  .priv_data_size = sizeof(MpegEncContext),
879  .close = ff_h263_decode_end,
882  .caps_internal = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
883  .p.max_lowres = 3,
884 };
885 
887  .p.name = "wmv1",
888  CODEC_LONG_NAME("Windows Media Video 7"),
889  .p.type = AVMEDIA_TYPE_VIDEO,
890  .p.id = AV_CODEC_ID_WMV1,
891  .priv_data_size = sizeof(MpegEncContext),
893  .close = ff_h263_decode_end,
896  .caps_internal = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
897  .p.max_lowres = 3,
898 };
MB_TYPE_L0
#define MB_TYPE_L0
Definition: mpegutils.h:55
MV_TYPE_16X16
#define MV_TYPE_16X16
1 vector for the whole mb
Definition: mpegvideo.h:267
h263data.h
ff_h263_cbpy_vlc
VLCElem ff_h263_cbpy_vlc[]
Definition: ituh263dec.c:104
level
uint8_t level
Definition: svq3.c:205
get_bits_left
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:695
AV_EF_COMPLIANT
#define AV_EF_COMPLIANT
consider all spec non compliances as errors
Definition: defs.h:55
thread.h
msmpeg4v1_pred_dc
static int msmpeg4v1_pred_dc(MpegEncContext *s, int n, int32_t **dc_val_ptr)
Definition: msmpeg4dec.c:48
mpeg4videodec.h
msmpeg4v2_decode_motion
static int msmpeg4v2_decode_motion(MpegEncContext *s, int pred, int f_code)
Definition: msmpeg4dec.c:74
get_bits_long
static unsigned int get_bits_long(GetBitContext *s, int n)
Read 0-32 bits.
Definition: get_bits.h:421
mv
static const int8_t mv[256][2]
Definition: 4xm.c:81
msmpeg4_decode_init_static
static av_cold void msmpeg4_decode_init_static(void)
Definition: msmpeg4dec.c:297
get_bits_count
static int get_bits_count(const GetBitContext *s)
Definition: get_bits.h:266
MBAC_BITRATE
#define MBAC_BITRATE
Definition: msmpeg4.h:30
start_code
static const uint8_t start_code[]
Definition: videotoolboxenc.c:221
ff_msmpeg4_common_init
av_cold void ff_msmpeg4_common_init(MpegEncContext *s)
Definition: msmpeg4.c:118
MSMP4_MB_INTRA_VLC_BITS
#define MSMP4_MB_INTRA_VLC_BITS
Definition: msmpeg4_vc1_data.h:36
MB_TYPE_16x16
#define MB_TYPE_16x16
Definition: mpegutils.h:42
ff_msmpeg4_decode_ext_header
int ff_msmpeg4_decode_ext_header(MpegEncContext *s, int buf_size)
Definition: msmpeg4dec.c:544
FFCodec
Definition: codec_internal.h:126
mpegvideo.h
UPDATE_CACHE
#define UPDATE_CACHE(name, gb)
Definition: get_bits.h:225
ff_rl_table
RLTable ff_rl_table[NB_RL_TABLES]
Definition: msmpeg4data.c:441
mpegutils.h
FF_DEBUG_PICT_INFO
#define FF_DEBUG_PICT_INFO
Definition: avcodec.h:1397
GET_CACHE
#define GET_CACHE(name, gb)
Definition: get_bits.h:263
skip_bits
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:381
get_bits
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:335
SKIP_CACHE
#define SKIP_CACHE(name, gb, num)
Definition: get_bits.h:228
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:130
ff_wmv2_inter_table
const uint32_t(*const [WMV2_INTER_CBP_TABLE_COUNT] ff_wmv2_inter_table)[2]
Definition: msmpeg4data.c:1760
ff_h263_pred_motion
int16_t * ff_h263_pred_motion(MpegEncContext *s, int block, int dir, int *px, int *py)
Definition: h263.c:190
ff_mpeg4_pred_ac
void ff_mpeg4_pred_ac(MpegEncContext *s, int16_t *block, int n, int dir)
Predict the ac.
Definition: mpeg4videodec.c:315
RLTable
RLTable.
Definition: rl.h:39
AV_EF_BITSTREAM
#define AV_EF_BITSTREAM
detect bitstream specification deviations
Definition: defs.h:49
ff_msmpeg4_decode_motion
void ff_msmpeg4_decode_motion(MpegEncContext *s, int *mx_ptr, int *my_ptr)
Definition: msmpeg4dec.c:812
val
static double val(void *priv, double ch)
Definition: aeval.c:78
AV_CODEC_ID_MSMPEG4V2
@ AV_CODEC_ID_MSMPEG4V2
Definition: codec_id.h:67
MV_VLC_BITS
#define MV_VLC_BITS
Definition: msmpeg4dec.c:43
V2_INTRA_CBPC_VLC_BITS
#define V2_INTRA_CBPC_VLC_BITS
Definition: msmpeg4dec.c:41
ff_thread_once
static int ff_thread_once(char *control, void(*routine)(void))
Definition: thread.h:205
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
INIT_FIRST_VLC_RL
#define INIT_FIRST_VLC_RL(rl, static_size)
Definition: rl.h:93
h263dec.h
av_cold
#define av_cold
Definition: attributes.h:90
ff_msmp4_vc1_vlcs_init_once
av_cold void ff_msmp4_vc1_vlcs_init_once(void)
Definition: msmpeg4_vc1_data.c:56
VLCInitState
For static VLCs, the number of bits can often be hardcoded at each get_vlc2() callsite.
Definition: vlc.h:212
ff_msmpeg4_decode_picture_header
int ff_msmpeg4_decode_picture_header(MpegEncContext *s)
Definition: msmpeg4dec.c:388
msmpeg4data.h
CLOSE_READER
#define CLOSE_READER(name, gb)
Definition: get_bits.h:188
FF_CODEC_DECODE_CB
#define FF_CODEC_DECODE_CB(func)
Definition: codec_internal.h:286
RLTable::max_level
int8_t * max_level[2]
encoding & decoding
Definition: rl.h:46
s
#define s(width, name)
Definition: cbs_vp9.c:198
ff_mb_non_intra_vlc
const VLCElem * ff_mb_non_intra_vlc[4]
Definition: msmpeg4dec.c:66
SHOW_SBITS
#define SHOW_SBITS(name, gb, num)
Definition: get_bits.h:260
ff_msmpeg4v1_decoder
const FFCodec ff_msmpeg4v1_decoder
Definition: msmpeg4dec.c:844
AV_LOG_DEBUG
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:201
AV_CODEC_ID_MSMPEG4V1
@ AV_CODEC_ID_MSMPEG4V1
Definition: codec_id.h:66
SKIP_BITS
#define SKIP_BITS(name, gb, num)
Definition: get_bits.h:241
CODEC_LONG_NAME
#define CODEC_LONG_NAME(str)
Definition: codec_internal.h:271
rl_vlc
static const VLCElem * rl_vlc[2]
Definition: mobiclip.c:278
DEFAULT_INTER_INDEX
#define DEFAULT_INTER_INDEX
Definition: msmpeg4dec.c:46
AV_ONCE_INIT
#define AV_ONCE_INIT
Definition: thread.h:203
NULL
#define NULL
Definition: coverity.c:32
run
uint8_t run
Definition: svq3.c:204
ff_v2_mb_type
const uint8_t ff_v2_mb_type[8][2]
Definition: msmpeg4data.c:1624
ff_h263_mv_vlc
VLCElem ff_h263_mv_vlc[]
Definition: ituh263dec.c:105
ff_v2_dc_lum_table
uint32_t ff_v2_dc_lum_table[512][2]
Definition: msmpeg4data.c:35
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:279
get_bits1
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:388
INTER_INTRA_VLC_BITS
#define INTER_INTRA_VLC_BITS
Definition: msmpeg4dec.h:28
ff_h263_decode_frame
int ff_h263_decode_frame(AVCodecContext *avctx, AVFrame *pict, int *got_frame, AVPacket *avpkt)
Definition: h263dec.c:423
LAST_SKIP_BITS
#define LAST_SKIP_BITS(name, gb, num)
Definition: get_bits.h:247
ff_h263_intra_MCBPC_vlc
VLCElem ff_h263_intra_MCBPC_vlc[]
Definition: ituh263dec.c:102
ff_v2_dc_chroma_table
uint32_t ff_v2_dc_chroma_table[512][2]
Definition: msmpeg4data.c:36
DC_MAX
#define DC_MAX
Definition: msmpeg4.h:32
AV_CODEC_ID_WMV1
@ AV_CODEC_ID_WMV1
Definition: codec_id.h:69
get_vlc2
static av_always_inline int get_vlc2(GetBitContext *s, const VLCElem *table, int bits, int max_depth)
Parse a vlc code.
Definition: get_bits.h:652
V2_MB_TYPE_VLC_BITS
#define V2_MB_TYPE_VLC_BITS
Definition: msmpeg4dec.c:42
AVOnce
#define AVOnce
Definition: thread.h:202
v2_intra_cbpc_vlc
static VLCElem v2_intra_cbpc_vlc[8]
Definition: msmpeg4dec.c:69
ff_h263_decode_end
av_cold int ff_h263_decode_end(AVCodecContext *avctx)
Definition: h263dec.c:162
ff_inter_intra_vlc
VLCElem ff_inter_intra_vlc[8]
Definition: msmpeg4dec.c:71
ff_dlog
#define ff_dlog(a,...)
Definition: tableprint_vlc.h:28
ff_msmp4_mb_i_vlc
VLCElem ff_msmp4_mb_i_vlc[536]
Definition: msmpeg4_vc1_data.c:35
init
int(* init)(AVBSFContext *ctx)
Definition: dts2pts.c:366
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
MB_NON_INTRA_VLC_BITS
#define MB_NON_INTRA_VLC_BITS
Definition: msmpeg4dec.h:29
ff_h263_rl_inter
RLTable ff_h263_rl_inter
Definition: h263data.c:159
RL_VLC_ELEM
Definition: vlc.h:56
codec_internal.h
shift
static int shift(int a, int b)
Definition: bonk.c:261
MSMP4_DC_VLC_BITS
#define MSMP4_DC_VLC_BITS
Definition: msmpeg4_vc1_data.h:38
VLCElem
Definition: vlc.h:32
msmpeg4v12_decode_mb
static int msmpeg4v12_decode_mb(MpegEncContext *s, int16_t block[6][64])
Definition: msmpeg4dec.c:105
CBPY_VLC_BITS
#define CBPY_VLC_BITS
Definition: h263dec.h:38
msmpeg4v34_decode_mb
static int msmpeg4v34_decode_mb(MpegEncContext *s, int16_t block[6][64])
Definition: msmpeg4dec.c:206
FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM
#define FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM
The decoder extracts and fills its parameters even if the frame is skipped due to the skip_frame sett...
Definition: codec_internal.h:54
MB_TYPE_SKIP
#define MB_TYPE_SKIP
Definition: mpegutils.h:50
II_BITRATE
#define II_BITRATE
Definition: msmpeg4.h:29
v2_mb_type_vlc
static VLCElem v2_mb_type_vlc[128]
Definition: msmpeg4dec.c:70
ff_msmpeg4v3_decoder
const FFCodec ff_msmpeg4v3_decoder
Definition: msmpeg4dec.c:872
OPEN_READER
#define OPEN_READER(name, gb)
Definition: get_bits.h:177
ff_msmpeg4_pred_dc
int ff_msmpeg4_pred_dc(MpegEncContext *s, int n, int16_t **dc_val_ptr, int *dir_ptr)
Definition: msmpeg4.c:198
ff_v2_intra_cbpc
const uint8_t ff_v2_intra_cbpc[4][2]
Definition: msmpeg4data.c:1629
msmpeg4dec.h
SKIP_COUNTER
#define SKIP_COUNTER(name, gb, num)
Definition: get_bits.h:233
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:256
code
and forward the test the status of outputs and forward it to the corresponding return FFERROR_NOT_READY If the filters stores internally one or a few frame for some it can consider them to be part of the FIFO and delay acknowledging a status change accordingly Example code
Definition: filter_design.txt:178
show_bits
static unsigned int show_bits(GetBitContext *s, int n)
Show 1-25 bits.
Definition: get_bits.h:371
ff_mv_tables
MVTable ff_mv_tables[2]
Definition: msmpeg4data.c:1613
RLTable::max_run
int8_t * max_run[2]
encoding & decoding
Definition: rl.h:47
ff_msmpeg4_decode_block
int ff_msmpeg4_decode_block(MpegEncContext *s, int16_t *block, int n, int coded, const uint8_t *scan_table)
Definition: msmpeg4dec.c:625
decode012
static int BS_FUNC() decode012(BSCTX *bc)
Return decoded truncated unary code for the values 0, 1, 2.
Definition: bitstream_template.h:436
INTRA_MCBPC_VLC_BITS
#define INTRA_MCBPC_VLC_BITS
Definition: h263dec.h:36
av_assert1
#define av_assert1(cond)
assert() equivalent, that does not lie in speed critical code.
Definition: avassert.h:56
state
static struct @416 state
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:194
ff_h263_decode_init
av_cold int ff_h263_decode_init(AVCodecContext *avctx)
Definition: h263dec.c:90
AVCodecContext::height
int height
Definition: avcodec.h:618
v2_dc_lum_vlc
static VLCElem v2_dc_lum_vlc[1472]
Definition: msmpeg4dec.c:67
avcodec.h
msmpeg4.h
ff_wmv1_decoder
const FFCodec ff_wmv1_decoder
Definition: msmpeg4dec.c:886
GET_RL_VLC
#define GET_RL_VLC(level, run, name, gb, table, bits, max_depth, need_update)
Definition: get_bits.h:606
av_uninit
#define av_uninit(x)
Definition: attributes.h:154
v2_dc_chroma_vlc
static VLCElem v2_dc_chroma_vlc[1506]
Definition: msmpeg4dec.c:68
ret
ret
Definition: filter_design.txt:187
pred
static const float pred[4]
Definition: siprdata.h:259
left
Tag MUST be and< 10hcoeff half pel interpolation filter coefficients, hcoeff[0] are the 2 middle coefficients[1] are the next outer ones and so on, resulting in a filter like:...eff[2], hcoeff[1], hcoeff[0], hcoeff[0], hcoeff[1], hcoeff[2] ... the sign of the coefficients is not explicitly stored but alternates after each coeff and coeff[0] is positive, so ...,+,-,+,-,+,+,-,+,-,+,... hcoeff[0] is not explicitly stored but found by subtracting the sum of all stored coefficients with signs from 32 hcoeff[0]=32 - hcoeff[1] - hcoeff[2] - ... a good choice for hcoeff and htaps is htaps=6 hcoeff={40,-10, 2} an alternative which requires more computations at both encoder and decoder side and may or may not be better is htaps=8 hcoeff={42,-14, 6,-2}ref_frames minimum of the number of available reference frames and max_ref_frames for example the first frame after a key frame always has ref_frames=1spatial_decomposition_type wavelet type 0 is a 9/7 symmetric compact integer wavelet 1 is a 5/3 symmetric compact integer wavelet others are reserved stored as delta from last, last is reset to 0 if always_reset||keyframeqlog quality(logarithmic quantizer scale) stored as delta from last, last is reset to 0 if always_reset||keyframemv_scale stored as delta from last, last is reset to 0 if always_reset||keyframe FIXME check that everything works fine if this changes between framesqbias dequantization bias stored as delta from last, last is reset to 0 if always_reset||keyframeblock_max_depth maximum depth of the block tree stored as delta from last, last is reset to 0 if always_reset||keyframequant_table quantization tableHighlevel bitstream structure:==============================--------------------------------------------|Header|--------------------------------------------|------------------------------------|||Block0||||split?||||yes no||||......... intra?||||:Block01 :yes no||||:Block02 :....... ..........||||:Block03 ::y DC ::ref index:||||:Block04 ::cb DC ::motion x :||||......... :cr DC ::motion y :||||....... ..........|||------------------------------------||------------------------------------|||Block1|||...|--------------------------------------------|------------ ------------ ------------|||Y subbands||Cb subbands||Cr subbands||||--- ---||--- ---||--- ---|||||LL0||HL0||||LL0||HL0||||LL0||HL0|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||LH0||HH0||||LH0||HH0||||LH0||HH0|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||HL1||LH1||||HL1||LH1||||HL1||LH1|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||HH1||HL2||||HH1||HL2||||HH1||HL2|||||...||...||...|||------------ ------------ ------------|--------------------------------------------Decoding process:=================------------|||Subbands|------------||||------------|Intra DC||||LL0 subband prediction ------------|\ Dequantization ------------------- \||Reference frames|\ IDWT|------- -------|Motion \|||Frame 0||Frame 1||Compensation . OBMC v -------|------- -------|--------------. \------> Frame n output Frame Frame<----------------------------------/|...|------------------- Range Coder:============Binary Range Coder:------------------- The implemented range coder is an adapted version based upon "Range encoding: an algorithm for removing redundancy from a digitised message." by G. N. N. Martin. The symbols encoded by the Snow range coder are bits(0|1). The associated probabilities are not fix but change depending on the symbol mix seen so far. bit seen|new state ---------+----------------------------------------------- 0|256 - state_transition_table[256 - old_state];1|state_transition_table[old_state];state_transition_table={ 0, 0, 0, 0, 0, 0, 0, 0, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 190, 191, 192, 194, 194, 195, 196, 197, 198, 199, 200, 201, 202, 202, 204, 205, 206, 207, 208, 209, 209, 210, 211, 212, 213, 215, 215, 216, 217, 218, 219, 220, 220, 222, 223, 224, 225, 226, 227, 227, 229, 229, 230, 231, 232, 234, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 248, 0, 0, 0, 0, 0, 0, 0};FIXME Range Coding of integers:------------------------- FIXME Neighboring Blocks:===================left and top are set to the respective blocks unless they are outside of the image in which case they are set to the Null block top-left is set to the top left block unless it is outside of the image in which case it is set to the left block if this block has no larger parent block or it is at the left side of its parent block and the top right block is not outside of the image then the top right block is used for top-right else the top-left block is used Null block y, cb, cr are 128 level, ref, mx and my are 0 Motion Vector Prediction:=========================1. the motion vectors of all the neighboring blocks are scaled to compensate for the difference of reference frames scaled_mv=(mv *(256 *(current_reference+1)/(mv.reference+1))+128)> the median of the scaled left
Definition: snow.txt:386
AVCodecContext
main external API structure.
Definition: avcodec.h:445
SHOW_UBITS
#define SHOW_UBITS(name, gb, num)
Definition: get_bits.h:259
ff_table_inter_intra
const uint8_t ff_table_inter_intra[4][2]
Definition: msmpeg4data.c:1648
VLC_INIT_STATIC_TABLE
#define VLC_INIT_STATIC_TABLE(vlc_table, nb_bits, nb_codes, bits, bits_wrap, bits_size, codes, codes_wrap, codes_size, flags)
Definition: vlc.h:270
MVTable
Definition: msmpeg4data.h:41
ff_vlc_init_tables_sparse
const av_cold VLCElem * ff_vlc_init_tables_sparse(VLCInitState *state, int nb_bits, int nb_codes, const void *bits, int bits_wrap, int bits_size, const void *codes, int codes_wrap, int codes_size, const void *symbols, int symbols_wrap, int symbols_size, int flags)
Definition: vlc.c:400
AV_PICTURE_TYPE_P
@ AV_PICTURE_TYPE_P
Predicted.
Definition: avutil.h:280
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
msmpeg4_vc1_data.h
msmpeg4_decode_dc
static int msmpeg4_decode_dc(MpegEncContext *s, int n, int *dir_ptr)
Definition: msmpeg4dec.c:572
ff_h263_inter_MCBPC_vlc
VLCElem ff_h263_inter_MCBPC_vlc[]
Definition: ituh263dec.c:103
ff_msmp4_dc_vlc
const VLCElem * ff_msmp4_dc_vlc[2][2]
Definition: msmpeg4_vc1_data.c:36
VLC_INIT_RL
#define VLC_INIT_RL(rl, static_size)
Definition: rl.h:83
MV_DIR_FORWARD
#define MV_DIR_FORWARD
Definition: mpegvideo.h:263
VLC_INIT_STATE
#define VLC_INIT_STATE(_table)
Definition: vlc.h:217
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:472
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:618
ff_msmpeg4v2_decoder
const FFCodec ff_msmpeg4v2_decoder
Definition: msmpeg4dec.c:858
int32_t
int32_t
Definition: audioconvert.c:56
imgutils.h
MSMPEG4_MV_TABLES_NB_ELEMS
#define MSMPEG4_MV_TABLES_NB_ELEMS
Definition: msmpeg4data.h:62
AV_CODEC_CAP_DRAW_HORIZ_BAND
#define AV_CODEC_CAP_DRAW_HORIZ_BAND
Decoder can use draw_horiz_band callback.
Definition: codec.h:44
block
The exact code depends on how similar the blocks are and how related they are to the block
Definition: filter_design.txt:207
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
AV_CODEC_ID_MSMPEG4V3
@ AV_CODEC_ID_MSMPEG4V3
Definition: codec_id.h:68
av_image_check_size
int av_image_check_size(unsigned int w, unsigned int h, int log_offset, void *log_ctx)
Check if the given dimension of an image is valid, meaning that all bytes of the image can be address...
Definition: imgutils.c:318
H263_MV_VLC_BITS
#define H263_MV_VLC_BITS
Definition: h263dec.h:35
ff_msmpeg4_decode_init
av_cold int ff_msmpeg4_decode_init(AVCodecContext *avctx)
Definition: msmpeg4dec.c:354
MpegEncContext
MpegEncContext.
Definition: mpegvideo.h:73
ff_msmpeg4_coded_block_pred
int ff_msmpeg4_coded_block_pred(MpegEncContext *s, int n, uint8_t **coded_block_ptr)
Definition: msmpeg4.c:158
RLTable::rl_vlc
RL_VLC_ELEM * rl_vlc[32]
decoding only
Definition: rl.h:48
TEX_VLC_BITS
#define TEX_VLC_BITS
Definition: msmpeg4dec.c:44
MB_TYPE_INTRA
#define MB_TYPE_INTRA
Definition: mpegutils.h:61
INTER_MCBPC_VLC_BITS
#define INTER_MCBPC_VLC_BITS
Definition: h263dec.h:37
h263.h