cavsdec.c
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1 /*
2  * Chinese AVS video (AVS1-P2, JiZhun profile) decoder.
3  * Copyright (c) 2006 Stefan Gehrer <stefan.gehrer@gmx.de>
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
28 #include "avcodec.h"
29 #include "get_bits.h"
30 #include "golomb.h"
31 #include "cavs.h"
32 
33 static const uint8_t mv_scan[4] = {
36 };
37 
38 static const uint8_t cbp_tab[64][2] = {
39  {63, 0},{15,15},{31,63},{47,31},{ 0,16},{14,32},{13,47},{11,13},
40  { 7,14},{ 5,11},{10,12},{ 8, 5},{12,10},{61, 7},{ 4,48},{55, 3},
41  { 1, 2},{ 2, 8},{59, 4},{ 3, 1},{62,61},{ 9,55},{ 6,59},{29,62},
42  {45,29},{51,27},{23,23},{39,19},{27,30},{46,28},{53, 9},{30, 6},
43  {43,60},{37,21},{60,44},{16,26},{21,51},{28,35},{19,18},{35,20},
44  {42,24},{26,53},{44,17},{32,37},{58,39},{24,45},{20,58},{17,43},
45  {18,42},{48,46},{22,36},{33,33},{25,34},{49,40},{40,52},{36,49},
46  {34,50},{50,56},{52,25},{54,22},{41,54},{56,57},{38,41},{57,38}
47 };
48 
49 /*****************************************************************************
50  *
51  * motion vector prediction
52  *
53  ****************************************************************************/
54 
55 static inline void store_mvs(AVSContext *h) {
56  h->col_mv[h->mbidx*4 + 0] = h->mv[MV_FWD_X0];
57  h->col_mv[h->mbidx*4 + 1] = h->mv[MV_FWD_X1];
58  h->col_mv[h->mbidx*4 + 2] = h->mv[MV_FWD_X2];
59  h->col_mv[h->mbidx*4 + 3] = h->mv[MV_FWD_X3];
60 }
61 
62 static inline void mv_pred_direct(AVSContext *h, cavs_vector *pmv_fw,
63  cavs_vector *col_mv) {
64  cavs_vector *pmv_bw = pmv_fw + MV_BWD_OFFS;
65  int den = h->direct_den[col_mv->ref];
66  int m = col_mv->x >> 31;
67 
68  pmv_fw->dist = h->dist[1];
69  pmv_bw->dist = h->dist[0];
70  pmv_fw->ref = 1;
71  pmv_bw->ref = 0;
72  /* scale the co-located motion vector according to its temporal span */
73  pmv_fw->x = (((den+(den*col_mv->x*pmv_fw->dist^m)-m-1)>>14)^m)-m;
74  pmv_bw->x = m-(((den+(den*col_mv->x*pmv_bw->dist^m)-m-1)>>14)^m);
75  m = col_mv->y >> 31;
76  pmv_fw->y = (((den+(den*col_mv->y*pmv_fw->dist^m)-m-1)>>14)^m)-m;
77  pmv_bw->y = m-(((den+(den*col_mv->y*pmv_bw->dist^m)-m-1)>>14)^m);
78 }
79 
80 static inline void mv_pred_sym(AVSContext *h, cavs_vector *src, enum cavs_block size) {
81  cavs_vector *dst = src + MV_BWD_OFFS;
82 
83  /* backward mv is the scaled and negated forward mv */
84  dst->x = -((src->x * h->sym_factor + 256) >> 9);
85  dst->y = -((src->y * h->sym_factor + 256) >> 9);
86  dst->ref = 0;
87  dst->dist = h->dist[0];
88  set_mvs(dst, size);
89 }
90 
91 /*****************************************************************************
92  *
93  * residual data decoding
94  *
95  ****************************************************************************/
96 
98 static inline int get_ue_code(GetBitContext *gb, int order) {
99  if(order) {
100  int ret = get_ue_golomb(gb) << order;
101  return ret + get_bits(gb,order);
102  }
103  return get_ue_golomb(gb);
104 }
105 
116  const struct dec_2dvlc *r, int esc_golomb_order,
117  int qp, uint8_t *dst, int stride) {
118  int i, level_code, esc_code, level, run, mask;
119  DCTELEM level_buf[65];
120  uint8_t run_buf[65];
121  DCTELEM *block = h->block;
122 
123  for(i=0;i<65;i++) {
124  level_code = get_ue_code(gb,r->golomb_order);
125  if(level_code >= ESCAPE_CODE) {
126  run = ((level_code - ESCAPE_CODE) >> 1) + 1;
127  esc_code = get_ue_code(gb,esc_golomb_order);
128  level = esc_code + (run > r->max_run ? 1 : r->level_add[run]);
129  while(level > r->inc_limit)
130  r++;
131  mask = -(level_code & 1);
132  level = (level^mask) - mask;
133  } else if (level_code >= 0) {
134  level = r->rltab[level_code][0];
135  if(!level) //end of block signal
136  break;
137  run = r->rltab[level_code][1];
138  r += r->rltab[level_code][2];
139  } else {
140  break;
141  }
142  level_buf[i] = level;
143  run_buf[i] = run;
144  }
145  if(dequant(h,level_buf, run_buf, block, ff_cavs_dequant_mul[qp],
146  ff_cavs_dequant_shift[qp], i))
147  return -1;
148  h->cdsp.cavs_idct8_add(dst,block,stride);
149  h->s.dsp.clear_block(block);
150  return 0;
151 }
152 
153 
154 static inline void decode_residual_chroma(AVSContext *h) {
155  if(h->cbp & (1<<4))
157  ff_cavs_chroma_qp[h->qp],h->cu,h->c_stride);
158  if(h->cbp & (1<<5))
160  ff_cavs_chroma_qp[h->qp],h->cv,h->c_stride);
161 }
162 
163 static inline int decode_residual_inter(AVSContext *h) {
164  int block;
165 
166  /* get coded block pattern */
167  int cbp= get_ue_golomb(&h->s.gb);
168  if(cbp > 63 || cbp < 0){
169  av_log(h->s.avctx, AV_LOG_ERROR, "illegal inter cbp %d\n", cbp);
170  return -1;
171  }
172  h->cbp = cbp_tab[cbp][1];
173 
174  /* get quantizer */
175  if(h->cbp && !h->qp_fixed)
176  h->qp = (h->qp + get_se_golomb(&h->s.gb)) & 63;
177  for(block=0;block<4;block++)
178  if(h->cbp & (1<<block))
180  h->cy + h->luma_scan[block], h->l_stride);
182 
183  return 0;
184 }
185 
186 /*****************************************************************************
187  *
188  * macroblock level
189  *
190  ****************************************************************************/
191 
192 static int decode_mb_i(AVSContext *h, int cbp_code) {
193  GetBitContext *gb = &h->s.gb;
194  unsigned pred_mode_uv;
195  int block;
196  uint8_t top[18];
197  uint8_t *left = NULL;
198  uint8_t *d;
199 
200  ff_cavs_init_mb(h);
201 
202  /* get intra prediction modes from stream */
203  for(block=0;block<4;block++) {
204  int nA,nB,predpred;
205  int pos = ff_cavs_scan3x3[block];
206 
207  nA = h->pred_mode_Y[pos-1];
208  nB = h->pred_mode_Y[pos-3];
209  predpred = FFMIN(nA,nB);
210  if(predpred == NOT_AVAIL) // if either is not available
211  predpred = INTRA_L_LP;
212  if(!get_bits1(gb)){
213  int rem_mode= get_bits(gb, 2);
214  predpred = rem_mode + (rem_mode >= predpred);
215  }
216  h->pred_mode_Y[pos] = predpred;
217  }
218  pred_mode_uv = get_ue_golomb(gb);
219  if(pred_mode_uv > 6) {
220  av_log(h->s.avctx, AV_LOG_ERROR, "illegal intra chroma pred mode\n");
221  return -1;
222  }
223  ff_cavs_modify_mb_i(h, &pred_mode_uv);
224 
225  /* get coded block pattern */
226  if(h->pic_type == AV_PICTURE_TYPE_I)
227  cbp_code = get_ue_golomb(gb);
228  if(cbp_code > 63 || cbp_code < 0 ){
229  av_log(h->s.avctx, AV_LOG_ERROR, "illegal intra cbp\n");
230  return -1;
231  }
232  h->cbp = cbp_tab[cbp_code][0];
233  if(h->cbp && !h->qp_fixed)
234  h->qp = (h->qp + get_se_golomb(gb)) & 63; //qp_delta
235 
236  /* luma intra prediction interleaved with residual decode/transform/add */
237  for(block=0;block<4;block++) {
238  d = h->cy + h->luma_scan[block];
239  ff_cavs_load_intra_pred_luma(h, top, &left, block);
241  (d, top, left, h->l_stride);
242  if(h->cbp & (1<<block))
244  }
245 
246  /* chroma intra prediction */
248  h->intra_pred_c[pred_mode_uv](h->cu, &h->top_border_u[h->mbx*10],
249  h->left_border_u, h->c_stride);
250  h->intra_pred_c[pred_mode_uv](h->cv, &h->top_border_v[h->mbx*10],
251  h->left_border_v, h->c_stride);
252 
255  set_mv_intra(h);
256  return 0;
257 }
258 
259 static void decode_mb_p(AVSContext *h, enum cavs_mb mb_type) {
260  GetBitContext *gb = &h->s.gb;
261  int ref[4];
262 
263  ff_cavs_init_mb(h);
264  switch(mb_type) {
265  case P_SKIP:
267  break;
268  case P_16X16:
269  ref[0] = h->ref_flag ? 0 : get_bits1(gb);
271  break;
272  case P_16X8:
273  ref[0] = h->ref_flag ? 0 : get_bits1(gb);
274  ref[2] = h->ref_flag ? 0 : get_bits1(gb);
277  break;
278  case P_8X16:
279  ref[0] = h->ref_flag ? 0 : get_bits1(gb);
280  ref[1] = h->ref_flag ? 0 : get_bits1(gb);
283  break;
284  case P_8X8:
285  ref[0] = h->ref_flag ? 0 : get_bits1(gb);
286  ref[1] = h->ref_flag ? 0 : get_bits1(gb);
287  ref[2] = h->ref_flag ? 0 : get_bits1(gb);
288  ref[3] = h->ref_flag ? 0 : get_bits1(gb);
293  }
294  ff_cavs_inter(h, mb_type);
296  store_mvs(h);
297  if(mb_type != P_SKIP)
299  ff_cavs_filter(h,mb_type);
300  h->col_type_base[h->mbidx] = mb_type;
301 }
302 
303 static void decode_mb_b(AVSContext *h, enum cavs_mb mb_type) {
304  int block;
305  enum cavs_sub_mb sub_type[4];
306  int flags;
307 
308  ff_cavs_init_mb(h);
309 
310  /* reset all MVs */
312  set_mvs(&h->mv[MV_FWD_X0], BLK_16X16);
314  set_mvs(&h->mv[MV_BWD_X0], BLK_16X16);
315  switch(mb_type) {
316  case B_SKIP:
317  case B_DIRECT:
318  if(!h->col_type_base[h->mbidx]) {
319  /* intra MB at co-location, do in-plane prediction */
322  } else
323  /* direct prediction from co-located P MB, block-wise */
324  for(block=0;block<4;block++)
325  mv_pred_direct(h,&h->mv[mv_scan[block]],
326  &h->col_mv[h->mbidx*4 + block]);
327  break;
328  case B_FWD_16X16:
330  break;
331  case B_SYM_16X16:
333  mv_pred_sym(h, &h->mv[MV_FWD_X0], BLK_16X16);
334  break;
335  case B_BWD_16X16:
337  break;
338  case B_8X8:
339  for(block=0;block<4;block++)
340  sub_type[block] = get_bits(&h->s.gb,2);
341  for(block=0;block<4;block++) {
342  switch(sub_type[block]) {
343  case B_SUB_DIRECT:
344  if(!h->col_type_base[h->mbidx]) {
345  /* intra MB at co-location, do in-plane prediction */
346  ff_cavs_mv(h, mv_scan[block], mv_scan[block]-3,
347  MV_PRED_BSKIP, BLK_8X8, 1);
348  ff_cavs_mv(h, mv_scan[block]+MV_BWD_OFFS,
349  mv_scan[block]-3+MV_BWD_OFFS,
350  MV_PRED_BSKIP, BLK_8X8, 0);
351  } else
352  mv_pred_direct(h,&h->mv[mv_scan[block]],
353  &h->col_mv[h->mbidx*4 + block]);
354  break;
355  case B_SUB_FWD:
356  ff_cavs_mv(h, mv_scan[block], mv_scan[block]-3,
357  MV_PRED_MEDIAN, BLK_8X8, 1);
358  break;
359  case B_SUB_SYM:
360  ff_cavs_mv(h, mv_scan[block], mv_scan[block]-3,
361  MV_PRED_MEDIAN, BLK_8X8, 1);
362  mv_pred_sym(h, &h->mv[mv_scan[block]], BLK_8X8);
363  break;
364  }
365  }
366  for(block=0;block<4;block++) {
367  if(sub_type[block] == B_SUB_BWD)
368  ff_cavs_mv(h, mv_scan[block]+MV_BWD_OFFS,
369  mv_scan[block]+MV_BWD_OFFS-3,
370  MV_PRED_MEDIAN, BLK_8X8, 0);
371  }
372  break;
373  default:
374  assert((mb_type > B_SYM_16X16) && (mb_type < B_8X8));
375  flags = ff_cavs_partition_flags[mb_type];
376  if(mb_type & 1) { /* 16x8 macroblock types */
377  if(flags & FWD0)
379  if(flags & SYM0)
380  mv_pred_sym(h, &h->mv[MV_FWD_X0], BLK_16X8);
381  if(flags & FWD1)
383  if(flags & SYM1)
384  mv_pred_sym(h, &h->mv[MV_FWD_X2], BLK_16X8);
385  if(flags & BWD0)
387  if(flags & BWD1)
389  } else { /* 8x16 macroblock types */
390  if(flags & FWD0)
392  if(flags & SYM0)
393  mv_pred_sym(h, &h->mv[MV_FWD_X0], BLK_8X16);
394  if(flags & FWD1)
396  if(flags & SYM1)
397  mv_pred_sym(h, &h->mv[MV_FWD_X1], BLK_8X16);
398  if(flags & BWD0)
400  if(flags & BWD1)
402  }
403  }
404  ff_cavs_inter(h, mb_type);
406  if(mb_type != B_SKIP)
408  ff_cavs_filter(h,mb_type);
409 }
410 
411 /*****************************************************************************
412  *
413  * slice level
414  *
415  ****************************************************************************/
416 
417 static inline int decode_slice_header(AVSContext *h, GetBitContext *gb) {
418  if(h->stc > 0xAF)
419  av_log(h->s.avctx, AV_LOG_ERROR, "unexpected start code 0x%02x\n", h->stc);
420  h->mby = h->stc;
421  h->mbidx = h->mby*h->mb_width;
422 
423  /* mark top macroblocks as unavailable */
424  h->flags &= ~(B_AVAIL|C_AVAIL);
425  if((h->mby == 0) && (!h->qp_fixed)){
426  h->qp_fixed = get_bits1(gb);
427  h->qp = get_bits(gb,6);
428  }
429  /* inter frame or second slice can have weighting params */
430  if((h->pic_type != AV_PICTURE_TYPE_I) || (!h->pic_structure && h->mby >= h->mb_width/2))
431  if(get_bits1(gb)) { //slice_weighting_flag
433  "weighted prediction not yet supported\n");
434  }
435  return 0;
436 }
437 
438 static inline int check_for_slice(AVSContext *h) {
439  GetBitContext *gb = &h->s.gb;
440  int align;
441 
442  if(h->mbx)
443  return 0;
444  align = (-get_bits_count(gb)) & 7;
445  /* check for stuffing byte */
446  if(!align && (show_bits(gb,8) == 0x80))
447  align = 8;
448  if((show_bits_long(gb,24+align) & 0xFFFFFF) == 0x000001) {
449  skip_bits_long(gb,24+align);
450  h->stc = get_bits(gb,8);
451  if (h->stc >= h->mb_height)
452  return 0;
453  decode_slice_header(h,gb);
454  return 1;
455  }
456  return 0;
457 }
458 
459 /*****************************************************************************
460  *
461  * frame level
462  *
463  ****************************************************************************/
464 
465 static int decode_pic(AVSContext *h) {
466  MpegEncContext *s = &h->s;
467  int skip_count = -1;
468  enum cavs_mb mb_type;
469 
470  if (!h->top_qp) {
471  av_log(h, AV_LOG_ERROR, "No sequence header decoded yet\n");
472  return AVERROR_INVALIDDATA;
473  }
474 
475  if (!s->context_initialized) {
477  if (MPV_common_init(s) < 0)
478  return -1;
480  }
481  skip_bits(&s->gb,16);//bbv_dwlay
482  if(h->stc == PIC_PB_START_CODE) {
483  h->pic_type = get_bits(&s->gb,2) + AV_PICTURE_TYPE_I;
484  if(h->pic_type > AV_PICTURE_TYPE_B) {
485  av_log(s->avctx, AV_LOG_ERROR, "illegal picture type\n");
486  return -1;
487  }
488  /* make sure we have the reference frames we need */
489  if(!h->DPB[0].f.data[0] ||
490  (!h->DPB[1].f.data[0] && h->pic_type == AV_PICTURE_TYPE_B))
491  return -1;
492  } else {
494  if(get_bits1(&s->gb))
495  skip_bits(&s->gb,24);//time_code
496  /* old sample clips were all progressive and no low_delay,
497  bump stream revision if detected otherwise */
498  if (s->low_delay || !(show_bits(&s->gb,9) & 1))
499  h->stream_revision = 1;
500  /* similarly test top_field_first and repeat_first_field */
501  else if(show_bits(&s->gb,11) & 3)
502  h->stream_revision = 1;
503  if(h->stream_revision > 0)
504  skip_bits(&s->gb,1); //marker_bit
505  }
506  /* release last B frame */
507  if(h->picture.f.data[0])
508  s->avctx->release_buffer(s->avctx, (AVFrame *)&h->picture);
509 
510  s->avctx->get_buffer(s->avctx, (AVFrame *)&h->picture);
511  ff_cavs_init_pic(h);
512  h->picture.poc = get_bits(&s->gb,8)*2;
513 
514  /* get temporal distances and MV scaling factors */
515  if(h->pic_type != AV_PICTURE_TYPE_B) {
516  h->dist[0] = (h->picture.poc - h->DPB[0].poc + 512) % 512;
517  } else {
518  h->dist[0] = (h->DPB[0].poc - h->picture.poc + 512) % 512;
519  }
520  h->dist[1] = (h->picture.poc - h->DPB[1].poc + 512) % 512;
521  h->scale_den[0] = h->dist[0] ? 512/h->dist[0] : 0;
522  h->scale_den[1] = h->dist[1] ? 512/h->dist[1] : 0;
523  if(h->pic_type == AV_PICTURE_TYPE_B) {
524  h->sym_factor = h->dist[0]*h->scale_den[1];
525  } else {
526  h->direct_den[0] = h->dist[0] ? 16384/h->dist[0] : 0;
527  h->direct_den[1] = h->dist[1] ? 16384/h->dist[1] : 0;
528  }
529 
530  if(s->low_delay)
531  get_ue_golomb(&s->gb); //bbv_check_times
532  h->progressive = get_bits1(&s->gb);
533  h->pic_structure = 1;
534  if(!h->progressive)
535  h->pic_structure = get_bits1(&s->gb);
536  if(!h->pic_structure && h->stc == PIC_PB_START_CODE)
537  skip_bits1(&s->gb); //advanced_pred_mode_disable
538  skip_bits1(&s->gb); //top_field_first
539  skip_bits1(&s->gb); //repeat_first_field
540  h->qp_fixed = get_bits1(&s->gb);
541  h->qp = get_bits(&s->gb,6);
542  if(h->pic_type == AV_PICTURE_TYPE_I) {
543  if(!h->progressive && !h->pic_structure)
544  skip_bits1(&s->gb);//what is this?
545  skip_bits(&s->gb,4); //reserved bits
546  } else {
547  if(!(h->pic_type == AV_PICTURE_TYPE_B && h->pic_structure == 1))
548  h->ref_flag = get_bits1(&s->gb);
549  skip_bits(&s->gb,4); //reserved bits
550  h->skip_mode_flag = get_bits1(&s->gb);
551  }
552  h->loop_filter_disable = get_bits1(&s->gb);
553  if(!h->loop_filter_disable && get_bits1(&s->gb)) {
554  h->alpha_offset = get_se_golomb(&s->gb);
555  h->beta_offset = get_se_golomb(&s->gb);
556  } else {
557  h->alpha_offset = h->beta_offset = 0;
558  }
559  if(h->pic_type == AV_PICTURE_TYPE_I) {
560  do {
561  check_for_slice(h);
562  decode_mb_i(h, 0);
563  } while(ff_cavs_next_mb(h));
564  } else if(h->pic_type == AV_PICTURE_TYPE_P) {
565  do {
566  if(check_for_slice(h))
567  skip_count = -1;
568  if(h->skip_mode_flag && (skip_count < 0))
569  skip_count = get_ue_golomb(&s->gb);
570  if(h->skip_mode_flag && skip_count--) {
571  decode_mb_p(h,P_SKIP);
572  } else {
573  mb_type = get_ue_golomb(&s->gb) + P_SKIP + h->skip_mode_flag;
574  if(mb_type > P_8X8)
575  decode_mb_i(h, mb_type - P_8X8 - 1);
576  else
577  decode_mb_p(h,mb_type);
578  }
579  } while(ff_cavs_next_mb(h));
580  } else { /* AV_PICTURE_TYPE_B */
581  do {
582  if(check_for_slice(h))
583  skip_count = -1;
584  if(h->skip_mode_flag && (skip_count < 0))
585  skip_count = get_ue_golomb(&s->gb);
586  if(h->skip_mode_flag && skip_count--) {
587  decode_mb_b(h,B_SKIP);
588  } else {
589  mb_type = get_ue_golomb(&s->gb) + B_SKIP + h->skip_mode_flag;
590  if(mb_type > B_8X8)
591  decode_mb_i(h, mb_type - B_8X8 - 1);
592  else
593  decode_mb_b(h,mb_type);
594  }
595  } while(ff_cavs_next_mb(h));
596  }
597  if(h->pic_type != AV_PICTURE_TYPE_B) {
598  if(h->DPB[1].f.data[0])
599  s->avctx->release_buffer(s->avctx, (AVFrame *)&h->DPB[1]);
600  h->DPB[1] = h->DPB[0];
601  h->DPB[0] = h->picture;
602  memset(&h->picture,0,sizeof(Picture));
603  }
604  return 0;
605 }
606 
607 /*****************************************************************************
608  *
609  * headers and interface
610  *
611  ****************************************************************************/
612 
614  MpegEncContext *s = &h->s;
615  int frame_rate_code;
616  int width, height;
617 
618  h->profile = get_bits(&s->gb,8);
619  h->level = get_bits(&s->gb,8);
620  skip_bits1(&s->gb); //progressive sequence
621 
622  width = get_bits(&s->gb, 14);
623  height = get_bits(&s->gb, 14);
624  if ((s->width || s->height) && (s->width != width || s->height != height)) {
625  av_log_missing_feature(s, "Width/height changing in CAVS is", 0);
626  return AVERROR_PATCHWELCOME;
627  }
628  s->width = width;
629  s->height = height;
630 
631  skip_bits(&s->gb,2); //chroma format
632  skip_bits(&s->gb,3); //sample_precision
633  h->aspect_ratio = get_bits(&s->gb,4);
634  frame_rate_code = get_bits(&s->gb,4);
635  skip_bits(&s->gb,18);//bit_rate_lower
636  skip_bits1(&s->gb); //marker_bit
637  skip_bits(&s->gb,12);//bit_rate_upper
638  s->low_delay = get_bits1(&s->gb);
639  h->mb_width = (s->width + 15) >> 4;
640  h->mb_height = (s->height + 15) >> 4;
641  h->s.avctx->time_base.den = avpriv_frame_rate_tab[frame_rate_code].num;
642  h->s.avctx->time_base.num = avpriv_frame_rate_tab[frame_rate_code].den;
643  h->s.avctx->width = s->width;
644  h->s.avctx->height = s->height;
645  if(!h->top_qp)
647  return 0;
648 }
649 
650 static void cavs_flush(AVCodecContext * avctx) {
651  AVSContext *h = avctx->priv_data;
652  h->got_keyframe = 0;
653 }
654 
655 static int cavs_decode_frame(AVCodecContext * avctx,void *data, int *data_size,
656  AVPacket *avpkt) {
657  const uint8_t *buf = avpkt->data;
658  int buf_size = avpkt->size;
659  AVSContext *h = avctx->priv_data;
660  MpegEncContext *s = &h->s;
661  int input_size;
662  const uint8_t *buf_end;
663  const uint8_t *buf_ptr;
664  AVFrame *picture = data;
665  uint32_t stc = -1;
666 
667  s->avctx = avctx;
668 
669  if (buf_size == 0) {
670  if (!s->low_delay && h->DPB[0].f.data[0]) {
671  *data_size = sizeof(AVPicture);
672  *picture = h->DPB[0].f;
673  memset(&h->DPB[0], 0, sizeof(h->DPB[0]));
674  }
675  return 0;
676  }
677 
678  buf_ptr = buf;
679  buf_end = buf + buf_size;
680  for(;;) {
681  buf_ptr = avpriv_mpv_find_start_code(buf_ptr,buf_end, &stc);
682  if((stc & 0xFFFFFE00) || buf_ptr == buf_end)
683  return FFMAX(0, buf_ptr - buf - s->parse_context.last_index);
684  input_size = (buf_end - buf_ptr)*8;
685  switch(stc) {
686  case CAVS_START_CODE:
687  init_get_bits(&s->gb, buf_ptr, input_size);
689  break;
690  case PIC_I_START_CODE:
691  if(!h->got_keyframe) {
692  if(h->DPB[0].f.data[0])
693  avctx->release_buffer(avctx, (AVFrame *)&h->DPB[0]);
694  if(h->DPB[1].f.data[0])
695  avctx->release_buffer(avctx, (AVFrame *)&h->DPB[1]);
696  h->got_keyframe = 1;
697  }
698  case PIC_PB_START_CODE:
699  *data_size = 0;
700  if(!h->got_keyframe)
701  break;
702  init_get_bits(&s->gb, buf_ptr, input_size);
703  h->stc = stc;
704  if(decode_pic(h))
705  break;
706  *data_size = sizeof(AVPicture);
707  if(h->pic_type != AV_PICTURE_TYPE_B) {
708  if(h->DPB[1].f.data[0]) {
709  *picture = *(AVFrame *) &h->DPB[1];
710  } else {
711  *data_size = 0;
712  }
713  } else
714  *picture = *(AVFrame *) &h->picture;
715  break;
716  case EXT_START_CODE:
717  //mpeg_decode_extension(avctx,buf_ptr, input_size);
718  break;
719  case USER_START_CODE:
720  //mpeg_decode_user_data(avctx,buf_ptr, input_size);
721  break;
722  default:
723  if (stc <= SLICE_MAX_START_CODE) {
724  init_get_bits(&s->gb, buf_ptr, input_size);
725  decode_slice_header(h, &s->gb);
726  }
727  break;
728  }
729  }
730 }
731 
733  .name = "cavs",
734  .type = AVMEDIA_TYPE_VIDEO,
735  .id = CODEC_ID_CAVS,
736  .priv_data_size = sizeof(AVSContext),
737  .init = ff_cavs_init,
738  .close = ff_cavs_end,
740  .capabilities = CODEC_CAP_DR1 | CODEC_CAP_DELAY,
741  .flush= cavs_flush,
742  .long_name= NULL_IF_CONFIG_SMALL("Chinese AVS video (AVS1-P2, JiZhun profile)"),
743 };