Libav
h263dec.c
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1 /*
2  * H.263 decoder
3  * Copyright (c) 2001 Fabrice Bellard
4  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
5  *
6  * This file is part of Libav.
7  *
8  * Libav is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * Libav is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with Libav; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
28 #include "libavutil/cpu.h"
29 #include "avcodec.h"
30 #include "error_resilience.h"
31 #include "flv.h"
32 #include "h263.h"
33 #include "h263_parser.h"
34 #include "internal.h"
35 #include "mpeg4video.h"
36 #include "mpeg4video_parser.h"
37 #include "mpegvideo.h"
38 #include "msmpeg4.h"
39 #include "thread.h"
40 
42 {
43  MpegEncContext *s = avctx->priv_data;
44  int ret;
45 
46  s->avctx = avctx;
47  s->out_format = FMT_H263;
48  s->width = avctx->coded_width;
49  s->height = avctx->coded_height;
50  s->workaround_bugs = avctx->workaround_bugs;
51 
52  // set defaults
54  s->quant_precision = 5;
56  s->low_delay = 1;
57  if (avctx->codec->id == AV_CODEC_ID_MSS2)
58  avctx->pix_fmt = AV_PIX_FMT_YUV420P;
59  else
60  avctx->pix_fmt = avctx->get_format(avctx, avctx->codec->pix_fmts);
61  s->unrestricted_mv = 1;
62 
63  /* select sub codec */
64  switch (avctx->codec->id) {
65  case AV_CODEC_ID_H263:
66  s->unrestricted_mv = 0;
68  break;
69  case AV_CODEC_ID_MPEG4:
70  break;
72  s->h263_pred = 1;
73  s->msmpeg4_version = 1;
74  break;
76  s->h263_pred = 1;
77  s->msmpeg4_version = 2;
78  break;
80  s->h263_pred = 1;
81  s->msmpeg4_version = 3;
82  break;
83  case AV_CODEC_ID_WMV1:
84  s->h263_pred = 1;
85  s->msmpeg4_version = 4;
86  break;
87  case AV_CODEC_ID_WMV2:
88  s->h263_pred = 1;
89  s->msmpeg4_version = 5;
90  break;
91  case AV_CODEC_ID_VC1:
92  case AV_CODEC_ID_WMV3:
95  case AV_CODEC_ID_MSS2:
96  s->h263_pred = 1;
97  s->msmpeg4_version = 6;
99  break;
100  case AV_CODEC_ID_H263I:
101  break;
102  case AV_CODEC_ID_FLV1:
103  s->h263_flv = 1;
104  break;
105  default:
106  av_log(avctx, AV_LOG_ERROR, "Unsupported codec %d\n",
107  avctx->codec->id);
108  return AVERROR(ENOSYS);
109  }
110  s->codec_id = avctx->codec->id;
111  avctx->hwaccel = ff_find_hwaccel(avctx);
112 
113  /* for h263, we allocate the images after having read the header */
114  if (avctx->codec->id != AV_CODEC_ID_H263 &&
115  avctx->codec->id != AV_CODEC_ID_MPEG4)
116  if ((ret = ff_MPV_common_init(s)) < 0)
117  return ret;
118 
121 
122  return 0;
123 }
124 
126 {
127  MpegEncContext *s = avctx->priv_data;
128 
130  return 0;
131 }
132 
136 static int get_consumed_bytes(MpegEncContext *s, int buf_size)
137 {
138  int pos = (get_bits_count(&s->gb) + 7) >> 3;
139 
140  if (s->divx_packed || s->avctx->hwaccel) {
141  /* We would have to scan through the whole buf to handle the weird
142  * reordering ... */
143  return buf_size;
144  } else if (s->flags & CODEC_FLAG_TRUNCATED) {
145  pos -= s->parse_context.last_index;
146  // padding is not really read so this might be -1
147  if (pos < 0)
148  pos = 0;
149  return pos;
150  } else {
151  // avoid infinite loops (maybe not needed...)
152  if (pos == 0)
153  pos = 1;
154  // oops ;)
155  if (pos + 10 > buf_size)
156  pos = buf_size;
157 
158  return pos;
159  }
160 }
161 
163 {
164  const int part_mask = s->partitioned_frame
165  ? (ER_AC_END | ER_AC_ERROR) : 0x7F;
166  const int mb_size = 16;
167  int ret;
168 
169  s->last_resync_gb = s->gb;
170  s->first_slice_line = 1;
171  s->resync_mb_x = s->mb_x;
172  s->resync_mb_y = s->mb_y;
173 
174  ff_set_qscale(s, s->qscale);
175 
176  if (s->avctx->hwaccel) {
177  const uint8_t *start = s->gb.buffer + get_bits_count(&s->gb) / 8;
178  const uint8_t *end = ff_h263_find_resync_marker(start + 1,
179  s->gb.buffer_end);
180  skip_bits_long(&s->gb, 8 * (end - start));
181  return s->avctx->hwaccel->decode_slice(s->avctx, start, end - start);
182  }
183 
184  if (s->partitioned_frame) {
185  const int qscale = s->qscale;
186 
188  if ((ret = ff_mpeg4_decode_partitions(s->avctx->priv_data)) < 0)
189  return ret;
190 
191  /* restore variables which were modified */
192  s->first_slice_line = 1;
193  s->mb_x = s->resync_mb_x;
194  s->mb_y = s->resync_mb_y;
195  ff_set_qscale(s, qscale);
196  }
197 
198  for (; s->mb_y < s->mb_height; s->mb_y++) {
199  /* per-row end of slice checks */
200  if (s->msmpeg4_version) {
201  if (s->resync_mb_y + s->slice_height == s->mb_y) {
203  s->mb_x - 1, s->mb_y, ER_MB_END);
204 
205  return 0;
206  }
207  }
208 
209  if (s->msmpeg4_version == 1) {
210  s->last_dc[0] =
211  s->last_dc[1] =
212  s->last_dc[2] = 128;
213  }
214 
216  for (; s->mb_x < s->mb_width; s->mb_x++) {
217  int ret;
218 
220 
221  if (s->resync_mb_x == s->mb_x && s->resync_mb_y + 1 == s->mb_y)
222  s->first_slice_line = 0;
223 
224  /* DCT & quantize */
225 
226  s->mv_dir = MV_DIR_FORWARD;
227  s->mv_type = MV_TYPE_16X16;
228  av_dlog(s, "%d %d %06X\n",
229  ret, get_bits_count(&s->gb), show_bits(&s->gb, 24));
230  ret = s->decode_mb(s, s->block);
231 
232  if (s->pict_type != AV_PICTURE_TYPE_B)
234 
235  if (ret < 0) {
236  const int xy = s->mb_x + s->mb_y * s->mb_stride;
237  if (ret == SLICE_END) {
238  ff_MPV_decode_mb(s, s->block);
239  if (s->loop_filter)
241 
243  s->mb_x, s->mb_y, ER_MB_END & part_mask);
244 
245  s->padding_bug_score--;
246 
247  if (++s->mb_x >= s->mb_width) {
248  s->mb_x = 0;
249  ff_mpeg_draw_horiz_band(s, s->mb_y * mb_size, mb_size);
251  s->mb_y++;
252  }
253  return 0;
254  } else if (ret == SLICE_NOEND) {
256  "Slice mismatch at MB: %d\n", xy);
258  s->mb_x + 1, s->mb_y,
259  ER_MB_END & part_mask);
260  return AVERROR_INVALIDDATA;
261  }
262  av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", xy);
264  s->mb_x, s->mb_y, ER_MB_ERROR & part_mask);
265 
266  return AVERROR_INVALIDDATA;
267  }
268 
269  ff_MPV_decode_mb(s, s->block);
270  if (s->loop_filter)
272  }
273 
274  ff_mpeg_draw_horiz_band(s, s->mb_y * mb_size, mb_size);
276 
277  s->mb_x = 0;
278  }
279 
280  assert(s->mb_x == 0 && s->mb_y == s->mb_height);
281 
282  if (s->codec_id == AV_CODEC_ID_MPEG4 &&
284  get_bits_left(&s->gb) >= 48 &&
285  show_bits(&s->gb, 24) == 0x4010 &&
286  !s->data_partitioning)
287  s->padding_bug_score += 32;
288 
289  /* try to detect the padding bug */
290  if (s->codec_id == AV_CODEC_ID_MPEG4 &&
292  get_bits_left(&s->gb) >= 0 &&
293  get_bits_left(&s->gb) < 48 &&
294  !s->data_partitioning) {
295  const int bits_count = get_bits_count(&s->gb);
296  const int bits_left = s->gb.size_in_bits - bits_count;
297 
298  if (bits_left == 0) {
299  s->padding_bug_score += 16;
300  } else if (bits_left != 1) {
301  int v = show_bits(&s->gb, 8);
302  v |= 0x7F >> (7 - (bits_count & 7));
303 
304  if (v == 0x7F && bits_left <= 8)
305  s->padding_bug_score--;
306  else if (v == 0x7F && ((get_bits_count(&s->gb) + 8) & 8) &&
307  bits_left <= 16)
308  s->padding_bug_score += 4;
309  else
310  s->padding_bug_score++;
311  }
312  }
313 
315  if (s->padding_bug_score > -2 && !s->data_partitioning)
317  else
319  }
320 
321  // handle formats which don't have unique end markers
322  if (s->msmpeg4_version || (s->workaround_bugs & FF_BUG_NO_PADDING)) { // FIXME perhaps solve this more cleanly
323  int left = get_bits_left(&s->gb);
324  int max_extra = 7;
325 
326  /* no markers in M$ crap */
328  max_extra += 17;
329 
330  /* buggy padding but the frame should still end approximately at
331  * the bitstream end */
332  if ((s->workaround_bugs & FF_BUG_NO_PADDING) &&
334  max_extra += 48;
335  else if ((s->workaround_bugs & FF_BUG_NO_PADDING))
336  max_extra += 256 * 256 * 256 * 64;
337 
338  if (left > max_extra)
340  "discarding %d junk bits at end, next would be %X\n",
341  left, show_bits(&s->gb, 24));
342  else if (left < 0)
343  av_log(s->avctx, AV_LOG_ERROR, "overreading %d bits\n", -left);
344  else
346  s->mb_x - 1, s->mb_y, ER_MB_END);
347 
348  return 0;
349  }
350 
352  "slice end not reached but screenspace end (%d left %06X, score= %d)\n",
353  get_bits_left(&s->gb), show_bits(&s->gb, 24), s->padding_bug_score);
354 
355  ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y,
356  ER_MB_END & part_mask);
357 
358  return AVERROR_INVALIDDATA;
359 }
360 
361 int ff_h263_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
362  AVPacket *avpkt)
363 {
364  const uint8_t *buf = avpkt->data;
365  int buf_size = avpkt->size;
366  MpegEncContext *s = avctx->priv_data;
367  int ret;
368  AVFrame *pict = data;
369 
370  s->flags = avctx->flags;
371  s->flags2 = avctx->flags2;
372 
373  /* no supplementary picture */
374  if (buf_size == 0) {
375  /* special case for last picture */
376  if (s->low_delay == 0 && s->next_picture_ptr) {
377  if ((ret = av_frame_ref(pict, &s->next_picture_ptr->f)) < 0)
378  return ret;
379  s->next_picture_ptr = NULL;
380 
381  *got_frame = 1;
382  }
383 
384  return 0;
385  }
386 
387  if (s->flags & CODEC_FLAG_TRUNCATED) {
388  int next;
389 
391  next = ff_mpeg4_find_frame_end(&s->parse_context, buf, buf_size);
392  } else if (CONFIG_H263_DECODER && s->codec_id == AV_CODEC_ID_H263) {
393  next = ff_h263_find_frame_end(&s->parse_context, buf, buf_size);
394  } else {
396  "this codec does not support truncated bitstreams\n");
397  return AVERROR(ENOSYS);
398  }
399 
400  if (ff_combine_frame(&s->parse_context, next, (const uint8_t **)&buf,
401  &buf_size) < 0)
402  return buf_size;
403  }
404 
405  if (s->bitstream_buffer_size && (s->divx_packed || buf_size < 20)) // divx 5.01+/xvid frame reorder
406  ret = init_get_bits8(&s->gb, s->bitstream_buffer,
408  else
409  ret = init_get_bits8(&s->gb, buf, buf_size);
410  s->bitstream_buffer_size = 0;
411 
412  if (ret < 0)
413  return ret;
414 
415  if (!s->context_initialized)
416  // we need the idct permutaton for reading a custom matrix
417  if ((ret = ff_MPV_common_init(s)) < 0)
418  return ret;
419 
420  /* We need to set current_picture_ptr before reading the header,
421  * otherwise we cannot store anyting in there */
422  if (s->current_picture_ptr == NULL || s->current_picture_ptr->f.data[0]) {
423  int i = ff_find_unused_picture(s, 0);
424  if (i < 0)
425  return i;
426  s->current_picture_ptr = &s->picture[i];
427  }
428 
429  /* let's go :-) */
430  if (CONFIG_WMV2_DECODER && s->msmpeg4_version == 5) {
432  } else if (CONFIG_MSMPEG4_DECODER && s->msmpeg4_version) {
434  } else if (CONFIG_MPEG4_DECODER && avctx->codec_id == AV_CODEC_ID_MPEG4) {
435  if (s->avctx->extradata_size && s->picture_number == 0) {
436  GetBitContext gb;
437 
438  ret = init_get_bits8(&gb, s->avctx->extradata,
439  s->avctx->extradata_size);
440  if (ret < 0)
441  return ret;
443  }
444  ret = ff_mpeg4_decode_picture_header(avctx->priv_data, &s->gb);
445  } else if (CONFIG_H263I_DECODER && s->codec_id == AV_CODEC_ID_H263I) {
447  } else if (CONFIG_FLV_DECODER && s->h263_flv) {
449  } else {
451  }
452 
453  if (ret == FRAME_SKIPPED)
454  return get_consumed_bytes(s, buf_size);
455 
456  /* skip if the header was thrashed */
457  if (ret < 0) {
458  av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
459  return ret;
460  }
461 
462  avctx->has_b_frames = !s->low_delay;
463 
464 #define SET_QPEL_FUNC(postfix1, postfix2) \
465  s->dsp.put_ ## postfix1 = ff_put_ ## postfix2; \
466  s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2; \
467  s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
468 
469  if (s->workaround_bugs & FF_BUG_STD_QPEL) {
470  SET_QPEL_FUNC(qpel_pixels_tab[0][5], qpel16_mc11_old_c)
471  SET_QPEL_FUNC(qpel_pixels_tab[0][7], qpel16_mc31_old_c)
472  SET_QPEL_FUNC(qpel_pixels_tab[0][9], qpel16_mc12_old_c)
473  SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
474  SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
475  SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
476 
477  SET_QPEL_FUNC(qpel_pixels_tab[1][5], qpel8_mc11_old_c)
478  SET_QPEL_FUNC(qpel_pixels_tab[1][7], qpel8_mc31_old_c)
479  SET_QPEL_FUNC(qpel_pixels_tab[1][9], qpel8_mc12_old_c)
480  SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
481  SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
482  SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
483  }
484 
485  /* After H263 & mpeg4 header decode we have the height, width,
486  * and other parameters. So then we could init the picture.
487  * FIXME: By the way H263 decoder is evolving it should have
488  * an H263EncContext */
489  if (s->width != avctx->coded_width ||
490  s->height != avctx->coded_height ||
491  s->context_reinit) {
492  /* H.263 could change picture size any time */
493  s->context_reinit = 0;
494 
495  ret = ff_set_dimensions(avctx, s->width, s->height);
496  if (ret < 0)
497  return ret;
498 
499  if ((ret = ff_MPV_common_frame_size_change(s)))
500  return ret;
501  }
502 
503  if (s->codec_id == AV_CODEC_ID_H263 ||
504  s->codec_id == AV_CODEC_ID_H263P ||
507 
508  // for skipping the frame
511 
512  /* skip B-frames if we don't have reference frames */
513  if (s->last_picture_ptr == NULL &&
514  (s->pict_type == AV_PICTURE_TYPE_B || s->droppable))
515  return get_consumed_bytes(s, buf_size);
516  if ((avctx->skip_frame >= AVDISCARD_NONREF &&
517  s->pict_type == AV_PICTURE_TYPE_B) ||
518  (avctx->skip_frame >= AVDISCARD_NONKEY &&
519  s->pict_type != AV_PICTURE_TYPE_I) ||
520  avctx->skip_frame >= AVDISCARD_ALL)
521  return get_consumed_bytes(s, buf_size);
522 
523  if (s->next_p_frame_damaged) {
524  if (s->pict_type == AV_PICTURE_TYPE_B)
525  return get_consumed_bytes(s, buf_size);
526  else
527  s->next_p_frame_damaged = 0;
528  }
529 
530  if ((!s->no_rounding) || s->pict_type == AV_PICTURE_TYPE_B) {
533  } else {
536  }
537 
538  if ((ret = ff_MPV_frame_start(s, avctx)) < 0)
539  return ret;
540 
541  if (!s->divx_packed && !avctx->hwaccel)
542  ff_thread_finish_setup(avctx);
543 
544  if (avctx->hwaccel) {
545  ret = avctx->hwaccel->start_frame(avctx, s->gb.buffer,
546  s->gb.buffer_end - s->gb.buffer);
547  if (ret < 0 )
548  return ret;
549  }
550 
552 
553  /* the second part of the wmv2 header contains the MB skip bits which
554  * are stored in current_picture->mb_type which is not available before
555  * ff_MPV_frame_start() */
556  if (CONFIG_WMV2_DECODER && s->msmpeg4_version == 5) {
558  if (ret < 0)
559  return ret;
560  if (ret == 1)
561  goto intrax8_decoded;
562  }
563 
564  /* decode each macroblock */
565  s->mb_x = 0;
566  s->mb_y = 0;
567 
568  ret = decode_slice(s);
569  while (s->mb_y < s->mb_height) {
570  if (s->msmpeg4_version) {
571  if (s->slice_height == 0 || s->mb_x != 0 ||
572  (s->mb_y % s->slice_height) != 0 || get_bits_left(&s->gb) < 0)
573  break;
574  } else {
575  int prev_x = s->mb_x, prev_y = s->mb_y;
576  if (ff_h263_resync(s) < 0)
577  break;
578  if (prev_y * s->mb_width + prev_x < s->mb_y * s->mb_width + s->mb_x)
579  s->er.error_occurred = 1;
580  }
581 
582  if (s->msmpeg4_version < 4 && s->h263_pred)
584 
585  if (decode_slice(s) < 0)
586  ret = AVERROR_INVALIDDATA;
587  }
588 
589  if (s->msmpeg4_version && s->msmpeg4_version < 4 &&
591  if (!CONFIG_MSMPEG4_DECODER ||
592  ff_msmpeg4_decode_ext_header(s, buf_size) < 0)
594 
595  assert(s->bitstream_buffer_size == 0);
596 
598  ff_mpeg4_frame_end(avctx, buf, buf_size);
599 
600 intrax8_decoded:
601  ff_er_frame_end(&s->er);
602 
603  if (avctx->hwaccel) {
604  ret = avctx->hwaccel->end_frame(avctx);
605  if (ret < 0)
606  return ret;
607  }
608 
609  ff_MPV_frame_end(s);
610 
611  if (!s->divx_packed && avctx->hwaccel)
612  ff_thread_finish_setup(avctx);
613 
614  assert(s->current_picture.f.pict_type ==
616  assert(s->current_picture.f.pict_type == s->pict_type);
617  if (s->pict_type == AV_PICTURE_TYPE_B || s->low_delay) {
618  if ((ret = av_frame_ref(pict, &s->current_picture_ptr->f)) < 0)
619  return ret;
621  } else if (s->last_picture_ptr != NULL) {
622  if ((ret = av_frame_ref(pict, &s->last_picture_ptr->f)) < 0)
623  return ret;
625  }
626 
627  if (s->last_picture_ptr || s->low_delay)
628  *got_frame = 1;
629 
630  if (ret && (avctx->err_recognition & AV_EF_EXPLODE))
631  return ret;
632  else
633  return get_consumed_bytes(s, buf_size);
634 }
635 
637 #if CONFIG_VAAPI
639 #endif
640 #if CONFIG_VDPAU
642 #endif
645 };
646 
648  .name = "h263",
649  .long_name = NULL_IF_CONFIG_SMALL("H.263 / H.263-1996, H.263+ / H.263-1998 / H.263 version 2"),
650  .type = AVMEDIA_TYPE_VIDEO,
651  .id = AV_CODEC_ID_H263,
652  .priv_data_size = sizeof(MpegEncContext),
656  .capabilities = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 |
658  .flush = ff_mpeg_flush,
660 };