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hevc_parser.c
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1 /*
2  * HEVC Annex B format parser
3  *
4  * Copyright (C) 2012 - 2013 Guillaume Martres
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg 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  * FFmpeg 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 FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include "libavutil/common.h"
24 
25 #include "parser.h"
26 #include "hevc.h"
27 #include "golomb.h"
28 
29 #define START_CODE 0x000001 ///< start_code_prefix_one_3bytes
30 
31 typedef struct HEVCParseContext {
35 
36 /**
37  * Find the end of the current frame in the bitstream.
38  * @return the position of the first byte of the next frame, or END_NOT_FOUND
39  */
41  int buf_size)
42 {
43  int i;
44  ParseContext *pc = &((HEVCParseContext *)s->priv_data)->pc;
45 
46  for (i = 0; i < buf_size; i++) {
47  int nut;
48 
49  pc->state64 = (pc->state64 << 8) | buf[i];
50 
51  if (((pc->state64 >> 3 * 8) & 0xFFFFFF) != START_CODE)
52  continue;
53 
54  nut = (pc->state64 >> 2 * 8 + 1) & 0x3F;
55  // Beginning of access unit
56  if ((nut >= NAL_VPS && nut <= NAL_AUD) || nut == NAL_SEI_PREFIX ||
57  (nut >= 41 && nut <= 44) || (nut >= 48 && nut <= 55)) {
58  if (pc->frame_start_found) {
59  pc->frame_start_found = 0;
60  return i - 5;
61  }
62  } else if (nut <= NAL_RASL_R ||
63  (nut >= NAL_BLA_W_LP && nut <= NAL_CRA_NUT)) {
64  int first_slice_segment_in_pic_flag = buf[i] >> 7;
65  if (first_slice_segment_in_pic_flag) {
66  if (!pc->frame_start_found) {
67  pc->frame_start_found = 1;
68  } else { // First slice of next frame found
69  pc->frame_start_found = 0;
70  return i - 5;
71  }
72  }
73  }
74  }
75 
76  return END_NOT_FOUND;
77 }
78 
79 /**
80  * Parse NAL units of found picture and decode some basic information.
81  *
82  * @param s parser context.
83  * @param avctx codec context.
84  * @param buf buffer with field/frame data.
85  * @param buf_size size of the buffer.
86  */
88  const uint8_t *buf, int buf_size)
89 {
90  HEVCContext *h = &((HEVCParseContext *)s->priv_data)->h;
91  GetBitContext *gb = &h->HEVClc->gb;
92  SliceHeader *sh = &h->sh;
93  const uint8_t *buf_end = buf + buf_size;
94  int state = -1, i;
95  HEVCNAL *nal;
96 
97  /* set some sane default values */
99  s->key_frame = 0;
101 
102  h->avctx = avctx;
103 
104  if (!buf_size)
105  return 0;
106 
107  if (h->nals_allocated < 1) {
108  HEVCNAL *tmp = av_realloc_array(h->nals, 1, sizeof(*tmp));
109  if (!tmp)
110  return AVERROR(ENOMEM);
111  h->nals = tmp;
112  memset(h->nals, 0, sizeof(*tmp));
113  h->nals_allocated = 1;
114  }
115 
116  nal = &h->nals[0];
117 
118  for (;;) {
119  int src_length, consumed;
120  buf = avpriv_find_start_code(buf, buf_end, &state);
121  if (--buf + 2 >= buf_end)
122  break;
123  src_length = buf_end - buf;
124 
125  h->nal_unit_type = (*buf >> 1) & 0x3f;
126  h->temporal_id = (*(buf + 1) & 0x07) - 1;
127  if (h->nal_unit_type <= NAL_CRA_NUT) {
128  // Do not walk the whole buffer just to decode slice segment header
129  if (src_length > 20)
130  src_length = 20;
131  }
132 
133  consumed = ff_hevc_extract_rbsp(h, buf, src_length, nal);
134  if (consumed < 0)
135  return consumed;
136 
137  init_get_bits8(gb, nal->data + 2, nal->size);
138  switch (h->nal_unit_type) {
139  case NAL_VPS:
141  break;
142  case NAL_SPS:
144  break;
145  case NAL_PPS:
147  break;
148  case NAL_SEI_PREFIX:
149  case NAL_SEI_SUFFIX:
151  break;
152  case NAL_TRAIL_N:
153  case NAL_TRAIL_R:
154  case NAL_TSA_N:
155  case NAL_TSA_R:
156  case NAL_STSA_N:
157  case NAL_STSA_R:
158  case NAL_RADL_N:
159  case NAL_RADL_R:
160  case NAL_RASL_N:
161  case NAL_RASL_R:
162  case NAL_BLA_W_LP:
163  case NAL_BLA_W_RADL:
164  case NAL_BLA_N_LP:
165  case NAL_IDR_W_RADL:
166  case NAL_IDR_N_LP:
167  case NAL_CRA_NUT:
170  s->field_order = h->picture_struct;
171 
172  if (IS_IRAP(h)) {
173  s->key_frame = 1;
175  }
176 
177  sh->pps_id = get_ue_golomb(gb);
178  if (sh->pps_id >= MAX_PPS_COUNT || !h->pps_list[sh->pps_id]) {
179  av_log(h->avctx, AV_LOG_ERROR, "PPS id out of range: %d\n", sh->pps_id);
180  return AVERROR_INVALIDDATA;
181  }
182  h->pps = (HEVCPPS*)h->pps_list[sh->pps_id]->data;
183 
184  if (h->pps->sps_id >= MAX_SPS_COUNT || !h->sps_list[h->pps->sps_id]) {
185  av_log(h->avctx, AV_LOG_ERROR, "SPS id out of range: %d\n", h->pps->sps_id);
186  return AVERROR_INVALIDDATA;
187  }
188  if (h->sps != (HEVCSPS*)h->sps_list[h->pps->sps_id]->data) {
189  h->sps = (HEVCSPS*)h->sps_list[h->pps->sps_id]->data;
190  h->vps = (HEVCVPS*)h->vps_list[h->sps->vps_id]->data;
191  }
192 
193  if (!sh->first_slice_in_pic_flag) {
194  int slice_address_length;
195 
198  else
200 
201  slice_address_length = av_ceil_log2_c(h->sps->ctb_width *
202  h->sps->ctb_height);
203  sh->slice_segment_addr = get_bits(gb, slice_address_length);
204  if (sh->slice_segment_addr >= h->sps->ctb_width * h->sps->ctb_height) {
205  av_log(h->avctx, AV_LOG_ERROR, "Invalid slice segment address: %u.\n",
206  sh->slice_segment_addr);
207  return AVERROR_INVALIDDATA;
208  }
209  } else
211 
213  break;
214 
215  for (i = 0; i < h->pps->num_extra_slice_header_bits; i++)
216  skip_bits(gb, 1); // slice_reserved_undetermined_flag[]
217 
218  sh->slice_type = get_ue_golomb(gb);
219  if (!(sh->slice_type == I_SLICE || sh->slice_type == P_SLICE ||
220  sh->slice_type == B_SLICE)) {
221  av_log(h->avctx, AV_LOG_ERROR, "Unknown slice type: %d.\n",
222  sh->slice_type);
223  return AVERROR_INVALIDDATA;
224  }
228 
230  sh->pic_output_flag = get_bits1(gb);
231 
233  sh->colour_plane_id = get_bits(gb, 2);
234 
235  if (!IS_IDR(h)) {
238  } else
239  s->output_picture_number = h->poc = 0;
240 
241  if (h->temporal_id == 0 &&
242  h->nal_unit_type != NAL_TRAIL_N &&
243  h->nal_unit_type != NAL_TSA_N &&
244  h->nal_unit_type != NAL_STSA_N &&
245  h->nal_unit_type != NAL_RADL_N &&
246  h->nal_unit_type != NAL_RASL_N &&
247  h->nal_unit_type != NAL_RADL_R &&
249  h->pocTid0 = h->poc;
250 
251  return 0; /* no need to evaluate the rest */
252  }
253  buf += consumed;
254  }
255  /* didn't find a picture! */
256  av_log(h->avctx, AV_LOG_ERROR, "missing picture in access unit\n");
257  return -1;
258 }
259 
261  AVCodecContext *avctx,
262  const uint8_t **poutbuf, int *poutbuf_size,
263  const uint8_t *buf, int buf_size)
264 {
265  int next;
266  ParseContext *pc = &((HEVCParseContext *)s->priv_data)->pc;
267 
269  next = buf_size;
270  } else {
271  next = hevc_find_frame_end(s, buf, buf_size);
272  if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
273  *poutbuf = NULL;
274  *poutbuf_size = 0;
275  return buf_size;
276  }
277  }
278 
279  parse_nal_units(s, avctx, buf, buf_size);
280 
281  *poutbuf = buf;
282  *poutbuf_size = buf_size;
283  return next;
284 }
285 
286 // Split after the parameter sets at the beginning of the stream if they exist.
287 static int hevc_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
288 {
289  int i;
290  uint32_t state = -1;
291  int has_ps = 0;
292 
293  for (i = 0; i < buf_size; i++) {
294  state = (state << 8) | buf[i];
295  if (((state >> 8) & 0xFFFFFF) == START_CODE) {
296  int nut = (state >> 1) & 0x3F;
297  if (nut >= NAL_VPS && nut <= NAL_PPS)
298  has_ps = 1;
299  else if (has_ps)
300  return i - 3;
301  else // no parameter set at the beginning of the stream
302  return 0;
303  }
304  }
305  return 0;
306 }
307 
309 {
310  HEVCContext *h = &((HEVCParseContext *)s->priv_data)->h;
311  h->HEVClc = av_mallocz(sizeof(HEVCLocalContext));
312  if (!h->HEVClc)
313  return AVERROR(ENOMEM);
314  h->skipped_bytes_pos_size = INT_MAX;
315 
316  return 0;
317 }
318 
320 {
321  int i;
322  HEVCContext *h = &((HEVCParseContext *)s->priv_data)->h;
323  ParseContext *pc = &((HEVCParseContext *)s->priv_data)->pc;
324 
326  av_freep(&h->HEVClc);
327  av_freep(&pc->buffer);
328 
329  for (i = 0; i < FF_ARRAY_ELEMS(h->vps_list); i++)
330  av_buffer_unref(&h->vps_list[i]);
331  for (i = 0; i < FF_ARRAY_ELEMS(h->sps_list); i++)
332  av_buffer_unref(&h->sps_list[i]);
333  for (i = 0; i < FF_ARRAY_ELEMS(h->pps_list); i++)
334  av_buffer_unref(&h->pps_list[i]);
335 
337  h->sps = NULL;
338 
339  for (i = 0; i < h->nals_allocated; i++)
340  av_freep(&h->nals[i].rbsp_buffer);
341  av_freep(&h->nals);
342  h->nals_allocated = 0;
343 }
344 
347  .priv_data_size = sizeof(HEVCParseContext),
348  .parser_init = hevc_init,
349  .parser_parse = hevc_parse,
350  .parser_close = hevc_close,
351  .split = hevc_split,
352 };