FFmpeg
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parser.c
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1 /*
2  * Audio and Video frame extraction
3  * Copyright (c) 2003 Fabrice Bellard
4  * Copyright (c) 2003 Michael Niedermayer
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 <string.h>
24 
25 #include "parser.h"
26 #include "libavutil/atomic.h"
27 #include "libavutil/mem.h"
28 
30 
32  if(p) return p->next;
33  else return av_first_parser;
34 }
35 
37 {
38  do {
39  parser->next = av_first_parser;
40  } while (parser->next != avpriv_atomic_ptr_cas((void * volatile *)&av_first_parser, parser->next, parser));
41 }
42 
44 {
45  AVCodecParserContext *s = NULL;
46  AVCodecParser *parser;
47  int ret;
48 
49  if(codec_id == AV_CODEC_ID_NONE)
50  return NULL;
51 
52  for(parser = av_first_parser; parser != NULL; parser = parser->next) {
53  if (parser->codec_ids[0] == codec_id ||
54  parser->codec_ids[1] == codec_id ||
55  parser->codec_ids[2] == codec_id ||
56  parser->codec_ids[3] == codec_id ||
57  parser->codec_ids[4] == codec_id)
58  goto found;
59  }
60  return NULL;
61  found:
62  s = av_mallocz(sizeof(AVCodecParserContext));
63  if (!s)
64  goto err_out;
65  s->parser = parser;
66  s->priv_data = av_mallocz(parser->priv_data_size);
67  if (!s->priv_data)
68  goto err_out;
69  s->fetch_timestamp=1;
71  if (parser->parser_init) {
72  ret = parser->parser_init(s);
73  if (ret != 0)
74  goto err_out;
75  }
76  s->key_frame = -1;
77  s->convergence_duration = 0;
78  s->dts_sync_point = INT_MIN;
79  s->dts_ref_dts_delta = INT_MIN;
80  s->pts_dts_delta = INT_MIN;
81  return s;
82 
83 err_out:
84  if (s)
85  av_freep(&s->priv_data);
86  av_free(s);
87  return NULL;
88 }
89 
90 void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove){
91  int i;
92 
93  s->dts= s->pts= AV_NOPTS_VALUE;
94  s->pos= -1;
95  s->offset= 0;
96  for(i = 0; i < AV_PARSER_PTS_NB; i++) {
97  if ( s->cur_offset + off >= s->cur_frame_offset[i]
98  && (s->frame_offset < s->cur_frame_offset[i] ||
99  (!s->frame_offset && !s->next_frame_offset)) // first field/frame
100  // check disabled since MPEG-TS does not send complete PES packets
101  && /*s->next_frame_offset + off <*/ s->cur_frame_end[i]){
102  s->dts= s->cur_frame_dts[i];
103  s->pts= s->cur_frame_pts[i];
104  s->pos= s->cur_frame_pos[i];
105  s->offset = s->next_frame_offset - s->cur_frame_offset[i];
106  if(remove)
107  s->cur_frame_offset[i]= INT64_MAX;
108  if(s->cur_offset + off < s->cur_frame_end[i])
109  break;
110  }
111  }
112 }
113 
115  AVCodecContext *avctx,
116  uint8_t **poutbuf, int *poutbuf_size,
117  const uint8_t *buf, int buf_size,
118  int64_t pts, int64_t dts,
119  int64_t pos)
120 {
121  int index, i;
123 
124  if(!(s->flags & PARSER_FLAG_FETCHED_OFFSET)) {
125  s->next_frame_offset =
126  s->cur_offset = pos;
128  }
129 
130  if (buf_size == 0) {
131  /* padding is always necessary even if EOF, so we add it here */
132  memset(dummy_buf, 0, sizeof(dummy_buf));
133  buf = dummy_buf;
134  } else if (s->cur_offset + buf_size !=
135  s->cur_frame_end[s->cur_frame_start_index]) { /* skip remainder packets */
136  /* add a new packet descriptor */
137  i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
138  s->cur_frame_start_index = i;
139  s->cur_frame_offset[i] = s->cur_offset;
140  s->cur_frame_end[i] = s->cur_offset + buf_size;
141  s->cur_frame_pts[i] = pts;
142  s->cur_frame_dts[i] = dts;
143  s->cur_frame_pos[i] = pos;
144  }
145 
146  if (s->fetch_timestamp){
147  s->fetch_timestamp=0;
148  s->last_pts = s->pts;
149  s->last_dts = s->dts;
150  s->last_pos = s->pos;
151  ff_fetch_timestamp(s, 0, 0);
152  }
153 
154  /* WARNING: the returned index can be negative */
155  index = s->parser->parser_parse(s, avctx, (const uint8_t **)poutbuf, poutbuf_size, buf, buf_size);
156  /* update the file pointer */
157  if (*poutbuf_size) {
158  /* fill the data for the current frame */
160 
161  /* offset of the next frame */
163  s->fetch_timestamp=1;
164  }
165  if (index < 0)
166  index = 0;
167  s->cur_offset += index;
168  return index;
169 }
170 
172  AVCodecContext *avctx,
173  uint8_t **poutbuf, int *poutbuf_size,
174  const uint8_t *buf, int buf_size, int keyframe){
175 
176  if(s && s->parser->split){
177  if((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)){
178  int i= s->parser->split(avctx, buf, buf_size);
179  buf += i;
180  buf_size -= i;
181  }
182  }
183 
184  /* cast to avoid warning about discarding qualifiers */
185  *poutbuf= (uint8_t *) buf;
186  *poutbuf_size= buf_size;
187  if(avctx->extradata){
188  if( (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER))
189  /*||(s->pict_type != AV_PICTURE_TYPE_I && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_NOKEY))*/
190  /*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){
191  int size= buf_size + avctx->extradata_size;
192  *poutbuf_size= size;
193  *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
194 
195  memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
196  memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
197  return 1;
198  }
199  }
200 
201  return 0;
202 }
203 
205 {
206  if(s){
207  if (s->parser->parser_close)
208  s->parser->parser_close(s);
209  av_free(s->priv_data);
210  av_free(s);
211  }
212 }
213 
214 /*****************************************************/
215 
216 int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
217 {
218  if(pc->overread){
219  av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
220  pc->overread, pc->state, next, pc->index, pc->overread_index);
221  av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
222  }
223 
224  /* Copy overread bytes from last frame into buffer. */
225  for(; pc->overread>0; pc->overread--){
226  pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
227  }
228 
229  /* flush remaining if EOF */
230  if(!*buf_size && next == END_NOT_FOUND){
231  next= 0;
232  }
233 
234  pc->last_index= pc->index;
235 
236  /* copy into buffer end return */
237  if(next == END_NOT_FOUND){
238  void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
239 
240  if(!new_buffer)
241  return AVERROR(ENOMEM);
242  pc->buffer = new_buffer;
243  memcpy(&pc->buffer[pc->index], *buf, *buf_size);
244  pc->index += *buf_size;
245  return -1;
246  }
247 
248  *buf_size=
249  pc->overread_index= pc->index + next;
250 
251  /* append to buffer */
252  if(pc->index){
253  void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
254 
255  if(!new_buffer)
256  return AVERROR(ENOMEM);
257  pc->buffer = new_buffer;
258  if (next > -FF_INPUT_BUFFER_PADDING_SIZE)
259  memcpy(&pc->buffer[pc->index], *buf,
261  pc->index = 0;
262  *buf= pc->buffer;
263  }
264 
265  /* store overread bytes */
266  for(;next < 0; next++){
267  pc->state = (pc->state<<8) | pc->buffer[pc->last_index + next];
268  pc->state64 = (pc->state64<<8) | pc->buffer[pc->last_index + next];
269  pc->overread++;
270  }
271 
272  if(pc->overread){
273  av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
274  pc->overread, pc->state, next, pc->index, pc->overread_index);
275  av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
276  }
277 
278  return 0;
279 }
280 
282 {
283  ParseContext *pc = s->priv_data;
284 
285  av_freep(&pc->buffer);
286 }
287 
288 /*************************/
289 
291  const uint8_t *buf, int buf_size)
292 {
293  int i;
294  uint32_t state= -1;
295 
296  for(i=0; i<buf_size; i++){
297  state= (state<<8) | buf[i];
298  if(state == 0x1B3 || state == 0x1B6)
299  return i-3;
300  }
301  return 0;
302 }