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/mem.h"
27 
29 
31  if(p) return p->next;
32  else return av_first_parser;
33 }
34 
36 {
37  parser->next = av_first_parser;
38  av_first_parser = parser;
39 }
40 
42 {
44  AVCodecParser *parser;
45  int ret;
46 
47  if(codec_id == AV_CODEC_ID_NONE)
48  return NULL;
49 
50  for(parser = av_first_parser; parser != NULL; parser = parser->next) {
51  if (parser->codec_ids[0] == codec_id ||
52  parser->codec_ids[1] == codec_id ||
53  parser->codec_ids[2] == codec_id ||
54  parser->codec_ids[3] == codec_id ||
55  parser->codec_ids[4] == codec_id)
56  goto found;
57  }
58  return NULL;
59  found:
60  s = av_mallocz(sizeof(AVCodecParserContext));
61  if (!s)
62  goto err_out;
63  s->parser = parser;
64  s->priv_data = av_mallocz(parser->priv_data_size);
65  if (!s->priv_data)
66  goto err_out;
67  s->fetch_timestamp=1;
69  if (parser->parser_init) {
70  ret = parser->parser_init(s);
71  if (ret != 0)
72  goto err_out;
73  }
74  s->key_frame = -1;
75  s->convergence_duration = 0;
76  s->dts_sync_point = INT_MIN;
77  s->dts_ref_dts_delta = INT_MIN;
78  s->pts_dts_delta = INT_MIN;
79  return s;
80 
81 err_out:
82  if (s)
83  av_freep(&s->priv_data);
84  av_free(s);
85  return NULL;
86 }
87 
88 void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove){
89  int i;
90 
91  s->dts= s->pts= AV_NOPTS_VALUE;
92  s->pos= -1;
93  s->offset= 0;
94  for(i = 0; i < AV_PARSER_PTS_NB; i++) {
95  if ( s->cur_offset + off >= s->cur_frame_offset[i]
96  && (s->frame_offset < s->cur_frame_offset[i] ||
97  (!s->frame_offset && !s->next_frame_offset)) // first field/frame
98  // check disabled since MPEG-TS does not send complete PES packets
99  && /*s->next_frame_offset + off <*/ s->cur_frame_end[i]){
100  s->dts= s->cur_frame_dts[i];
101  s->pts= s->cur_frame_pts[i];
102  s->pos= s->cur_frame_pos[i];
103  s->offset = s->next_frame_offset - s->cur_frame_offset[i];
104  if(remove)
105  s->cur_frame_offset[i]= INT64_MAX;
106  if(s->cur_offset + off < s->cur_frame_end[i])
107  break;
108  }
109  }
110 }
111 
113  AVCodecContext *avctx,
114  uint8_t **poutbuf, int *poutbuf_size,
115  const uint8_t *buf, int buf_size,
116  int64_t pts, int64_t dts,
117  int64_t pos)
118 {
119  int index, i;
121 
122  if(!(s->flags & PARSER_FLAG_FETCHED_OFFSET)) {
123  s->next_frame_offset =
124  s->cur_offset = pos;
126  }
127 
128  if (buf_size == 0) {
129  /* padding is always necessary even if EOF, so we add it here */
130  memset(dummy_buf, 0, sizeof(dummy_buf));
131  buf = dummy_buf;
132  } else if (s->cur_offset + buf_size !=
133  s->cur_frame_end[s->cur_frame_start_index]) { /* skip remainder packets */
134  /* add a new packet descriptor */
135  i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
136  s->cur_frame_start_index = i;
137  s->cur_frame_offset[i] = s->cur_offset;
138  s->cur_frame_end[i] = s->cur_offset + buf_size;
139  s->cur_frame_pts[i] = pts;
140  s->cur_frame_dts[i] = dts;
141  s->cur_frame_pos[i] = pos;
142  }
143 
144  if (s->fetch_timestamp){
145  s->fetch_timestamp=0;
146  s->last_pts = s->pts;
147  s->last_dts = s->dts;
148  s->last_pos = s->pos;
149  ff_fetch_timestamp(s, 0, 0);
150  }
151 
152  /* WARNING: the returned index can be negative */
153  index = s->parser->parser_parse(s, avctx, (const uint8_t **)poutbuf, poutbuf_size, buf, buf_size);
154  /* update the file pointer */
155  if (*poutbuf_size) {
156  /* fill the data for the current frame */
158 
159  /* offset of the next frame */
161  s->fetch_timestamp=1;
162  }
163  if (index < 0)
164  index = 0;
165  s->cur_offset += index;
166  return index;
167 }
168 
170  AVCodecContext *avctx,
171  uint8_t **poutbuf, int *poutbuf_size,
172  const uint8_t *buf, int buf_size, int keyframe){
173 
174  if(s && s->parser->split){
175  if((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)){
176  int i= s->parser->split(avctx, buf, buf_size);
177  buf += i;
178  buf_size -= i;
179  }
180  }
181 
182  /* cast to avoid warning about discarding qualifiers */
183  *poutbuf= (uint8_t *) buf;
184  *poutbuf_size= buf_size;
185  if(avctx->extradata){
186  if( (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER))
187  /*||(s->pict_type != AV_PICTURE_TYPE_I && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_NOKEY))*/
188  /*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){
189  int size= buf_size + avctx->extradata_size;
190  *poutbuf_size= size;
191  *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
192 
193  memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
194  memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
195  return 1;
196  }
197  }
198 
199  return 0;
200 }
201 
203 {
204  if(s){
205  if (s->parser->parser_close)
206  s->parser->parser_close(s);
207  av_free(s->priv_data);
208  av_free(s);
209  }
210 }
211 
212 /*****************************************************/
213 
214 int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
215 {
216  if(pc->overread){
217  av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
218  pc->overread, pc->state, next, pc->index, pc->overread_index);
219  av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
220  }
221 
222  /* Copy overread bytes from last frame into buffer. */
223  for(; pc->overread>0; pc->overread--){
224  pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
225  }
226 
227  /* flush remaining if EOF */
228  if(!*buf_size && next == END_NOT_FOUND){
229  next= 0;
230  }
231 
232  pc->last_index= pc->index;
233 
234  /* copy into buffer end return */
235  if(next == END_NOT_FOUND){
236  void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
237 
238  if(!new_buffer)
239  return AVERROR(ENOMEM);
240  pc->buffer = new_buffer;
241  memcpy(&pc->buffer[pc->index], *buf, *buf_size);
242  pc->index += *buf_size;
243  return -1;
244  }
245 
246  *buf_size=
247  pc->overread_index= pc->index + next;
248 
249  /* append to buffer */
250  if(pc->index){
251  void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
252 
253  if(!new_buffer)
254  return AVERROR(ENOMEM);
255  pc->buffer = new_buffer;
256  if (next > -FF_INPUT_BUFFER_PADDING_SIZE)
257  memcpy(&pc->buffer[pc->index], *buf,
259  pc->index = 0;
260  *buf= pc->buffer;
261  }
262 
263  /* store overread bytes */
264  for(;next < 0; next++){
265  pc->state = (pc->state<<8) | pc->buffer[pc->last_index + next];
266  pc->state64 = (pc->state64<<8) | pc->buffer[pc->last_index + next];
267  pc->overread++;
268  }
269 
270  if(pc->overread){
271  av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
272  pc->overread, pc->state, next, pc->index, pc->overread_index);
273  av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
274  }
275 
276  return 0;
277 }
278 
280 {
281  ParseContext *pc = s->priv_data;
282 
283  av_freep(&pc->buffer);
284 }
285 
286 /*************************/
287 
289  const uint8_t *buf, int buf_size)
290 {
291  int i;
292  uint32_t state= -1;
293 
294  for(i=0; i<buf_size; i++){
295  state= (state<<8) | buf[i];
296  if(state == 0x1B3 || state == 0x1B6)
297  return i-3;
298  }
299  return 0;
300 }