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 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 
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  return NULL;
63  s->parser = parser;
64  if (parser->priv_data_size) {
65  s->priv_data = av_mallocz(parser->priv_data_size);
66  if (!s->priv_data) {
67  av_free(s);
68  return NULL;
69  }
70  }
71  if (parser->parser_init) {
72  ret = parser->parser_init(s);
73  if (ret != 0) {
74  av_free(s->priv_data);
75  av_free(s);
76  return NULL;
77  }
78  }
79  s->fetch_timestamp=1;
81  s->key_frame = -1;
82  s->convergence_duration = 0;
83  s->dts_sync_point = INT_MIN;
84  s->dts_ref_dts_delta = INT_MIN;
85  s->pts_dts_delta = INT_MIN;
86  return s;
87 }
88 
89 void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove){
90  int i;
91 
92  s->dts= s->pts= AV_NOPTS_VALUE;
93  s->pos= -1;
94  s->offset= 0;
95  for(i = 0; i < AV_PARSER_PTS_NB; i++) {
96  if ( s->cur_offset + off >= s->cur_frame_offset[i]
97  && (s->frame_offset < s->cur_frame_offset[i] ||
98  (!s->frame_offset && !s->next_frame_offset)) // first field/frame
99  // check disabled since MPEG-TS does not send complete PES packets
100  && /*s->next_frame_offset + off <*/ s->cur_frame_end[i]){
101  s->dts= s->cur_frame_dts[i];
102  s->pts= s->cur_frame_pts[i];
103  s->pos= s->cur_frame_pos[i];
104  s->offset = s->next_frame_offset - s->cur_frame_offset[i];
105  if(remove)
106  s->cur_frame_offset[i]= INT64_MAX;
107  if(s->cur_offset + off < s->cur_frame_end[i])
108  break;
109  }
110  }
111 }
112 
114  AVCodecContext *avctx,
115  uint8_t **poutbuf, int *poutbuf_size,
116  const uint8_t *buf, int buf_size,
117  int64_t pts, int64_t dts,
118  int64_t pos)
119 {
120  int index, i;
122 
123  if(!(s->flags & PARSER_FLAG_FETCHED_OFFSET)) {
124  s->next_frame_offset =
125  s->cur_offset = pos;
127  }
128 
129  if (buf_size == 0) {
130  /* padding is always necessary even if EOF, so we add it here */
131  memset(dummy_buf, 0, sizeof(dummy_buf));
132  buf = dummy_buf;
133  } else if (s->cur_offset + buf_size !=
134  s->cur_frame_end[s->cur_frame_start_index]) { /* skip remainder packets */
135  /* add a new packet descriptor */
136  i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
137  s->cur_frame_start_index = i;
138  s->cur_frame_offset[i] = s->cur_offset;
139  s->cur_frame_end[i] = s->cur_offset + buf_size;
140  s->cur_frame_pts[i] = pts;
141  s->cur_frame_dts[i] = dts;
142  s->cur_frame_pos[i] = pos;
143  }
144 
145  if (s->fetch_timestamp){
146  s->fetch_timestamp=0;
147  s->last_pts = s->pts;
148  s->last_dts = s->dts;
149  s->last_pos = s->pos;
150  ff_fetch_timestamp(s, 0, 0);
151  }
152 
153  /* WARNING: the returned index can be negative */
154  index = s->parser->parser_parse(s, avctx, (const uint8_t **)poutbuf, poutbuf_size, buf, buf_size);
155  /* update the file pointer */
156  if (*poutbuf_size) {
157  /* fill the data for the current frame */
159 
160  /* offset of the next frame */
162  s->fetch_timestamp=1;
163  }
164  if (index < 0)
165  index = 0;
166  s->cur_offset += index;
167  return index;
168 }
169 
171  AVCodecContext *avctx,
172  uint8_t **poutbuf, int *poutbuf_size,
173  const uint8_t *buf, int buf_size, int keyframe){
174 
175  if(s && s->parser->split){
176  if((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)){
177  int i= s->parser->split(avctx, buf, buf_size);
178  buf += i;
179  buf_size -= i;
180  }
181  }
182 
183  /* cast to avoid warning about discarding qualifiers */
184  *poutbuf= (uint8_t *) buf;
185  *poutbuf_size= buf_size;
186  if(avctx->extradata){
187  if( (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER))
188  /*||(s->pict_type != AV_PICTURE_TYPE_I && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_NOKEY))*/
189  /*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){
190  int size= buf_size + avctx->extradata_size;
191  *poutbuf_size= size;
192  *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
193 
194  memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
195  memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
196  return 1;
197  }
198  }
199 
200  return 0;
201 }
202 
204 {
205  if(s){
206  if (s->parser->parser_close)
207  s->parser->parser_close(s);
208  av_free(s->priv_data);
209  av_free(s);
210  }
211 }
212 
213 /*****************************************************/
214 
215 int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
216 {
217  if(pc->overread){
218  av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
219  pc->overread, pc->state, next, pc->index, pc->overread_index);
220  av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
221  }
222 
223  /* Copy overread bytes from last frame into buffer. */
224  for(; pc->overread>0; pc->overread--){
225  pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
226  }
227 
228  /* flush remaining if EOF */
229  if(!*buf_size && next == END_NOT_FOUND){
230  next= 0;
231  }
232 
233  pc->last_index= pc->index;
234 
235  /* copy into buffer end return */
236  if(next == END_NOT_FOUND){
237  void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
238 
239  if(!new_buffer)
240  return AVERROR(ENOMEM);
241  pc->buffer = new_buffer;
242  memcpy(&pc->buffer[pc->index], *buf, *buf_size);
243  pc->index += *buf_size;
244  return -1;
245  }
246 
247  *buf_size=
248  pc->overread_index= pc->index + next;
249 
250  /* append to buffer */
251  if(pc->index){
252  void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
253 
254  if(!new_buffer)
255  return AVERROR(ENOMEM);
256  pc->buffer = new_buffer;
257  if (next > -FF_INPUT_BUFFER_PADDING_SIZE)
258  memcpy(&pc->buffer[pc->index], *buf,
260  pc->index = 0;
261  *buf= pc->buffer;
262  }
263 
264  /* store overread bytes */
265  for(;next < 0; next++){
266  pc->state = (pc->state<<8) | pc->buffer[pc->last_index + next];
267  pc->state64 = (pc->state64<<8) | pc->buffer[pc->last_index + next];
268  pc->overread++;
269  }
270 
271  if(pc->overread){
272  av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
273  pc->overread, pc->state, next, pc->index, pc->overread_index);
274  av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
275  }
276 
277  return 0;
278 }
279 
281 {
282  ParseContext *pc = s->priv_data;
283 
284  av_freep(&pc->buffer);
285 }
286 
287 /*************************/
288 
290  const uint8_t *buf, int buf_size)
291 {
292  int i;
293  uint32_t state= -1;
294 
295  for(i=0; i<buf_size; i++){
296  state= (state<<8) | buf[i];
297  if(state == 0x1B3 || state == 0x1B6)
298  return i-3;
299  }
300  return 0;
301 }
int(* parser_init)(AVCodecParserContext *s)
Definition: avcodec.h:3857
void * av_malloc(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:61
int size
memory handling functions
int64_t next_frame_offset
Definition: avcodec.h:3725
int codec_ids[5]
Definition: avcodec.h:3855
av_dlog(ac->avr,"%d samples - audio_convert: %s to %s (%s)\n", len, av_get_sample_fmt_name(ac->in_fmt), av_get_sample_fmt_name(ac->out_fmt), use_generic?ac->func_descr_generic:ac->func_descr)
int64_t cur_frame_pos[AV_PARSER_PTS_NB]
Position of the packet in file.
Definition: avcodec.h:3834
int dts_ref_dts_delta
Offset of the current timestamp against last timestamp sync point in units of AVCodecContext.time_base.
Definition: avcodec.h:3813
int ff_mpeg4video_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
Definition: parser.c:289
void av_freep(void *arg)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc() and set the pointer ...
Definition: mem.c:151
uint8_t
int av_parser_change(AVCodecParserContext *s, AVCodecContext *avctx, uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size, int keyframe)
Definition: parser.c:170
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:1454
struct AVCodecParser * next
Definition: avcodec.h:3864
int(* parser_parse)(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size)
Definition: avcodec.h:3858
void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove)
Fetch timestamps for a specific byte within the current access unit.
Definition: parser.c:89
unsigned int buffer_size
Definition: parser.h:32
void av_free(void *ptr)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc(). ...
Definition: mem.c:139
int64_t pos
Byte position of currently parsed frame in stream.
Definition: avcodec.h:3839
int priv_data_size
Definition: avcodec.h:3856
void * av_fast_realloc(void *ptr, unsigned int *size, size_t min_size)
Reallocate the given block if it is not large enough, otherwise do nothing.
Definition: utils.c:53
struct AVCodecParser * parser
Definition: avcodec.h:3721
int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
Combine the (truncated) bitstream to a complete frame.
Definition: parser.c:215
int flags
CODEC_FLAG_*.
Definition: avcodec.h:1434
int overread_index
the index into ParseContext.buffer of the overread bytes
Definition: parser.h:36
int64_t cur_frame_dts[AV_PARSER_PTS_NB]
Definition: avcodec.h:3750
enum AVCodecID codec_id
Definition: mov_chan.c:432
AVCodecParser * av_parser_next(AVCodecParser *p)
Definition: parser.c:30
int off
Definition: dsputil_bfin.c:28
void ff_parse_close(AVCodecParserContext *s)
Definition: parser.c:280
int overread
the number of bytes which where irreversibly read from the next frame
Definition: parser.h:35
int last_index
Definition: parser.h:31
int av_parser_parse2(AVCodecParserContext *s, AVCodecContext *avctx, uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size, int64_t pts, int64_t dts, int64_t pos)
Parse a packet.
Definition: parser.c:113
void(* parser_close)(AVCodecParserContext *s)
Definition: avcodec.h:3862
int64_t offset
byte offset from starting packet start
Definition: avcodec.h:3758
int64_t convergence_duration
Time difference in stream time base units from the pts of this packet to the point at which the outpu...
Definition: avcodec.h:3786
void av_parser_close(AVCodecParserContext *s)
Definition: parser.c:203
int64_t cur_frame_end[AV_PARSER_PTS_NB]
Definition: avcodec.h:3759
int64_t cur_frame_pts[AV_PARSER_PTS_NB]
Definition: avcodec.h:3749
int64_t last_pos
Previous frame byte position.
Definition: avcodec.h:3844
int pts_dts_delta
Presentation delay of current frame in units of AVCodecContext.time_base.
Definition: avcodec.h:3827
NULL
Definition: eval.c:52
AVCodecParserContext * av_parser_init(int codec_id)
Definition: parser.c:41
uint8_t * buffer
Definition: parser.h:29
main external API structure.
Definition: avcodec.h:1339
uint32_t state
contains the last few bytes in MSB order
Definition: parser.h:33
int extradata_size
Definition: avcodec.h:1455
int index
Definition: gxfenc.c:72
uint64_t state64
contains the last 8 bytes in MSB order
Definition: parser.h:37
void av_register_codec_parser(AVCodecParser *parser)
Definition: parser.c:35
static AVCodecParser * av_first_parser
Definition: parser.c:28
#define END_NOT_FOUND
Definition: parser.h:40
static uint32_t state
Definition: trasher.c:27
int(* split)(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
Definition: avcodec.h:3863
int index
Definition: parser.h:30
int64_t cur_frame_offset[AV_PARSER_PTS_NB]
Definition: avcodec.h:3748
int64_t frame_offset
Definition: avcodec.h:3722
int flags2
CODEC_FLAG2_*.
Definition: avcodec.h:1441
int key_frame
Set by parser to 1 for key frames and 0 for non-key frames.
Definition: avcodec.h:3767
void * av_mallocz(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:158
int dts_sync_point
Synchronization point for start of timestamp generation.
Definition: avcodec.h:3798