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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 <stdint.h>
24 #include <string.h>
25 
26 #include "libavutil/avassert.h"
27 #include "libavutil/atomic.h"
28 #include "libavutil/internal.h"
29 #include "libavutil/mem.h"
30 
31 #include "internal.h"
32 #include "parser.h"
33 
35 
37 {
38  if (p)
39  return p->next;
40  else
41  return av_first_parser;
42 }
43 
45 {
46  do {
47  parser->next = av_first_parser;
48  } while (parser->next != avpriv_atomic_ptr_cas((void * volatile *)&av_first_parser, parser->next, parser));
49 }
50 
52 {
54  AVCodecParser *parser;
55  int ret;
56 
57  if (codec_id == AV_CODEC_ID_NONE)
58  return NULL;
59 
60  for (parser = av_first_parser; parser; parser = parser->next) {
61  if (parser->codec_ids[0] == codec_id ||
62  parser->codec_ids[1] == codec_id ||
63  parser->codec_ids[2] == codec_id ||
64  parser->codec_ids[3] == codec_id ||
65  parser->codec_ids[4] == codec_id)
66  goto found;
67  }
68  return NULL;
69 
70 found:
71  s = av_mallocz(sizeof(AVCodecParserContext));
72  if (!s)
73  goto err_out;
74  s->parser = parser;
75  s->priv_data = av_mallocz(parser->priv_data_size);
76  if (!s->priv_data)
77  goto err_out;
78  s->fetch_timestamp=1;
80  if (parser->parser_init) {
81  ret = parser->parser_init(s);
82  if (ret != 0)
83  goto err_out;
84  }
85  s->key_frame = -1;
86 #if FF_API_CONVERGENCE_DURATION
88  s->convergence_duration = 0;
90 #endif
91  s->dts_sync_point = INT_MIN;
92  s->dts_ref_dts_delta = INT_MIN;
93  s->pts_dts_delta = INT_MIN;
94  s->format = -1;
95 
96  return s;
97 
98 err_out:
99  if (s)
100  av_freep(&s->priv_data);
101  av_free(s);
102  return NULL;
103 }
104 
105 void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove, int fuzzy)
106 {
107  int i;
108 
109  if (!fuzzy) {
110  s->dts =
111  s->pts = AV_NOPTS_VALUE;
112  s->pos = -1;
113  s->offset = 0;
114  }
115  for (i = 0; i < AV_PARSER_PTS_NB; i++) {
116  if (s->cur_offset + off >= s->cur_frame_offset[i] &&
117  (s->frame_offset < s->cur_frame_offset[i] ||
118  (!s->frame_offset && !s->next_frame_offset)) && // first field/frame
119  // check disabled since MPEG-TS does not send complete PES packets
120  /*s->next_frame_offset + off <*/ s->cur_frame_end[i]){
121 
122  if (!fuzzy || s->cur_frame_dts[i] != AV_NOPTS_VALUE) {
123  s->dts = s->cur_frame_dts[i];
124  s->pts = s->cur_frame_pts[i];
125  s->pos = s->cur_frame_pos[i];
126  s->offset = s->next_frame_offset - s->cur_frame_offset[i];
127  }
128  if (remove)
129  s->cur_frame_offset[i] = INT64_MAX;
130  if (s->cur_offset + off < s->cur_frame_end[i])
131  break;
132  }
133  }
134 }
135 
137  uint8_t **poutbuf, int *poutbuf_size,
138  const uint8_t *buf, int buf_size,
139  int64_t pts, int64_t dts, int64_t pos)
140 {
141  int index, i;
143 
145 
146  /* Parsers only work for the specified codec ids. */
147  av_assert1(avctx->codec_id == s->parser->codec_ids[0] ||
148  avctx->codec_id == s->parser->codec_ids[1] ||
149  avctx->codec_id == s->parser->codec_ids[2] ||
150  avctx->codec_id == s->parser->codec_ids[3] ||
151  avctx->codec_id == s->parser->codec_ids[4]);
152 
153  if (!(s->flags & PARSER_FLAG_FETCHED_OFFSET)) {
154  s->next_frame_offset =
155  s->cur_offset = pos;
157  }
158 
159  if (buf_size == 0) {
160  /* padding is always necessary even if EOF, so we add it here */
161  memset(dummy_buf, 0, sizeof(dummy_buf));
162  buf = dummy_buf;
163  } else if (s->cur_offset + buf_size != s->cur_frame_end[s->cur_frame_start_index]) { /* skip remainder packets */
164  /* add a new packet descriptor */
165  i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
166  s->cur_frame_start_index = i;
167  s->cur_frame_offset[i] = s->cur_offset;
168  s->cur_frame_end[i] = s->cur_offset + buf_size;
169  s->cur_frame_pts[i] = pts;
170  s->cur_frame_dts[i] = dts;
171  s->cur_frame_pos[i] = pos;
172  }
173 
174  if (s->fetch_timestamp) {
175  s->fetch_timestamp = 0;
176  s->last_pts = s->pts;
177  s->last_dts = s->dts;
178  s->last_pos = s->pos;
179  ff_fetch_timestamp(s, 0, 0, 0);
180  }
181  /* WARNING: the returned index can be negative */
182  index = s->parser->parser_parse(s, avctx, (const uint8_t **) poutbuf,
183  poutbuf_size, buf, buf_size);
184  av_assert0(index > -0x20000000); // The API does not allow returning AVERROR codes
185  /* update the file pointer */
186  if (*poutbuf_size) {
187  /* fill the data for the current frame */
189 
190  /* offset of the next frame */
192  s->fetch_timestamp = 1;
193  }
194  if (index < 0)
195  index = 0;
196  s->cur_offset += index;
197  return index;
198 }
199 
201  uint8_t **poutbuf, int *poutbuf_size,
202  const uint8_t *buf, int buf_size, int keyframe)
203 {
204  if (s && s->parser->split) {
205  if (avctx->flags & AV_CODEC_FLAG_GLOBAL_HEADER ||
207  int i = s->parser->split(avctx, buf, buf_size);
208  buf += i;
209  buf_size -= i;
210  }
211  }
212 
213  /* cast to avoid warning about discarding qualifiers */
214  *poutbuf = (uint8_t *) buf;
215  *poutbuf_size = buf_size;
216  if (avctx->extradata) {
217  if (keyframe && (avctx->flags2 & AV_CODEC_FLAG2_LOCAL_HEADER)) {
218  int size = buf_size + avctx->extradata_size;
219 
220  *poutbuf_size = size;
221  *poutbuf = av_malloc(size + AV_INPUT_BUFFER_PADDING_SIZE);
222  if (!*poutbuf)
223  return AVERROR(ENOMEM);
224 
225  memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
226  memcpy(*poutbuf + avctx->extradata_size, buf,
227  buf_size + AV_INPUT_BUFFER_PADDING_SIZE);
228  return 1;
229  }
230  }
231 
232  return 0;
233 }
234 
236 {
237  if (s) {
238  if (s->parser->parser_close)
239  s->parser->parser_close(s);
240  av_freep(&s->priv_data);
241  av_free(s);
242  }
243 }
244 
245 int ff_combine_frame(ParseContext *pc, int next,
246  const uint8_t **buf, int *buf_size)
247 {
248  if (pc->overread) {
249  ff_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
250  pc->overread, pc->state, next, pc->index, pc->overread_index);
251  ff_dlog(NULL, "%X %X %X %X\n",
252  (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
253  }
254 
255  /* Copy overread bytes from last frame into buffer. */
256  for (; pc->overread > 0; pc->overread--)
257  pc->buffer[pc->index++] = pc->buffer[pc->overread_index++];
258 
259  /* flush remaining if EOF */
260  if (!*buf_size && next == END_NOT_FOUND)
261  next = 0;
262 
263  pc->last_index = pc->index;
264 
265  /* copy into buffer end return */
266  if (next == END_NOT_FOUND) {
267  void *new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size,
268  *buf_size + pc->index +
270 
271  if (!new_buffer) {
272  av_log(NULL, AV_LOG_ERROR, "Failed to reallocate parser buffer to %d\n", *buf_size + pc->index + AV_INPUT_BUFFER_PADDING_SIZE);
273  pc->index = 0;
274  return AVERROR(ENOMEM);
275  }
276  pc->buffer = new_buffer;
277  memcpy(&pc->buffer[pc->index], *buf, *buf_size);
278  pc->index += *buf_size;
279  return -1;
280  }
281 
282  *buf_size =
283  pc->overread_index = pc->index + next;
284 
285  /* append to buffer */
286  if (pc->index) {
287  void *new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size,
288  next + pc->index +
290  if (!new_buffer) {
291  av_log(NULL, AV_LOG_ERROR, "Failed to reallocate parser buffer to %d\n", next + pc->index + AV_INPUT_BUFFER_PADDING_SIZE);
292  pc->overread_index =
293  pc->index = 0;
294  return AVERROR(ENOMEM);
295  }
296  pc->buffer = new_buffer;
297  if (next > -AV_INPUT_BUFFER_PADDING_SIZE)
298  memcpy(&pc->buffer[pc->index], *buf,
300  pc->index = 0;
301  *buf = pc->buffer;
302  }
303 
304  /* store overread bytes */
305  for (; next < 0; next++) {
306  pc->state = pc->state << 8 | pc->buffer[pc->last_index + next];
307  pc->state64 = pc->state64 << 8 | pc->buffer[pc->last_index + next];
308  pc->overread++;
309  }
310 
311  if (pc->overread) {
312  ff_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
313  pc->overread, pc->state, next, pc->index, pc->overread_index);
314  ff_dlog(NULL, "%X %X %X %X\n",
315  (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
316  }
317 
318  return 0;
319 }
320 
322 {
323  ParseContext *pc = s->priv_data;
324 
325  av_freep(&pc->buffer);
326 }
327 
328 int ff_mpeg4video_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
329 {
330  uint32_t state = -1;
331  const uint8_t *ptr = buf, *end = buf + buf_size;
332 
333  while (ptr < end) {
334  ptr = avpriv_find_start_code(ptr, end, &state);
335  if (state == 0x1B3 || state == 0x1B6)
336  return ptr - 4 - buf;
337  }
338 
339  return 0;
340 }
int(* parser_init)(AVCodecParserContext *s)
Definition: avcodec.h:5150
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:768
enum AVCodecID codec_id
Definition: ffmpeg_vaapi.c:149
Memory handling functions.
int64_t next_frame_offset
Definition: avcodec.h:4986
int codec_ids[5]
Definition: avcodec.h:5148
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:252
int64_t cur_frame_pos[AV_PARSER_PTS_NB]
Position of the packet in file.
Definition: avcodec.h:5085
int dts_ref_dts_delta
Offset of the current timestamp against last timestamp sync point in units of AVCodecContext.time_base.
Definition: avcodec.h:5064
int ff_mpeg4video_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
Definition: parser.c:328
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
uint8_t
#define av_malloc(s)
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:200
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:1790
struct AVCodecParser * next
Definition: avcodec.h:5159
#define ff_dlog(a,...)
int(* parser_parse)(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size)
Definition: avcodec.h:5153
ptrdiff_t size
Definition: opengl_enc.c:101
#define av_log(a,...)
const uint8_t * avpriv_find_start_code(const uint8_t *p, const uint8_t *end, uint32_t *state)
unsigned int buffer_size
Definition: parser.h:32
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define avpriv_atomic_ptr_cas
Definition: atomic_gcc.h:60
int64_t pos
Byte position of currently parsed frame in stream.
Definition: avcodec.h:5090
int priv_data_size
Definition: avcodec.h:5149
struct AVCodecParser * parser
Definition: avcodec.h:4982
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:245
#define AVERROR(e)
Definition: error.h:43
int flags
AV_CODEC_FLAG_*.
Definition: avcodec.h:1770
simple assert() macros that are a bit more flexible than ISO C assert().
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:5011
AVCodecParser * av_parser_next(const AVCodecParser *p)
Definition: parser.c:36
void ff_parse_close(AVCodecParserContext *s)
Definition: parser.c:321
common internal API header
#define av_assert1(cond)
assert() equivalent, that does not lie in speed critical code.
Definition: avassert.h:53
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:136
void(* parser_close)(AVCodecParserContext *s)
Definition: avcodec.h:5157
int64_t offset
byte offset from starting packet start
Definition: avcodec.h:5020
void av_parser_close(AVCodecParserContext *s)
Definition: parser.c:235
void * av_fast_realloc(void *ptr, unsigned int *size, size_t min_size)
Reallocate the given buffer if it is not large enough, otherwise do nothing.
Definition: mem.c:480
int64_t cur_frame_end[AV_PARSER_PTS_NB]
Definition: avcodec.h:5021
int64_t cur_frame_pts[AV_PARSER_PTS_NB]
Definition: avcodec.h:5010
int64_t last_pos
Previous frame byte position.
Definition: avcodec.h:5095
int pts_dts_delta
Presentation delay of current frame in units of AVCodecContext.time_base.
Definition: avcodec.h:5078
AVCodecParserContext * av_parser_init(int codec_id)
Definition: parser.c:51
uint8_t * buffer
Definition: parser.h:29
enum AVCodecID codec_id
Definition: avcodec.h:1692
main external API structure.
Definition: avcodec.h:1675
#define AV_CODEC_FLAG2_LOCAL_HEADER
Place global headers at every keyframe instead of in extradata.
Definition: avcodec.h:908
static struct @246 state
#define PARSER_FLAG_FETCHED_OFFSET
Set if the parser has a valid file offset.
Definition: avcodec.h:5017
void * buf
Definition: avisynth_c.h:690
uint32_t state
contains the last few bytes in MSB order
Definition: parser.h:33
int extradata_size
Definition: avcodec.h:1791
int index
Definition: gxfenc.c:89
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:44
static AVCodecParser * av_first_parser
Definition: parser.c:34
#define END_NOT_FOUND
Definition: parser.h:40
#define AV_PARSER_PTS_NB
Definition: avcodec.h:5007
attribute_deprecated int64_t convergence_duration
Definition: avcodec.h:5036
static int64_t pts
Global timestamp for the audio frames.
#define AV_CODEC_FLAG_GLOBAL_HEADER
Place global headers in extradata instead of every keyframe.
Definition: avcodec.h:881
int(* split)(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
Definition: avcodec.h:5158
#define FF_DISABLE_DEPRECATION_WARNINGS
Definition: internal.h:80
common internal api header.
if(ret< 0)
Definition: vf_mcdeint.c:282
int index
Definition: parser.h:30
int64_t cur_frame_offset[AV_PARSER_PTS_NB]
Definition: avcodec.h:5009
#define AV_INPUT_BUFFER_PADDING_SIZE
Required number of additionally allocated bytes at the end of the input bitstream for decoding...
Definition: avcodec.h:733
int64_t frame_offset
Definition: avcodec.h:4983
#define av_free(p)
#define FF_ENABLE_DEPRECATION_WARNINGS
Definition: internal.h:81
int format
The format of the coded data, corresponds to enum AVPixelFormat for video and for enum AVSampleFormat...
Definition: avcodec.h:5144
int flags2
AV_CODEC_FLAG2_*.
Definition: avcodec.h:1777
#define av_freep(p)
void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove, int fuzzy)
Fetch timestamps for a specific byte within the current access unit.
Definition: parser.c:105
int key_frame
Set by parser to 1 for key frames and 0 for non-key frames.
Definition: avcodec.h:5029
int dts_sync_point
Synchronization point for start of timestamp generation.
Definition: avcodec.h:5049
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:242