FFmpeg  4.4
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 <inttypes.h>
24 #include <stdint.h>
25 #include <string.h>
26 
27 #include "libavutil/avassert.h"
28 #include "libavutil/internal.h"
29 #include "libavutil/mem.h"
30 
31 #include "internal.h"
32 #include "parser.h"
33 
35 {
37  const AVCodecParser *parser;
38  void *i = 0;
39  int ret;
40 
42  return NULL;
43 
44  while ((parser = av_parser_iterate(&i))) {
45  if (parser->codec_ids[0] == codec_id ||
46  parser->codec_ids[1] == codec_id ||
47  parser->codec_ids[2] == codec_id ||
48  parser->codec_ids[3] == codec_id ||
49  parser->codec_ids[4] == codec_id)
50  goto found;
51  }
52  return NULL;
53 
54 found:
56  if (!s)
57  goto err_out;
58  s->parser = (AVCodecParser*)parser;
59  s->priv_data = av_mallocz(parser->priv_data_size);
60  if (!s->priv_data)
61  goto err_out;
62  s->fetch_timestamp=1;
63  s->pict_type = AV_PICTURE_TYPE_I;
64  if (parser->parser_init) {
65  ret = parser->parser_init(s);
66  if (ret != 0)
67  goto err_out;
68  }
69  s->key_frame = -1;
70 #if FF_API_CONVERGENCE_DURATION
72  s->convergence_duration = 0;
74 #endif
75  s->dts_sync_point = INT_MIN;
76  s->dts_ref_dts_delta = INT_MIN;
77  s->pts_dts_delta = INT_MIN;
78  s->format = -1;
79 
80  return s;
81 
82 err_out:
83  if (s)
84  av_freep(&s->priv_data);
85  av_free(s);
86  return NULL;
87 }
88 
89 void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove, int fuzzy)
90 {
91  int i;
92 
93  if (!fuzzy) {
94  s->dts =
95  s->pts = AV_NOPTS_VALUE;
96  s->pos = -1;
97  s->offset = 0;
98  }
99  for (i = 0; i < AV_PARSER_PTS_NB; i++) {
100  if (s->cur_offset + off >= s->cur_frame_offset[i] &&
101  (s->frame_offset < s->cur_frame_offset[i] ||
102  (!s->frame_offset && !s->next_frame_offset)) && // first field/frame
103  // check disabled since MPEG-TS does not send complete PES packets
104  /*s->next_frame_offset + off <*/ s->cur_frame_end[i]){
105 
106  if (!fuzzy || s->cur_frame_dts[i] != AV_NOPTS_VALUE) {
107  s->dts = s->cur_frame_dts[i];
108  s->pts = s->cur_frame_pts[i];
109  s->pos = s->cur_frame_pos[i];
110  s->offset = s->next_frame_offset - s->cur_frame_offset[i];
111  }
112  if (remove)
113  s->cur_frame_offset[i] = INT64_MAX;
114  if (s->cur_offset + off < s->cur_frame_end[i])
115  break;
116  }
117  }
118 }
119 
121  uint8_t **poutbuf, int *poutbuf_size,
122  const uint8_t *buf, int buf_size,
123  int64_t pts, int64_t dts, int64_t pos)
124 {
125  int index, i;
127 
129 
130  /* Parsers only work for the specified codec ids. */
131  av_assert1(avctx->codec_id == s->parser->codec_ids[0] ||
132  avctx->codec_id == s->parser->codec_ids[1] ||
133  avctx->codec_id == s->parser->codec_ids[2] ||
134  avctx->codec_id == s->parser->codec_ids[3] ||
135  avctx->codec_id == s->parser->codec_ids[4]);
136 
137  if (!(s->flags & PARSER_FLAG_FETCHED_OFFSET)) {
138  s->next_frame_offset =
139  s->cur_offset = pos;
140  s->flags |= PARSER_FLAG_FETCHED_OFFSET;
141  }
142 
143  if (buf_size == 0) {
144  /* padding is always necessary even if EOF, so we add it here */
145  memset(dummy_buf, 0, sizeof(dummy_buf));
146  buf = dummy_buf;
147  } else if (s->cur_offset + buf_size != s->cur_frame_end[s->cur_frame_start_index]) { /* skip remainder packets */
148  /* add a new packet descriptor */
149  i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
150  s->cur_frame_start_index = i;
151  s->cur_frame_offset[i] = s->cur_offset;
152  s->cur_frame_end[i] = s->cur_offset + buf_size;
153  s->cur_frame_pts[i] = pts;
154  s->cur_frame_dts[i] = dts;
155  s->cur_frame_pos[i] = pos;
156  }
157 
158  if (s->fetch_timestamp) {
159  s->fetch_timestamp = 0;
160  s->last_pts = s->pts;
161  s->last_dts = s->dts;
162  s->last_pos = s->pos;
163  ff_fetch_timestamp(s, 0, 0, 0);
164  }
165  /* WARNING: the returned index can be negative */
166  index = s->parser->parser_parse(s, avctx, (const uint8_t **) poutbuf,
167  poutbuf_size, buf, buf_size);
168  av_assert0(index > -0x20000000); // The API does not allow returning AVERROR codes
169 #define FILL(name) if(s->name > 0 && avctx->name <= 0) avctx->name = s->name
170  if (avctx->codec_type == AVMEDIA_TYPE_VIDEO) {
171  FILL(field_order);
172  }
173 
174  /* update the file pointer */
175  if (*poutbuf_size) {
176  /* fill the data for the current frame */
177  s->frame_offset = s->next_frame_offset;
178 
179  /* offset of the next frame */
180  s->next_frame_offset = s->cur_offset + index;
181  s->fetch_timestamp = 1;
182  } else {
183  /* Don't return a pointer to dummy_buf. */
184  *poutbuf = NULL;
185  }
186  if (index < 0)
187  index = 0;
188  s->cur_offset += index;
189  return index;
190 }
191 
192 #if FF_API_PARSER_CHANGE
194  uint8_t **poutbuf, int *poutbuf_size,
195  const uint8_t *buf, int buf_size, int keyframe)
196 {
197  if (s && s->parser->split) {
198  if (avctx->flags & AV_CODEC_FLAG_GLOBAL_HEADER ||
200  int i = s->parser->split(avctx, buf, buf_size);
201  buf += i;
202  buf_size -= i;
203  }
204  }
205 
206  /* cast to avoid warning about discarding qualifiers */
207  *poutbuf = (uint8_t *) buf;
208  *poutbuf_size = buf_size;
209  if (avctx->extradata) {
210  if (keyframe && (avctx->flags2 & AV_CODEC_FLAG2_LOCAL_HEADER)) {
211  int size = buf_size + avctx->extradata_size;
212 
213  *poutbuf_size = size;
215  if (!*poutbuf)
216  return AVERROR(ENOMEM);
217 
218  memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
219  memcpy(*poutbuf + avctx->extradata_size, buf,
220  buf_size + AV_INPUT_BUFFER_PADDING_SIZE);
221  return 1;
222  }
223  }
224 
225  return 0;
226 }
227 #endif
229 {
230  if (s) {
231  if (s->parser->parser_close)
232  s->parser->parser_close(s);
233  av_freep(&s->priv_data);
234  av_free(s);
235  }
236 }
237 
238 int ff_combine_frame(ParseContext *pc, int next,
239  const uint8_t **buf, int *buf_size)
240 {
241  if (pc->overread) {
242  ff_dlog(NULL, "overread %d, state:%"PRIX32" next:%d index:%d o_index:%d\n",
243  pc->overread, pc->state, next, pc->index, pc->overread_index);
244  ff_dlog(NULL, "%X %X %X %X\n",
245  (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
246  }
247 
248  /* Copy overread bytes from last frame into buffer. */
249  for (; pc->overread > 0; pc->overread--)
250  pc->buffer[pc->index++] = pc->buffer[pc->overread_index++];
251 
252  if (next > *buf_size)
253  return AVERROR(EINVAL);
254 
255  /* flush remaining if EOF */
256  if (!*buf_size && next == END_NOT_FOUND)
257  next = 0;
258 
259  pc->last_index = pc->index;
260 
261  /* copy into buffer end return */
262  if (next == END_NOT_FOUND) {
263  void *new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size,
264  *buf_size + pc->index +
266 
267  if (!new_buffer) {
268  av_log(NULL, AV_LOG_ERROR, "Failed to reallocate parser buffer to %d\n", *buf_size + pc->index + AV_INPUT_BUFFER_PADDING_SIZE);
269  pc->index = 0;
270  return AVERROR(ENOMEM);
271  }
272  pc->buffer = new_buffer;
273  memcpy(&pc->buffer[pc->index], *buf, *buf_size);
274  pc->index += *buf_size;
275  return -1;
276  }
277 
278  av_assert0(next >= 0 || pc->buffer);
279 
280  *buf_size =
281  pc->overread_index = pc->index + next;
282 
283  /* append to buffer */
284  if (pc->index) {
285  void *new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size,
286  next + pc->index +
288  if (!new_buffer) {
289  av_log(NULL, AV_LOG_ERROR, "Failed to reallocate parser buffer to %d\n", next + pc->index + AV_INPUT_BUFFER_PADDING_SIZE);
290  pc->overread_index =
291  pc->index = 0;
292  return AVERROR(ENOMEM);
293  }
294  pc->buffer = new_buffer;
295  if (next > -AV_INPUT_BUFFER_PADDING_SIZE)
296  memcpy(&pc->buffer[pc->index], *buf,
298  pc->index = 0;
299  *buf = pc->buffer;
300  }
301 
302  if (next < -8) {
303  pc->overread += -8 - next;
304  next = -8;
305  }
306  /* store overread bytes */
307  for (; next < 0; next++) {
308  pc->state = pc->state << 8 | pc->buffer[pc->last_index + next];
309  pc->state64 = pc->state64 << 8 | pc->buffer[pc->last_index + next];
310  pc->overread++;
311  }
312 
313  if (pc->overread) {
314  ff_dlog(NULL, "overread %d, state:%"PRIX32" next:%d index:%d o_index:%d\n",
315  pc->overread, pc->state, next, pc->index, pc->overread_index);
316  ff_dlog(NULL, "%X %X %X %X\n",
317  (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
318  }
319 
320  return 0;
321 }
322 
324 {
325  ParseContext *pc = s->priv_data;
326 
327  av_freep(&pc->buffer);
328 }
329 
330 int ff_mpeg4video_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
331 {
332  uint32_t state = -1;
333  const uint8_t *ptr = buf, *end = buf + buf_size;
334 
335  while (ptr < end) {
336  ptr = avpriv_find_start_code(ptr, end, &state);
337  if (state == 0x1B3 || state == 0x1B6)
338  return ptr - 4 - buf;
339  }
340 
341  return 0;
342 }
uint8_t
simple assert() macros that are a bit more flexible than ISO C assert().
#define av_assert1(cond)
assert() equivalent, that does not lie in speed critical code.
Definition: avassert.h:53
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
#define PARSER_FLAG_FETCHED_OFFSET
Set if the parser has a valid file offset.
Definition: avcodec.h:3414
#define AV_PARSER_PTS_NB
Definition: avcodec.h:3404
#define s(width, name)
Definition: cbs_vp9.c:257
static struct @321 state
#define NULL
Definition: coverity.c:32
#define AV_CODEC_FLAG2_LOCAL_HEADER
Place global headers at every keyframe instead of in extradata.
Definition: avcodec.h:356
#define AV_CODEC_FLAG_GLOBAL_HEADER
Place global headers in extradata instead of every keyframe.
Definition: avcodec.h:329
@ AV_CODEC_ID_NONE
Definition: codec_id.h:47
#define AV_INPUT_BUFFER_PADDING_SIZE
Required number of additionally allocated bytes at the end of the input bitstream for decoding.
Definition: avcodec.h:215
AVCodecParserContext * av_parser_init(int codec_id)
Definition: parser.c:34
void av_parser_close(AVCodecParserContext *s)
Definition: parser.c:228
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:120
const AVCodecParser * av_parser_iterate(void **opaque)
Iterate over all registered codec parsers.
Definition: parsers.c:113
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:193
#define AVERROR(e)
Definition: error.h:43
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:237
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:478
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:274
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
int index
Definition: gxfenc.c:89
int i
Definition: input.c:407
const uint8_t * avpriv_find_start_code(const uint8_t *p, const uint8_t *end, uint32_t *state)
common internal API header
#define FF_DISABLE_DEPRECATION_WARNINGS
Definition: internal.h:83
#define FF_ENABLE_DEPRECATION_WARNINGS
Definition: internal.h:84
Memory handling functions.
int ff_mpeg4video_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
Definition: parser.c:330
#define FILL(name)
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:238
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:89
void ff_parse_close(AVCodecParserContext *s)
Definition: parser.c:323
#define END_NOT_FOUND
Definition: parser.h:40
unsigned int pos
Definition: spdifenc.c:412
main external API structure.
Definition: avcodec.h:536
int flags2
AV_CODEC_FLAG2_*.
Definition: avcodec.h:623
enum AVMediaType codec_type
Definition: avcodec.h:544
int flags
AV_CODEC_FLAG_*.
Definition: avcodec.h:616
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:637
enum AVCodecID codec_id
Definition: avcodec.h:546
int extradata_size
Definition: avcodec.h:638
int codec_ids[5]
Definition: avcodec.h:3545
int priv_data_size
Definition: avcodec.h:3546
int(* parser_init)(AVCodecParserContext *s)
Definition: avcodec.h:3547
int overread_index
the index into ParseContext.buffer of the overread bytes
Definition: parser.h:36
int index
Definition: parser.h:30
uint32_t state
contains the last few bytes in MSB order
Definition: parser.h:33
unsigned int buffer_size
Definition: parser.h:32
uint64_t state64
contains the last 8 bytes in MSB order
Definition: parser.h:37
int overread
the number of bytes which where irreversibly read from the next frame
Definition: parser.h:35
uint8_t * buffer
Definition: parser.h:29
int last_index
Definition: parser.h:31
#define av_free(p)
#define ff_dlog(a,...)
#define av_freep(p)
#define av_malloc(s)
#define av_log(a,...)
static int64_t pts
int size
enum AVCodecID codec_id
Definition: vaapi_decode.c:369
if(ret< 0)
Definition: vf_mcdeint.c:282