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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 <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 
41  if (codec_id == AV_CODEC_ID_NONE)
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:
55  s = av_mallocz(sizeof(AVCodecParserContext));
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;
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;
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 */
178 
179  /* offset of the next frame */
181  s->fetch_timestamp = 1;
182  }
183  if (index < 0)
184  index = 0;
185  s->cur_offset += index;
186  return index;
187 }
188 
190  uint8_t **poutbuf, int *poutbuf_size,
191  const uint8_t *buf, int buf_size, int keyframe)
192 {
193  if (s && s->parser->split) {
194  if (avctx->flags & AV_CODEC_FLAG_GLOBAL_HEADER ||
196  int i = s->parser->split(avctx, buf, buf_size);
197  buf += i;
198  buf_size -= i;
199  }
200  }
201 
202  /* cast to avoid warning about discarding qualifiers */
203  *poutbuf = (uint8_t *) buf;
204  *poutbuf_size = buf_size;
205  if (avctx->extradata) {
206  if (keyframe && (avctx->flags2 & AV_CODEC_FLAG2_LOCAL_HEADER)) {
207  int size = buf_size + avctx->extradata_size;
208 
209  *poutbuf_size = size;
210  *poutbuf = av_malloc(size + AV_INPUT_BUFFER_PADDING_SIZE);
211  if (!*poutbuf)
212  return AVERROR(ENOMEM);
213 
214  memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
215  memcpy(*poutbuf + avctx->extradata_size, buf,
216  buf_size + AV_INPUT_BUFFER_PADDING_SIZE);
217  return 1;
218  }
219  }
220 
221  return 0;
222 }
223 
225 {
226  if (s) {
227  if (s->parser->parser_close)
228  s->parser->parser_close(s);
229  av_freep(&s->priv_data);
230  av_free(s);
231  }
232 }
233 
234 int ff_combine_frame(ParseContext *pc, int next,
235  const uint8_t **buf, int *buf_size)
236 {
237  if (pc->overread) {
238  ff_dlog(NULL, "overread %d, state:%"PRIX32" next:%d index:%d o_index:%d\n",
239  pc->overread, pc->state, next, pc->index, pc->overread_index);
240  ff_dlog(NULL, "%X %X %X %X\n",
241  (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
242  }
243 
244  /* Copy overread bytes from last frame into buffer. */
245  for (; pc->overread > 0; pc->overread--)
246  pc->buffer[pc->index++] = pc->buffer[pc->overread_index++];
247 
248  /* flush remaining if EOF */
249  if (!*buf_size && next == END_NOT_FOUND)
250  next = 0;
251 
252  pc->last_index = pc->index;
253 
254  /* copy into buffer end return */
255  if (next == END_NOT_FOUND) {
256  void *new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size,
257  *buf_size + pc->index +
259 
260  if (!new_buffer) {
261  av_log(NULL, AV_LOG_ERROR, "Failed to reallocate parser buffer to %d\n", *buf_size + pc->index + AV_INPUT_BUFFER_PADDING_SIZE);
262  pc->index = 0;
263  return AVERROR(ENOMEM);
264  }
265  pc->buffer = new_buffer;
266  memcpy(&pc->buffer[pc->index], *buf, *buf_size);
267  pc->index += *buf_size;
268  return -1;
269  }
270 
271  av_assert0(next >= 0 || pc->buffer);
272 
273  *buf_size =
274  pc->overread_index = pc->index + next;
275 
276  /* append to buffer */
277  if (pc->index) {
278  void *new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size,
279  next + pc->index +
281  if (!new_buffer) {
282  av_log(NULL, AV_LOG_ERROR, "Failed to reallocate parser buffer to %d\n", next + pc->index + AV_INPUT_BUFFER_PADDING_SIZE);
283  pc->overread_index =
284  pc->index = 0;
285  return AVERROR(ENOMEM);
286  }
287  pc->buffer = new_buffer;
288  if (next > -AV_INPUT_BUFFER_PADDING_SIZE)
289  memcpy(&pc->buffer[pc->index], *buf,
291  pc->index = 0;
292  *buf = pc->buffer;
293  }
294 
295  /* store overread bytes */
296  for (; next < 0; next++) {
297  pc->state = pc->state << 8 | pc->buffer[pc->last_index + next];
298  pc->state64 = pc->state64 << 8 | pc->buffer[pc->last_index + next];
299  pc->overread++;
300  }
301 
302  if (pc->overread) {
303  ff_dlog(NULL, "overread %d, state:%"PRIX32" next:%d index:%d o_index:%d\n",
304  pc->overread, pc->state, next, pc->index, pc->overread_index);
305  ff_dlog(NULL, "%X %X %X %X\n",
306  (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
307  }
308 
309  return 0;
310 }
311 
313 {
314  ParseContext *pc = s->priv_data;
315 
316  av_freep(&pc->buffer);
317 }
318 
319 int ff_mpeg4video_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
320 {
321  uint32_t state = -1;
322  const uint8_t *ptr = buf, *end = buf + buf_size;
323 
324  while (ptr < end) {
325  ptr = avpriv_find_start_code(ptr, end, &state);
326  if (state == 0x1B3 || state == 0x1B6)
327  return ptr - 4 - buf;
328  }
329 
330  return 0;
331 }
int(* parser_init)(AVCodecParserContext *s)
Definition: avcodec.h:5217
#define NULL
Definition: coverity.c:32
Memory handling functions.
int64_t next_frame_offset
Definition: avcodec.h:5053
int codec_ids[5]
Definition: avcodec.h:5215
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:236
int64_t cur_frame_pos[AV_PARSER_PTS_NB]
Position of the packet in file.
Definition: avcodec.h:5152
int dts_ref_dts_delta
Offset of the current timestamp against last timestamp sync point in units of AVCodecContext.time_base.
Definition: avcodec.h:5131
int ff_mpeg4video_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
Definition: parser.c:319
#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:189
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:1633
#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:5220
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)
#define FILL(name)
unsigned int buffer_size
Definition: parser.h:32
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
int64_t pos
Byte position of currently parsed frame in stream.
Definition: avcodec.h:5157
int priv_data_size
Definition: avcodec.h:5216
struct AVCodecParser * parser
Definition: avcodec.h:5049
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:234
#define AVERROR(e)
Definition: error.h:43
int flags
AV_CODEC_FLAG_*.
Definition: avcodec.h:1612
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:5078
void ff_parse_close(AVCodecParserContext *s)
Definition: parser.c:312
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:120
void(* parser_close)(AVCodecParserContext *s)
Definition: avcodec.h:5224
int64_t offset
byte offset from starting packet start
Definition: avcodec.h:5087
void av_parser_close(AVCodecParserContext *s)
Definition: parser.c:224
#define s(width, name)
Definition: cbs_vp9.c:257
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:464
enum AVCodecID codec_id
Definition: vaapi_decode.c:362
int64_t cur_frame_end[AV_PARSER_PTS_NB]
Definition: avcodec.h:5088
int64_t cur_frame_pts[AV_PARSER_PTS_NB]
Definition: avcodec.h:5077
int64_t last_pos
Previous frame byte position.
Definition: avcodec.h:5162
int pts_dts_delta
Presentation delay of current frame in units of AVCodecContext.time_base.
Definition: avcodec.h:5145
AVCodecParserContext * av_parser_init(int codec_id)
Definition: parser.c:34
uint8_t * buffer
Definition: parser.h:29
enum AVMediaType codec_type
Definition: avcodec.h:1540
enum AVCodecID codec_id
Definition: avcodec.h:1542
const AVCodecParser * av_parser_iterate(void **opaque)
Iterate over all registered codec parsers.
Definition: parsers.c:93
main external API structure.
Definition: avcodec.h:1532
#define AV_CODEC_FLAG2_LOCAL_HEADER
Place global headers at every keyframe instead of in extradata.
Definition: avcodec.h:917
#define PARSER_FLAG_FETCHED_OFFSET
Set if the parser has a valid file offset.
Definition: avcodec.h:5084
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:1634
int index
Definition: gxfenc.c:89
uint64_t state64
contains the last 8 bytes in MSB order
Definition: parser.h:37
#define END_NOT_FOUND
Definition: parser.h:40
#define AV_PARSER_PTS_NB
Definition: avcodec.h:5074
attribute_deprecated int64_t convergence_duration
Definition: avcodec.h:5103
static int64_t pts
#define AV_CODEC_FLAG_GLOBAL_HEADER
Place global headers in extradata instead of every keyframe.
Definition: avcodec.h:890
static struct @283 state
int(* split)(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
Definition: avcodec.h:5225
#define FF_DISABLE_DEPRECATION_WARNINGS
Definition: internal.h:84
common internal api header.
if(ret< 0)
Definition: vf_mcdeint.c:279
int index
Definition: parser.h:30
int64_t cur_frame_offset[AV_PARSER_PTS_NB]
Definition: avcodec.h:5076
#define AV_INPUT_BUFFER_PADDING_SIZE
Required number of additionally allocated bytes at the end of the input bitstream for decoding...
Definition: avcodec.h:781
int64_t frame_offset
Definition: avcodec.h:5050
#define av_free(p)
#define FF_ENABLE_DEPRECATION_WARNINGS
Definition: internal.h:85
int format
The format of the coded data, corresponds to enum AVPixelFormat for video and for enum AVSampleFormat...
Definition: avcodec.h:5211
int flags2
AV_CODEC_FLAG2_*.
Definition: avcodec.h:1619
#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:89
int key_frame
Set by parser to 1 for key frames and 0 for non-key frames.
Definition: avcodec.h:5096
int dts_sync_point
Synchronization point for start of timestamp generation.
Definition: avcodec.h:5116
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248