FFmpeg
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];
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);
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  } 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;
214  *poutbuf = av_malloc(size + AV_INPUT_BUFFER_PADDING_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 }
#define NULL
Definition: coverity.c:32
void(* parser_close)(AVCodecParserContext *s)
Definition: avcodec.h:3554
Memory handling functions.
int64_t next_frame_offset
Definition: avcodec.h:3383
int codec_ids[5]
Definition: avcodec.h:3545
int(* split)(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
Definition: avcodec.h:3555
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
int64_t cur_frame_pos[AV_PARSER_PTS_NB]
Position of the packet in file.
Definition: avcodec.h:3482
int dts_ref_dts_delta
Offset of the current timestamp against last timestamp sync point in units of AVCodecContext.time_base.
Definition: avcodec.h:3461
fg index
int ff_mpeg4video_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
Definition: parser.c:330
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
uint8_t
#define av_malloc(s)
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:637
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 ff_dlog(a,...)
ptrdiff_t size
Definition: opengl_enc.c:100
static struct @321 state
#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:194
int64_t pos
Byte position of currently parsed frame in stream.
Definition: avcodec.h:3487
int priv_data_size
Definition: avcodec.h:3546
struct AVCodecParser * parser
Definition: avcodec.h:3379
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
unsigned int pos
Definition: spdifenc.c:412
int flags
AV_CODEC_FLAG_*.
Definition: avcodec.h:616
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:3408
int(* parser_parse)(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size)
Definition: avcodec.h:3550
void ff_parse_close(AVCodecParserContext *s)
Definition: parser.c:323
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
int64_t offset
byte offset from starting packet start
Definition: avcodec.h:3417
void av_parser_close(AVCodecParserContext *s)
Definition: parser.c:228
#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:478
enum AVCodecID codec_id
Definition: vaapi_decode.c:369
int64_t cur_frame_end[AV_PARSER_PTS_NB]
Definition: avcodec.h:3418
int64_t cur_frame_pts[AV_PARSER_PTS_NB]
Definition: avcodec.h:3407
int64_t last_pos
Previous frame byte position.
Definition: avcodec.h:3492
if(ret)
int pts_dts_delta
Presentation delay of current frame in units of AVCodecContext.time_base.
Definition: avcodec.h:3475
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:544
enum AVCodecID codec_id
Definition: avcodec.h:546
const AVCodecParser * av_parser_iterate(void **opaque)
Iterate over all registered codec parsers.
Definition: parsers.c:113
main external API structure.
Definition: avcodec.h:536
#define AV_CODEC_FLAG2_LOCAL_HEADER
Place global headers at every keyframe instead of in extradata.
Definition: avcodec.h:356
#define PARSER_FLAG_FETCHED_OFFSET
Set if the parser has a valid file offset.
Definition: avcodec.h:3414
uint32_t state
contains the last few bytes in MSB order
Definition: parser.h:33
int extradata_size
Definition: avcodec.h:638
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:3404
int(* parser_init)(AVCodecParserContext *s)
Definition: avcodec.h:3547
attribute_deprecated int64_t convergence_duration
Definition: avcodec.h:3433
static int64_t pts
#define AV_CODEC_FLAG_GLOBAL_HEADER
Place global headers in extradata instead of every keyframe.
Definition: avcodec.h:329
#define FF_DISABLE_DEPRECATION_WARNINGS
Definition: internal.h:83
common internal api header.
int index
Definition: parser.h:30
int64_t cur_frame_offset[AV_PARSER_PTS_NB]
Definition: avcodec.h:3406
#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
int64_t frame_offset
Definition: avcodec.h:3380
#define av_free(p)
#define FF_ENABLE_DEPRECATION_WARNINGS
Definition: internal.h:84
int format
The format of the coded data, corresponds to enum AVPixelFormat for video and for enum AVSampleFormat...
Definition: avcodec.h:3541
int flags2
AV_CODEC_FLAG2_*.
Definition: avcodec.h:623
#define av_freep(p)
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
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:3426
int dts_sync_point
Synchronization point for start of timestamp generation.
Definition: avcodec.h:3446
int i
Definition: input.c:407
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248