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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/atomic.h"
29 #include "libavutil/internal.h"
30 #include "libavutil/mem.h"
31 
32 #include "internal.h"
33 #include "parser.h"
34 
36 
38 {
39  if (p)
40  return p->next;
41  else
42  return av_first_parser;
43 }
44 
46 {
47  do {
48  parser->next = av_first_parser;
49  } while (parser->next != avpriv_atomic_ptr_cas((void * volatile *)&av_first_parser, parser->next, parser));
50 }
51 
53 {
55  AVCodecParser *parser;
56  int ret;
57 
58  if (codec_id == AV_CODEC_ID_NONE)
59  return NULL;
60 
61  for (parser = av_first_parser; parser; parser = parser->next) {
62  if (parser->codec_ids[0] == codec_id ||
63  parser->codec_ids[1] == codec_id ||
64  parser->codec_ids[2] == codec_id ||
65  parser->codec_ids[3] == codec_id ||
66  parser->codec_ids[4] == codec_id)
67  goto found;
68  }
69  return NULL;
70 
71 found:
72  s = av_mallocz(sizeof(AVCodecParserContext));
73  if (!s)
74  goto err_out;
75  s->parser = parser;
76  s->priv_data = av_mallocz(parser->priv_data_size);
77  if (!s->priv_data)
78  goto err_out;
79  s->fetch_timestamp=1;
81  if (parser->parser_init) {
82  ret = parser->parser_init(s);
83  if (ret != 0)
84  goto err_out;
85  }
86  s->key_frame = -1;
87 #if FF_API_CONVERGENCE_DURATION
89  s->convergence_duration = 0;
91 #endif
92  s->dts_sync_point = INT_MIN;
93  s->dts_ref_dts_delta = INT_MIN;
94  s->pts_dts_delta = INT_MIN;
95  s->format = -1;
96 
97  return s;
98 
99 err_out:
100  if (s)
101  av_freep(&s->priv_data);
102  av_free(s);
103  return NULL;
104 }
105 
106 void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove, int fuzzy)
107 {
108  int i;
109 
110  if (!fuzzy) {
111  s->dts =
112  s->pts = AV_NOPTS_VALUE;
113  s->pos = -1;
114  s->offset = 0;
115  }
116  for (i = 0; i < AV_PARSER_PTS_NB; i++) {
117  if (s->cur_offset + off >= s->cur_frame_offset[i] &&
118  (s->frame_offset < s->cur_frame_offset[i] ||
119  (!s->frame_offset && !s->next_frame_offset)) && // first field/frame
120  // check disabled since MPEG-TS does not send complete PES packets
121  /*s->next_frame_offset + off <*/ s->cur_frame_end[i]){
122 
123  if (!fuzzy || s->cur_frame_dts[i] != AV_NOPTS_VALUE) {
124  s->dts = s->cur_frame_dts[i];
125  s->pts = s->cur_frame_pts[i];
126  s->pos = s->cur_frame_pos[i];
127  s->offset = s->next_frame_offset - s->cur_frame_offset[i];
128  }
129  if (remove)
130  s->cur_frame_offset[i] = INT64_MAX;
131  if (s->cur_offset + off < s->cur_frame_end[i])
132  break;
133  }
134  }
135 }
136 
138  uint8_t **poutbuf, int *poutbuf_size,
139  const uint8_t *buf, int buf_size,
140  int64_t pts, int64_t dts, int64_t pos)
141 {
142  int index, i;
144 
146 
147  /* Parsers only work for the specified codec ids. */
148  av_assert1(avctx->codec_id == s->parser->codec_ids[0] ||
149  avctx->codec_id == s->parser->codec_ids[1] ||
150  avctx->codec_id == s->parser->codec_ids[2] ||
151  avctx->codec_id == s->parser->codec_ids[3] ||
152  avctx->codec_id == s->parser->codec_ids[4]);
153 
154  if (!(s->flags & PARSER_FLAG_FETCHED_OFFSET)) {
155  s->next_frame_offset =
156  s->cur_offset = pos;
158  }
159 
160  if (buf_size == 0) {
161  /* padding is always necessary even if EOF, so we add it here */
162  memset(dummy_buf, 0, sizeof(dummy_buf));
163  buf = dummy_buf;
164  } else if (s->cur_offset + buf_size != s->cur_frame_end[s->cur_frame_start_index]) { /* skip remainder packets */
165  /* add a new packet descriptor */
166  i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
167  s->cur_frame_start_index = i;
168  s->cur_frame_offset[i] = s->cur_offset;
169  s->cur_frame_end[i] = s->cur_offset + buf_size;
170  s->cur_frame_pts[i] = pts;
171  s->cur_frame_dts[i] = dts;
172  s->cur_frame_pos[i] = pos;
173  }
174 
175  if (s->fetch_timestamp) {
176  s->fetch_timestamp = 0;
177  s->last_pts = s->pts;
178  s->last_dts = s->dts;
179  s->last_pos = s->pos;
180  ff_fetch_timestamp(s, 0, 0, 0);
181  }
182  /* WARNING: the returned index can be negative */
183  index = s->parser->parser_parse(s, avctx, (const uint8_t **) poutbuf,
184  poutbuf_size, buf, buf_size);
185  av_assert0(index > -0x20000000); // The API does not allow returning AVERROR codes
186 #define FILL(name) if(s->name > 0 && avctx->name <= 0) avctx->name = s->name
187  if (avctx->codec_type == AVMEDIA_TYPE_VIDEO) {
188  FILL(field_order);
189  }
190 
191  /* update the file pointer */
192  if (*poutbuf_size) {
193  /* fill the data for the current frame */
195 
196  /* offset of the next frame */
198  s->fetch_timestamp = 1;
199  }
200  if (index < 0)
201  index = 0;
202  s->cur_offset += index;
203  return index;
204 }
205 
207  uint8_t **poutbuf, int *poutbuf_size,
208  const uint8_t *buf, int buf_size, int keyframe)
209 {
210  if (s && s->parser->split) {
211  if (avctx->flags & AV_CODEC_FLAG_GLOBAL_HEADER ||
213  int i = s->parser->split(avctx, buf, buf_size);
214  buf += i;
215  buf_size -= i;
216  }
217  }
218 
219  /* cast to avoid warning about discarding qualifiers */
220  *poutbuf = (uint8_t *) buf;
221  *poutbuf_size = buf_size;
222  if (avctx->extradata) {
223  if (keyframe && (avctx->flags2 & AV_CODEC_FLAG2_LOCAL_HEADER)) {
224  int size = buf_size + avctx->extradata_size;
225 
226  *poutbuf_size = size;
227  *poutbuf = av_malloc(size + AV_INPUT_BUFFER_PADDING_SIZE);
228  if (!*poutbuf)
229  return AVERROR(ENOMEM);
230 
231  memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
232  memcpy(*poutbuf + avctx->extradata_size, buf,
233  buf_size + AV_INPUT_BUFFER_PADDING_SIZE);
234  return 1;
235  }
236  }
237 
238  return 0;
239 }
240 
242 {
243  if (s) {
244  if (s->parser->parser_close)
245  s->parser->parser_close(s);
246  av_freep(&s->priv_data);
247  av_free(s);
248  }
249 }
250 
251 int ff_combine_frame(ParseContext *pc, int next,
252  const uint8_t **buf, int *buf_size)
253 {
254  if (pc->overread) {
255  ff_dlog(NULL, "overread %d, state:%"PRIX32" next:%d index:%d o_index:%d\n",
256  pc->overread, pc->state, next, pc->index, pc->overread_index);
257  ff_dlog(NULL, "%X %X %X %X\n",
258  (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
259  }
260 
261  /* Copy overread bytes from last frame into buffer. */
262  for (; pc->overread > 0; pc->overread--)
263  pc->buffer[pc->index++] = pc->buffer[pc->overread_index++];
264 
265  /* flush remaining if EOF */
266  if (!*buf_size && next == END_NOT_FOUND)
267  next = 0;
268 
269  pc->last_index = pc->index;
270 
271  /* copy into buffer end return */
272  if (next == END_NOT_FOUND) {
273  void *new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size,
274  *buf_size + pc->index +
276 
277  if (!new_buffer) {
278  av_log(NULL, AV_LOG_ERROR, "Failed to reallocate parser buffer to %d\n", *buf_size + pc->index + AV_INPUT_BUFFER_PADDING_SIZE);
279  pc->index = 0;
280  return AVERROR(ENOMEM);
281  }
282  pc->buffer = new_buffer;
283  memcpy(&pc->buffer[pc->index], *buf, *buf_size);
284  pc->index += *buf_size;
285  return -1;
286  }
287 
288  av_assert0(next >= 0 || pc->buffer);
289 
290  *buf_size =
291  pc->overread_index = pc->index + next;
292 
293  /* append to buffer */
294  if (pc->index) {
295  void *new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size,
296  next + pc->index +
298  if (!new_buffer) {
299  av_log(NULL, AV_LOG_ERROR, "Failed to reallocate parser buffer to %d\n", next + pc->index + AV_INPUT_BUFFER_PADDING_SIZE);
300  pc->overread_index =
301  pc->index = 0;
302  return AVERROR(ENOMEM);
303  }
304  pc->buffer = new_buffer;
305  if (next > -AV_INPUT_BUFFER_PADDING_SIZE)
306  memcpy(&pc->buffer[pc->index], *buf,
308  pc->index = 0;
309  *buf = pc->buffer;
310  }
311 
312  /* store overread bytes */
313  for (; next < 0; next++) {
314  pc->state = pc->state << 8 | pc->buffer[pc->last_index + next];
315  pc->state64 = pc->state64 << 8 | pc->buffer[pc->last_index + next];
316  pc->overread++;
317  }
318 
319  if (pc->overread) {
320  ff_dlog(NULL, "overread %d, state:%"PRIX32" next:%d index:%d o_index:%d\n",
321  pc->overread, pc->state, next, pc->index, pc->overread_index);
322  ff_dlog(NULL, "%X %X %X %X\n",
323  (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
324  }
325 
326  return 0;
327 }
328 
330 {
331  ParseContext *pc = s->priv_data;
332 
333  av_freep(&pc->buffer);
334 }
335 
336 int ff_mpeg4video_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
337 {
338  uint32_t state = -1;
339  const uint8_t *ptr = buf, *end = buf + buf_size;
340 
341  while (ptr < end) {
342  ptr = avpriv_find_start_code(ptr, end, &state);
343  if (state == 0x1B3 || state == 0x1B6)
344  return ptr - 4 - buf;
345  }
346 
347  return 0;
348 }
int(* parser_init)(AVCodecParserContext *s)
Definition: avcodec.h:5308
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:768
Memory handling functions.
int64_t next_frame_offset
Definition: avcodec.h:5144
int codec_ids[5]
Definition: avcodec.h:5306
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:222
int64_t cur_frame_pos[AV_PARSER_PTS_NB]
Position of the packet in file.
Definition: avcodec.h:5243
int dts_ref_dts_delta
Offset of the current timestamp against last timestamp sync point in units of AVCodecContext.time_base.
Definition: avcodec.h:5222
int ff_mpeg4video_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
Definition: parser.c:336
#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:206
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:1861
struct AVCodecParser * next
Definition: avcodec.h:5317
#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:5311
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
#define avpriv_atomic_ptr_cas
Definition: atomic_gcc.h:48
int64_t pos
Byte position of currently parsed frame in stream.
Definition: avcodec.h:5248
int priv_data_size
Definition: avcodec.h:5307
struct AVCodecParser * parser
Definition: avcodec.h:5140
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:251
#define AVERROR(e)
Definition: error.h:43
int flags
AV_CODEC_FLAG_*.
Definition: avcodec.h:1841
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:5169
AVCodecParser * av_parser_next(const AVCodecParser *p)
Definition: parser.c:37
void ff_parse_close(AVCodecParserContext *s)
Definition: parser.c:329
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:137
void(* parser_close)(AVCodecParserContext *s)
Definition: avcodec.h:5315
int64_t offset
byte offset from starting packet start
Definition: avcodec.h:5178
void av_parser_close(AVCodecParserContext *s)
Definition: parser.c:241
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:450
enum AVCodecID codec_id
Definition: vaapi_decode.c:235
int64_t cur_frame_end[AV_PARSER_PTS_NB]
Definition: avcodec.h:5179
int64_t cur_frame_pts[AV_PARSER_PTS_NB]
Definition: avcodec.h:5168
int64_t last_pos
Previous frame byte position.
Definition: avcodec.h:5253
int pts_dts_delta
Presentation delay of current frame in units of AVCodecContext.time_base.
Definition: avcodec.h:5236
AVCodecParserContext * av_parser_init(int codec_id)
Definition: parser.c:52
uint8_t * buffer
Definition: parser.h:29
enum AVMediaType codec_type
Definition: avcodec.h:1754
enum AVCodecID codec_id
Definition: avcodec.h:1763
static struct @259 state
main external API structure.
Definition: avcodec.h:1746
#define AV_CODEC_FLAG2_LOCAL_HEADER
Place global headers at every keyframe instead of in extradata.
Definition: avcodec.h:951
#define PARSER_FLAG_FETCHED_OFFSET
Set if the parser has a valid file offset.
Definition: avcodec.h:5175
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:1862
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:45
static AVCodecParser * av_first_parser
Definition: parser.c:35
#define END_NOT_FOUND
Definition: parser.h:40
#define AV_PARSER_PTS_NB
Definition: avcodec.h:5165
attribute_deprecated int64_t convergence_duration
Definition: avcodec.h:5194
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:924
int(* split)(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
Definition: avcodec.h:5316
#define FF_DISABLE_DEPRECATION_WARNINGS
Definition: internal.h:83
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:5167
#define AV_INPUT_BUFFER_PADDING_SIZE
Required number of additionally allocated bytes at the end of the input bitstream for decoding...
Definition: avcodec.h:776
int64_t frame_offset
Definition: avcodec.h:5141
#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:5302
int flags2
AV_CODEC_FLAG2_*.
Definition: avcodec.h:1848
#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:106
int key_frame
Set by parser to 1 for key frames and 0 for non-key frames.
Definition: avcodec.h:5187
int dts_sync_point
Synchronization point for start of timestamp generation.
Definition: avcodec.h:5207
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248