FFmpeg: libavformat/format.c Source File

FFmpeg
format.c
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1 /*
2  * Format register and lookup
3  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "libavutil/atomic.h"
23 #include "libavutil/avstring.h"
24 #include "libavutil/bprint.h"
25 #include "libavutil/opt.h"
26 
27 #include "avio_internal.h"
28 #include "avformat.h"
29 #include "id3v2.h"
30 #include "internal.h"
31 
32 
33 /**
34  * @file
35  * Format register and lookup
36  */
37 /** head of registered input format linked list */
38  static AVInputFormat *first_iformat = NULL;
39 /** head of registered output format linked list */
40  static AVOutputFormat *first_oformat = NULL;
41 
42  static AVInputFormat **last_iformat = &first_iformat;
43  static AVOutputFormat **last_oformat = &first_oformat;
44 
45  AVInputFormat *av_iformat_next(const AVInputFormat *f)
46 {
47  if (f)
48  return f->next;
49  else
50  return first_iformat;
51 }
52 
53  AVOutputFormat *av_oformat_next(const AVOutputFormat *f)
54 {
55  if (f)
56  return f->next;
57  else
58  return first_oformat;
59 }
60 
61  void av_register_input_format(AVInputFormat *format)
62 {
63  AVInputFormat **p = last_iformat;
64 
65  format->next = NULL;
66  while(*p || avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))
67  p = &(*p)->next;
68  last_iformat = &format->next;
69 }
70 
71  void av_register_output_format(AVOutputFormat *format)
72 {
73  AVOutputFormat **p = last_oformat;
74 
75  format->next = NULL;
76  while(*p || avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))
77  p = &(*p)->next;
78  last_oformat = &format->next;
79 }
80 
81  int av_match_ext(const char *filename, const char *extensions)
82 {
83  const char *ext;
84 
85  if (!filename)
86  return 0;
87 
88  ext = strrchr(filename, '.');
89  if (ext)
90  return av_match_name(ext + 1, extensions);
91  return 0;
92 }
93 
94  AVOutputFormat *av_guess_format(const char *short_name, const char *filename,
95  const char *mime_type)
96 {
97  AVOutputFormat *fmt = NULL, *fmt_found;
98  int score_max, score;
99 
100  /* specific test for image sequences */
101 #if CONFIG_IMAGE2_MUXER
102  if (!short_name && filename &&
103  av_filename_number_test(filename) &&
104  ff_guess_image2_codec(filename) != AV_CODEC_ID_NONE) {
105  return av_guess_format("image2", NULL, NULL);
106  }
107 #endif
108  /* Find the proper file type. */
109  fmt_found = NULL;
110  score_max = 0;
111  while ((fmt = av_oformat_next(fmt))) {
112  score = 0;
113  if (fmt->name && short_name && av_match_name(short_name, fmt->name))
114  score += 100;
115  if (fmt->mime_type && mime_type && !strcmp(fmt->mime_type, mime_type))
116  score += 10;
117  if (filename && fmt->extensions &&
118  av_match_ext(filename, fmt->extensions)) {
119  score += 5;
120  }
121  if (score > score_max) {
122  score_max = score;
123  fmt_found = fmt;
124  }
125  }
126  return fmt_found;
127 }
128 
129  enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
130  const char *filename, const char *mime_type,
131  enum AVMediaType type)
132 {
133  if (av_match_name("segment", fmt->name) || av_match_name("ssegment", fmt->name)) {
134  AVOutputFormat *fmt2 = av_guess_format(NULL, filename, NULL);
135  if (fmt2)
136  fmt = fmt2;
137  }
138 
139  if (type == AVMEDIA_TYPE_VIDEO) {
140  enum AVCodecID codec_id = AV_CODEC_ID_NONE;
141 
142 #if CONFIG_IMAGE2_MUXER
143  if (!strcmp(fmt->name, "image2") || !strcmp(fmt->name, "image2pipe")) {
144  codec_id = ff_guess_image2_codec(filename);
145  }
146 #endif
147  if (codec_id == AV_CODEC_ID_NONE)
148  codec_id = fmt->video_codec;
149  return codec_id;
150  } else if (type == AVMEDIA_TYPE_AUDIO)
151  return fmt->audio_codec;
152  else if (type == AVMEDIA_TYPE_SUBTITLE)
153  return fmt->subtitle_codec;
154  else if (type == AVMEDIA_TYPE_DATA)
155  return fmt->data_codec;
156  else
157  return AV_CODEC_ID_NONE;
158 }
159 
160  AVInputFormat *av_find_input_format(const char *short_name)
161 {
162  AVInputFormat *fmt = NULL;
163  while ((fmt = av_iformat_next(fmt)))
164  if (av_match_name(short_name, fmt->name))
165  return fmt;
166  return NULL;
167 }
168 
169  AVInputFormat *av_probe_input_format3(AVProbeData *pd, int is_opened,
170  int *score_ret)
171 {
172  AVProbeData lpd = *pd;
173  AVInputFormat *fmt1 = NULL, *fmt;
174  int score, score_max = 0;
175  const static uint8_t zerobuffer[AVPROBE_PADDING_SIZE];
176  enum nodat {
177  NO_ID3,
178  ID3_ALMOST_GREATER_PROBE,
179  ID3_GREATER_PROBE,
180  ID3_GREATER_MAX_PROBE,
181  } nodat = NO_ID3;
182 
183  if (!lpd.buf)
184  lpd.buf = (unsigned char *) zerobuffer;
185 
186  if (lpd.buf_size > 10 && ff_id3v2_match(lpd.buf, ID3v2_DEFAULT_MAGIC)) {
187  int id3len = ff_id3v2_tag_len(lpd.buf);
188  if (lpd.buf_size > id3len + 16) {
189  if (lpd.buf_size < 2LL*id3len + 16)
190  nodat = ID3_ALMOST_GREATER_PROBE;
191  lpd.buf += id3len;
192  lpd.buf_size -= id3len;
193  } else if (id3len >= PROBE_BUF_MAX) {
194  nodat = ID3_GREATER_MAX_PROBE;
195  } else
196  nodat = ID3_GREATER_PROBE;
197  }
198 
199  fmt = NULL;
200  while ((fmt1 = av_iformat_next(fmt1))) {
201  if (!is_opened == !(fmt1->flags & AVFMT_NOFILE) && strcmp(fmt1->name, "image2"))
202  continue;
203  score = 0;
204  if (fmt1->read_probe) {
205  score = fmt1->read_probe(&lpd);
206  if (score)
207  av_log(NULL, AV_LOG_TRACE, "Probing %s score:%d size:%d\n", fmt1->name, score, lpd.buf_size);
208  if (fmt1->extensions && av_match_ext(lpd.filename, fmt1->extensions)) {
209  switch (nodat) {
210  case NO_ID3:
211  score = FFMAX(score, 1);
212  break;
213  case ID3_GREATER_PROBE:
214  case ID3_ALMOST_GREATER_PROBE:
215  score = FFMAX(score, AVPROBE_SCORE_EXTENSION / 2 - 1);
216  break;
217  case ID3_GREATER_MAX_PROBE:
218  score = FFMAX(score, AVPROBE_SCORE_EXTENSION);
219  break;
220  }
221  }
222  } else if (fmt1->extensions) {
223  if (av_match_ext(lpd.filename, fmt1->extensions))
224  score = AVPROBE_SCORE_EXTENSION;
225  }
226  if (av_match_name(lpd.mime_type, fmt1->mime_type))
227  score = FFMAX(score, AVPROBE_SCORE_MIME);
228  if (score > score_max) {
229  score_max = score;
230  fmt = fmt1;
231  } else if (score == score_max)
232  fmt = NULL;
233  }
234  if (nodat == ID3_GREATER_PROBE)
235  score_max = FFMIN(AVPROBE_SCORE_EXTENSION / 2 - 1, score_max);
236  *score_ret = score_max;
237 
238  return fmt;
239 }
240 
241  AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max)
242 {
243  int score_ret;
244  AVInputFormat *fmt = av_probe_input_format3(pd, is_opened, &score_ret);
245  if (score_ret > *score_max) {
246  *score_max = score_ret;
247  return fmt;
248  } else
249  return NULL;
250 }
251 
252  AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened)
253 {
254  int score = 0;
255  return av_probe_input_format2(pd, is_opened, &score);
256 }
257 
258  int av_probe_input_buffer2(AVIOContext *pb, AVInputFormat **fmt,
259  const char *filename, void *logctx,
260  unsigned int offset, unsigned int max_probe_size)
261 {
262  AVProbeData pd = { filename ? filename : "" };
263  uint8_t *buf = NULL;
264  int ret = 0, probe_size, buf_offset = 0;
265  int score = 0;
266  int ret2;
267 
268  if (!max_probe_size)
269  max_probe_size = PROBE_BUF_MAX;
270  else if (max_probe_size < PROBE_BUF_MIN) {
271  av_log(logctx, AV_LOG_ERROR,
272  "Specified probe size value %u cannot be < %u\n", max_probe_size, PROBE_BUF_MIN);
273  return AVERROR(EINVAL);
274  }
275 
276  if (offset >= max_probe_size)
277  return AVERROR(EINVAL);
278 
279  if (pb->av_class) {
280  uint8_t *mime_type_opt = NULL;
281  char *semi;
282  av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type_opt);
283  pd.mime_type = (const char *)mime_type_opt;
284  semi = pd.mime_type ? strchr(pd.mime_type, ';') : NULL;
285  if (semi) {
286  *semi = '0円';
287  }
288  }
289 #if 0
290  if (!*fmt && pb->av_class && av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type) >= 0 && mime_type) {
291  if (!av_strcasecmp(mime_type, "audio/aacp")) {
292  *fmt = av_find_input_format("aac");
293  }
294  av_freep(&mime_type);
295  }
296 #endif
297 
298  for (probe_size = PROBE_BUF_MIN; probe_size <= max_probe_size && !*fmt;
299  probe_size = FFMIN(probe_size << 1,
300  FFMAX(max_probe_size, probe_size + 1))) {
301  score = probe_size < max_probe_size ? AVPROBE_SCORE_RETRY : 0;
302 
303  /* Read probe data. */
304  if ((ret = av_reallocp(&buf, probe_size + AVPROBE_PADDING_SIZE)) < 0)
305  goto fail;
306  if ((ret = avio_read(pb, buf + buf_offset,
307  probe_size - buf_offset)) < 0) {
308  /* Fail if error was not end of file, otherwise, lower score. */
309  if (ret != AVERROR_EOF)
310  goto fail;
311 
312  score = 0;
313  ret = 0; /* error was end of file, nothing read */
314  }
315  buf_offset += ret;
316  if (buf_offset < offset)
317  continue;
318  pd.buf_size = buf_offset - offset;
319  pd.buf = &buf[offset];
320 
321  memset(pd.buf + pd.buf_size, 0, AVPROBE_PADDING_SIZE);
322 
323  /* Guess file format. */
324  *fmt = av_probe_input_format2(&pd, 1, &score);
325  if (*fmt) {
326  /* This can only be true in the last iteration. */
327  if (score <= AVPROBE_SCORE_RETRY) {
328  av_log(logctx, AV_LOG_WARNING,
329  "Format %s detected only with low score of %d, "
330  "misdetection possible!\n", (*fmt)->name, score);
331  } else
332  av_log(logctx, AV_LOG_DEBUG,
333  "Format %s probed with size=%d and score=%d\n",
334  (*fmt)->name, probe_size, score);
335 #if 0
336  FILE *f = fopen("probestat.tmp", "ab");
337  fprintf(f, "probe_size:%d format:%s score:%d filename:%s\n", probe_size, (*fmt)->name, score, filename);
338  fclose(f);
339 #endif
340  }
341  }
342 
343  if (!*fmt)
344  ret = AVERROR_INVALIDDATA;
345 
346 fail:
347  /* Rewind. Reuse probe buffer to avoid seeking. */
348  ret2 = ffio_rewind_with_probe_data(pb, &buf, buf_offset);
349  if (ret >= 0)
350  ret = ret2;
351 
352  av_freep(&pd.mime_type);
353  return ret < 0 ? ret : score;
354 }
355 
356  int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,
357  const char *filename, void *logctx,
358  unsigned int offset, unsigned int max_probe_size)
359 {
360  int ret = av_probe_input_buffer2(pb, fmt, filename, logctx, offset, max_probe_size);
361  return ret < 0 ? ret : 0;
362 }
NULL
#define NULL
Definition: coverity.c:32
AVIOContext
Bytestream IO Context.
Definition: avio.h:111
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
AV_CODEC_ID_NONE
Definition: avcodec.h:102
last_iformat
static AVInputFormat ** last_iformat
Definition: format.c:42
fmt
const char * fmt
Definition: avisynth_c.h:632
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
AVProbeData::filename
const char * filename
Definition: avformat.h:461
ffio_rewind_with_probe_data
int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char **buf, int buf_size)
Rewind the AVIOContext using the specified buffer containing the first buf_size bytes of the file...
Definition: aviobuf.c:882
last_oformat
static AVOutputFormat ** last_oformat
Definition: format.c:43
AVOutputFormat::video_codec
enum AVCodecID video_codec
default video codec
Definition: avformat.h:534
ID3v2_DEFAULT_MAGIC
#define ID3v2_DEFAULT_MAGIC
Default magic bytes for ID3v2 header: "ID3".
Definition: id3v2.h:35
AVPROBE_PADDING_SIZE
#define AVPROBE_PADDING_SIZE
extra allocated bytes at the end of the probe buffer
Definition: avformat.h:474
av_probe_input_format3
AVInputFormat * av_probe_input_format3(AVProbeData *pd, int is_opened, int *score_ret)
Guess the file format.
Definition: format.c:169
PROBE_BUF_MAX
#define PROBE_BUF_MAX
Definition: internal.h:32
uint8_t
uint8_t
Definition: audio_convert.c:194
AVMEDIA_TYPE_DATA
Opaque data information usually continuous.
Definition: avutil.h:195
opt.h
AVOptions.
AVInputFormat::flags
int flags
Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS, AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH, AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK, AVFMT_SEEK_TO_PTS.
Definition: avformat.h:675
AV_LOG_TRACE
#define AV_LOG_TRACE
Extremely verbose debugging, useful for libav* development.
Definition: log.h:202
AVPROBE_SCORE_MIME
#define AVPROBE_SCORE_MIME
score for file mime type
Definition: avformat.h:471
AVIOContext::av_class
const AVClass * av_class
A class for private options.
Definition: avio.h:124
avio_internal.h
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:55
av_match_ext
int av_match_ext(const char *filename, const char *extensions)
Return a positive value if the given filename has one of the given extensions, 0 otherwise.
Definition: format.c:81
av_probe_input_buffer2
int av_probe_input_buffer2(AVIOContext *pb, AVInputFormat **fmt, const char *filename, void *logctx, unsigned int offset, unsigned int max_probe_size)
Probe a bytestream to determine the input format.
Definition: format.c:258
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
avio_read
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:545
av_probe_input_buffer
int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt, const char *filename, void *logctx, unsigned int offset, unsigned int max_probe_size)
Like av_probe_input_buffer2() but returns 0 on success.
Definition: format.c:356
AVCodecID
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: avcodec.h:101
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
avpriv_atomic_ptr_cas
#define avpriv_atomic_ptr_cas
Definition: atomic_gcc.h:60
AVInputFormat::read_probe
int(* read_probe)(AVProbeData *)
Tell if a given file has a chance of being parsed as this format.
Definition: avformat.h:719
first_oformat
static AVOutputFormat * first_oformat
head of registered output format linked list
Definition: format.c:40
AVERROR
#define AVERROR(e)
Definition: error.h:43
AV_LOG_DEBUG
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:197
AVMEDIA_TYPE_AUDIO
Definition: avutil.h:194
av_match_name
int av_match_name(const char *name, const char *names)
Match instances of a name in a comma-separated list of names.
Definition: avstring.c:320
codec_id
enum AVCodecID codec_id
Definition: mov_chan.c:433
offset
static const uint8_t offset[127][2]
Definition: vf_spp.c:92
FFMAX
#define FFMAX(a, b)
Definition: common.h:94
av_probe_input_format2
AVInputFormat * av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max)
Guess the file format.
Definition: format.c:241
fail
#define fail()
Definition: checkasm.h:80
AVProbeData::mime_type
const char * mime_type
mime_type, when known.
Definition: avformat.h:464
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:463
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:462
av_find_input_format
AVInputFormat * av_find_input_format(const char *short_name)
Find AVInputFormat based on the short name of the input format.
Definition: format.c:160
FFMIN
#define FFMIN(a, b)
Definition: common.h:96
av_strcasecmp
int av_strcasecmp(const char *a, const char *b)
Locale-independent case-insensitive compare.
Definition: avstring.c:213
AV_OPT_SEARCH_CHILDREN
#define AV_OPT_SEARCH_CHILDREN
Search in possible children of the given object first.
Definition: opt.h:556
av_guess_codec
enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name, const char *filename, const char *mime_type, enum AVMediaType type)
Guess the codec ID based upon muxer and filename.
Definition: format.c:129
AVOutputFormat::name
const char * name
Definition: avformat.h:523
av_guess_format
AVOutputFormat * av_guess_format(const char *short_name, const char *filename, const char *mime_type)
Return the output format in the list of registered output formats which best matches the provided par...
Definition: format.c:94
AVPROBE_SCORE_RETRY
#define AVPROBE_SCORE_RETRY
Definition: avformat.h:467
av_register_input_format
void av_register_input_format(AVInputFormat *format)
Definition: format.c:61
av_oformat_next
AVOutputFormat * av_oformat_next(const AVOutputFormat *f)
If f is NULL, returns the first registered output format, if f is non-NULL, returns the next register...
Definition: format.c:53
PROBE_BUF_MIN
#define PROBE_BUF_MIN
size of probe buffer, for guessing file type from file contents
Definition: internal.h:31
av_register_output_format
void av_register_output_format(AVOutputFormat *format)
Definition: format.c:71
AVOutputFormat::next
struct AVOutputFormat * next
Definition: avformat.h:560
av_filename_number_test
int av_filename_number_test(const char *filename)
Check whether filename actually is a numbered sequence generator.
Definition: utils.c:269
format
static const char * format
Definition: movenc-test.c:47
buf
void * buf
Definition: avisynth_c.h:553
type
GLint GLenum type
Definition: opengl_enc.c:105
AVOutputFormat::subtitle_codec
enum AVCodecID subtitle_codec
default subtitle codec
Definition: avformat.h:535
AVMediaType
AVMediaType
Definition: avutil.h:191
AVPROBE_SCORE_EXTENSION
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:470
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:460
AVInputFormat::mime_type
const char * mime_type
Comma-separated list of mime types.
Definition: avformat.h:693
AVInputFormat::extensions
const char * extensions
If extensions are defined, then no probe is done.
Definition: avformat.h:682
avformat.h
Main libavformat public API header.
first_iformat
static AVInputFormat * first_iformat
head of registered input format linked list
Definition: format.c:38
AVFMT_NOFILE
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:477
ff_id3v2_match
int ff_id3v2_match(const uint8_t *buf, const char *magic)
Detect ID3v2 Header.
Definition: id3v2.c:141
AVOutputFormat::data_codec
enum AVCodecID data_codec
default data codec
Definition: avformat.h:623
av_reallocp
int av_reallocp(void *ptr, size_t size)
Allocate or reallocate a block of memory.
Definition: mem.c:187
ff_guess_image2_codec
enum AVCodecID ff_guess_image2_codec(const char *filename)
Definition: img2.c:100
av_opt_get
int av_opt_get(void *obj, const char *name, int search_flags, uint8_t **out_val)
Definition: opt.c:678
AVOutputFormat::audio_codec
enum AVCodecID audio_codec
default audio codec
Definition: avformat.h:533
ff_id3v2_tag_len
int ff_id3v2_tag_len(const uint8_t *buf)
Get the length of an ID3v2 tag.
Definition: id3v2.c:154
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:661
AVMEDIA_TYPE_VIDEO
Definition: avutil.h:193
AVInputFormat::next
struct AVInputFormat * next
Definition: avformat.h:702
AVMEDIA_TYPE_SUBTITLE
Definition: avutil.h:196
AVOutputFormat::extensions
const char * extensions
comma-separated filename extensions
Definition: avformat.h:531
av_probe_input_format
AVInputFormat * av_probe_input_format(AVProbeData *pd, int is_opened)
Guess the file format.
Definition: format.c:252
AVOutputFormat::mime_type
const char * mime_type
Definition: avformat.h:530
av_iformat_next
AVInputFormat * av_iformat_next(const AVInputFormat *f)
If f is NULL, returns the first registered input format, if f is non-NULL, returns the next registere...
Definition: format.c:45
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