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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 */
39 /** head of registered output format linked list */
41 
44 
46 {
47  if (f)
48  return f->next;
49  else
50  return first_iformat;
51 }
52 
54 {
55  if (f)
56  return f->next;
57  else
58  return first_oformat;
59 }
60 
62 {
64 
65  // Note, format could be added after the first 2 checks but that implies that *p is no longer NULL
66  while(p != &format->next && !format->next && avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))
67  p = &(*p)->next;
68 
69  if (!format->next)
70  last_iformat = &format->next;
71 }
72 
74 {
76 
77  // Note, format could be added after the first 2 checks but that implies that *p is no longer NULL
78  while(p != &format->next && !format->next && avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))
79  p = &(*p)->next;
80 
81  if (!format->next)
82  last_oformat = &format->next;
83 }
84 
85 int av_match_ext(const char *filename, const char *extensions)
86 {
87  const char *ext;
88 
89  if (!filename)
90  return 0;
91 
92  ext = strrchr(filename, '.');
93  if (ext)
94  return av_match_name(ext + 1, extensions);
95  return 0;
96 }
97 
98 AVOutputFormat *av_guess_format(const char *short_name, const char *filename,
99  const char *mime_type)
100 {
101  AVOutputFormat *fmt = NULL, *fmt_found;
102  int score_max, score;
103 
104  /* specific test for image sequences */
105 #if CONFIG_IMAGE2_MUXER
106  if (!short_name && filename &&
107  av_filename_number_test(filename) &&
109  return av_guess_format("image2", NULL, NULL);
110  }
111 #endif
112  /* Find the proper file type. */
113  fmt_found = NULL;
114  score_max = 0;
115  while ((fmt = av_oformat_next(fmt))) {
116  score = 0;
117  if (fmt->name && short_name && av_match_name(short_name, fmt->name))
118  score += 100;
119  if (fmt->mime_type && mime_type && !strcmp(fmt->mime_type, mime_type))
120  score += 10;
121  if (filename && fmt->extensions &&
122  av_match_ext(filename, fmt->extensions)) {
123  score += 5;
124  }
125  if (score > score_max) {
126  score_max = score;
127  fmt_found = fmt;
128  }
129  }
130  return fmt_found;
131 }
132 
133 enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
134  const char *filename, const char *mime_type,
135  enum AVMediaType type)
136 {
137  if (av_match_name("segment", fmt->name) || av_match_name("ssegment", fmt->name)) {
138  AVOutputFormat *fmt2 = av_guess_format(NULL, filename, NULL);
139  if (fmt2)
140  fmt = fmt2;
141  }
142 
143  if (type == AVMEDIA_TYPE_VIDEO) {
145 
146 #if CONFIG_IMAGE2_MUXER
147  if (!strcmp(fmt->name, "image2") || !strcmp(fmt->name, "image2pipe")) {
148  codec_id = ff_guess_image2_codec(filename);
149  }
150 #endif
151  if (codec_id == AV_CODEC_ID_NONE)
152  codec_id = fmt->video_codec;
153  return codec_id;
154  } else if (type == AVMEDIA_TYPE_AUDIO)
155  return fmt->audio_codec;
156  else if (type == AVMEDIA_TYPE_SUBTITLE)
157  return fmt->subtitle_codec;
158  else if (type == AVMEDIA_TYPE_DATA)
159  return fmt->data_codec;
160  else
161  return AV_CODEC_ID_NONE;
162 }
163 
164 AVInputFormat *av_find_input_format(const char *short_name)
165 {
167  while ((fmt = av_iformat_next(fmt)))
168  if (av_match_name(short_name, fmt->name))
169  return fmt;
170  return NULL;
171 }
172 
174  int *score_ret)
175 {
176  AVProbeData lpd = *pd;
177  AVInputFormat *fmt1 = NULL, *fmt;
178  int score, score_max = 0;
179  const static uint8_t zerobuffer[AVPROBE_PADDING_SIZE];
180  enum nodat {
181  NO_ID3,
182  ID3_ALMOST_GREATER_PROBE,
183  ID3_GREATER_PROBE,
184  ID3_GREATER_MAX_PROBE,
185  } nodat = NO_ID3;
186 
187  if (!lpd.buf)
188  lpd.buf = (unsigned char *) zerobuffer;
189 
190  if (lpd.buf_size > 10 && ff_id3v2_match(lpd.buf, ID3v2_DEFAULT_MAGIC)) {
191  int id3len = ff_id3v2_tag_len(lpd.buf);
192  if (lpd.buf_size > id3len + 16) {
193  if (lpd.buf_size < 2LL*id3len + 16)
194  nodat = ID3_ALMOST_GREATER_PROBE;
195  lpd.buf += id3len;
196  lpd.buf_size -= id3len;
197  } else if (id3len >= PROBE_BUF_MAX) {
198  nodat = ID3_GREATER_MAX_PROBE;
199  } else
200  nodat = ID3_GREATER_PROBE;
201  }
202 
203  fmt = NULL;
204  while ((fmt1 = av_iformat_next(fmt1))) {
205  if (!is_opened == !(fmt1->flags & AVFMT_NOFILE) && strcmp(fmt1->name, "image2"))
206  continue;
207  score = 0;
208  if (fmt1->read_probe) {
209  score = fmt1->read_probe(&lpd);
210  if (score)
211  av_log(NULL, AV_LOG_TRACE, "Probing %s score:%d size:%d\n", fmt1->name, score, lpd.buf_size);
212  if (fmt1->extensions && av_match_ext(lpd.filename, fmt1->extensions)) {
213  switch (nodat) {
214  case NO_ID3:
215  score = FFMAX(score, 1);
216  break;
217  case ID3_GREATER_PROBE:
218  case ID3_ALMOST_GREATER_PROBE:
219  score = FFMAX(score, AVPROBE_SCORE_EXTENSION / 2 - 1);
220  break;
221  case ID3_GREATER_MAX_PROBE:
222  score = FFMAX(score, AVPROBE_SCORE_EXTENSION);
223  break;
224  }
225  }
226  } else if (fmt1->extensions) {
227  if (av_match_ext(lpd.filename, fmt1->extensions))
228  score = AVPROBE_SCORE_EXTENSION;
229  }
230  if (av_match_name(lpd.mime_type, fmt1->mime_type)) {
231  if (AVPROBE_SCORE_MIME > score) {
232  av_log(NULL, AV_LOG_DEBUG, "Probing %s score:%d increased to %d due to MIME type\n", fmt1->name, score, AVPROBE_SCORE_MIME);
233  score = AVPROBE_SCORE_MIME;
234  }
235  }
236  if (score > score_max) {
237  score_max = score;
238  fmt = fmt1;
239  } else if (score == score_max)
240  fmt = NULL;
241  }
242  if (nodat == ID3_GREATER_PROBE)
243  score_max = FFMIN(AVPROBE_SCORE_EXTENSION / 2 - 1, score_max);
244  *score_ret = score_max;
245 
246  return fmt;
247 }
248 
249 AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max)
250 {
251  int score_ret;
252  AVInputFormat *fmt = av_probe_input_format3(pd, is_opened, &score_ret);
253  if (score_ret > *score_max) {
254  *score_max = score_ret;
255  return fmt;
256  } else
257  return NULL;
258 }
259 
261 {
262  int score = 0;
263  return av_probe_input_format2(pd, is_opened, &score);
264 }
265 
267  const char *filename, void *logctx,
268  unsigned int offset, unsigned int max_probe_size)
269 {
270  AVProbeData pd = { filename ? filename : "" };
271  uint8_t *buf = NULL;
272  int ret = 0, probe_size, buf_offset = 0;
273  int score = 0;
274  int ret2;
275 
276  if (!max_probe_size)
277  max_probe_size = PROBE_BUF_MAX;
278  else if (max_probe_size < PROBE_BUF_MIN) {
279  av_log(logctx, AV_LOG_ERROR,
280  "Specified probe size value %u cannot be < %u\n", max_probe_size, PROBE_BUF_MIN);
281  return AVERROR(EINVAL);
282  }
283 
284  if (offset >= max_probe_size)
285  return AVERROR(EINVAL);
286 
287  if (pb->av_class) {
288  uint8_t *mime_type_opt = NULL;
289  char *semi;
290  av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type_opt);
291  pd.mime_type = (const char *)mime_type_opt;
292  semi = pd.mime_type ? strchr(pd.mime_type, ';') : NULL;
293  if (semi) {
294  *semi = '\0';
295  }
296  }
297 #if 0
298  if (!*fmt && pb->av_class && av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type) >= 0 && mime_type) {
299  if (!av_strcasecmp(mime_type, "audio/aacp")) {
300  *fmt = av_find_input_format("aac");
301  }
302  av_freep(&mime_type);
303  }
304 #endif
305 
306  for (probe_size = PROBE_BUF_MIN; probe_size <= max_probe_size && !*fmt;
307  probe_size = FFMIN(probe_size << 1,
308  FFMAX(max_probe_size, probe_size + 1))) {
309  score = probe_size < max_probe_size ? AVPROBE_SCORE_RETRY : 0;
310 
311  /* Read probe data. */
312  if ((ret = av_reallocp(&buf, probe_size + AVPROBE_PADDING_SIZE)) < 0)
313  goto fail;
314  if ((ret = avio_read(pb, buf + buf_offset,
315  probe_size - buf_offset)) < 0) {
316  /* Fail if error was not end of file, otherwise, lower score. */
317  if (ret != AVERROR_EOF)
318  goto fail;
319 
320  score = 0;
321  ret = 0; /* error was end of file, nothing read */
322  }
323  buf_offset += ret;
324  if (buf_offset < offset)
325  continue;
326  pd.buf_size = buf_offset - offset;
327  pd.buf = &buf[offset];
328 
329  memset(pd.buf + pd.buf_size, 0, AVPROBE_PADDING_SIZE);
330 
331  /* Guess file format. */
332  *fmt = av_probe_input_format2(&pd, 1, &score);
333  if (*fmt) {
334  /* This can only be true in the last iteration. */
335  if (score <= AVPROBE_SCORE_RETRY) {
336  av_log(logctx, AV_LOG_WARNING,
337  "Format %s detected only with low score of %d, "
338  "misdetection possible!\n", (*fmt)->name, score);
339  } else
340  av_log(logctx, AV_LOG_DEBUG,
341  "Format %s probed with size=%d and score=%d\n",
342  (*fmt)->name, probe_size, score);
343 #if 0
344  FILE *f = fopen("probestat.tmp", "ab");
345  fprintf(f, "probe_size:%d format:%s score:%d filename:%s\n", probe_size, (*fmt)->name, score, filename);
346  fclose(f);
347 #endif
348  }
349  }
350 
351  if (!*fmt)
352  ret = AVERROR_INVALIDDATA;
353 
354 fail:
355  /* Rewind. Reuse probe buffer to avoid seeking. */
356  ret2 = ffio_rewind_with_probe_data(pb, &buf, buf_offset);
357  if (ret >= 0)
358  ret = ret2;
359 
360  av_freep(&pd.mime_type);
361  return ret < 0 ? ret : score;
362 }
363 
365  const char *filename, void *logctx,
366  unsigned int offset, unsigned int max_probe_size)
367 {
368  int ret = av_probe_input_buffer2(pb, fmt, filename, logctx, offset, max_probe_size);
369  return ret < 0 ? ret : 0;
370 }
#define NULL
Definition: coverity.c:32
Bytestream IO Context.
Definition: avio.h:147
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
enum AVCodecID codec_id
Definition: ffmpeg_vaapi.c:149
static AVInputFormat ** last_iformat
Definition: format.c:42
const char * fmt
Definition: avisynth_c.h:632
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
const char * filename
Definition: avformat.h:460
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:983
static AVOutputFormat ** last_oformat
Definition: format.c:43
enum AVCodecID video_codec
default video codec
Definition: avformat.h:533
#define ID3v2_DEFAULT_MAGIC
Default magic bytes for ID3v2 header: "ID3".
Definition: id3v2.h:35
#define AVPROBE_PADDING_SIZE
extra allocated bytes at the end of the probe buffer
Definition: avformat.h:473
AVInputFormat * av_probe_input_format3(AVProbeData *pd, int is_opened, int *score_ret)
Guess the file format.
Definition: format.c:173
#define PROBE_BUF_MAX
Definition: internal.h:34
uint8_t
Opaque data information usually continuous.
Definition: avutil.h:195
AVOptions.
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:674
#define AV_LOG_TRACE
Extremely verbose debugging, useful for libav* development.
Definition: log.h:202
#define AVPROBE_SCORE_MIME
score for file mime type
Definition: avformat.h:470
const AVClass * av_class
A class for private options.
Definition: avio.h:160
#define AVERROR_EOF
End of file.
Definition: error.h:55
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:85
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:266
#define av_log(a,...)
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:598
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:364
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: avcodec.h:189
#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:60
int(* read_probe)(AVProbeData *)
Tell if a given file has a chance of being parsed as this format.
Definition: avformat.h:718
static AVOutputFormat * first_oformat
head of registered output format linked list
Definition: format.c:40
#define AVERROR(e)
Definition: error.h:43
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:197
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
static const uint8_t offset[127][2]
Definition: vf_spp.c:92
#define FFMAX(a, b)
Definition: common.h:94
AVInputFormat * av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max)
Guess the file format.
Definition: format.c:249
#define fail()
Definition: checkasm.h:82
const char * mime_type
mime_type, when known.
Definition: avformat.h:463
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:462
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:461
AVInputFormat * av_find_input_format(const char *short_name)
Find AVInputFormat based on the short name of the input format.
Definition: format.c:164
#define FFMIN(a, b)
Definition: common.h:96
int av_strcasecmp(const char *a, const char *b)
Locale-independent case-insensitive compare.
Definition: avstring.c:213
#define AV_OPT_SEARCH_CHILDREN
Search in possible children of the given object first.
Definition: opt.h:556
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:133
const char * name
Definition: avformat.h:522
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:98
#define AVPROBE_SCORE_RETRY
Definition: avformat.h:466
void av_register_input_format(AVInputFormat *format)
Definition: format.c:61
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
#define PROBE_BUF_MIN
size of probe buffer, for guessing file type from file contents
Definition: internal.h:33
void av_register_output_format(AVOutputFormat *format)
Definition: format.c:73
struct AVOutputFormat * next
Definition: avformat.h:559
int av_filename_number_test(const char *filename)
Check whether filename actually is a numbered sequence generator.
Definition: utils.c:277
void * buf
Definition: avisynth_c.h:553
GLint GLenum type
Definition: opengl_enc.c:105
static const char * format
Definition: movenc.c:47
enum AVCodecID subtitle_codec
default subtitle codec
Definition: avformat.h:534
AVMediaType
Definition: avutil.h:191
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:469
This structure contains the data a format has to probe a file.
Definition: avformat.h:459
const char * mime_type
Comma-separated list of mime types.
Definition: avformat.h:692
const char * extensions
If extensions are defined, then no probe is done.
Definition: avformat.h:681
Main libavformat public API header.
static AVInputFormat * first_iformat
head of registered input format linked list
Definition: format.c:38
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:476
int ff_id3v2_match(const uint8_t *buf, const char *magic)
Detect ID3v2 Header.
Definition: id3v2.c:141
enum AVCodecID data_codec
default data codec
Definition: avformat.h:622
int av_reallocp(void *ptr, size_t size)
Allocate or reallocate a block of memory.
Definition: mem.c:187
enum AVCodecID ff_guess_image2_codec(const char *filename)
Definition: img2.c:99
int av_opt_get(void *obj, const char *name, int search_flags, uint8_t **out_val)
Definition: opt.c:732
enum AVCodecID audio_codec
default audio codec
Definition: avformat.h:532
int ff_id3v2_tag_len(const uint8_t *buf)
Get the length of an ID3v2 tag.
Definition: id3v2.c:154
#define av_freep(p)
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:660
struct AVInputFormat * next
Definition: avformat.h:701
const char * extensions
comma-separated filename extensions
Definition: avformat.h:530
AVInputFormat * av_probe_input_format(AVProbeData *pd, int is_opened)
Guess the file format.
Definition: format.c:260
const char * mime_type
Definition: avformat.h:529
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