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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/avstring.h"
23 #include "libavutil/bprint.h"
24 #include "libavutil/opt.h"
25 #include "libavutil/thread.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 
38 int av_match_ext(const char *filename, const char *extensions)
39 {
40  const char *ext;
41 
42  if (!filename)
43  return 0;
44 
45  ext = strrchr(filename, '.');
46  if (ext)
47  return av_match_name(ext + 1, extensions);
48  return 0;
49 }
50 
51 AVOutputFormat *av_guess_format(const char *short_name, const char *filename,
52  const char *mime_type)
53 {
54  const AVOutputFormat *fmt = NULL;
55  AVOutputFormat *fmt_found = NULL;
56  void *i = 0;
57  int score_max, score;
58 
59  /* specific test for image sequences */
60 #if CONFIG_IMAGE2_MUXER
61  if (!short_name && filename &&
62  av_filename_number_test(filename) &&
64  return av_guess_format("image2", NULL, NULL);
65  }
66 #endif
67  /* Find the proper file type. */
68  score_max = 0;
69  while ((fmt = av_muxer_iterate(&i))) {
70  score = 0;
71  if (fmt->name && short_name && av_match_name(short_name, fmt->name))
72  score += 100;
73  if (fmt->mime_type && mime_type && !strcmp(fmt->mime_type, mime_type))
74  score += 10;
75  if (filename && fmt->extensions &&
76  av_match_ext(filename, fmt->extensions)) {
77  score += 5;
78  }
79  if (score > score_max) {
80  score_max = score;
81  fmt_found = (AVOutputFormat*)fmt;
82  }
83  }
84  return fmt_found;
85 }
86 
87 enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
88  const char *filename, const char *mime_type,
89  enum AVMediaType type)
90 {
91  if (av_match_name("segment", fmt->name) || av_match_name("ssegment", fmt->name)) {
92  AVOutputFormat *fmt2 = av_guess_format(NULL, filename, NULL);
93  if (fmt2)
94  fmt = fmt2;
95  }
96 
97  if (type == AVMEDIA_TYPE_VIDEO) {
99 
100 #if CONFIG_IMAGE2_MUXER
101  if (!strcmp(fmt->name, "image2") || !strcmp(fmt->name, "image2pipe")) {
102  codec_id = ff_guess_image2_codec(filename);
103  }
104 #endif
105  if (codec_id == AV_CODEC_ID_NONE)
106  codec_id = fmt->video_codec;
107  return codec_id;
108  } else if (type == AVMEDIA_TYPE_AUDIO)
109  return fmt->audio_codec;
110  else if (type == AVMEDIA_TYPE_SUBTITLE)
111  return fmt->subtitle_codec;
112  else if (type == AVMEDIA_TYPE_DATA)
113  return fmt->data_codec;
114  else
115  return AV_CODEC_ID_NONE;
116 }
117 
118 AVInputFormat *av_find_input_format(const char *short_name)
119 {
120  const AVInputFormat *fmt = NULL;
121  void *i = 0;
122  while ((fmt = av_demuxer_iterate(&i)))
123  if (av_match_name(short_name, fmt->name))
124  return (AVInputFormat*)fmt;
125  return NULL;
126 }
127 
129  int *score_ret)
130 {
131  AVProbeData lpd = *pd;
132  const AVInputFormat *fmt1 = NULL;
134  int score, score_max = 0;
135  void *i = 0;
136  const static uint8_t zerobuffer[AVPROBE_PADDING_SIZE];
137  enum nodat {
138  NO_ID3,
139  ID3_ALMOST_GREATER_PROBE,
140  ID3_GREATER_PROBE,
141  ID3_GREATER_MAX_PROBE,
142  } nodat = NO_ID3;
143 
144  if (!lpd.buf)
145  lpd.buf = (unsigned char *) zerobuffer;
146 
147  if (lpd.buf_size > 10 && ff_id3v2_match(lpd.buf, ID3v2_DEFAULT_MAGIC)) {
148  int id3len = ff_id3v2_tag_len(lpd.buf);
149  if (lpd.buf_size > id3len + 16) {
150  if (lpd.buf_size < 2LL*id3len + 16)
151  nodat = ID3_ALMOST_GREATER_PROBE;
152  lpd.buf += id3len;
153  lpd.buf_size -= id3len;
154  } else if (id3len >= PROBE_BUF_MAX) {
155  nodat = ID3_GREATER_MAX_PROBE;
156  } else
157  nodat = ID3_GREATER_PROBE;
158  }
159 
160  while ((fmt1 = av_demuxer_iterate(&i))) {
161  if (!is_opened == !(fmt1->flags & AVFMT_NOFILE) && strcmp(fmt1->name, "image2"))
162  continue;
163  score = 0;
164  if (fmt1->read_probe) {
165  score = fmt1->read_probe(&lpd);
166  if (score)
167  av_log(NULL, AV_LOG_TRACE, "Probing %s score:%d size:%d\n", fmt1->name, score, lpd.buf_size);
168  if (fmt1->extensions && av_match_ext(lpd.filename, fmt1->extensions)) {
169  switch (nodat) {
170  case NO_ID3:
171  score = FFMAX(score, 1);
172  break;
173  case ID3_GREATER_PROBE:
174  case ID3_ALMOST_GREATER_PROBE:
175  score = FFMAX(score, AVPROBE_SCORE_EXTENSION / 2 - 1);
176  break;
177  case ID3_GREATER_MAX_PROBE:
178  score = FFMAX(score, AVPROBE_SCORE_EXTENSION);
179  break;
180  }
181  }
182  } else if (fmt1->extensions) {
183  if (av_match_ext(lpd.filename, fmt1->extensions))
184  score = AVPROBE_SCORE_EXTENSION;
185  }
186  if (av_match_name(lpd.mime_type, fmt1->mime_type)) {
187  if (AVPROBE_SCORE_MIME > score) {
188  av_log(NULL, AV_LOG_DEBUG, "Probing %s score:%d increased to %d due to MIME type\n", fmt1->name, score, AVPROBE_SCORE_MIME);
189  score = AVPROBE_SCORE_MIME;
190  }
191  }
192  if (score > score_max) {
193  score_max = score;
194  fmt = (AVInputFormat*)fmt1;
195  } else if (score == score_max)
196  fmt = NULL;
197  }
198  if (nodat == ID3_GREATER_PROBE)
199  score_max = FFMIN(AVPROBE_SCORE_EXTENSION / 2 - 1, score_max);
200  *score_ret = score_max;
201 
202  return fmt;
203 }
204 
205 AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max)
206 {
207  int score_ret;
208  AVInputFormat *fmt = av_probe_input_format3(pd, is_opened, &score_ret);
209  if (score_ret > *score_max) {
210  *score_max = score_ret;
211  return fmt;
212  } else
213  return NULL;
214 }
215 
217 {
218  int score = 0;
219  return av_probe_input_format2(pd, is_opened, &score);
220 }
221 
223  const char *filename, void *logctx,
224  unsigned int offset, unsigned int max_probe_size)
225 {
226  AVProbeData pd = { filename ? filename : "" };
227  uint8_t *buf = NULL;
228  int ret = 0, probe_size, buf_offset = 0;
229  int score = 0;
230  int ret2;
231 
232  if (!max_probe_size)
233  max_probe_size = PROBE_BUF_MAX;
234  else if (max_probe_size < PROBE_BUF_MIN) {
235  av_log(logctx, AV_LOG_ERROR,
236  "Specified probe size value %u cannot be < %u\n", max_probe_size, PROBE_BUF_MIN);
237  return AVERROR(EINVAL);
238  }
239 
240  if (offset >= max_probe_size)
241  return AVERROR(EINVAL);
242 
243  if (pb->av_class) {
244  uint8_t *mime_type_opt = NULL;
245  char *semi;
246  av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type_opt);
247  pd.mime_type = (const char *)mime_type_opt;
248  semi = pd.mime_type ? strchr(pd.mime_type, ';') : NULL;
249  if (semi) {
250  *semi = '\0';
251  }
252  }
253 
254  for (probe_size = PROBE_BUF_MIN; probe_size <= max_probe_size && !*fmt;
255  probe_size = FFMIN(probe_size << 1,
256  FFMAX(max_probe_size, probe_size + 1))) {
257  score = probe_size < max_probe_size ? AVPROBE_SCORE_RETRY : 0;
258 
259  /* Read probe data. */
260  if ((ret = av_reallocp(&buf, probe_size + AVPROBE_PADDING_SIZE)) < 0)
261  goto fail;
262  if ((ret = avio_read(pb, buf + buf_offset,
263  probe_size - buf_offset)) < 0) {
264  /* Fail if error was not end of file, otherwise, lower score. */
265  if (ret != AVERROR_EOF)
266  goto fail;
267 
268  score = 0;
269  ret = 0; /* error was end of file, nothing read */
270  }
271  buf_offset += ret;
272  if (buf_offset < offset)
273  continue;
274  pd.buf_size = buf_offset - offset;
275  pd.buf = &buf[offset];
276 
277  memset(pd.buf + pd.buf_size, 0, AVPROBE_PADDING_SIZE);
278 
279  /* Guess file format. */
280  *fmt = av_probe_input_format2(&pd, 1, &score);
281  if (*fmt) {
282  /* This can only be true in the last iteration. */
283  if (score <= AVPROBE_SCORE_RETRY) {
284  av_log(logctx, AV_LOG_WARNING,
285  "Format %s detected only with low score of %d, "
286  "misdetection possible!\n", (*fmt)->name, score);
287  } else
288  av_log(logctx, AV_LOG_DEBUG,
289  "Format %s probed with size=%d and score=%d\n",
290  (*fmt)->name, probe_size, score);
291 #if 0
292  FILE *f = fopen("probestat.tmp", "ab");
293  fprintf(f, "probe_size:%d format:%s score:%d filename:%s\n", probe_size, (*fmt)->name, score, filename);
294  fclose(f);
295 #endif
296  }
297  }
298 
299  if (!*fmt)
300  ret = AVERROR_INVALIDDATA;
301 
302 fail:
303  /* Rewind. Reuse probe buffer to avoid seeking. */
304  ret2 = ffio_rewind_with_probe_data(pb, &buf, buf_offset);
305  if (ret >= 0)
306  ret = ret2;
307 
308  av_freep(&pd.mime_type);
309  return ret < 0 ? ret : score;
310 }
311 
313  const char *filename, void *logctx,
314  unsigned int offset, unsigned int max_probe_size)
315 {
316  int ret = av_probe_input_buffer2(pb, fmt, filename, logctx, offset, max_probe_size);
317  return ret < 0 ? ret : 0;
318 }
#define NULL
Definition: coverity.c:32
Bytestream IO Context.
Definition: avio.h:161
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
const char * fmt
Definition: avisynth_c.h:769
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
const char * filename
Definition: avformat.h:449
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:1111
enum AVCodecID video_codec
default video codec
Definition: avformat.h:518
#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:462
AVInputFormat * av_probe_input_format3(AVProbeData *pd, int is_opened, int *score_ret)
Guess the file format.
Definition: format.c:128
#define PROBE_BUF_MAX
Definition: internal.h:34
uint8_t
Opaque data information usually continuous.
Definition: avutil.h:203
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:661
#define AV_LOG_TRACE
Extremely verbose debugging, useful for libav* development.
Definition: log.h:202
#define f(width, name)
Definition: cbs_vp9.c:255
#define AVPROBE_SCORE_MIME
score for file mime type
Definition: avformat.h:459
const AVClass * av_class
A class for private options.
Definition: avio.h:174
#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:38
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:222
#define av_log(a,...)
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:648
const AVOutputFormat * av_muxer_iterate(void **opaque)
Iterate over all registered muxers.
Definition: allformats.c:493
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:312
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: avcodec.h:215
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
int(* read_probe)(AVProbeData *)
Tell if a given file has a chance of being parsed as this format.
Definition: avformat.h:705
#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:343
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:205
#define fail()
Definition: checkasm.h:117
const char * mime_type
mime_type, when known.
Definition: avformat.h:452
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:451
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:450
AVInputFormat * av_find_input_format(const char *short_name)
Find AVInputFormat based on the short name of the input format.
Definition: format.c:118
#define FFMIN(a, b)
Definition: common.h:96
#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:87
const char * name
Definition: avformat.h:507
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:51
#define AVPROBE_SCORE_RETRY
Definition: avformat.h:455
enum AVCodecID codec_id
Definition: vaapi_decode.c:362
const AVInputFormat * av_demuxer_iterate(void **opaque)
Iterate over all registered demuxers.
Definition: allformats.c:510
#define PROBE_BUF_MIN
size of probe buffer, for guessing file type from file contents
Definition: internal.h:33
int av_reallocp(void *ptr, size_t size)
Allocate, reallocate, or free a block of memory through a pointer to a pointer.
Definition: mem.c:163
int av_filename_number_test(const char *filename)
Check whether filename actually is a numbered sequence generator.
Definition: utils.c:327
void * buf
Definition: avisynth_c.h:690
GLint GLenum type
Definition: opengl_enc.c:105
enum AVCodecID subtitle_codec
default subtitle codec
Definition: avformat.h:519
AVMediaType
Definition: avutil.h:199
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:458
This structure contains the data a format has to probe a file.
Definition: avformat.h:448
const char * mime_type
Comma-separated list of mime types.
Definition: avformat.h:679
const char * extensions
If extensions are defined, then no probe is done.
Definition: avformat.h:668
Main libavformat public API header.
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:465
int ff_id3v2_match(const uint8_t *buf, const char *magic)
Detect ID3v2 Header.
Definition: id3v2.c:142
enum AVCodecID data_codec
default data codec
Definition: avformat.h:607
enum AVCodecID ff_guess_image2_codec(const char *filename)
Definition: img2.c:102
int av_opt_get(void *obj, const char *name, int search_flags, uint8_t **out_val)
Definition: opt.c:754
enum AVCodecID audio_codec
default audio codec
Definition: avformat.h:517
int ff_id3v2_tag_len(const uint8_t *buf)
Get the length of an ID3v2 tag.
Definition: id3v2.c:155
#define av_freep(p)
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:647
const char * extensions
comma-separated filename extensions
Definition: avformat.h:515
AVInputFormat * av_probe_input_format(AVProbeData *pd, int is_opened)
Guess the file format.
Definition: format.c:216
const char * mime_type
Definition: avformat.h:514