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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  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 
72 {
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_list(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) &&
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) {
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
155  return AV_CODEC_ID_NONE;
156 }
157 
158 AVInputFormat *av_find_input_format(const char *short_name)
159 {
160  AVInputFormat *fmt = NULL;
161  while ((fmt = av_iformat_next(fmt)))
162  if (av_match_name(short_name, fmt->name))
163  return fmt;
164  return NULL;
165 }
166 
168  int *score_ret)
169 {
170  AVProbeData lpd = *pd;
171  AVInputFormat *fmt1 = NULL, *fmt;
172  int score, nodat = 0, score_max = 0;
173  const static uint8_t zerobuffer[AVPROBE_PADDING_SIZE];
174 
175  if (!lpd.buf)
176  lpd.buf = zerobuffer;
177 
178  if (lpd.buf_size > 10 && ff_id3v2_match(lpd.buf, ID3v2_DEFAULT_MAGIC)) {
179  int id3len = ff_id3v2_tag_len(lpd.buf);
180  if (lpd.buf_size > id3len + 16) {
181  lpd.buf += id3len;
182  lpd.buf_size -= id3len;
183  } else if (id3len >= PROBE_BUF_MAX) {
184  nodat = 2;
185  } else
186  nodat = 1;
187  }
188 
189  fmt = NULL;
190  while ((fmt1 = av_iformat_next(fmt1))) {
191  if (!is_opened == !(fmt1->flags & AVFMT_NOFILE) && strcmp(fmt1->name, "image2"))
192  continue;
193  score = 0;
194  if (fmt1->read_probe) {
195  score = fmt1->read_probe(&lpd);
196  if (fmt1->extensions && av_match_ext(lpd.filename, fmt1->extensions)) {
197  if (nodat == 0) score = FFMAX(score, 1);
198  else if (nodat == 1) score = FFMAX(score, AVPROBE_SCORE_EXTENSION / 2 - 1);
199  else score = FFMAX(score, AVPROBE_SCORE_EXTENSION);
200  }
201  } else if (fmt1->extensions) {
202  if (av_match_ext(lpd.filename, fmt1->extensions))
203  score = AVPROBE_SCORE_EXTENSION;
204  }
205  if (av_match_name(lpd.mime_type, fmt1->mime_type))
206  score = FFMAX(score, AVPROBE_SCORE_MIME);
207  if (score > score_max) {
208  score_max = score;
209  fmt = fmt1;
210  } else if (score == score_max)
211  fmt = NULL;
212  }
213  if (nodat == 1)
214  score_max = FFMIN(AVPROBE_SCORE_EXTENSION / 2 - 1, score_max);
215  *score_ret = score_max;
216 
217  return fmt;
218 }
219 
220 AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max)
221 {
222  int score_ret;
223  AVInputFormat *fmt = av_probe_input_format3(pd, is_opened, &score_ret);
224  if (score_ret > *score_max) {
225  *score_max = score_ret;
226  return fmt;
227  } else
228  return NULL;
229 }
230 
232 {
233  int score = 0;
234  return av_probe_input_format2(pd, is_opened, &score);
235 }
236 
238  const char *filename, void *logctx,
239  unsigned int offset, unsigned int max_probe_size)
240 {
241  AVProbeData pd = { filename ? filename : "" };
242  uint8_t *buf = NULL;
243  int ret = 0, probe_size, buf_offset = 0;
244  int score = 0;
245  int ret2;
246 
247  if (!max_probe_size)
248  max_probe_size = PROBE_BUF_MAX;
249  else if (max_probe_size < PROBE_BUF_MIN) {
250  av_log(logctx, AV_LOG_ERROR,
251  "Specified probe size value %u cannot be < %u\n", max_probe_size, PROBE_BUF_MIN);
252  return AVERROR(EINVAL);
253  }
254 
255  if (offset >= max_probe_size)
256  return AVERROR(EINVAL);
257 
258  if (pb->av_class) {
259  uint8_t *mime_type_opt = NULL;
260  av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type_opt);
261  pd.mime_type = (const char *)mime_type_opt;
262  }
263 #if 0
264  if (!*fmt && pb->av_class && av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type) >= 0 && mime_type) {
265  if (!av_strcasecmp(mime_type, "audio/aacp")) {
266  *fmt = av_find_input_format("aac");
267  }
268  av_freep(&mime_type);
269  }
270 #endif
271 
272  for (probe_size = PROBE_BUF_MIN; probe_size <= max_probe_size && !*fmt;
273  probe_size = FFMIN(probe_size << 1,
274  FFMAX(max_probe_size, probe_size + 1))) {
275  score = probe_size < max_probe_size ? AVPROBE_SCORE_RETRY : 0;
276 
277  /* Read probe data. */
278  if ((ret = av_reallocp(&buf, probe_size + AVPROBE_PADDING_SIZE)) < 0)
279  goto fail;
280  if ((ret = avio_read(pb, buf + buf_offset,
281  probe_size - buf_offset)) < 0) {
282  /* Fail if error was not end of file, otherwise, lower score. */
283  if (ret != AVERROR_EOF)
284  goto fail;
285 
286  score = 0;
287  ret = 0; /* error was end of file, nothing read */
288  }
289  buf_offset += ret;
290  if (buf_offset < offset)
291  continue;
292  pd.buf_size = buf_offset - offset;
293  pd.buf = &buf[offset];
294 
295  memset(pd.buf + pd.buf_size, 0, AVPROBE_PADDING_SIZE);
296 
297  /* Guess file format. */
298  *fmt = av_probe_input_format2(&pd, 1, &score);
299  if (*fmt) {
300  /* This can only be true in the last iteration. */
301  if (score <= AVPROBE_SCORE_RETRY) {
302  av_log(logctx, AV_LOG_WARNING,
303  "Format %s detected only with low score of %d, "
304  "misdetection possible!\n", (*fmt)->name, score);
305  } else
306  av_log(logctx, AV_LOG_DEBUG,
307  "Format %s probed with size=%d and score=%d\n",
308  (*fmt)->name, probe_size, score);
309 #if 0
310  FILE *f = fopen("probestat.tmp", "ab");
311  fprintf(f, "probe_size:%d format:%s score:%d filename:%s\n", probe_size, (*fmt)->name, score, filename);
312  fclose(f);
313 #endif
314  }
315  }
316 
317  if (!*fmt)
318  ret = AVERROR_INVALIDDATA;
319 
320 fail:
321  /* Rewind. Reuse probe buffer to avoid seeking. */
322  ret2 = ffio_rewind_with_probe_data(pb, &buf, buf_offset);
323  if (ret >= 0)
324  ret = ret2;
325 
326  av_freep(&pd.mime_type);
327  return ret < 0 ? ret : score;
328 }
329 
331  const char *filename, void *logctx,
332  unsigned int offset, unsigned int max_probe_size)
333 {
334  int ret = av_probe_input_buffer2(pb, fmt, filename, logctx, offset, max_probe_size);
335  return ret < 0 ? ret : 0;
336 }