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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, *p;
84  char ext1[32], *q;
85 
86  if (!filename)
87  return 0;
88 
89  ext = strrchr(filename, '.');
90  if (ext) {
91  ext++;
92  p = extensions;
93  for (;;) {
94  q = ext1;
95  while (*p != '\0' && *p != ',' && q - ext1 < sizeof(ext1) - 1)
96  *q++ = *p++;
97  *q = '\0';
98  if (!av_strcasecmp(ext1, ext))
99  return 1;
100  if (*p == '\0')
101  break;
102  p++;
103  }
104  }
105  return 0;
106 }
107 
108 AVOutputFormat *av_guess_format(const char *short_name, const char *filename,
109  const char *mime_type)
110 {
111  AVOutputFormat *fmt = NULL, *fmt_found;
112  int score_max, score;
113 
114  /* specific test for image sequences */
115 #if CONFIG_IMAGE2_MUXER
116  if (!short_name && filename &&
117  av_filename_number_test(filename) &&
119  return av_guess_format("image2", NULL, NULL);
120  }
121 #endif
122  /* Find the proper file type. */
123  fmt_found = NULL;
124  score_max = 0;
125  while ((fmt = av_oformat_next(fmt))) {
126  score = 0;
127  if (fmt->name && short_name && av_match_name(short_name, fmt->name))
128  score += 100;
129  if (fmt->mime_type && mime_type && !strcmp(fmt->mime_type, mime_type))
130  score += 10;
131  if (filename && fmt->extensions &&
132  av_match_ext(filename, fmt->extensions)) {
133  score += 5;
134  }
135  if (score > score_max) {
136  score_max = score;
137  fmt_found = fmt;
138  }
139  }
140  return fmt_found;
141 }
142 
143 enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
144  const char *filename, const char *mime_type,
145  enum AVMediaType type)
146 {
147  if (av_match_name("segment", fmt->name) || av_match_name("ssegment", fmt->name)) {
148  AVOutputFormat *fmt2 = av_guess_format(NULL, filename, NULL);
149  if (fmt2)
150  fmt = fmt2;
151  }
152 
153  if (type == AVMEDIA_TYPE_VIDEO) {
155 
156 #if CONFIG_IMAGE2_MUXER
157  if (!strcmp(fmt->name, "image2") || !strcmp(fmt->name, "image2pipe")) {
158  codec_id = ff_guess_image2_codec(filename);
159  }
160 #endif
161  if (codec_id == AV_CODEC_ID_NONE)
162  codec_id = fmt->video_codec;
163  return codec_id;
164  } else if (type == AVMEDIA_TYPE_AUDIO)
165  return fmt->audio_codec;
166  else if (type == AVMEDIA_TYPE_SUBTITLE)
167  return fmt->subtitle_codec;
168  else
169  return AV_CODEC_ID_NONE;
170 }
171 
172 AVInputFormat *av_find_input_format(const char *short_name)
173 {
174  AVInputFormat *fmt = NULL;
175  while ((fmt = av_iformat_next(fmt)))
176  if (av_match_name(short_name, fmt->name))
177  return fmt;
178  return NULL;
179 }
180 
182  int *score_ret)
183 {
184  AVProbeData lpd = *pd;
185  AVInputFormat *fmt1 = NULL, *fmt;
186  int score, nodat = 0, score_max = 0;
187  const static uint8_t zerobuffer[AVPROBE_PADDING_SIZE];
188 
189  if (!lpd.buf)
190  lpd.buf = zerobuffer;
191 
192  if (lpd.buf_size > 10 && ff_id3v2_match(lpd.buf, ID3v2_DEFAULT_MAGIC)) {
193  int id3len = ff_id3v2_tag_len(lpd.buf);
194  if (lpd.buf_size > id3len + 16) {
195  lpd.buf += id3len;
196  lpd.buf_size -= id3len;
197  } else if (id3len >= PROBE_BUF_MAX) {
198  nodat = 2;
199  } else
200  nodat = 1;
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 (fmt1->extensions && av_match_ext(lpd.filename, fmt1->extensions)) {
211  if (nodat == 0) score = FFMAX(score, 1);
212  else if (nodat == 1) score = FFMAX(score, AVPROBE_SCORE_EXTENSION / 2 - 1);
213  else score = FFMAX(score, AVPROBE_SCORE_EXTENSION);
214  }
215  } else if (fmt1->extensions) {
216  if (av_match_ext(lpd.filename, fmt1->extensions))
217  score = AVPROBE_SCORE_EXTENSION;
218  }
219  if (av_match_name(lpd.mime_type, fmt1->mime_type))
220  score = FFMAX(score, AVPROBE_SCORE_MIME);
221  if (score > score_max) {
222  score_max = score;
223  fmt = fmt1;
224  } else if (score == score_max)
225  fmt = NULL;
226  }
227  if (nodat == 1)
228  score_max = FFMIN(AVPROBE_SCORE_EXTENSION / 2 - 1, score_max);
229  *score_ret = score_max;
230 
231  return fmt;
232 }
233 
234 AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max)
235 {
236  int score_ret;
237  AVInputFormat *fmt = av_probe_input_format3(pd, is_opened, &score_ret);
238  if (score_ret > *score_max) {
239  *score_max = score_ret;
240  return fmt;
241  } else
242  return NULL;
243 }
244 
246 {
247  int score = 0;
248  return av_probe_input_format2(pd, is_opened, &score);
249 }
250 
252  const char *filename, void *logctx,
253  unsigned int offset, unsigned int max_probe_size)
254 {
255  AVProbeData pd = { filename ? filename : "" };
256  uint8_t *buf = NULL;
257  int ret = 0, probe_size, buf_offset = 0;
258  int score = 0;
259  int ret2;
260 
261  if (!max_probe_size)
262  max_probe_size = PROBE_BUF_MAX;
263  else if (max_probe_size < PROBE_BUF_MIN) {
264  av_log(logctx, AV_LOG_ERROR,
265  "Specified probe size value %u cannot be < %u\n", max_probe_size, PROBE_BUF_MIN);
266  return AVERROR(EINVAL);
267  }
268 
269  if (offset >= max_probe_size)
270  return AVERROR(EINVAL);
271 
272  if (pb->av_class)
273  av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &pd.mime_type);
274 #if 0
275  if (!*fmt && pb->av_class && av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type) >= 0 && mime_type) {
276  if (!av_strcasecmp(mime_type, "audio/aacp")) {
277  *fmt = av_find_input_format("aac");
278  }
279  av_freep(&mime_type);
280  }
281 #endif
282 
283  for (probe_size = PROBE_BUF_MIN; probe_size <= max_probe_size && !*fmt;
284  probe_size = FFMIN(probe_size << 1,
285  FFMAX(max_probe_size, probe_size + 1))) {
286  score = probe_size < max_probe_size ? AVPROBE_SCORE_RETRY : 0;
287 
288  /* Read probe data. */
289  if ((ret = av_reallocp(&buf, probe_size + AVPROBE_PADDING_SIZE)) < 0)
290  goto fail;
291  if ((ret = avio_read(pb, buf + buf_offset,
292  probe_size - buf_offset)) < 0) {
293  /* Fail if error was not end of file, otherwise, lower score. */
294  if (ret != AVERROR_EOF)
295  goto fail;
296 
297  score = 0;
298  ret = 0; /* error was end of file, nothing read */
299  }
300  buf_offset += ret;
301  if (buf_offset < offset)
302  continue;
303  pd.buf_size = buf_offset - offset;
304  pd.buf = &buf[offset];
305 
306  memset(pd.buf + pd.buf_size, 0, AVPROBE_PADDING_SIZE);
307 
308  /* Guess file format. */
309  *fmt = av_probe_input_format2(&pd, 1, &score);
310  if (*fmt) {
311  /* This can only be true in the last iteration. */
312  if (score <= AVPROBE_SCORE_RETRY) {
313  av_log(logctx, AV_LOG_WARNING,
314  "Format %s detected only with low score of %d, "
315  "misdetection possible!\n", (*fmt)->name, score);
316  } else
317  av_log(logctx, AV_LOG_DEBUG,
318  "Format %s probed with size=%d and score=%d\n",
319  (*fmt)->name, probe_size, score);
320 #if 0
321  FILE *f = fopen("probestat.tmp", "ab");
322  fprintf(f, "probe_size:%d format:%s score:%d filename:%s\n", probe_size, (*fmt)->name, score, filename);
323  fclose(f);
324 #endif
325  }
326  }
327 
328  if (!*fmt)
329  ret = AVERROR_INVALIDDATA;
330 
331 fail:
332  /* Rewind. Reuse probe buffer to avoid seeking. */
333  ret2 = ffio_rewind_with_probe_data(pb, &buf, buf_offset);
334  if (ret >= 0)
335  ret = ret2;
336 
337  av_free(pd.mime_type);
338  return ret < 0 ? ret : score;
339 }
340 
342  const char *filename, void *logctx,
343  unsigned int offset, unsigned int max_probe_size)
344 {
345  int ret = av_probe_input_buffer2(pb, fmt, filename, logctx, offset, max_probe_size);
346  return ret < 0 ? ret : 0;
347 }