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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_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) &&
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 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 
170  int *score_ret)
171 {
172  AVProbeData lpd = *pd;
173  AVInputFormat *fmt1 = NULL, *fmt;
174  int score, nodat = 0, score_max = 0;
175  const static uint8_t zerobuffer[AVPROBE_PADDING_SIZE];
176 
177  if (!lpd.buf)
178  lpd.buf = zerobuffer;
179 
180  if (lpd.buf_size > 10 && ff_id3v2_match(lpd.buf, ID3v2_DEFAULT_MAGIC)) {
181  int id3len = ff_id3v2_tag_len(lpd.buf);
182  if (lpd.buf_size > id3len + 16) {
183  lpd.buf += id3len;
184  lpd.buf_size -= id3len;
185  } else if (id3len >= PROBE_BUF_MAX) {
186  nodat = 2;
187  } else
188  nodat = 1;
189  }
190 
191  fmt = NULL;
192  while ((fmt1 = av_iformat_next(fmt1))) {
193  if (!is_opened == !(fmt1->flags & AVFMT_NOFILE) && strcmp(fmt1->name, "image2"))
194  continue;
195  score = 0;
196  if (fmt1->read_probe) {
197  score = fmt1->read_probe(&lpd);
198  if (fmt1->extensions && av_match_ext(lpd.filename, fmt1->extensions)) {
199  if (nodat == 0) score = FFMAX(score, 1);
200  else if (nodat == 1) score = FFMAX(score, AVPROBE_SCORE_EXTENSION / 2 - 1);
201  else score = FFMAX(score, AVPROBE_SCORE_EXTENSION);
202  }
203  } else if (fmt1->extensions) {
204  if (av_match_ext(lpd.filename, fmt1->extensions))
205  score = AVPROBE_SCORE_EXTENSION;
206  }
207  if (av_match_name(lpd.mime_type, fmt1->mime_type))
208  score = FFMAX(score, AVPROBE_SCORE_MIME);
209  if (score > score_max) {
210  score_max = score;
211  fmt = fmt1;
212  } else if (score == score_max)
213  fmt = NULL;
214  }
215  if (nodat == 1)
216  score_max = FFMIN(AVPROBE_SCORE_EXTENSION / 2 - 1, score_max);
217  *score_ret = score_max;
218 
219  return fmt;
220 }
221 
222 AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max)
223 {
224  int score_ret;
225  AVInputFormat *fmt = av_probe_input_format3(pd, is_opened, &score_ret);
226  if (score_ret > *score_max) {
227  *score_max = score_ret;
228  return fmt;
229  } else
230  return NULL;
231 }
232 
234 {
235  int score = 0;
236  return av_probe_input_format2(pd, is_opened, &score);
237 }
238 
240  const char *filename, void *logctx,
241  unsigned int offset, unsigned int max_probe_size)
242 {
243  AVProbeData pd = { filename ? filename : "" };
244  uint8_t *buf = NULL;
245  int ret = 0, probe_size, buf_offset = 0;
246  int score = 0;
247  int ret2;
248 
249  if (!max_probe_size)
250  max_probe_size = PROBE_BUF_MAX;
251  else if (max_probe_size < PROBE_BUF_MIN) {
252  av_log(logctx, AV_LOG_ERROR,
253  "Specified probe size value %u cannot be < %u\n", max_probe_size, PROBE_BUF_MIN);
254  return AVERROR(EINVAL);
255  }
256 
257  if (offset >= max_probe_size)
258  return AVERROR(EINVAL);
259 
260  if (pb->av_class) {
261  uint8_t *mime_type_opt = NULL;
262  av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type_opt);
263  pd.mime_type = (const char *)mime_type_opt;
264  }
265 #if 0
266  if (!*fmt && pb->av_class && av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type) >= 0 && mime_type) {
267  if (!av_strcasecmp(mime_type, "audio/aacp")) {
268  *fmt = av_find_input_format("aac");
269  }
270  av_freep(&mime_type);
271  }
272 #endif
273 
274  for (probe_size = PROBE_BUF_MIN; probe_size <= max_probe_size && !*fmt;
275  probe_size = FFMIN(probe_size << 1,
276  FFMAX(max_probe_size, probe_size + 1))) {
277  score = probe_size < max_probe_size ? AVPROBE_SCORE_RETRY : 0;
278 
279  /* Read probe data. */
280  if ((ret = av_reallocp(&buf, probe_size + AVPROBE_PADDING_SIZE)) < 0)
281  goto fail;
282  if ((ret = avio_read(pb, buf + buf_offset,
283  probe_size - buf_offset)) < 0) {
284  /* Fail if error was not end of file, otherwise, lower score. */
285  if (ret != AVERROR_EOF)
286  goto fail;
287 
288  score = 0;
289  ret = 0; /* error was end of file, nothing read */
290  }
291  buf_offset += ret;
292  if (buf_offset < offset)
293  continue;
294  pd.buf_size = buf_offset - offset;
295  pd.buf = &buf[offset];
296 
297  memset(pd.buf + pd.buf_size, 0, AVPROBE_PADDING_SIZE);
298 
299  /* Guess file format. */
300  *fmt = av_probe_input_format2(&pd, 1, &score);
301  if (*fmt) {
302  /* This can only be true in the last iteration. */
303  if (score <= AVPROBE_SCORE_RETRY) {
304  av_log(logctx, AV_LOG_WARNING,
305  "Format %s detected only with low score of %d, "
306  "misdetection possible!\n", (*fmt)->name, score);
307  } else
308  av_log(logctx, AV_LOG_DEBUG,
309  "Format %s probed with size=%d and score=%d\n",
310  (*fmt)->name, probe_size, score);
311 #if 0
312  FILE *f = fopen("probestat.tmp", "ab");
313  fprintf(f, "probe_size:%d format:%s score:%d filename:%s\n", probe_size, (*fmt)->name, score, filename);
314  fclose(f);
315 #endif
316  }
317  }
318 
319  if (!*fmt)
320  ret = AVERROR_INVALIDDATA;
321 
322 fail:
323  /* Rewind. Reuse probe buffer to avoid seeking. */
324  ret2 = ffio_rewind_with_probe_data(pb, &buf, buf_offset);
325  if (ret >= 0)
326  ret = ret2;
327 
328  av_freep(&pd.mime_type);
329  return ret < 0 ? ret : score;
330 }
331 
333  const char *filename, void *logctx,
334  unsigned int offset, unsigned int max_probe_size)
335 {
336  int ret = av_probe_input_buffer2(pb, fmt, filename, logctx, offset, max_probe_size);
337  return ret < 0 ? ret : 0;
338 }