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concatdec.c
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1 /*
2  * Copyright (c) 2012 Nicolas George
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public License
8  * as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public License
17  * along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include "libavutil/avstring.h"
22 #include "libavutil/opt.h"
23 #include "libavutil/parseutils.h"
24 #include "avformat.h"
25 #include "internal.h"
26 #include "url.h"
27 
28 typedef struct {
29  char *url;
30  int64_t start_time;
31  int64_t duration;
32 } ConcatFile;
33 
34 typedef struct {
35  AVClass *class;
38  unsigned nb_files;
40  int safe;
41  int seekable;
43 
45 {
46  return memcmp(probe->buf, "ffconcat version 1.0", 20) ?
48 }
49 
50 static char *get_keyword(uint8_t **cursor)
51 {
52  char *ret = *cursor += strspn(*cursor, SPACE_CHARS);
53  *cursor += strcspn(*cursor, SPACE_CHARS);
54  if (**cursor) {
55  *((*cursor)++) = 0;
56  *cursor += strspn(*cursor, SPACE_CHARS);
57  }
58  return ret;
59 }
60 
61 static int safe_filename(const char *f)
62 {
63  const char *start = f;
64 
65  for (; *f; f++) {
66  /* A-Za-z0-9_- */
67  if (!((unsigned)((*f | 32) - 'a') < 26 ||
68  (unsigned)(*f - '0') < 10 || *f == '_' || *f == '-')) {
69  if (f == start)
70  return 0;
71  else if (*f == '/')
72  start = f + 1;
73  else if (*f != '.')
74  return 0;
75  }
76  }
77  return 1;
78 }
79 
80 #define FAIL(retcode) do { ret = (retcode); goto fail; } while(0)
81 
82 static int add_file(AVFormatContext *avf, char *filename, ConcatFile **rfile,
83  unsigned *nb_files_alloc)
84 {
85  ConcatContext *cat = avf->priv_data;
86  ConcatFile *file;
87  char *url = NULL;
88  size_t url_len;
89  int ret;
90 
91  if (cat->safe > 0 && !safe_filename(filename)) {
92  av_log(avf, AV_LOG_ERROR, "Unsafe file name '%s'\n", filename);
93  FAIL(AVERROR(EPERM));
94  }
95  url_len = strlen(avf->filename) + strlen(filename) + 16;
96  if (!(url = av_malloc(url_len)))
97  FAIL(AVERROR(ENOMEM));
98  ff_make_absolute_url(url, url_len, avf->filename, filename);
99  av_freep(&filename);
100 
101  if (cat->nb_files >= *nb_files_alloc) {
102  size_t n = FFMAX(*nb_files_alloc * 2, 16);
103  ConcatFile *new_files;
104  if (n <= cat->nb_files || n > SIZE_MAX / sizeof(*cat->files) ||
105  !(new_files = av_realloc(cat->files, n * sizeof(*cat->files))))
106  FAIL(AVERROR(ENOMEM));
107  cat->files = new_files;
108  *nb_files_alloc = n;
109  }
110 
111  file = &cat->files[cat->nb_files++];
112  memset(file, 0, sizeof(*file));
113  *rfile = file;
114 
115  file->url = url;
116  file->start_time = AV_NOPTS_VALUE;
117  file->duration = AV_NOPTS_VALUE;
118 
119  return 0;
120 
121 fail:
122  av_free(url);
123  av_free(filename);
124  return ret;
125 }
126 
127 static int open_file(AVFormatContext *avf, unsigned fileno)
128 {
129  ConcatContext *cat = avf->priv_data;
130  ConcatFile *file = &cat->files[fileno];
131  int ret;
132 
133  if (cat->avf)
134  avformat_close_input(&cat->avf);
135 
136  cat->avf = avformat_alloc_context();
137  if (!cat->avf)
138  return AVERROR(ENOMEM);
139 
141  if ((ret = avformat_open_input(&cat->avf, file->url, NULL, NULL)) < 0 ||
142  (ret = avformat_find_stream_info(cat->avf, NULL)) < 0) {
143  av_log(avf, AV_LOG_ERROR, "Impossible to open '%s'\n", file->url);
144  avformat_close_input(&cat->avf);
145  return ret;
146  }
147  cat->cur_file = file;
148  if (file->start_time == AV_NOPTS_VALUE)
149  file->start_time = !fileno ? 0 :
150  cat->files[fileno - 1].start_time +
151  cat->files[fileno - 1].duration;
152  return 0;
153 }
154 
156 {
157  ConcatContext *cat = avf->priv_data;
158  unsigned i;
159 
160  if (cat->avf)
161  avformat_close_input(&cat->avf);
162  for (i = 0; i < cat->nb_files; i++)
163  av_freep(&cat->files[i].url);
164  av_freep(&cat->files);
165  return 0;
166 }
167 
169 {
170  ConcatContext *cat = avf->priv_data;
171  uint8_t buf[4096];
172  uint8_t *cursor, *keyword;
173  int ret, line = 0, i;
174  unsigned nb_files_alloc = 0;
175  ConcatFile *file = NULL;
176  AVStream *st, *source_st;
177  int64_t time = 0;
178 
179  while (1) {
180  if ((ret = ff_get_line(avf->pb, buf, sizeof(buf))) <= 0)
181  break;
182  line++;
183  cursor = buf;
184  keyword = get_keyword(&cursor);
185  if (!*keyword || *keyword == '#')
186  continue;
187 
188  if (!strcmp(keyword, "file")) {
189  char *filename = av_get_token((const char **)&cursor, SPACE_CHARS);
190  if (!filename) {
191  av_log(avf, AV_LOG_ERROR, "Line %d: filename required\n", line);
193  }
194  if ((ret = add_file(avf, filename, &file, &nb_files_alloc)) < 0)
195  FAIL(ret);
196  } else if (!strcmp(keyword, "duration")) {
197  char *dur_str = get_keyword(&cursor);
198  int64_t dur;
199  if (!file) {
200  av_log(avf, AV_LOG_ERROR, "Line %d: duration without file\n",
201  line);
203  }
204  if ((ret = av_parse_time(&dur, dur_str, 1)) < 0) {
205  av_log(avf, AV_LOG_ERROR, "Line %d: invalid duration '%s'\n",
206  line, dur_str);
207  FAIL(ret);
208  }
209  file->duration = dur;
210  } else if (!strcmp(keyword, "ffconcat")) {
211  char *ver_kw = get_keyword(&cursor);
212  char *ver_val = get_keyword(&cursor);
213  if (strcmp(ver_kw, "version") || strcmp(ver_val, "1.0")) {
214  av_log(avf, AV_LOG_ERROR, "Line %d: invalid version\n", line);
216  }
217  if (cat->safe < 0)
218  cat->safe = 1;
219  } else {
220  av_log(avf, AV_LOG_ERROR, "Line %d: unknown keyword '%s'\n",
221  line, keyword);
223  }
224  }
225  if (ret < 0)
226  FAIL(ret);
227  if (!cat->nb_files)
229 
230  for (i = 0; i < cat->nb_files; i++) {
231  if (cat->files[i].start_time == AV_NOPTS_VALUE)
232  cat->files[i].start_time = time;
233  else
234  time = cat->files[i].start_time;
235  if (cat->files[i].duration == AV_NOPTS_VALUE)
236  break;
237  time += cat->files[i].duration;
238  }
239  if (i == cat->nb_files) {
240  avf->duration = time;
241  cat->seekable = 1;
242  }
243 
244  if ((ret = open_file(avf, 0)) < 0)
245  FAIL(ret);
246  for (i = 0; i < cat->avf->nb_streams; i++) {
247  if (!(st = avformat_new_stream(avf, NULL)))
248  FAIL(AVERROR(ENOMEM));
249  source_st = cat->avf->streams[i];
250  if ((ret = avcodec_copy_context(st->codec, source_st->codec)) < 0)
251  FAIL(ret);
252  st->r_frame_rate = source_st->r_frame_rate;
253  st->avg_frame_rate = source_st->avg_frame_rate;
254  st->time_base = source_st->time_base;
255  st->sample_aspect_ratio = source_st->sample_aspect_ratio;
256  }
257 
258  return 0;
259 
260 fail:
261  concat_read_close(avf);
262  return ret;
263 }
264 
266 {
267  ConcatContext *cat = avf->priv_data;
268  unsigned fileno = cat->cur_file - cat->files;
269 
270  if (cat->cur_file->duration == AV_NOPTS_VALUE)
271  cat->cur_file->duration = cat->avf->duration;
272 
273  if (++fileno >= cat->nb_files)
274  return AVERROR_EOF;
275  return open_file(avf, fileno);
276 }
277 
279 {
280  ConcatContext *cat = avf->priv_data;
281  int ret;
282  int64_t delta;
283 
284  while (1) {
285  if ((ret = av_read_frame(cat->avf, pkt)) != AVERROR_EOF ||
286  (ret = open_next_file(avf)) < 0)
287  break;
288  }
289  if (ret < 0)
290  return ret;
291 
292  delta = av_rescale_q(cat->cur_file->start_time - cat->avf->start_time,
294  cat->avf->streams[pkt->stream_index]->time_base);
295  if (pkt->pts != AV_NOPTS_VALUE)
296  pkt->pts += delta;
297  if (pkt->dts != AV_NOPTS_VALUE)
298  pkt->dts += delta;
299  return ret;
300 }
301 
302 static void rescale_interval(AVRational tb_in, AVRational tb_out,
303  int64_t *min_ts, int64_t *ts, int64_t *max_ts)
304 {
305  *ts = av_rescale_q (* ts, tb_in, tb_out);
306  *min_ts = av_rescale_q_rnd(*min_ts, tb_in, tb_out,
308  *max_ts = av_rescale_q_rnd(*max_ts, tb_in, tb_out,
310 }
311 
312 static int try_seek(AVFormatContext *avf, int stream,
313  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
314 {
315  ConcatContext *cat = avf->priv_data;
316  int64_t t0 = cat->cur_file->start_time - cat->avf->start_time;
317 
318  ts -= t0;
319  min_ts = min_ts == INT64_MIN ? INT64_MIN : min_ts - t0;
320  max_ts = max_ts == INT64_MAX ? INT64_MAX : max_ts - t0;
321  if (stream >= 0) {
322  if (stream >= cat->avf->nb_streams)
323  return AVERROR(EIO);
325  &min_ts, &ts, &max_ts);
326  }
327  return avformat_seek_file(cat->avf, stream, min_ts, ts, max_ts, flags);
328 }
329 
330 static int real_seek(AVFormatContext *avf, int stream,
331  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
332 {
333  ConcatContext *cat = avf->priv_data;
334  int ret, left, right;
335 
336  if (stream >= 0) {
337  if (stream >= avf->nb_streams)
338  return AVERROR(EINVAL);
340  &min_ts, &ts, &max_ts);
341  }
342 
343  left = 0;
344  right = cat->nb_files;
345  while (right - left > 1) {
346  int mid = (left + right) / 2;
347  if (ts < cat->files[mid].start_time)
348  right = mid;
349  else
350  left = mid;
351  }
352 
353  if ((ret = open_file(avf, left)) < 0)
354  return ret;
355 
356  ret = try_seek(avf, stream, min_ts, ts, max_ts, flags);
357  if (ret < 0 &&
358  left < cat->nb_files - 1 &&
359  cat->files[left + 1].start_time < max_ts) {
360  if ((ret = open_file(avf, left + 1)) < 0)
361  return ret;
362  ret = try_seek(avf, stream, min_ts, ts, max_ts, flags);
363  }
364  return ret;
365 }
366 
367 static int concat_seek(AVFormatContext *avf, int stream,
368  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
369 {
370  ConcatContext *cat = avf->priv_data;
371  ConcatFile *cur_file_saved = cat->cur_file;
372  AVFormatContext *cur_avf_saved = cat->avf;
373  int ret;
374 
375  if (!cat->seekable)
376  return AVERROR(ESPIPE); /* XXX: can we use it? */
377  if (flags & (AVSEEK_FLAG_BYTE | AVSEEK_FLAG_FRAME))
378  return AVERROR(ENOSYS);
379  cat->avf = NULL;
380  if ((ret = real_seek(avf, stream, min_ts, ts, max_ts, flags)) < 0) {
381  if (cat->avf)
382  avformat_close_input(&cat->avf);
383  cat->avf = cur_avf_saved;
384  cat->cur_file = cur_file_saved;
385  } else {
386  avformat_close_input(&cur_avf_saved);
387  }
388  return ret;
389 }
390 
391 #define OFFSET(x) offsetof(ConcatContext, x)
392 #define DEC AV_OPT_FLAG_DECODING_PARAM
393 
394 static const AVOption options[] = {
395  { "safe", "enable safe mode",
396  OFFSET(safe), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 1, DEC },
397  { NULL }
398 };
399 
400 static const AVClass concat_class = {
401  .class_name = "concat demuxer",
402  .item_name = av_default_item_name,
403  .option = options,
404  .version = LIBAVUTIL_VERSION_INT,
405 };
406 
407 
409  .name = "concat",
410  .long_name = NULL_IF_CONFIG_SMALL("Virtual concatenation script"),
411  .priv_data_size = sizeof(ConcatContext),
416  .read_seek2 = concat_seek,
417  .priv_class = &concat_class,
418 };