FFmpeg  4.4.5
ffmetadec.c
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1 /*
2  * Metadata demuxer
3  * Copyright (c) 2010 Anton Khirnov
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/bprint.h"
23 #include "libavutil/mathematics.h"
24 #include "avformat.h"
25 #include "ffmeta.h"
26 #include "internal.h"
27 #include "libavutil/dict.h"
28 
29 static int probe(const AVProbeData *p)
30 {
31  if(!memcmp(p->buf, ID_STRING, strlen(ID_STRING)))
32  return AVPROBE_SCORE_MAX;
33  return 0;
34 }
35 
37 {
38  int len, end;
39  int64_t read = 0;
40  char tmp[1024];
41  char c;
42  char prev = ' ';
43 
44  do {
45  len = 0;
46  do {
47  c = avio_r8(s);
48  end = prev != '\\' && (c == '\r' || c == '\n' || c == '\0');
49  if (!end)
50  tmp[len++] = c;
51  prev = c;
52  } while (!end && len < sizeof(tmp));
54  read += len;
55  } while (!end);
56 
57  if (c == '\r' && avio_r8(s) != '\n' && !avio_feof(s))
58  avio_skip(s, -1);
59 
60  if (!c && s->error)
61  return s->error;
62 
63  if (!c && !read && avio_feof(s))
64  return AVERROR_EOF;
65 
66  return read;
67 }
68 
69 static void get_bprint_line(AVIOContext *s, AVBPrint *bp)
70 {
71 
72  do {
73  av_bprint_clear(bp);
75  } while (!avio_feof(s) && (bp->str[0] == ';' || bp->str[0] == '#' || bp->str[0] == 0));
76 }
77 
78 static void get_line(AVIOContext *s, uint8_t *buf, int size)
79 {
80  do {
81  uint8_t c;
82  int i = 0;
83 
84  while ((c = avio_r8(s))) {
85  if (c == '\\') {
86  if (i < size - 1)
87  buf[i++] = c;
88  c = avio_r8(s);
89  } else if (c == '\n')
90  break;
91 
92  if (i < size - 1)
93  buf[i++] = c;
94  }
95  buf[i] = 0;
96  } while (!avio_feof(s) && (buf[0] == ';' || buf[0] == '#' || buf[0] == 0));
97 }
98 
100 {
101  uint8_t line[256];
102  int64_t start, end;
103  AVRational tb = {1, 1e9};
104  int ret;
105 
106  get_line(s->pb, line, sizeof(line));
107 
108  if (sscanf(line, "TIMEBASE=%d/%d", &tb.num, &tb.den))
109  get_line(s->pb, line, sizeof(line));
110  ret = sscanf(line, "START=%"SCNd64, &start);
111  if (ret <= 0) {
112  av_log(s, AV_LOG_ERROR, "Expected chapter start timestamp, found %s.\n", line);
113  start = (s->nb_chapters && s->chapters[s->nb_chapters - 1]->end != AV_NOPTS_VALUE) ?
114  s->chapters[s->nb_chapters - 1]->end : 0;
115  } else
116  get_line(s->pb, line, sizeof(line));
117 
118  ret = sscanf(line, "END=%"SCNd64, &end);
119  if (ret <= 0) {
120  av_log(s, AV_LOG_ERROR, "Expected chapter end timestamp, found %s.\n", line);
121  end = AV_NOPTS_VALUE;
122  }
123 
124  return avpriv_new_chapter(s, s->nb_chapters, tb, start, end, NULL);
125 }
126 
127 static uint8_t *unescape(const uint8_t *buf, int size)
128 {
129  uint8_t *ret = av_malloc(size + 1);
130  uint8_t *p1 = ret;
131  const uint8_t *p2 = buf;
132 
133  if (!ret)
134  return NULL;
135 
136  while (p2 < buf + size) {
137  if (*p2 == '\\')
138  p2++;
139  *p1++ = *p2++;
140  }
141  *p1 = 0;
142  return ret;
143 }
144 
145 static int read_tag(const uint8_t *line, AVDictionary **m)
146 {
147  uint8_t *key, *value;
148  const uint8_t *p = line;
149 
150  /* find first not escaped '=' */
151  while (1) {
152  if (*p == '=')
153  break;
154  else if (*p == '\\')
155  p++;
156 
157  if (*p++)
158  continue;
159 
160  return 0;
161  }
162 
163  if (!(key = unescape(line, p - line)))
164  return AVERROR(ENOMEM);
165  if (!(value = unescape(p + 1, strlen(p + 1)))) {
166  av_free(key);
167  return AVERROR(ENOMEM);
168  }
169 
171  return 0;
172 }
173 
175 {
176  AVDictionary **m = &s->metadata;
177  AVBPrint bp;
178 
180 
181  while(!avio_feof(s->pb)) {
182  get_bprint_line(s->pb, &bp);
183 
184  if (!memcmp(bp.str, ID_STREAM, strlen(ID_STREAM))) {
186 
187  if (!st)
188  goto nomem;
189 
192 
193  m = &st->metadata;
194  } else if (!memcmp(bp.str, ID_CHAPTER, strlen(ID_CHAPTER))) {
195  AVChapter *ch = read_chapter(s);
196 
197  if (!ch)
198  goto nomem;
199 
200  m = &ch->metadata;
201  } else
202  read_tag(bp.str, m);
203  }
204 
205  av_bprint_finalize(&bp, NULL);
206 
207  s->start_time = 0;
208  if (s->nb_chapters)
209  s->duration = av_rescale_q(s->chapters[s->nb_chapters - 1]->end,
210  s->chapters[s->nb_chapters - 1]->time_base,
212 
213  return 0;
214 nomem:
215  av_bprint_finalize(&bp, NULL);
216 
217  return AVERROR(ENOMEM);
218 }
219 
221 {
222  return AVERROR_EOF;
223 }
224 
226  .name = "ffmetadata",
227  .long_name = NULL_IF_CONFIG_SMALL("FFmpeg metadata in text"),
228  .read_probe = probe,
229  .read_header = read_header,
230  .read_packet = read_packet,
231 };
uint8_t
Main libavformat public API header.
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:453
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:364
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:337
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:624
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
Definition: bprint.c:69
int av_bprint_finalize(AVBPrint *buf, char **ret_str)
Finalize a print buffer.
Definition: bprint.c:235
void av_bprint_append_data(AVBPrint *buf, const char *data, unsigned size)
Append data to a print buffer.
Definition: bprint.c:158
void av_bprint_clear(AVBPrint *buf)
Reset the string to "" but keep internal allocated data.
Definition: bprint.c:227
#define AV_BPRINT_SIZE_UNLIMITED
#define s(width, name)
Definition: cbs_vp9.c:257
#define NULL
Definition: coverity.c:32
long long int64_t
Definition: coverity.c:34
Public dictionary API.
double value
Definition: eval.c:98
#define ID_CHAPTER
Definition: ffmeta.h:26
#define ID_STRING
Definition: ffmeta.h:25
#define ID_STREAM
Definition: ffmeta.h:27
static int read_tag(const uint8_t *line, AVDictionary **m)
Definition: ffmetadec.c:145
static int64_t read_line_to_bprint_escaped(AVIOContext *s, AVBPrint *bp)
Definition: ffmetadec.c:36
static AVChapter * read_chapter(AVFormatContext *s)
Definition: ffmetadec.c:99
static int read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: ffmetadec.c:220
AVInputFormat ff_ffmetadata_demuxer
Definition: ffmetadec.c:225
static void get_line(AVIOContext *s, uint8_t *buf, int size)
Definition: ffmetadec.c:78
static void get_bprint_line(AVIOContext *s, AVBPrint *bp)
Definition: ffmetadec.c:69
static int read_header(AVFormatContext *s)
Definition: ffmetadec.c:174
static uint8_t * unescape(const uint8_t *buf, int size)
Definition: ffmetadec.c:127
static int probe(const AVProbeData *p)
Definition: ffmetadec.c:29
@ AV_CODEC_ID_FFMETADATA
Dummy codec for streams containing only metadata information.
Definition: codec_id.h:573
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4509
#define AV_DICT_DONT_STRDUP_VAL
Take ownership of a value that's been allocated with av_malloc() or another memory allocation functio...
Definition: dict.h:74
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
Definition: dict.c:70
#define AV_DICT_DONT_STRDUP_KEY
Take ownership of a key that's been allocated with av_malloc() or another memory allocation function.
Definition: dict.h:72
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define AVERROR(e)
Definition: error.h:43
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
Rescale a 64-bit integer by 2 rational numbers.
Definition: mathematics.c:142
@ AVMEDIA_TYPE_DATA
Opaque data information usually continuous.
Definition: avutil.h:203
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
#define AV_TIME_BASE_Q
Internal time base represented as fractional value.
Definition: avutil.h:260
const char * key
int i
Definition: input.c:407
AVChapter * avpriv_new_chapter(AVFormatContext *s, int id, AVRational time_base, int64_t start, int64_t end, const char *title)
Add a new chapter.
Definition: utils.c:4639
common internal API header
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
#define tb
Definition: regdef.h:68
AVDictionary * metadata
Definition: avformat.h:1193
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
Format I/O context.
Definition: avformat.h:1232
Bytestream IO Context.
Definition: avio.h:161
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:645
This structure stores compressed data.
Definition: packet.h:346
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
Rational number (pair of numerator and denominator).
Definition: rational.h:58
Stream structure.
Definition: avformat.h:873
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1038
AVDictionary * metadata
Definition: avformat.h:937
Definition: graph2dot.c:48
#define av_free(p)
#define av_malloc(s)
#define av_log(a,...)
static uint8_t tmp[11]
Definition: aes_ctr.c:27
AVPacket * pkt
Definition: movenc.c:59
int size
int len
static double c[64]