FFmpeg  4.3.8
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));
53  av_bprint_append_data(bp, tmp, len);
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 
105  get_line(s->pb, line, sizeof(line));
106 
107  if (sscanf(line, "TIMEBASE=%d/%d", &tb.num, &tb.den))
108  get_line(s->pb, line, sizeof(line));
109  if (!sscanf(line, "START=%"SCNd64, &start)) {
110  av_log(s, AV_LOG_ERROR, "Expected chapter start timestamp, found %s.\n", line);
111  start = (s->nb_chapters && s->chapters[s->nb_chapters - 1]->end != AV_NOPTS_VALUE) ?
112  s->chapters[s->nb_chapters - 1]->end : 0;
113  } else
114  get_line(s->pb, line, sizeof(line));
115 
116  if (!sscanf(line, "END=%"SCNd64, &end)) {
117  av_log(s, AV_LOG_ERROR, "Expected chapter end timestamp, found %s.\n", line);
118  end = AV_NOPTS_VALUE;
119  }
120 
121  return avpriv_new_chapter(s, s->nb_chapters, tb, start, end, NULL);
122 }
123 
124 static uint8_t *unescape(const uint8_t *buf, int size)
125 {
126  uint8_t *ret = av_malloc(size + 1);
127  uint8_t *p1 = ret;
128  const uint8_t *p2 = buf;
129 
130  if (!ret)
131  return NULL;
132 
133  while (p2 < buf + size) {
134  if (*p2 == '\\')
135  p2++;
136  *p1++ = *p2++;
137  }
138  *p1 = 0;
139  return ret;
140 }
141 
142 static int read_tag(const uint8_t *line, AVDictionary **m)
143 {
144  uint8_t *key, *value;
145  const uint8_t *p = line;
146 
147  /* find first not escaped '=' */
148  while (1) {
149  if (*p == '=')
150  break;
151  else if (*p == '\\')
152  p++;
153 
154  if (*p++)
155  continue;
156 
157  return 0;
158  }
159 
160  if (!(key = unescape(line, p - line)))
161  return AVERROR(ENOMEM);
162  if (!(value = unescape(p + 1, strlen(p + 1)))) {
163  av_free(key);
164  return AVERROR(ENOMEM);
165  }
166 
168  return 0;
169 }
170 
172 {
173  AVDictionary **m = &s->metadata;
174  AVBPrint bp;
175 
177 
178  while(!avio_feof(s->pb)) {
179  get_bprint_line(s->pb, &bp);
180 
181  if (!memcmp(bp.str, ID_STREAM, strlen(ID_STREAM))) {
183 
184  if (!st)
185  goto nomem;
186 
189 
190  m = &st->metadata;
191  } else if (!memcmp(bp.str, ID_CHAPTER, strlen(ID_CHAPTER))) {
192  AVChapter *ch = read_chapter(s);
193 
194  if (!ch)
195  goto nomem;
196 
197  m = &ch->metadata;
198  } else
199  read_tag(bp.str, m);
200  }
201 
202  av_bprint_finalize(&bp, NULL);
203 
204  s->start_time = 0;
205  if (s->nb_chapters)
206  s->duration = av_rescale_q(s->chapters[s->nb_chapters - 1]->end,
207  s->chapters[s->nb_chapters - 1]->time_base,
209 
210  return 0;
211 nomem:
212  av_bprint_finalize(&bp, NULL);
213 
214  return AVERROR(ENOMEM);
215 }
216 
218 {
219  return AVERROR_EOF;
220 }
221 
223  .name = "ffmetadata",
224  .long_name = NULL_IF_CONFIG_SMALL("FFmpeg metadata in text"),
225  .read_probe = probe,
226  .read_header = read_header,
227  .read_packet = read_packet,
228 };
unsigned int nb_chapters
Number of chapters in AVChapter array.
Definition: avformat.h:1580
static void get_line(AVIOContext *s, uint8_t *buf, int size)
Definition: ffmetadec.c:78
#define ID_CHAPTER
Definition: ffmeta.h:26
#define NULL
Definition: coverity.c:32
Bytestream IO Context.
Definition: avio.h:161
int size
static int read_header(AVFormatContext *s)
Definition: ffmetadec.c:171
Dummy codec for streams containing only metadata information.
Definition: codec_id.h:558
static int read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: ffmetadec.c:217
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
int num
Numerator.
Definition: rational.h:59
static int probe(const AVProbeData *p)
Definition: ffmetadec.c:29
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:329
const char * key
static AVPacket pkt
AVDictionary * metadata
Definition: avformat.h:1312
int av_bprint_finalize(AVBPrint *buf, char **ret_str)
Finalize a print buffer.
Definition: bprint.c:235
static int read_tag(const uint8_t *line, AVDictionary **m)
Definition: ffmetadec.c:142
#define AV_DICT_DONT_STRDUP_KEY
Take ownership of a key that&#39;s been allocated with av_malloc() or another memory allocation function...
Definition: dict.h:73
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:4654
Format I/O context.
Definition: avformat.h:1351
Public dictionary API.
static uint8_t * unescape(const uint8_t *buf, int size)
Definition: ffmetadec.c:124
uint8_t
#define av_malloc(s)
Opaque data information usually continuous.
Definition: avutil.h:203
#define ID_STRING
Definition: ffmeta.h:25
static void get_bprint_line(AVIOContext *s, AVBPrint *bp)
Definition: ffmetadec.c:69
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:92
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4526
void av_bprint_append_data(AVBPrint *buf, const char *data, unsigned size)
Append data to a print buffer.
Definition: bprint.c:158
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define av_log(a,...)
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
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1591
#define AV_BPRINT_SIZE_UNLIMITED
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:188
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
Definition: bprint.c:69
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
AVChapter ** chapters
Definition: avformat.h:1581
Definition: graph2dot.c:48
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:616
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
#define AV_DICT_DONT_STRDUP_VAL
Take ownership of a value that&#39;s been allocated with av_malloc() or another memory allocation functio...
Definition: dict.h:76
#define ID_STREAM
Definition: ffmeta.h:27
#define s(width, name)
Definition: cbs_vp9.c:257
AVDictionary * metadata
Definition: avformat.h:940
Stream structure.
Definition: avformat.h:876
int64_t end
chapter start/end time in time_base units
Definition: avformat.h:1311
#define AV_TIME_BASE_Q
Internal time base represented as fractional value.
Definition: avutil.h:260
AVIOContext * pb
I/O context.
Definition: avformat.h:1393
long long int64_t
Definition: coverity.c:34
AVInputFormat ff_ffmetadata_demuxer
Definition: ffmetadec.c:222
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
double value
Definition: eval.c:98
static int64_t read_line_to_bprint_escaped(AVIOContext *s, AVBPrint *bp)
Definition: ffmetadec.c:36
Rational number (pair of numerator and denominator).
Definition: rational.h:58
int error
contains the error code or 0 if no error happened
Definition: avio.h:245
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
int64_t start_time
Position of the first frame of the component, in AV_TIME_BASE fractional seconds. ...
Definition: avformat.h:1456
void av_bprint_clear(AVBPrint *buf)
Reset the string to "" but keep internal allocated data.
Definition: bprint.c:227
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:453
Main libavformat public API header.
static AVChapter * read_chapter(AVFormatContext *s)
Definition: ffmetadec.c:99
static double c[64]
AVRational time_base
time base in which the start/end timestamps are specified
Definition: avformat.h:1310
int den
Denominator.
Definition: rational.h:60
#define av_free(p)
int len
int64_t duration
Duration of the stream, in AV_TIME_BASE fractional seconds.
Definition: avformat.h:1466
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:650
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1023
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:356
This structure stores compressed data.
Definition: packet.h:332
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
#define tb
Definition: regdef.h:68
static uint8_t tmp[11]
Definition: aes_ctr.c:26