FFmpeg
vorbiscomment.c
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1 /*
2  * VorbisComment writer
3  * Copyright (c) 2009 James Darnley
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 "avio.h"
23 #include "avformat.h"
24 #include "metadata.h"
25 #include "vorbiscomment.h"
26 #include "libavutil/dict.h"
27 
28 /**
29  * VorbisComment metadata conversion mapping.
30  * from Ogg Vorbis I format specification: comment field and header specification
31  * http://xiph.org/vorbis/doc/v-comment.html
32  */
33 const AVMetadataConv ff_vorbiscomment_metadata_conv[] = {
34  { "ALBUMARTIST", "album_artist"},
35  { "TRACKNUMBER", "track" },
36  { "DISCNUMBER", "disc" },
37  { "DESCRIPTION", "comment" },
38  { 0 }
39 };
40 
41 int64_t ff_vorbiscomment_length(const AVDictionary *m, const char *vendor_string,
42  AVChapter **chapters, unsigned int nb_chapters)
43 {
44  int64_t len = 8;
45  len += strlen(vendor_string);
46  if (chapters && nb_chapters) {
47  for (int i = 0; i < nb_chapters; i++) {
48  AVDictionaryEntry *tag = NULL;
49  len += 4 + 12 + 1 + 10;
50  while ((tag = av_dict_get(chapters[i]->metadata, "", tag, AV_DICT_IGNORE_SUFFIX))) {
51  int64_t len1 = !strcmp(tag->key, "title") ? 4 : strlen(tag->key);
52  len += 4 + 10 + len1 + 1 + strlen(tag->value);
53  }
54  }
55  }
56  if (m) {
57  AVDictionaryEntry *tag = NULL;
58  while ((tag = av_dict_get(m, "", tag, AV_DICT_IGNORE_SUFFIX))) {
59  len += 4 +strlen(tag->key) + 1 + strlen(tag->value);
60  }
61  }
62  return len;
63 }
64 
65 int ff_vorbiscomment_write(AVIOContext *pb, const AVDictionary *m,
66  const char *vendor_string,
67  AVChapter **chapters, unsigned int nb_chapters)
68 {
69  int cm_count = 0;
70  avio_wl32(pb, strlen(vendor_string));
71  avio_write(pb, vendor_string, strlen(vendor_string));
72  if (chapters && nb_chapters) {
73  for (int i = 0; i < nb_chapters; i++) {
74  cm_count += av_dict_count(chapters[i]->metadata) + 1;
75  }
76  }
77  if (m) {
78  int count = av_dict_count(m) + cm_count;
79  AVDictionaryEntry *tag = NULL;
80  avio_wl32(pb, count);
81  while ((tag = av_dict_get(m, "", tag, AV_DICT_IGNORE_SUFFIX))) {
82  int64_t len1 = strlen(tag->key);
83  int64_t len2 = strlen(tag->value);
84  if (len1+1+len2 > UINT32_MAX)
85  return AVERROR(EINVAL);
86  avio_wl32(pb, len1 + 1 + len2);
87  avio_write(pb, tag->key, len1);
88  avio_w8(pb, '=');
89  avio_write(pb, tag->value, len2);
90  }
91  for (int i = 0; i < nb_chapters; i++) {
92  AVChapter *chp = chapters[i];
93  char chapter_time[13];
94  char chapter_number[4];
95  int h, m, s, ms;
96 
97  s = av_rescale(chp->start, chp->time_base.num, chp->time_base.den);
98  h = s / 3600;
99  m = (s / 60) % 60;
100  ms = av_rescale_q(chp->start, chp->time_base, av_make_q( 1, 1000)) % 1000;
101  s = s % 60;
102  snprintf(chapter_number, sizeof(chapter_number), "%03d", i);
103  snprintf(chapter_time, sizeof(chapter_time), "%02d:%02d:%02d.%03d", h, m, s, ms);
104  avio_wl32(pb, 10 + 1 + 12);
105  avio_write(pb, "CHAPTER", 7);
106  avio_write(pb, chapter_number, 3);
107  avio_w8(pb, '=');
108  avio_write(pb, chapter_time, 12);
109 
110  tag = NULL;
111  while ((tag = av_dict_get(chapters[i]->metadata, "", tag, AV_DICT_IGNORE_SUFFIX))) {
112  int64_t len1 = !strcmp(tag->key, "title") ? 4 : strlen(tag->key);
113  int64_t len2 = strlen(tag->value);
114  if (len1+1+len2+10 > UINT32_MAX)
115  return AVERROR(EINVAL);
116  avio_wl32(pb, 10 + len1 + 1 + len2);
117  avio_write(pb, "CHAPTER", 7);
118  avio_write(pb, chapter_number, 3);
119  if (!strcmp(tag->key, "title"))
120  avio_write(pb, "NAME", 4);
121  else
122  avio_write(pb, tag->key, len1);
123  avio_w8(pb, '=');
124  avio_write(pb, tag->value, len2);
125  }
126  }
127  } else
128  avio_wl32(pb, 0);
129  return 0;
130 }
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
av_dict_count
int av_dict_count(const AVDictionary *m)
Get number of entries in dictionary.
Definition: dict.c:35
vorbiscomment.h
AVChapter::start
int64_t start
Definition: avformat.h:1192
AV_DICT_IGNORE_SUFFIX
#define AV_DICT_IGNORE_SUFFIX
Return first entry in a dictionary whose first part corresponds to the search key,...
Definition: dict.h:70
AVMetadataConv
Definition: metadata.h:34
AVDictionary
Definition: dict.c:30
ff_vorbiscomment_write
int ff_vorbiscomment_write(AVIOContext *pb, const AVDictionary *m, const char *vendor_string, AVChapter **chapters, unsigned int nb_chapters)
Write a VorbisComment into an AVIOContext.
Definition: vorbiscomment.c:65
AVChapter
Definition: avformat.h:1185
AVRational::num
int num
Numerator.
Definition: rational.h:59
av_dict_get
AVDictionaryEntry * av_dict_get(const AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags)
Get a dictionary entry with matching key.
Definition: dict.c:40
s
#define s(width, name)
Definition: cbs_vp9.c:257
av_rescale_q
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
ff_vorbiscomment_metadata_conv
const AVMetadataConv ff_vorbiscomment_metadata_conv[]
VorbisComment metadata conversion mapping.
Definition: vorbiscomment.c:33
NULL
#define NULL
Definition: coverity.c:32
avio_w8
void avio_w8(AVIOContext *s, int b)
Definition: aviobuf.c:203
ff_vorbiscomment_length
int64_t ff_vorbiscomment_length(const AVDictionary *m, const char *vendor_string, AVChapter **chapters, unsigned int nb_chapters)
Calculate the length in bytes of a VorbisComment.
Definition: vorbiscomment.c:41
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
av_make_q
static AVRational av_make_q(int num, int den)
Create an AVRational.
Definition: rational.h:71
avio.h
avio_write
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:225
avio_wl32
void avio_wl32(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:375
i
int i
Definition: input.c:407
len
int len
Definition: vorbis_enc_data.h:452
av_rescale
int64_t av_rescale(int64_t a, int64_t b, int64_t c)
Rescale a 64-bit integer with rounding to nearest.
Definition: mathematics.c:129
tag
uint32_t tag
Definition: movenc.c:1611
metadata.h
avformat.h
dict.h
AVRational::den
int den
Denominator.
Definition: rational.h:60
AVDictionaryEntry
Definition: dict.h:81
h
h
Definition: vp9dsp_template.c:2038
AVChapter::time_base
AVRational time_base
time base in which the start/end timestamps are specified
Definition: avformat.h:1191
snprintf
#define snprintf
Definition: snprintf.h:34
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