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lrcenc.c
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1 /*
2  * LRC lyrics file format decoder
3  * Copyright (c) 2014 StarBrilliant <m13253@hotmail.com>
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 <inttypes.h>
23 #include <stdint.h>
24 #include <string.h>
25 
26 #include "avformat.h"
27 #include "internal.h"
28 #include "lrc.h"
29 #include "metadata.h"
30 #include "subtitles.h"
31 #include "version.h"
32 #include "libavutil/bprint.h"
33 #include "libavutil/dict.h"
34 #include "libavutil/log.h"
35 #include "libavutil/macros.h"
36 
38 {
39  const AVDictionaryEntry *metadata_item;
40 
41  if(s->nb_streams != 1 ||
44  "LRC supports only a single subtitle stream.\n");
45  return AVERROR(EINVAL);
46  }
47  if(s->streams[0]->codec->codec_id != AV_CODEC_ID_SUBRIP &&
49  av_log(s, AV_LOG_ERROR, "Unsupported subtitle codec: %s\n",
51  return AVERROR(EINVAL);
52  }
53  avpriv_set_pts_info(s->streams[0], 64, 1, 100);
54 
56  if(!(s->flags & AVFMT_FLAG_BITEXACT)) { // avoid breaking regression tests
57  /* LRC provides a metadata slot for specifying encoder version
58  * in addition to encoder name. We will store LIBAVFORMAT_VERSION
59  * to it.
60  */
62  } else {
63  av_dict_set(&s->metadata, "ve", NULL, 0);
64  }
65  for(metadata_item = NULL;
66  (metadata_item = av_dict_get(s->metadata, "", metadata_item,
67  AV_DICT_IGNORE_SUFFIX)) != NULL;) {
68  char *delim;
69  if(!metadata_item->value[0]) {
70  continue;
71  }
72  while((delim = strchr(metadata_item->value, '\n')) != NULL) {
73  *delim = ' ';
74  }
75  while((delim = strchr(metadata_item->value, '\r')) != NULL) {
76  *delim = ' ';
77  }
78  avio_printf(s->pb, "[%s:%s]\n",
79  metadata_item->key, metadata_item->value);
80  }
81  avio_printf(s->pb, "\n");
82  return 0;
83 }
84 
86 {
87  if(pkt->pts != AV_NOPTS_VALUE) {
88  char *data = av_malloc(pkt->size + 1);
89  char *line;
90  char *delim;
91 
92  if(!data) {
93  return AVERROR(ENOMEM);
94  }
95  memcpy(data, pkt->data, pkt->size);
96  data[pkt->size] = '\0';
97 
98  for(delim = data + pkt->size - 1;
99  delim >= data && (delim[0] == '\n' || delim[0] == '\r'); delim--) {
100  delim[0] = '\0'; // Strip last empty lines
101  }
102  line = data;
103  while(line[0] == '\n' || line[0] == '\r') {
104  line++; // Skip first empty lines
105  }
106 
107  while(line) {
108  delim = strchr(line, '\n');
109  if(delim) {
110  if(delim > line && delim[-1] == '\r') {
111  delim[-1] = '\0';
112  }
113  delim[0] = '\0';
114  delim++;
115  }
116  if(line[0] == '[') {
118  "Subtitle starts with '[', may cause problems with LRC format.\n");
119  }
120 
121  if(pkt->pts >= 0) {
122  avio_printf(s->pb, "[%02"PRId64":%02"PRId64".%02"PRId64"]",
123  (pkt->pts / 6000),
124  ((pkt->pts / 100) % 60),
125  (pkt->pts % 100));
126  } else {
127  /* Offset feature of LRC can easily make pts negative,
128  * we just output it directly and let the player drop it. */
129  avio_printf(s->pb, "[-%02"PRId64":%02"PRId64".%02"PRId64"]",
130  (-pkt->pts) / 6000,
131  ((-pkt->pts) / 100) % 60,
132  (-pkt->pts) % 100);
133  }
134  avio_printf(s->pb, "%s\n", line);
135  line = delim;
136  }
137  av_free(data);
138  }
139  return 0;
140 }
141 
143  .name = "lrc",
144  .long_name = NULL_IF_CONFIG_SMALL("LRC lyrics"),
145  .extensions = "lrc",
146  .priv_data_size = 0,
147  .write_header = lrc_write_header,
148  .write_packet = lrc_write_packet,
151  .subtitle_codec = AV_CODEC_ID_SUBRIP
152 };