2 * LRC lyrics file format decoder
3 * Copyright (c) 2014 StarBrilliant <m13253@hotmail.com>
5 * This file is part of FFmpeg.
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.
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.
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
32 #include "libavutil/dict.h"
33 #include "libavutil/log.h"
34 #include "libavutil/macros.h"
36 static int lrc_write_header(AVFormatContext *s)
38 const AVDictionaryEntry *metadata_item;
40 if(s->nb_streams != 1 ||
41 s->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE) {
42 av_log(s, AV_LOG_ERROR,
43 "LRC supports only a single subtitle stream.\n");
44 return AVERROR(EINVAL);
46 if(s->streams[0]->codecpar->codec_id != AV_CODEC_ID_SUBRIP &&
47 s->streams[0]->codecpar->codec_id != AV_CODEC_ID_TEXT) {
48 av_log(s, AV_LOG_ERROR, "Unsupported subtitle codec: %s\n",
49 avcodec_get_name(s->streams[0]->codecpar->codec_id));
50 return AVERROR(EINVAL);
52 avpriv_set_pts_info(s->streams[0], 64, 1, 100);
54 ff_standardize_creation_time(s);
55 ff_metadata_conv_ctx(s, ff_lrc_metadata_conv, NULL);
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
61 av_dict_set(&s->metadata, "ve", AV_STRINGIFY(LIBAVFORMAT_VERSION), 0);
63 av_dict_set(&s->metadata, "ve", NULL, 0);
65 for(metadata_item = NULL;
66 (metadata_item = av_dict_iterate(s->metadata, metadata_item));) {
68 if(!metadata_item->value[0]) {
71 while((delim = strchr(metadata_item->value, '\n'))) {
74 while((delim = strchr(metadata_item->value, '\r'))) {
77 avio_printf(s->pb, "[%s:%s]\n",
78 metadata_item->key, metadata_item->value);
84 static int lrc_write_packet(AVFormatContext *s, AVPacket *pkt)
86 if(pkt->pts != AV_NOPTS_VALUE) {
87 const uint8_t *line = pkt->data;
88 const uint8_t *end = pkt->data + pkt->size;
90 while (end > line && (end[-1] == '\n' || end[-1] == '\r'))
93 while (line[0] == '\n' || line[0] == '\r')
94 line++; // Skip first empty lines
98 const uint8_t *next_line = memchr(line, '\n', end - line);
99 size_t size = end - line;
102 size = next_line - line;
103 if (next_line > line && next_line[-1] == '\r')
107 if (size && line[0] == '[') {
108 av_log(s, AV_LOG_WARNING,
109 "Subtitle starts with '[', may cause problems with LRC format.\n");
112 /* Offset feature of LRC can easily make pts negative,
113 * we just output it directly and let the player drop it. */
114 avio_write(s->pb, "[-", 1 + (pkt->pts < 0));
115 avio_printf(s->pb, "%02"PRIu64":%02"PRIu64".%02"PRIu64"]",
116 (FFABS64U(pkt->pts) / 6000),
117 ((FFABS64U(pkt->pts) / 100) % 60),
118 (FFABS64U(pkt->pts) % 100));
120 avio_write(s->pb, line, size);
121 avio_w8(s->pb, '\n');
128 const FFOutputFormat ff_lrc_muxer = {
130 .p.long_name = NULL_IF_CONFIG_SMALL("LRC lyrics"),
131 .p.extensions = "lrc",
132 .p.flags = AVFMT_VARIABLE_FPS | AVFMT_GLOBALHEADER |
133 AVFMT_TS_NEGATIVE | AVFMT_TS_NONSTRICT,
134 .p.subtitle_codec = AV_CODEC_ID_SUBRIP,
136 .write_header = lrc_write_header,
137 .write_packet = lrc_write_packet,