• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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 "mux.h"
31 #include "version.h"
32 #include "libavutil/dict.h"
33 #include "libavutil/log.h"
34 #include "libavutil/macros.h"
35 
lrc_write_header(AVFormatContext * s)36 static int lrc_write_header(AVFormatContext *s)
37 {
38     const AVDictionaryEntry *metadata_item;
39 
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);
45     }
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);
51     }
52     avpriv_set_pts_info(s->streams[0], 64, 1, 100);
53 
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
59          * to it.
60          */
61         av_dict_set(&s->metadata, "ve", AV_STRINGIFY(LIBAVFORMAT_VERSION), 0);
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));) {
68         char *delim;
69         if(!metadata_item->value[0]) {
70             continue;
71         }
72         while((delim = strchr(metadata_item->value, '\n'))) {
73             *delim = ' ';
74         }
75         while((delim = strchr(metadata_item->value, '\r'))) {
76             *delim = ' ';
77         }
78         avio_printf(s->pb, "[%s:%s]\n",
79                     metadata_item->key, metadata_item->value);
80     }
81     avio_w8(s->pb, '\n');
82     return 0;
83 }
84 
lrc_write_packet(AVFormatContext * s,AVPacket * pkt)85 static int lrc_write_packet(AVFormatContext *s, AVPacket *pkt)
86 {
87     if(pkt->pts != AV_NOPTS_VALUE) {
88         const uint8_t *line = pkt->data;
89         const uint8_t *end  = pkt->data + pkt->size;
90 
91         while (end > line && (end[-1] == '\n' || end[-1] == '\r'))
92             end--;
93         if (line != end) {
94             while (line[0] == '\n' || line[0] == '\r')
95                 line++; // Skip first empty lines
96         }
97 
98         while(line) {
99             const uint8_t *next_line = memchr(line, '\n', end - line);
100             size_t size = end - line;
101 
102             if (next_line) {
103                 size = next_line - line;
104                 if (next_line > line && next_line[-1] == '\r')
105                     size--;
106                 next_line++;
107             }
108             if(line[0] == '[') {
109                 av_log(s, AV_LOG_WARNING,
110                        "Subtitle starts with '[', may cause problems with LRC format.\n");
111             }
112 
113             /* Offset feature of LRC can easily make pts negative,
114              * we just output it directly and let the player drop it. */
115             avio_write(s->pb, "[-", 1 + (pkt->pts < 0));
116             avio_printf(s->pb, "%02"PRIu64":%02"PRIu64".%02"PRIu64"]",
117                         (FFABS64U(pkt->pts) / 6000),
118                         ((FFABS64U(pkt->pts) / 100) % 60),
119                         (FFABS64U(pkt->pts) % 100));
120 
121             avio_write(s->pb, line, size);
122             avio_w8(s->pb, '\n');
123             line = next_line;
124         }
125     }
126     return 0;
127 }
128 
129 const AVOutputFormat ff_lrc_muxer = {
130     .name           = "lrc",
131     .long_name      = NULL_IF_CONFIG_SMALL("LRC lyrics"),
132     .extensions     = "lrc",
133     .priv_data_size = 0,
134     .write_header   = lrc_write_header,
135     .write_packet   = lrc_write_packet,
136     .flags          = AVFMT_VARIABLE_FPS | AVFMT_GLOBALHEADER |
137                       AVFMT_TS_NEGATIVE | AVFMT_TS_NONSTRICT,
138     .subtitle_codec = AV_CODEC_ID_SUBRIP
139 };
140