1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
|
/*
* LRC lyrics file format decoder
* Copyright (c) 2014 StarBrilliant <m13253@hotmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <inttypes.h>
#include <stdint.h>
#include <string.h>
#include "avformat.h"
#include "internal.h"
#include "lrc.h"
#include "metadata.h"
#include "subtitles.h"
#include "libavutil/bprint.h"
#include "libavutil/dict.h"
typedef struct LRCContext {
FFDemuxSubtitlesQueue q;
int64_t ts_offset; // offset metadata item
} LRCContext;
static int64_t find_header(const char *p)
{
int64_t offset = 0;
while(p[offset] == ' ' || p[offset] == '\t') {
offset++;
}
if(p[offset] == '[' && p[offset + 1] >= 'a' && p[offset + 1] <= 'z') {
return offset;
} else {
return -1;
}
}
static int64_t count_ts(const char *p)
{
int64_t offset = 0;
int in_brackets = 0;
for(;;) {
if(p[offset] == ' ' || p[offset] == '\t') {
offset++;
} else if(p[offset] == '[') {
offset++;
in_brackets++;
} else if (p[offset] == ']' && in_brackets) {
offset++;
in_brackets--;
} else if(in_brackets &&
(p[offset] == ':' || p[offset] == '.' || p[offset] == '-' ||
(p[offset] >= '0' && p[offset] <= '9'))) {
offset++;
} else {
break;
}
}
return offset;
}
static int64_t read_ts(const char *p, int64_t *start)
{
int64_t offset = 0;
uint64_t mm, ss, cs;
while(p[offset] == ' ' || p[offset] == '\t') {
offset++;
}
if(p[offset] != '[') {
return 0;
}
if(sscanf(p, "[-%"SCNu64":%"SCNu64".%"SCNu64"]", &mm, &ss, &cs) == 3) {
/* Just in case negative pts, players may drop it but we won't. */
*start = -(int64_t) (mm*60000 + ss*1000 + cs*10);
} else if(sscanf(p, "[%"SCNu64":%"SCNu64".%"SCNu64"]", &mm, &ss, &cs) == 3) {
*start = mm*60000 + ss*1000 + cs*10;
} else {
return 0;
}
do {
offset++;
} while(p[offset] && p[offset-1] != ']');
return offset;
}
static int64_t read_line(AVBPrint *buf, AVIOContext *pb)
{
int64_t pos = avio_tell(pb);
av_bprint_clear(buf);
while(!avio_feof(pb)) {
int c = avio_r8(pb);
if(c != '\r') {
av_bprint_chars(buf, c, 1);
}
if(c == '\n') {
break;
}
}
return pos;
}
static int lrc_probe(const AVProbeData *p)
{
int64_t offset = 0;
int64_t mm;
uint64_t ss, cs;
const AVMetadataConv *metadata_item;
if(!memcmp(p->buf, "\xef\xbb\xbf", 3)) { // Skip UTF-8 BOM header
offset += 3;
}
while(p->buf[offset] == '\n' || p->buf[offset] == '\r') {
offset++;
}
if(p->buf[offset] != '[') {
return 0;
}
offset++;
// Common metadata item but not exist in ff_lrc_metadata_conv
if(!memcmp(p->buf + offset, "offset:", 7)) {
return 40;
}
if(sscanf(p->buf + offset, "%"SCNd64":%"SCNu64".%"SCNu64"]",
&mm, &ss, &cs) == 3) {
return 50;
}
// Metadata items exist in ff_lrc_metadata_conv
for(metadata_item = ff_lrc_metadata_conv;
metadata_item->native; metadata_item++) {
size_t metadata_item_len = strlen(metadata_item->native);
if(p->buf[offset + metadata_item_len] == ':' &&
!memcmp(p->buf + offset, metadata_item->native, metadata_item_len)) {
return 40;
}
}
return 5; // Give it 5 scores since it starts with a bracket
}
static int lrc_read_header(AVFormatContext *s)
{
LRCContext *lrc = s->priv_data;
AVBPrint line;
AVStream *st;
st = avformat_new_stream(s, NULL);
if(!st) {
return AVERROR(ENOMEM);
}
avpriv_set_pts_info(st, 64, 1, 1000);
lrc->ts_offset = 0;
st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
st->codecpar->codec_id = AV_CODEC_ID_TEXT;
av_bprint_init(&line, 0, AV_BPRINT_SIZE_UNLIMITED);
while(!avio_feof(s->pb)) {
int64_t pos = read_line(&line, s->pb);
if (!av_bprint_is_complete(&line))
goto err_nomem_out;
int64_t header_offset = find_header(line.str);
if(header_offset >= 0) {
char *comma_offset = strchr(line.str, ':');
if(comma_offset) {
char *right_bracket_offset = strchr(line.str, ']');
if(!right_bracket_offset) {
continue;
}
*right_bracket_offset = *comma_offset = '\0';
if(strcmp(line.str + 1, "offset") ||
sscanf(comma_offset + 1, "%"SCNd64, &lrc->ts_offset) != 1) {
av_dict_set(&s->metadata, line.str + 1, comma_offset + 1, 0);
}
lrc->ts_offset = av_clip64(lrc->ts_offset, INT64_MIN/4, INT64_MAX/4);
*comma_offset = ':';
*right_bracket_offset = ']';
}
} else {
AVPacket *sub;
int64_t ts_start = AV_NOPTS_VALUE;
int64_t ts_stroffset = 0;
int64_t ts_stroffset_incr = 0;
int64_t ts_strlength = count_ts(line.str);
while((ts_stroffset_incr = read_ts(line.str + ts_stroffset,
&ts_start)) != 0) {
ts_start = av_clip64(ts_start, INT64_MIN/4, INT64_MAX/4);
ts_stroffset += ts_stroffset_incr;
sub = ff_subtitles_queue_insert(&lrc->q, line.str + ts_strlength,
line.len - ts_strlength, 0);
if (!sub)
goto err_nomem_out;
sub->pos = pos;
sub->pts = ts_start - lrc->ts_offset;
sub->duration = -1;
}
}
}
ff_subtitles_queue_finalize(s, &lrc->q);
ff_metadata_conv_ctx(s, NULL, ff_lrc_metadata_conv);
av_bprint_finalize(&line, NULL);
return 0;
err_nomem_out:
av_bprint_finalize(&line, NULL);
return AVERROR(ENOMEM);
}
const AVInputFormat ff_lrc_demuxer = {
.name = "lrc",
.long_name = NULL_IF_CONFIG_SMALL("LRC lyrics"),
.priv_data_size = sizeof (LRCContext),
.flags_internal = FF_FMT_INIT_CLEANUP,
.read_probe = lrc_probe,
.read_header = lrc_read_header,
.read_packet = ff_subtitles_read_packet,
.read_close = ff_subtitles_read_close,
.read_seek2 = ff_subtitles_read_seek
};
|
