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
|
/*
* SubRip subtitle demuxer
* Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
* Copyright (c) 2015 Clément Bœsch <u pkh me>
*
* 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 "avformat.h"
#include "internal.h"
#include "subtitles.h"
#include "libavutil/bprint.h"
#include "libavutil/intreadwrite.h"
typedef struct {
FFDemuxSubtitlesQueue q;
} SRTContext;
static int srt_probe(const AVProbeData *p)
{
int v;
char buf[64], *pbuf;
FFTextReader tr;
ff_text_init_buf(&tr, p->buf, p->buf_size);
while (ff_text_peek_r8(&tr) == '\r' || ff_text_peek_r8(&tr) == '\n')
ff_text_r8(&tr);
/* Check if the first non-empty line is a number. We do not check what the
* number is because in practice it can be anything.
* Also, that number can be followed by random garbage, so we can not
* unfortunately check that we only have a number. */
if (ff_subtitles_read_line(&tr, buf, sizeof(buf)) < 0 ||
strtol(buf, &pbuf, 10) < 0 || pbuf == buf)
return 0;
/* Check if the next line matches a SRT timestamp */
if (ff_subtitles_read_line(&tr, buf, sizeof(buf)) < 0)
return 0;
pbuf = buf;
if (buf[0] == '-')
pbuf++;
if (pbuf[0] >= '0' && pbuf[0] <= '9' && strstr(buf, " --> ")
&& sscanf(buf, "%*d:%*d:%*d%*1[,.]%*d --> %*d:%*d:%*d%*1[,.]%d", &v) == 1)
return AVPROBE_SCORE_MAX;
return 0;
}
struct event_info {
int32_t x1, x2, y1, y2;
int duration;
int64_t pts;
int64_t pos;
};
static int get_event_info(const char *line, struct event_info *ei)
{
int hh1, mm1, ss1, ms1;
int hh2, mm2, ss2, ms2;
ei->x1 = ei->x2 = ei->y1 = ei->y2 = ei->duration = -1;
ei->pts = AV_NOPTS_VALUE;
ei->pos = -1;
if (sscanf(line, "%d:%d:%d%*1[,.]%d --> %d:%d:%d%*1[,.]%d"
"%*[ ]X1:%"PRId32" X2:%"PRId32" Y1:%"PRId32" Y2:%"PRId32,
&hh1, &mm1, &ss1, &ms1,
&hh2, &mm2, &ss2, &ms2,
&ei->x1, &ei->x2, &ei->y1, &ei->y2) >= 8) {
const int64_t start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1;
const int64_t end = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2;
ei->duration = end - start;
ei->pts = start;
return 0;
}
return -1;
}
static int add_event(FFDemuxSubtitlesQueue *q, AVBPrint *buf, char *line_cache,
const struct event_info *ei, int append_cache)
{
if (append_cache && line_cache[0])
av_bprintf(buf, "%s\n", line_cache);
line_cache[0] = 0;
if (!av_bprint_is_complete(buf))
return AVERROR(ENOMEM);
while (buf->len > 0 && buf->str[buf->len - 1] == '\n')
buf->str[--buf->len] = 0;
if (buf->len) {
AVPacket *sub = ff_subtitles_queue_insert_bprint(q, buf, 0);
if (!sub)
return AVERROR(ENOMEM);
av_bprint_clear(buf);
sub->pos = ei->pos;
sub->pts = ei->pts;
sub->duration = ei->duration;
if (ei->x1 != -1) {
uint8_t *p = av_packet_new_side_data(sub, AV_PKT_DATA_SUBTITLE_POSITION, 16);
if (p) {
AV_WL32(p, ei->x1);
AV_WL32(p + 4, ei->y1);
AV_WL32(p + 8, ei->x2);
AV_WL32(p + 12, ei->y2);
}
}
}
return 0;
}
static int srt_read_header(AVFormatContext *s)
{
SRTContext *srt = s->priv_data;
AVBPrint buf;
AVStream *st = avformat_new_stream(s, NULL);
int res = 0;
char line[4096], line_cache[4096];
int has_event_info = 0;
struct event_info ei;
FFTextReader tr;
ff_text_init_avio(s, &tr, s->pb);
if (!st)
return AVERROR(ENOMEM);
avpriv_set_pts_info(st, 64, 1, 1000);
st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
st->codecpar->codec_id = AV_CODEC_ID_SUBRIP;
av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
line_cache[0] = 0;
while (!ff_text_eof(&tr)) {
struct event_info tmp_ei;
const int64_t pos = ff_text_pos(&tr);
ptrdiff_t len = ff_subtitles_read_line(&tr, line, sizeof(line));
if (len < 0)
break;
if (!len || !line[0])
continue;
if (get_event_info(line, &tmp_ei) < 0) {
char *pline;
if (!has_event_info)
continue;
if (line_cache[0]) {
/* We got some cache and a new line so we assume the cached
* line was actually part of the payload */
av_bprintf(&buf, "%s\n", line_cache);
line_cache[0] = 0;
}
/* If the line doesn't start with a number, we assume it's part of
* the payload, otherwise is likely an event number preceding the
* timing information... but we can't be sure of this yet, so we
* cache it */
if (strtol(line, &pline, 10) < 0 || line == pline)
av_bprintf(&buf, "%s\n", line);
else
strcpy(line_cache, line);
} else {
if (has_event_info) {
/* We have the information of previous event, append it to the
* queue. We insert the cached line if and only if the payload
* is empty and the cached line is not a standalone number. */
char *pline = NULL;
const int standalone_number = strtol(line_cache, &pline, 10) >= 0 && pline && !*pline;
res = add_event(&srt->q, &buf, line_cache, &ei, !buf.len && !standalone_number);
if (res < 0)
goto end;
} else {
has_event_info = 1;
}
tmp_ei.pos = pos;
ei = tmp_ei;
}
}
/* Append the last event. Here we force the cache to be flushed, because a
* trailing number is more likely to be geniune (for example a copyright
* date) and not the event index of an inexistant event */
if (has_event_info) {
res = add_event(&srt->q, &buf, line_cache, &ei, 1);
if (res < 0)
goto end;
}
ff_subtitles_queue_finalize(s, &srt->q);
end:
av_bprint_finalize(&buf, NULL);
return res;
}
const AVInputFormat ff_srt_demuxer = {
.name = "srt",
.long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
.priv_data_size = sizeof(SRTContext),
.flags_internal = FF_FMT_INIT_CLEANUP,
.read_probe = srt_probe,
.read_header = srt_read_header,
.read_packet = ff_subtitles_read_packet,
.read_seek2 = ff_subtitles_read_seek,
.read_close = ff_subtitles_read_close,
};
|
