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
|
/*
* SSA/ASS demuxer
* Copyright (c) 2008 Michael Niedermayer
*
* 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"
#define MAX_LINESIZE 2000
typedef struct ASSContext{
uint8_t *event_buffer;
uint8_t **event;
unsigned int event_count;
unsigned int event_index;
}ASSContext;
static int probe(AVProbeData *p)
{
const char *header= "[Script Info]";
if( !memcmp(p->buf , header, strlen(header))
|| !memcmp(p->buf+3, header, strlen(header)))
return AVPROBE_SCORE_MAX;
return 0;
}
static int read_close(AVFormatContext *s)
{
ASSContext *ass = s->priv_data;
av_freep(&ass->event_buffer);
av_freep(&ass->event);
return 0;
}
static int64_t get_pts(const uint8_t *p)
{
int hour, min, sec, hsec;
if(sscanf(p, "%*[^,],%d:%d:%d%*c%d", &hour, &min, &sec, &hsec) != 4)
return AV_NOPTS_VALUE;
// av_log(NULL, AV_LOG_ERROR, "%d %d %d %d %d [%s]\n", i, hour, min, sec, hsec, p);
min+= 60*hour;
sec+= 60*min;
return sec*100+hsec;
}
static int event_cmp(uint8_t **a, uint8_t **b)
{
return get_pts(*a) - get_pts(*b);
}
static int read_header(AVFormatContext *s, AVFormatParameters *ap)
{
int i, len, header_remaining;
ASSContext *ass = s->priv_data;
ByteIOContext *pb = s->pb;
AVStream *st;
int allocated[2]={0};
uint8_t *p, **dst[2]={0};
int pos[2]={0};
st = av_new_stream(s, 0);
if (!st)
return -1;
av_set_pts_info(st, 64, 1, 100);
st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
st->codec->codec_id= CODEC_ID_SSA;
header_remaining= INT_MAX;
dst[0] = &st->codec->extradata;
dst[1] = &ass->event_buffer;
while(!url_feof(pb)){
uint8_t line[MAX_LINESIZE];
len = ff_get_line(pb, line, sizeof(line));
if(!memcmp(line, "[Events]", 8))
header_remaining= 2;
else if(line[0]=='[')
header_remaining= INT_MAX;
i= header_remaining==0;
if(i && get_pts(line) == AV_NOPTS_VALUE)
continue;
p = av_fast_realloc(*(dst[i]), &allocated[i], pos[i]+MAX_LINESIZE);
if(!p)
goto fail;
*(dst[i])= p;
memcpy(p + pos[i], line, len+1);
pos[i] += len;
if(i) ass->event_count++;
else header_remaining--;
}
st->codec->extradata_size= pos[0];
if(ass->event_count >= UINT_MAX / sizeof(*ass->event))
goto fail;
ass->event= av_malloc(ass->event_count * sizeof(*ass->event));
p= ass->event_buffer;
for(i=0; i<ass->event_count; i++){
ass->event[i]= p;
while(*p && *p != '\n')
p++;
p++;
}
qsort(ass->event, ass->event_count, sizeof(*ass->event), (void*)event_cmp);
return 0;
fail:
read_close(s);
return -1;
}
static int read_packet(AVFormatContext *s, AVPacket *pkt)
{
ASSContext *ass = s->priv_data;
uint8_t *p, *end;
if(ass->event_index >= ass->event_count)
return AVERROR(EIO);
p= ass->event[ ass->event_index ];
end= strchr(p, '\n');
av_new_packet(pkt, end ? end-p+1 : strlen(p));
pkt->flags |= AV_PKT_FLAG_KEY;
pkt->pos= p - ass->event_buffer + s->streams[0]->codec->extradata_size;
pkt->pts= pkt->dts= get_pts(p);
memcpy(pkt->data, p, pkt->size);
ass->event_index++;
return 0;
}
static int read_seek2(AVFormatContext *s, int stream_index,
int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
{
ASSContext *ass = s->priv_data;
if (flags & AVSEEK_FLAG_BYTE) {
return AVERROR_NOTSUPP;
} else if (flags & AVSEEK_FLAG_FRAME) {
if (ts < 0 || ts >= ass->event_count)
return AVERROR(ERANGE);
ass->event_index = ts;
} else {
int i, idx = -1;
int64_t min_ts_diff = INT64_MAX;
if (stream_index == -1) {
AVRational time_base = s->streams[0]->time_base;
ts = av_rescale_q(ts, AV_TIME_BASE_Q, time_base);
min_ts = av_rescale_rnd(min_ts, time_base.den,
time_base.num * (int64_t)AV_TIME_BASE,
AV_ROUND_UP);
max_ts = av_rescale_rnd(max_ts, time_base.den,
time_base.num * (int64_t)AV_TIME_BASE,
AV_ROUND_DOWN);
}
/* TODO: ass->event[] is sorted by pts so we could do a binary search */
for (i=0; i<ass->event_count; i++) {
int64_t pts = get_pts(ass->event[i]);
int64_t ts_diff = FFABS(pts - ts);
if (pts >= min_ts && pts <= max_ts && ts_diff < min_ts_diff) {
min_ts_diff = ts_diff;
idx = i;
}
}
if (idx < 0)
return AVERROR(ERANGE);
ass->event_index = idx;
}
return 0;
}
AVInputFormat ass_demuxer = {
"ass",
NULL_IF_CONFIG_SMALL("Advanced SubStation Alpha subtitle format"),
sizeof(ASSContext),
probe,
read_header,
read_packet,
read_close,
.read_seek2 = read_seek2,
};
|
