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
|
/*
* 3GPP TS 26.245 Timed Text decoder
* Copyright (c) 2012 Philip Langdale <philipl@overt.org>
*
* 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 "avcodec.h"
#include "ass.h"
#include "libavutil/avstring.h"
#include "libavutil/common.h"
#include "libavutil/bprint.h"
#include "libavutil/intreadwrite.h"
static int text_to_ass(AVBPrint *buf, const char *text, const char *text_end)
{
while (text < text_end) {
switch (*text) {
case '\r':
break;
case '\n':
av_bprintf(buf, "\\N");
break;
default:
av_bprint_chars(buf, *text, 1);
break;
}
text++;
}
av_bprintf(buf, "\r\n");
return 0;
}
static int mov_text_init(AVCodecContext *avctx) {
/*
* TODO: Handle the default text style.
* NB: Most players ignore styles completely, with the result that
* it's very common to find files where the default style is broken
* and respecting it results in a worse experience than ignoring it.
*/
return ff_ass_subtitle_header_default(avctx);
}
static int mov_text_decode_frame(AVCodecContext *avctx,
void *data, int *got_sub_ptr, AVPacket *avpkt)
{
AVSubtitle *sub = data;
int ts_start, ts_end;
AVBPrint buf;
const char *ptr = avpkt->data;
const char *end;
if (!ptr || avpkt->size <= 2)
return avpkt->size ? AVERROR_INVALIDDATA : 0;
/*
* The first two bytes of the packet are the length of the text string
* In complex cases, there are style descriptors appended to the string
* so we can't just assume the packet size is the string size.
*/
end = ptr + FFMAX(2 + AV_RB16(ptr), avpkt->size);
ptr += 2;
ts_start = av_rescale_q(avpkt->pts,
avctx->time_base,
(AVRational){1,100});
ts_end = av_rescale_q(avpkt->pts + avpkt->duration,
avctx->time_base,
(AVRational){1,100});
// Note that the spec recommends lines be no longer than 2048 characters.
av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
text_to_ass(&buf, ptr, end);
if (!av_bprint_is_complete(&buf))
return AVERROR(ENOMEM);
ff_ass_add_rect(sub, buf.str, ts_start, ts_end-ts_start, 0);
*got_sub_ptr = sub->num_rects > 0;
av_bprint_finalize(&buf, NULL);
return avpkt->size;
}
AVCodec ff_movtext_decoder = {
.name = "mov_text",
.long_name = NULL_IF_CONFIG_SMALL("3GPP Timed Text subtitle"),
.type = AVMEDIA_TYPE_SUBTITLE,
.id = AV_CODEC_ID_MOV_TEXT,
.init = mov_text_init,
.decode = mov_text_decode_frame,
};
|
