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
|
/*
* XSUB subtitle decoder
* Copyright (c) 2007 Reimar Döffinger
*
* 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 "libavutil/mathematics.h"
#include "libavutil/imgutils.h"
#include "avcodec.h"
#include "get_bits.h"
#include "bytestream.h"
static av_cold int decode_init(AVCodecContext *avctx) {
avctx->pix_fmt = PIX_FMT_PAL8;
return 0;
}
static const uint8_t tc_offsets[9] = { 0, 1, 3, 4, 6, 7, 9, 10, 11 };
static const uint8_t tc_muls[9] = { 10, 6, 10, 6, 10, 10, 10, 10, 1 };
static int64_t parse_timecode(const uint8_t *buf, int64_t packet_time) {
int i;
int64_t ms = 0;
if (buf[2] != ':' || buf[5] != ':' || buf[8] != '.')
return AV_NOPTS_VALUE;
for (i = 0; i < sizeof(tc_offsets); i++) {
uint8_t c = buf[tc_offsets[i]] - '0';
if (c > 9) return AV_NOPTS_VALUE;
ms = (ms + c) * tc_muls[i];
}
return ms - packet_time;
}
static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
AVPacket *avpkt) {
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
AVSubtitle *sub = data;
const uint8_t *buf_end = buf + buf_size;
uint8_t *bitmap;
int w, h, x, y, i;
int64_t packet_time = 0;
GetBitContext gb;
int has_alpha = avctx->codec_tag == MKTAG('D','X','S','A');
// check that at least header fits
if (buf_size < 27 + 7 * 2 + 4 * 3) {
av_log(avctx, AV_LOG_ERROR, "coded frame too small\n");
return -1;
}
// read start and end time
if (buf[0] != '[' || buf[13] != '-' || buf[26] != ']') {
av_log(avctx, AV_LOG_ERROR, "invalid time code\n");
return -1;
}
if (avpkt->pts != AV_NOPTS_VALUE)
packet_time = av_rescale_q(avpkt->pts, AV_TIME_BASE_Q, (AVRational){1, 1000});
sub->start_display_time = parse_timecode(buf + 1, packet_time);
sub->end_display_time = parse_timecode(buf + 14, packet_time);
buf += 27;
// read header
w = bytestream_get_le16(&buf);
h = bytestream_get_le16(&buf);
if (av_image_check_size(w, h, 0, avctx) < 0)
return -1;
x = bytestream_get_le16(&buf);
y = bytestream_get_le16(&buf);
// skip bottom right position, it gives no new information
bytestream_get_le16(&buf);
bytestream_get_le16(&buf);
// The following value is supposed to indicate the start offset
// (relative to the palette) of the data for the second field,
// however there are files where it has a bogus value and thus
// we just ignore it
bytestream_get_le16(&buf);
// allocate sub and set values
sub->rects = av_mallocz(sizeof(*sub->rects));
sub->rects[0] = av_mallocz(sizeof(*sub->rects[0]));
sub->num_rects = 1;
sub->rects[0]->x = x; sub->rects[0]->y = y;
sub->rects[0]->w = w; sub->rects[0]->h = h;
sub->rects[0]->type = SUBTITLE_BITMAP;
sub->rects[0]->pict.linesize[0] = w;
sub->rects[0]->pict.data[0] = av_malloc(w * h);
sub->rects[0]->nb_colors = 4;
sub->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE);
// read palette
for (i = 0; i < sub->rects[0]->nb_colors; i++)
((uint32_t*)sub->rects[0]->pict.data[1])[i] = bytestream_get_be24(&buf);
// make all except background (first entry) non-transparent
for (i = 0; i < sub->rects[0]->nb_colors; i++)
((uint32_t*)sub->rects[0]->pict.data[1])[i] |= (has_alpha ? *buf++ : (i ? 0xff : 0)) << 24;
// process RLE-compressed data
init_get_bits(&gb, buf, (buf_end - buf) * 8);
bitmap = sub->rects[0]->pict.data[0];
for (y = 0; y < h; y++) {
// interlaced: do odd lines
if (y == (h + 1) / 2) bitmap = sub->rects[0]->pict.data[0] + w;
for (x = 0; x < w; ) {
int log2 = ff_log2_tab[show_bits(&gb, 8)];
int run = get_bits(&gb, 14 - 4 * (log2 >> 1));
int color = get_bits(&gb, 2);
run = FFMIN(run, w - x);
// run length 0 means till end of row
if (!run) run = w - x;
memset(bitmap, color, run);
bitmap += run;
x += run;
}
// interlaced, skip every second line
bitmap += w;
align_get_bits(&gb);
}
*data_size = 1;
return buf_size;
}
AVCodec ff_xsub_decoder = {
.name = "xsub",
.type = AVMEDIA_TYPE_SUBTITLE,
.id = CODEC_ID_XSUB,
.init = decode_init,
.decode = decode_frame,
.long_name = NULL_IF_CONFIG_SMALL("XSUB"),
};
|
