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
|
/*
* DVD subtitle encoding for ffmpeg
* Copyright (c) 2005 Wolfram Gloger.
*
* 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 "bytestream.h"
#undef NDEBUG
#include <assert.h>
// ncnt is the nibble counter
#define PUTNIBBLE(val)\
do {\
if (ncnt++ & 1)\
*q++ = bitbuf | ((val) & 0x0f);\
else\
bitbuf = (val) << 4;\
} while(0)
static void dvd_encode_rle(uint8_t **pq,
const uint8_t *bitmap, int linesize,
int w, int h,
const int cmap[256])
{
uint8_t *q;
unsigned int bitbuf = 0;
int ncnt;
int x, y, len, color;
q = *pq;
for (y = 0; y < h; ++y) {
ncnt = 0;
for(x = 0; x < w; x += len) {
color = bitmap[x];
for (len=1; x+len < w; ++len)
if (bitmap[x+len] != color)
break;
color = cmap[color];
assert(color < 4);
if (len < 0x04) {
PUTNIBBLE((len << 2)|color);
} else if (len < 0x10) {
PUTNIBBLE(len >> 2);
PUTNIBBLE((len << 2)|color);
} else if (len < 0x40) {
PUTNIBBLE(0);
PUTNIBBLE(len >> 2);
PUTNIBBLE((len << 2)|color);
} else if (x+len == w) {
PUTNIBBLE(0);
PUTNIBBLE(0);
PUTNIBBLE(0);
PUTNIBBLE(color);
} else {
if (len > 0xff)
len = 0xff;
PUTNIBBLE(0);
PUTNIBBLE(len >> 6);
PUTNIBBLE(len >> 2);
PUTNIBBLE((len << 2)|color);
}
}
/* end of line */
if (ncnt & 1)
PUTNIBBLE(0);
bitmap += linesize;
}
*pq = q;
}
static int encode_dvd_subtitles(uint8_t *outbuf, int outbuf_size,
const AVSubtitle *h)
{
uint8_t *q, *qq;
int object_id;
int offset1[20], offset2[20];
int i, imax, color, alpha, rects = h->num_rects;
unsigned long hmax;
unsigned long hist[256];
int cmap[256];
if (rects == 0 || h->rects == NULL)
return -1;
if (rects > 20)
rects = 20;
// analyze bitmaps, compress to 4 colors
for (i=0; i<256; ++i) {
hist[i] = 0;
cmap[i] = 0;
}
for (object_id = 0; object_id < rects; object_id++)
for (i=0; i<h->rects[object_id].w*h->rects[object_id].h; ++i) {
color = h->rects[object_id].bitmap[i];
// only count non-transparent pixels
alpha = h->rects[object_id].rgba_palette[color] >> 24;
hist[color] += alpha;
}
for (color=3;; --color) {
hmax = 0;
imax = 0;
for (i=0; i<256; ++i)
if (hist[i] > hmax) {
imax = i;
hmax = hist[i];
}
if (hmax == 0)
break;
if (color == 0)
color = 3;
av_log(NULL, AV_LOG_DEBUG, "dvd_subtitle hist[%d]=%ld -> col %d\n",
imax, hist[imax], color);
cmap[imax] = color;
hist[imax] = 0;
}
// encode data block
q = outbuf + 4;
for (object_id = 0; object_id < rects; object_id++) {
offset1[object_id] = q - outbuf;
// worst case memory requirement: 1 nibble per pixel..
if ((q - outbuf) + h->rects[object_id].w*h->rects[object_id].h/2
+ 17*rects + 21 > outbuf_size) {
av_log(NULL, AV_LOG_ERROR, "dvd_subtitle too big\n");
return -1;
}
dvd_encode_rle(&q, h->rects[object_id].bitmap,
h->rects[object_id].w*2,
h->rects[object_id].w, h->rects[object_id].h >> 1,
cmap);
offset2[object_id] = q - outbuf;
dvd_encode_rle(&q, h->rects[object_id].bitmap + h->rects[object_id].w,
h->rects[object_id].w*2,
h->rects[object_id].w, h->rects[object_id].h >> 1,
cmap);
}
// set data packet size
qq = outbuf + 2;
bytestream_put_be16(&qq, q - outbuf);
// send start display command
bytestream_put_be16(&q, (h->start_display_time*90) >> 10);
bytestream_put_be16(&q, (q - outbuf) /*- 2 */ + 8 + 12*rects + 2);
*q++ = 0x03; // palette - 4 nibbles
*q++ = 0x03; *q++ = 0x7f;
*q++ = 0x04; // alpha - 4 nibbles
*q++ = 0xf0; *q++ = 0x00;
//*q++ = 0x0f; *q++ = 0xff;
// XXX not sure if more than one rect can really be encoded..
// 12 bytes per rect
for (object_id = 0; object_id < rects; object_id++) {
int x2 = h->rects[object_id].x + h->rects[object_id].w - 1;
int y2 = h->rects[object_id].y + h->rects[object_id].h - 1;
*q++ = 0x05;
// x1 x2 -> 6 nibbles
*q++ = h->rects[object_id].x >> 4;
*q++ = (h->rects[object_id].x << 4) | ((x2 >> 8) & 0xf);
*q++ = x2;
// y1 y2 -> 6 nibbles
*q++ = h->rects[object_id].y >> 4;
*q++ = (h->rects[object_id].y << 4) | ((y2 >> 8) & 0xf);
*q++ = y2;
*q++ = 0x06;
// offset1, offset2
bytestream_put_be16(&q, offset1[object_id]);
bytestream_put_be16(&q, offset2[object_id]);
}
*q++ = 0x01; // start command
*q++ = 0xff; // terminating command
// send stop display command last
bytestream_put_be16(&q, (h->end_display_time*90) >> 10);
bytestream_put_be16(&q, (q - outbuf) - 2 /*+ 4*/);
*q++ = 0x02; // set end
*q++ = 0xff; // terminating command
qq = outbuf;
bytestream_put_be16(&qq, q - outbuf);
av_log(NULL, AV_LOG_DEBUG, "subtitle_packet size=%td\n", q - outbuf);
return q - outbuf;
}
static int dvdsub_encode(AVCodecContext *avctx,
unsigned char *buf, int buf_size, void *data)
{
//DVDSubtitleContext *s = avctx->priv_data;
AVSubtitle *sub = data;
int ret;
ret = encode_dvd_subtitles(buf, buf_size, sub);
return ret;
}
AVCodec dvdsub_encoder = {
"dvdsub",
CODEC_TYPE_SUBTITLE,
CODEC_ID_DVD_SUBTITLE,
0,
NULL,
dvdsub_encode,
};
|
