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libavcodec
ansi.c
Go to the documentation of this file.
1
/*
2
* ASCII/ANSI art decoder
3
* Copyright (c) 2010 Peter Ross <pross@xvid.org>
4
*
5
* This file is part of FFmpeg.
6
*
7
* FFmpeg is free software; you can redistribute it and/or
8
* modify it under the terms of the GNU Lesser General Public
9
* License as published by the Free Software Foundation; either
10
* version 2.1 of the License, or (at your option) any later version.
11
*
12
* FFmpeg is distributed in the hope that it will be useful,
13
* but WITHOUT ANY WARRANTY; without even the implied warranty of
14
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15
* Lesser General Public License for more details.
16
*
17
* You should have received a copy of the GNU Lesser General Public
18
* License along with FFmpeg; if not, write to the Free Software
19
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20
*/
21
22
/**
23
* @file
24
* ASCII/ANSI art decoder
25
*/
26
27
#include "
libavutil/common.h
"
28
#include "
libavutil/frame.h
"
29
#include "
libavutil/lfg.h
"
30
#include "
libavutil/xga_font_data.h
"
31
#include "
avcodec.h
"
32
#include "
cga_data.h
"
33
#include "
internal.h
"
34
35
#define ATTR_BOLD 0x01
/**< Bold/Bright-foreground (mode 1) */
36
#define ATTR_FAINT 0x02
/**< Faint (mode 2) */
37
#define ATTR_UNDERLINE 0x08
/**< Underline (mode 4) */
38
#define ATTR_BLINK 0x10
/**< Blink/Bright-background (mode 5) */
39
#define ATTR_REVERSE 0x40
/**< Reverse (mode 7) */
40
#define ATTR_CONCEALED 0x80
/**< Concealed (mode 8) */
41
42
#define DEFAULT_FG_COLOR 7
/**< CGA color index */
43
#define DEFAULT_BG_COLOR 0
44
#define DEFAULT_SCREEN_MODE 3
/**< 80x25 */
45
46
#define FONT_WIDTH 8
/**< Font width */
47
48
/** map ansi color index to cga palette index */
49
static
const
uint8_t
ansi_to_cga
[16] = {
50
0, 4, 2, 6, 1, 5, 3, 7, 8, 12, 10, 14, 9, 13, 11, 15
51
};
52
53
typedef
struct
{
54
AVFrame
*
frame
;
55
int
x
;
/**< x cursor position (pixels) */
56
int
y
;
/**< y cursor position (pixels) */
57
int
sx
;
/**< saved x cursor position (pixels) */
58
int
sy
;
/**< saved y cursor position (pixels) */
59
const
uint8_t
*
font
;
/**< font */
60
int
font_height
;
/**< font height */
61
int
attributes
;
/**< attribute flags */
62
int
fg
;
/**< foreground color */
63
int
bg
;
/**< background color */
64
int
first_frame
;
65
66
/* ansi parser state machine */
67
enum
{
68
STATE_NORMAL = 0,
69
STATE_ESCAPE
,
70
STATE_CODE
,
71
STATE_MUSIC_PREAMBLE
72
}
state
;
73
#define MAX_NB_ARGS 4
74
int
args
[
MAX_NB_ARGS
];
75
int
nb_args
;
/**< number of arguments (may exceed MAX_NB_ARGS) */
76
}
AnsiContext
;
77
78
static
av_cold
int
decode_init
(
AVCodecContext
*avctx)
79
{
80
AnsiContext
*
s
= avctx->
priv_data
;
81
avctx->
pix_fmt
=
AV_PIX_FMT_PAL8
;
82
83
s->
frame
=
av_frame_alloc
();
84
if
(!s->
frame
)
85
return
AVERROR
(ENOMEM);
86
87
/* defaults */
88
s->
font
=
avpriv_vga16_font
;
89
s->
font_height
= 16;
90
s->
fg
=
DEFAULT_FG_COLOR
;
91
s->
bg
=
DEFAULT_BG_COLOR
;
92
93
if
(!avctx->
width
|| !avctx->
height
)
94
avcodec_set_dimensions
(avctx, 80<<3, 25<<4);
95
96
return
0;
97
}
98
99
static
void
set_palette
(uint32_t *pal)
100
{
101
int
r
,
g
,
b
;
102
memcpy(pal,
ff_cga_palette
, 16 * 4);
103
pal += 16;
104
#define COLOR(x) ((x) * 40 + 55)
105
for
(r = 0; r < 6; r++)
106
for
(g = 0; g < 6; g++)
107
for
(b = 0; b < 6; b++)
108
*pal++ = 0xFF000000 | (
COLOR
(r) << 16) | (
COLOR
(g) << 8) |
COLOR
(b);
109
#define GRAY(x) ((x) * 10 + 8)
110
for
(g = 0; g < 24; g++)
111
*pal++ = 0xFF000000 | (
GRAY
(g) << 16) | (
GRAY
(g) << 8) |
GRAY
(g);
112
}
113
114
static
void
hscroll
(
AVCodecContext
*avctx)
115
{
116
AnsiContext
*
s
= avctx->
priv_data
;
117
int
i;
118
119
if
(s->
y
<= avctx->
height
- 2*s->
font_height
) {
120
s->
y
+= s->
font_height
;
121
return
;
122
}
123
124
i = 0;
125
for
(; i < avctx->
height
- s->
font_height
; i++)
126
memcpy(s->
frame
->
data
[0] + i * s->
frame
->
linesize
[0],
127
s->
frame
->
data
[0] + (i + s->
font_height
) * s->
frame
->
linesize
[0],
128
avctx->
width
);
129
for
(; i < avctx->
height
; i++)
130
memset(s->
frame
->
data
[0] + i * s->
frame
->
linesize
[0],
131
DEFAULT_BG_COLOR
, avctx->
width
);
132
}
133
134
static
void
erase_line
(
AVCodecContext
* avctx,
int
xoffset,
int
xlength)
135
{
136
AnsiContext
*
s
= avctx->
priv_data
;
137
int
i;
138
for
(i = 0; i < s->
font_height
; i++)
139
memset(s->
frame
->
data
[0] + (s->
y
+ i)*s->
frame
->
linesize
[0] + xoffset,
140
DEFAULT_BG_COLOR
, xlength);
141
}
142
143
static
void
erase_screen
(
AVCodecContext
*avctx)
144
{
145
AnsiContext
*
s
= avctx->
priv_data
;
146
int
i;
147
for
(i = 0; i < avctx->
height
; i++)
148
memset(s->
frame
->
data
[0] + i * s->
frame
->
linesize
[0],
DEFAULT_BG_COLOR
, avctx->
width
);
149
s->
x
= s->
y
= 0;
150
}
151
152
/**
153
* Draw character to screen
154
*/
155
static
void
draw_char
(
AVCodecContext
*avctx,
int
c
)
156
{
157
AnsiContext
*
s
= avctx->
priv_data
;
158
int
fg = s->
fg
;
159
int
bg = s->
bg
;
160
161
if
((s->
attributes
&
ATTR_BOLD
))
162
fg += 8;
163
if
((s->
attributes
&
ATTR_BLINK
))
164
bg += 8;
165
if
((s->
attributes
&
ATTR_REVERSE
))
166
FFSWAP
(
int
, fg, bg);
167
if
((s->
attributes
&
ATTR_CONCEALED
))
168
fg = bg;
169
ff_draw_pc_font
(s->
frame
->
data
[0] + s->
y
* s->
frame
->
linesize
[0] + s->
x
,
170
s->
frame
->
linesize
[0], s->
font
, s->
font_height
, c, fg, bg);
171
s->
x
+=
FONT_WIDTH
;
172
if
(s->
x
> avctx->
width
-
FONT_WIDTH
) {
173
s->
x
= 0;
174
hscroll
(avctx);
175
}
176
}
177
178
/**
179
* Execute ANSI escape code
180
* @return 0 on success, negative on error
181
*/
182
static
int
execute_code
(
AVCodecContext
* avctx,
int
c
)
183
{
184
AnsiContext
*
s
= avctx->
priv_data
;
185
int
ret
, i,
width
,
height
;
186
switch
(c) {
187
case
'A'
:
//Cursor Up
188
s->
y
=
FFMAX
(s->
y
- (s->
nb_args
> 0 ? s->
args
[0]*s->
font_height
: s->
font_height
), 0);
189
break
;
190
case
'B'
:
//Cursor Down
191
s->
y
=
FFMIN
(s->
y
+ (s->
nb_args
> 0 ? s->
args
[0]*s->
font_height
: s->
font_height
), avctx->
height
- s->
font_height
);
192
break
;
193
case
'C'
:
//Cursor Right
194
s->
x
=
FFMIN
(s->
x
+ (s->
nb_args
> 0 ? s->
args
[0]*
FONT_WIDTH
:
FONT_WIDTH
), avctx->
width
- FONT_WIDTH);
195
break
;
196
case
'D'
:
//Cursor Left
197
s->
x
=
FFMAX
(s->
x
- (s->
nb_args
> 0 ? s->
args
[0]*FONT_WIDTH : FONT_WIDTH), 0);
198
break
;
199
case
'H'
:
//Cursor Position
200
case
'f'
:
//Horizontal and Vertical Position
201
s->
y
= s->
nb_args
> 0 ? av_clip((s->
args
[0] - 1)*s->
font_height
, 0, avctx->
height
- s->
font_height
) : 0;
202
s->
x
= s->
nb_args
> 1 ? av_clip((s->
args
[1] - 1)*FONT_WIDTH, 0, avctx->
width
- FONT_WIDTH) : 0;
203
break
;
204
case
'h'
:
//set creen mode
205
case
'l'
:
//reset screen mode
206
if
(s->
nb_args
< 2)
207
s->
args
[0] =
DEFAULT_SCREEN_MODE
;
208
width = avctx->
width
;
209
height = avctx->
height
;
210
switch
(s->
args
[0]) {
211
case
0:
case
1:
case
4:
case
5:
case
13:
case
19:
//320x200 (25 rows)
212
s->
font
=
avpriv_cga_font
;
213
s->
font_height
= 8;
214
width = 40<<3;
215
height = 25<<3;
216
break
;
217
case
2:
case
3:
//640x400 (25 rows)
218
s->
font
=
avpriv_vga16_font
;
219
s->
font_height
= 16;
220
width = 80<<3;
221
height = 25<<4;
222
break
;
223
case
6:
case
14:
//640x200 (25 rows)
224
s->
font
=
avpriv_cga_font
;
225
s->
font_height
= 8;
226
width = 80<<3;
227
height = 25<<3;
228
break
;
229
case
7:
//set line wrapping
230
break
;
231
case
15:
case
16:
//640x350 (43 rows)
232
s->
font
=
avpriv_cga_font
;
233
s->
font_height
= 8;
234
width = 80<<3;
235
height = 43<<3;
236
break
;
237
case
17:
case
18:
//640x480 (60 rows)
238
s->
font
=
avpriv_cga_font
;
239
s->
font_height
= 8;
240
width = 80<<3;
241
height = 60<<4;
242
break
;
243
default
:
244
avpriv_request_sample
(avctx,
"Unsupported screen mode"
);
245
}
246
s->
x
= av_clip(s->
x
, 0, width - FONT_WIDTH);
247
s->
y
= av_clip(s->
y
, 0, height - s->
font_height
);
248
if
(width != avctx->
width
|| height != avctx->
height
) {
249
av_frame_unref
(s->
frame
);
250
avcodec_set_dimensions
(avctx, width, height);
251
if
((ret =
ff_get_buffer
(avctx, s->
frame
,
252
AV_GET_BUFFER_FLAG_REF
)) < 0)
253
return
ret
;
254
s->
frame
->
pict_type
=
AV_PICTURE_TYPE_I
;
255
s->
frame
->
palette_has_changed
= 1;
256
set_palette
((uint32_t *)s->
frame
->
data
[1]);
257
erase_screen
(avctx);
258
}
else
if
(c ==
'l'
) {
259
erase_screen
(avctx);
260
}
261
break
;
262
case
'J'
:
//Erase in Page
263
switch
(s->
args
[0]) {
264
case
0:
265
erase_line
(avctx, s->
x
, avctx->
width
- s->
x
);
266
if
(s->
y
< avctx->
height
- s->
font_height
)
267
memset(s->
frame
->
data
[0] + (s->
y
+ s->
font_height
)*s->
frame
->
linesize
[0],
268
DEFAULT_BG_COLOR
, (avctx->
height
- s->
y
- s->
font_height
)*s->
frame
->
linesize
[0]);
269
break
;
270
case
1:
271
erase_line
(avctx, 0, s->
x
);
272
if
(s->
y
> 0)
273
memset(s->
frame
->
data
[0],
DEFAULT_BG_COLOR
, s->
y
* s->
frame
->
linesize
[0]);
274
break
;
275
case
2:
276
erase_screen
(avctx);
277
}
278
break
;
279
case
'K'
:
//Erase in Line
280
switch
(s->
args
[0]) {
281
case
0:
282
erase_line
(avctx, s->
x
, avctx->
width
- s->
x
);
283
break
;
284
case
1:
285
erase_line
(avctx, 0, s->
x
);
286
break
;
287
case
2:
288
erase_line
(avctx, 0, avctx->
width
);
289
}
290
break
;
291
case
'm'
:
//Select Graphics Rendition
292
if
(s->
nb_args
== 0) {
293
s->
nb_args
= 1;
294
s->
args
[0] = 0;
295
}
296
for
(i = 0; i <
FFMIN
(s->
nb_args
,
MAX_NB_ARGS
); i++) {
297
int
m
= s->
args
[i];
298
if
(m == 0) {
299
s->
attributes
= 0;
300
s->
fg
=
DEFAULT_FG_COLOR
;
301
s->
bg
=
DEFAULT_BG_COLOR
;
302
}
else
if
(m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) {
303
s->
attributes
|= 1 << (m - 1);
304
}
else
if
(m >= 30 && m <= 37) {
305
s->
fg
=
ansi_to_cga
[m - 30];
306
}
else
if
(m == 38 && i + 2 <
FFMIN
(s->
nb_args
,
MAX_NB_ARGS
) && s->
args
[i + 1] == 5 && s->
args
[i + 2] < 256) {
307
int
index
= s->
args
[i + 2];
308
s->
fg
= index < 16 ?
ansi_to_cga
[
index
] :
index
;
309
i += 2;
310
}
else
if
(m == 39) {
311
s->
fg
=
ansi_to_cga
[
DEFAULT_FG_COLOR
];
312
}
else
if
(m >= 40 && m <= 47) {
313
s->
bg
=
ansi_to_cga
[m - 40];
314
}
else
if
(m == 48 && i + 2 <
FFMIN
(s->
nb_args
,
MAX_NB_ARGS
) && s->
args
[i + 1] == 5 && s->
args
[i + 2] < 256) {
315
int
index
= s->
args
[i + 2];
316
s->
bg
= index < 16 ?
ansi_to_cga
[
index
] :
index
;
317
i += 2;
318
}
else
if
(m == 49) {
319
s->
fg
=
ansi_to_cga
[
DEFAULT_BG_COLOR
];
320
}
else
{
321
avpriv_request_sample
(avctx,
"Unsupported rendition parameter"
);
322
}
323
}
324
break
;
325
case
'n'
:
//Device Status Report
326
case
'R'
:
//report current line and column
327
/* ignore */
328
break
;
329
case
's'
:
//Save Cursor Position
330
s->
sx
= s->
x
;
331
s->
sy
= s->
y
;
332
break
;
333
case
'u'
:
//Restore Cursor Position
334
s->
x
= av_clip(s->
sx
, 0, avctx->
width
- FONT_WIDTH);
335
s->
y
= av_clip(s->
sy
, 0, avctx->
height
- s->
font_height
);
336
break
;
337
default
:
338
avpriv_request_sample
(avctx,
"Unknown escape code"
);
339
break
;
340
}
341
s->
x
= av_clip(s->
x
, 0, avctx->
width
-
FONT_WIDTH
);
342
s->
y
= av_clip(s->
y
, 0, avctx->
height
- s->
font_height
);
343
return
0;
344
}
345
346
static
int
decode_frame
(
AVCodecContext
*avctx,
347
void
*
data
,
int
*got_frame,
348
AVPacket
*avpkt)
349
{
350
AnsiContext
*
s
= avctx->
priv_data
;
351
uint8_t
*
buf
= avpkt->
data
;
352
int
buf_size = avpkt->
size
;
353
const
uint8_t
*buf_end = buf+buf_size;
354
int
ret
, i,
count
;
355
356
if
((ret =
ff_reget_buffer
(avctx, s->
frame
)) < 0)
357
return
ret
;
358
if
(!avctx->
frame_number
) {
359
for
(i=0; i<avctx->
height
; i++)
360
memset(s->
frame
->
data
[0]+ i*s->
frame
->
linesize
[0], 0, avctx->
width
);
361
memset(s->
frame
->
data
[1], 0,
AVPALETTE_SIZE
);
362
}
363
364
s->
frame
->
pict_type
=
AV_PICTURE_TYPE_I
;
365
s->
frame
->
palette_has_changed
= 1;
366
set_palette
((uint32_t *)s->
frame
->
data
[1]);
367
if
(!s->
first_frame
) {
368
erase_screen
(avctx);
369
s->
first_frame
= 1;
370
}
371
372
while
(buf < buf_end) {
373
switch
(s->
state
) {
374
case
STATE_NORMAL:
375
switch
(buf[0]) {
376
case
0x00:
//NUL
377
case
0x07:
//BEL
378
case
0x1A:
//SUB
379
/* ignore */
380
break
;
381
case
0x08:
//BS
382
s->
x
=
FFMAX
(s->
x
- 1, 0);
383
break
;
384
case
0x09:
//HT
385
i = s->
x
/
FONT_WIDTH
;
386
count = ((i + 8) & ~7) - i;
387
for
(i = 0; i <
count
; i++)
388
draw_char
(avctx,
' '
);
389
break
;
390
case
0x0A:
//LF
391
hscroll
(avctx);
392
case
0x0D:
//CR
393
s->
x
= 0;
394
break
;
395
case
0x0C:
//FF
396
erase_screen
(avctx);
397
break
;
398
case
0x1B:
//ESC
399
s->
state
= STATE_ESCAPE;
400
break
;
401
default
:
402
draw_char
(avctx, buf[0]);
403
}
404
break
;
405
case
STATE_ESCAPE:
406
if
(buf[0] ==
'['
) {
407
s->
state
= STATE_CODE;
408
s->
nb_args
= 0;
409
s->
args
[0] = -1;
410
}
else
{
411
s->
state
= STATE_NORMAL;
412
draw_char
(avctx, 0x1B);
413
continue
;
414
}
415
break
;
416
case
STATE_CODE:
417
switch
(buf[0]) {
418
case
'0'
:
case
'1'
:
case
'2'
:
case
'3'
:
case
'4'
:
419
case
'5'
:
case
'6'
:
case
'7'
:
case
'8'
:
case
'9'
:
420
if
(s->
nb_args
<
MAX_NB_ARGS
)
421
s->
args
[s->
nb_args
] =
FFMAX
(s->
args
[s->
nb_args
], 0) * 10 + buf[0] -
'0'
;
422
break
;
423
case
';'
:
424
s->
nb_args
++;
425
if
(s->
nb_args
<
MAX_NB_ARGS
)
426
s->
args
[s->
nb_args
] = 0;
427
break
;
428
case
'M'
:
429
s->
state
= STATE_MUSIC_PREAMBLE;
430
break
;
431
case
'='
:
case
'?'
:
432
/* ignore */
433
break
;
434
default
:
435
if
(s->
nb_args
>
MAX_NB_ARGS
)
436
av_log
(avctx,
AV_LOG_WARNING
,
"args overflow (%i)\n"
, s->
nb_args
);
437
if
(s->
nb_args
<
MAX_NB_ARGS
&& s->
args
[s->
nb_args
] >= 0)
438
s->
nb_args
++;
439
if
((ret =
execute_code
(avctx, buf[0])) < 0)
440
return
ret
;
441
s->
state
= STATE_NORMAL;
442
}
443
break
;
444
case
STATE_MUSIC_PREAMBLE:
445
if
(buf[0] == 0x0E || buf[0] == 0x1B)
446
s->
state
= STATE_NORMAL;
447
/* ignore music data */
448
break
;
449
}
450
buf++;
451
}
452
453
*got_frame = 1;
454
if
((ret =
av_frame_ref
(data, s->
frame
)) < 0)
455
return
ret
;
456
return
buf_size;
457
}
458
459
static
av_cold
int
decode_close
(
AVCodecContext
*avctx)
460
{
461
AnsiContext
*
s
= avctx->
priv_data
;
462
463
av_frame_free
(&s->
frame
);
464
return
0;
465
}
466
467
AVCodec
ff_ansi_decoder
= {
468
.
name
=
"ansi"
,
469
.long_name =
NULL_IF_CONFIG_SMALL
(
"ASCII/ANSI art"
),
470
.type =
AVMEDIA_TYPE_VIDEO
,
471
.id =
AV_CODEC_ID_ANSI
,
472
.priv_data_size =
sizeof
(
AnsiContext
),
473
.
init
=
decode_init
,
474
.
close
=
decode_close
,
475
.
decode
=
decode_frame
,
476
.capabilities =
CODEC_CAP_DR1
,
477
};
Generated on Sat Jan 25 2014 19:51:44 for FFmpeg by
1.8.2