Libav
ansi.c
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1 /*
2  * ASCII/ANSI art decoder
3  * Copyright (c) 2010 Peter Ross <pross@xvid.org>
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
27 #include "libavutil/common.h"
28 #include "libavutil/frame.h"
29 #include "libavutil/lfg.h"
30 #include "avcodec.h"
31 #include "cga_data.h"
32 #include "internal.h"
33 
34 #define ATTR_BOLD 0x01
35 #define ATTR_FAINT 0x02
36 #define ATTR_UNDERLINE 0x08
37 #define ATTR_BLINK 0x10
38 #define ATTR_REVERSE 0x40
39 #define ATTR_CONCEALED 0x80
41 #define DEFAULT_FG_COLOR 7
42 #define DEFAULT_BG_COLOR 0
43 #define DEFAULT_SCREEN_MODE 3
45 #define FONT_WIDTH 8
48 static const uint8_t ansi_to_cga[16] = {
49  0, 4, 2, 6, 1, 5, 3, 7, 8, 12, 10, 14, 9, 13, 11, 15
50 };
51 
52 typedef struct {
54  int x;
55  int y;
56  int sx;
57  int sy;
58  const uint8_t* font;
60  int attributes;
61  int fg;
62  int bg;
64  /* ansi parser state machine */
65  enum {
66  STATE_NORMAL = 0,
69  STATE_MUSIC_PREAMBLE
70  } state;
71 #define MAX_NB_ARGS 4
72  int args[MAX_NB_ARGS];
73  int nb_args;
74 } AnsiContext;
75 
77 {
78  AnsiContext *s = avctx->priv_data;
79  avctx->pix_fmt = AV_PIX_FMT_PAL8;
80 
81  s->frame = av_frame_alloc();
82  if (!s->frame)
83  return AVERROR(ENOMEM);
84 
85  /* defaults */
86  s->font = ff_vga16_font;
87  s->font_height = 16;
88  s->fg = DEFAULT_FG_COLOR;
89  s->bg = DEFAULT_BG_COLOR;
90 
91  if (!avctx->width || !avctx->height)
92  ff_set_dimensions(avctx, 80 << 3, 25 << 4);
93 
94  return 0;
95 }
96 
97 static void hscroll(AVCodecContext *avctx)
98 {
99  AnsiContext *s = avctx->priv_data;
100  int i;
101 
102  if (s->y < avctx->height - s->font_height) {
103  s->y += s->font_height;
104  return;
105  }
106 
107  i = 0;
108  for (; i < avctx->height - s->font_height; i++)
109  memcpy(s->frame->data[0] + i * s->frame->linesize[0],
110  s->frame->data[0] + (i + s->font_height) * s->frame->linesize[0],
111  avctx->width);
112  for (; i < avctx->height; i++)
113  memset(s->frame->data[0] + i * s->frame->linesize[0],
114  DEFAULT_BG_COLOR, avctx->width);
115 }
116 
117 static void erase_line(AVCodecContext * avctx, int xoffset, int xlength)
118 {
119  AnsiContext *s = avctx->priv_data;
120  int i;
121  for (i = 0; i < s->font_height; i++)
122  memset(s->frame->data[0] + (s->y + i)*s->frame->linesize[0] + xoffset,
123  DEFAULT_BG_COLOR, xlength);
124 }
125 
126 static void erase_screen(AVCodecContext *avctx)
127 {
128  AnsiContext *s = avctx->priv_data;
129  int i;
130  for (i = 0; i < avctx->height; i++)
131  memset(s->frame->data[0] + i * s->frame->linesize[0], DEFAULT_BG_COLOR, avctx->width);
132  s->x = s->y = 0;
133 }
134 
138 static void draw_char(AVCodecContext *avctx, int c)
139 {
140  AnsiContext *s = avctx->priv_data;
141  int fg = s->fg;
142  int bg = s->bg;
143 
144  if ((s->attributes & ATTR_BOLD))
145  fg += 8;
146  if ((s->attributes & ATTR_BLINK))
147  bg += 8;
148  if ((s->attributes & ATTR_REVERSE))
149  FFSWAP(int, fg, bg);
150  if ((s->attributes & ATTR_CONCEALED))
151  fg = bg;
152  ff_draw_pc_font(s->frame->data[0] + s->y * s->frame->linesize[0] + s->x,
153  s->frame->linesize[0], s->font, s->font_height, c, fg, bg);
154  s->x += FONT_WIDTH;
155  if (s->x >= avctx->width) {
156  s->x = 0;
157  hscroll(avctx);
158  }
159 }
160 
165 static int execute_code(AVCodecContext * avctx, int c)
166 {
167  AnsiContext *s = avctx->priv_data;
168  int ret, i;
169  int width = 0;
170  int height = 0;
171 
172  switch(c) {
173  case 'A': //Cursor Up
174  s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0);
175  break;
176  case 'B': //Cursor Down
177  s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height);
178  break;
179  case 'C': //Cursor Right
180  s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width - FONT_WIDTH);
181  break;
182  case 'D': //Cursor Left
183  s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0);
184  break;
185  case 'H': //Cursor Position
186  case 'f': //Horizontal and Vertical Position
187  s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0;
188  s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH, 0, avctx->width - FONT_WIDTH) : 0;
189  break;
190  case 'h': //set creen mode
191  case 'l': //reset screen mode
192  if (s->nb_args < 2)
193  s->args[0] = DEFAULT_SCREEN_MODE;
194  switch(s->args[0]) {
195  case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows)
196  s->font = ff_cga_font;
197  s->font_height = 8;
198  width = 40<<3;
199  height = 25<<3;
200  break;
201  case 2: case 3: //640x400 (25 rows)
202  s->font = ff_vga16_font;
203  s->font_height = 16;
204  width = 80<<3;
205  height = 25<<4;
206  break;
207  case 6: case 14: //640x200 (25 rows)
208  s->font = ff_cga_font;
209  s->font_height = 8;
210  width = 80<<3;
211  height = 25<<3;
212  break;
213  case 7: //set line wrapping
214  break;
215  case 15: case 16: //640x350 (43 rows)
216  s->font = ff_cga_font;
217  s->font_height = 8;
218  width = 80<<3;
219  height = 43<<3;
220  break;
221  case 17: case 18: //640x480 (60 rows)
222  s->font = ff_cga_font;
223  s->font_height = 8;
224  width = 80<<3;
225  height = 60<<4;
226  break;
227  default:
228  avpriv_request_sample(avctx, "Unsupported screen mode");
229  }
230  if (width != 0 && height != 0 &&
231  (width != avctx->width || height != avctx->height)) {
232  av_frame_unref(s->frame);
233  ret = ff_set_dimensions(avctx, width, height);
234  if (ret < 0)
235  return ret;
236  ret = ff_get_buffer(avctx, s->frame, AV_GET_BUFFER_FLAG_REF);
237  if (ret < 0) {
238  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
239  return ret;
240  }
242  s->frame->palette_has_changed = 1;
243  memcpy(s->frame->data[1], ff_cga_palette, 16 * 4);
244  erase_screen(avctx);
245  } else if (c == 'l') {
246  erase_screen(avctx);
247  }
248  break;
249  case 'J': //Erase in Page
250  switch (s->args[0]) {
251  case 0:
252  erase_line(avctx, s->x, avctx->width - s->x);
253  if (s->y < avctx->height - s->font_height)
254  memset(s->frame->data[0] + (s->y + s->font_height)*s->frame->linesize[0],
255  DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame->linesize[0]);
256  break;
257  case 1:
258  erase_line(avctx, 0, s->x);
259  if (s->y > 0)
260  memset(s->frame->data[0], DEFAULT_BG_COLOR, s->y * s->frame->linesize[0]);
261  break;
262  case 2:
263  erase_screen(avctx);
264  }
265  break;
266  case 'K': //Erase in Line
267  switch(s->args[0]) {
268  case 0:
269  erase_line(avctx, s->x, avctx->width - s->x);
270  break;
271  case 1:
272  erase_line(avctx, 0, s->x);
273  break;
274  case 2:
275  erase_line(avctx, 0, avctx->width);
276  }
277  break;
278  case 'm': //Select Graphics Rendition
279  if (s->nb_args == 0) {
280  s->nb_args = 1;
281  s->args[0] = 0;
282  }
283  for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) {
284  int m = s->args[i];
285  if (m == 0) {
286  s->attributes = 0;
287  s->fg = DEFAULT_FG_COLOR;
288  s->bg = DEFAULT_BG_COLOR;
289  } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) {
290  s->attributes |= 1 << (m - 1);
291  } else if (m >= 30 && m <= 38) {
292  s->fg = ansi_to_cga[m - 30];
293  } else if (m == 39) {
295  } else if (m >= 40 && m <= 47) {
296  s->bg = ansi_to_cga[m - 40];
297  } else if (m == 49) {
299  } else {
300  avpriv_request_sample(avctx, "Unsupported rendition parameter");
301  }
302  }
303  break;
304  case 'n': //Device Status Report
305  case 'R': //report current line and column
306  /* ignore */
307  break;
308  case 's': //Save Cursor Position
309  s->sx = s->x;
310  s->sy = s->y;
311  break;
312  case 'u': //Restore Cursor Position
313  s->x = av_clip(s->sx, 0, avctx->width - FONT_WIDTH);
314  s->y = av_clip(s->sy, 0, avctx->height - s->font_height);
315  break;
316  default:
317  avpriv_request_sample(avctx, "Unknown escape code");
318  break;
319  }
320  return 0;
321 }
322 
323 static int decode_frame(AVCodecContext *avctx,
324  void *data, int *got_frame,
325  AVPacket *avpkt)
326 {
327  AnsiContext *s = avctx->priv_data;
328  uint8_t *buf = avpkt->data;
329  int buf_size = avpkt->size;
330  const uint8_t *buf_end = buf+buf_size;
331  int ret, i, count;
332 
333  ret = ff_reget_buffer(avctx, s->frame);
334  if (ret < 0){
335  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
336  return ret;
337  }
338  if (!avctx->frame_number) {
339  memset(s->frame->data[0], 0, avctx->height * FFABS(s->frame->linesize[0]));
340  memset(s->frame->data[1], 0, AVPALETTE_SIZE);
341  }
342 
344  s->frame->palette_has_changed = 1;
345  memcpy(s->frame->data[1], ff_cga_palette, 16 * 4);
346 
347  while(buf < buf_end) {
348  switch(s->state) {
349  case STATE_NORMAL:
350  switch (buf[0]) {
351  case 0x00: //NUL
352  case 0x07: //BEL
353  case 0x1A: //SUB
354  /* ignore */
355  break;
356  case 0x08: //BS
357  s->x = FFMAX(s->x - 1, 0);
358  break;
359  case 0x09: //HT
360  i = s->x / FONT_WIDTH;
361  count = ((i + 8) & ~7) - i;
362  for (i = 0; i < count; i++)
363  draw_char(avctx, ' ');
364  break;
365  case 0x0A: //LF
366  hscroll(avctx);
367  case 0x0D: //CR
368  s->x = 0;
369  break;
370  case 0x0C: //FF
371  erase_screen(avctx);
372  break;
373  case 0x1B: //ESC
374  s->state = STATE_ESCAPE;
375  break;
376  default:
377  draw_char(avctx, buf[0]);
378  }
379  break;
380  case STATE_ESCAPE:
381  if (buf[0] == '[') {
382  s->state = STATE_CODE;
383  s->nb_args = 0;
384  s->args[0] = 0;
385  } else {
386  s->state = STATE_NORMAL;
387  draw_char(avctx, 0x1B);
388  continue;
389  }
390  break;
391  case STATE_CODE:
392  switch(buf[0]) {
393  case '0': case '1': case '2': case '3': case '4':
394  case '5': case '6': case '7': case '8': case '9':
395  if (s->nb_args < MAX_NB_ARGS)
396  s->args[s->nb_args] = s->args[s->nb_args] * 10 + buf[0] - '0';
397  break;
398  case ';':
399  s->nb_args++;
400  if (s->nb_args < MAX_NB_ARGS)
401  s->args[s->nb_args] = 0;
402  break;
403  case 'M':
404  s->state = STATE_MUSIC_PREAMBLE;
405  break;
406  case '=': case '?':
407  /* ignore */
408  break;
409  default:
410  if (s->nb_args > MAX_NB_ARGS)
411  av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args);
412  if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args])
413  s->nb_args++;
414  if ((ret = execute_code(avctx, buf[0])) < 0)
415  return ret;
416  s->state = STATE_NORMAL;
417  }
418  break;
419  case STATE_MUSIC_PREAMBLE:
420  if (buf[0] == 0x0E || buf[0] == 0x1B)
421  s->state = STATE_NORMAL;
422  /* ignore music data */
423  break;
424  }
425  buf++;
426  }
427 
428  *got_frame = 1;
429  if ((ret = av_frame_ref(data, s->frame)) < 0)
430  return ret;
431  return buf_size;
432 }
433 
435 {
436  AnsiContext *s = avctx->priv_data;
437 
438  av_frame_free(&s->frame);
439  return 0;
440 }
441 
443  .name = "ansi",
444  .long_name = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"),
445  .type = AVMEDIA_TYPE_VIDEO,
446  .id = AV_CODEC_ID_ANSI,
447  .priv_data_size = sizeof(AnsiContext),
448  .init = decode_init,
449  .close = decode_close,
450  .decode = decode_frame,
451  .capabilities = CODEC_CAP_DR1,
452 };
#define AVPALETTE_SIZE
Definition: avcodec.h:3029
static void draw_char(AVCodecContext *avctx, int c)
Draw character to screen.
Definition: ansi.c:138
#define FONT_WIDTH
Font width.
Definition: ansi.c:45
const uint8_t ff_cga_font[2048]
Definition: cga_data.c:29
int x
x cursor position (pixels)
Definition: ansi.c:54
#define ATTR_REVERSE
Reverse (mode 7)
Definition: ansi.c:38
This structure describes decoded (raw) audio or video data.
Definition: frame.h:135
int bg
background color
Definition: ansi.c:62
#define ATTR_CONCEALED
Concealed (mode 8)
Definition: ansi.c:39
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:129
int ff_set_dimensions(AVCodecContext *s, int width, int height)
Check that the provided frame dimensions are valid and set them on the codec context.
Definition: utils.c:133
int nb_args
number of arguments (may exceed MAX_NB_ARGS)
Definition: ansi.c:73
int size
Definition: avcodec.h:968
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1248
#define DEFAULT_SCREEN_MODE
80x25
Definition: ansi.c:43
const uint8_t ff_vga16_font[4096]
Definition: cga_data.c:160
AVCodec.
Definition: avcodec.h:2790
static void erase_screen(AVCodecContext *avctx)
Definition: ansi.c:126
static int execute_code(AVCodecContext *avctx, int c)
Execute ANSI escape code.
Definition: ansi.c:165
static void hscroll(AVCodecContext *avctx)
Definition: ansi.c:97
enum AnsiContext::@10 state
static int decode(MimicContext *ctx, int quality, int num_coeffs, int is_iframe)
Definition: mimic.c:275
void void avpriv_request_sample(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
uint8_t
#define av_cold
Definition: attributes.h:66
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:57
8 bit with PIX_FMT_RGB32 palette
Definition: pixfmt.h:76
int av_frame_ref(AVFrame *dst, const AVFrame *src)
Set up a new reference to the data described by the source frame.
Definition: frame.c:188
#define CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:684
const char data[16]
Definition: mxf.c:70
uint8_t * data
Definition: avcodec.h:967
CGA/EGA/VGA ROM data.
#define DEFAULT_BG_COLOR
Definition: ansi.c:42
static av_cold int decode_close(AVCodecContext *avctx)
Definition: ansi.c:434
const uint8_t * font
font
Definition: ansi.c:58
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:123
int sy
saved y cursor position (pixels)
Definition: ansi.c:57
#define AVERROR(e)
Definition: error.h:43
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:69
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:150
static void erase_line(AVCodecContext *avctx, int xoffset, int xlength)
Definition: ansi.c:117
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:168
const char * name
Name of the codec implementation.
Definition: avcodec.h:2797
#define FFMAX(a, b)
Definition: common.h:55
reference-counted frame API
#define ATTR_BLINK
Blink/Bright-background (mode 5)
Definition: ansi.c:37
int ff_reget_buffer(AVCodecContext *avctx, AVFrame *frame)
Identical in function to av_frame_make_writable(), except it uses ff_get_buffer() to allocate the buf...
Definition: utils.c:799
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:196
#define FFMIN(a, b)
Definition: common.h:57
int width
picture width / height.
Definition: avcodec.h:1218
#define FFABS(a)
Definition: common.h:52
static av_cold int decode_init(AVCodecContext *avctx)
Definition: ansi.c:76
#define ATTR_BOLD
Bold/Bright-foreground (mode 1)
Definition: ansi.c:34
void ff_draw_pc_font(uint8_t *dst, int linesize, const uint8_t *font, int font_height, int ch, int fg, int bg)
Draw CGA/EGA/VGA font to 8-bit pixel buffer.
Definition: cga_data.c:435
static int width
Definition: utils.c:156
Libavcodec external API header.
int font_height
font height
Definition: ansi.c:59
int args[MAX_NB_ARGS]
Definition: ansi.c:72
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:153
main external API structure.
Definition: avcodec.h:1044
static void close(AVCodecParserContext *s)
Definition: h264_parser.c:490
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: utils.c:603
int palette_has_changed
Tell user application that palette has changed from previous frame.
Definition: frame.h:330
int fg
foreground color
Definition: ansi.c:61
static const uint8_t ansi_to_cga[16]
map ansi color index to cga palette index
Definition: ansi.c:48
const uint32_t ff_cga_palette[16]
Definition: cga_data.c:419
void av_frame_unref(AVFrame *frame)
Unreference all the buffers referenced by frame and reset the frame fields.
Definition: frame.c:283
static uint32_t state
Definition: trasher.c:27
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:141
int height
Definition: gxfenc.c:72
int sx
saved x cursor position (pixels)
Definition: ansi.c:56
common internal api header.
common internal and external API header
AVFrame * frame
Definition: ansi.c:53
int y
y cursor position (pixels)
Definition: ansi.c:55
static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: ansi.c:323
static av_cold int init(AVCodecParserContext *s)
Definition: h264_parser.c:499
void * priv_data
Definition: avcodec.h:1086
int frame_number
Frame counter, set by libavcodec.
Definition: avcodec.h:1816
#define MAX_NB_ARGS
Definition: ansi.c:71
#define DEFAULT_FG_COLOR
CGA color index.
Definition: ansi.c:41
#define FFSWAP(type, a, b)
Definition: common.h:60
int attributes
attribute flags
Definition: ansi.c:60
This structure stores compressed data.
Definition: avcodec.h:944
#define AV_GET_BUFFER_FLAG_REF
The decoder will keep a reference to the frame and may reuse it later.
Definition: avcodec.h:850
AVCodec ff_ansi_decoder
Definition: ansi.c:442