FFmpeg  1.2.12
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 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 
27 #include "libavutil/common.h"
28 #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 
65  /* ansi parser state machine */
66  enum {
67  STATE_NORMAL = 0,
70  STATE_MUSIC_PREAMBLE
71  } state;
72 #define MAX_NB_ARGS 4
73  int args[MAX_NB_ARGS];
74  int nb_args;
75 } AnsiContext;
76 
78 {
79  AnsiContext *s = avctx->priv_data;
80  avctx->pix_fmt = AV_PIX_FMT_PAL8;
81 
82  /* defaults */
84  s->font_height = 16;
85  s->fg = DEFAULT_FG_COLOR;
86  s->bg = DEFAULT_BG_COLOR;
87 
89  if (!avctx->width || !avctx->height)
90  avcodec_set_dimensions(avctx, 80<<3, 25<<4);
91 
92  return 0;
93 }
94 
95 static void set_palette(uint32_t *pal)
96 {
97  int r, g, b;
98  memcpy(pal, ff_cga_palette, 16 * 4);
99  pal += 16;
100 #define COLOR(x) ((x) * 40 + 55)
101  for (r = 0; r < 6; r++)
102  for (g = 0; g < 6; g++)
103  for (b = 0; b < 6; b++)
104  *pal++ = 0xFF000000 | (COLOR(r) << 16) | (COLOR(g) << 8) | COLOR(b);
105 #define GRAY(x) ((x) * 10 + 8)
106  for (g = 0; g < 24; g++)
107  *pal++ = 0xFF000000 | (GRAY(g) << 16) | (GRAY(g) << 8) | GRAY(g);
108 }
109 
110 static void hscroll(AVCodecContext *avctx)
111 {
112  AnsiContext *s = avctx->priv_data;
113  int i;
114 
115  if (s->y <= avctx->height - 2*s->font_height) {
116  s->y += s->font_height;
117  return;
118  }
119 
120  i = 0;
121  for (; i < avctx->height - s->font_height; i++)
122  memcpy(s->frame.data[0] + i * s->frame.linesize[0],
123  s->frame.data[0] + (i + s->font_height) * s->frame.linesize[0],
124  avctx->width);
125  for (; i < avctx->height; i++)
126  memset(s->frame.data[0] + i * s->frame.linesize[0],
127  DEFAULT_BG_COLOR, avctx->width);
128 }
129 
130 static void erase_line(AVCodecContext * avctx, int xoffset, int xlength)
131 {
132  AnsiContext *s = avctx->priv_data;
133  int i;
134  for (i = 0; i < s->font_height; i++)
135  memset(s->frame.data[0] + (s->y + i)*s->frame.linesize[0] + xoffset,
136  DEFAULT_BG_COLOR, xlength);
137 }
138 
139 static void erase_screen(AVCodecContext *avctx)
140 {
141  AnsiContext *s = avctx->priv_data;
142  int i;
143  for (i = 0; i < avctx->height; i++)
144  memset(s->frame.data[0] + i * s->frame.linesize[0], DEFAULT_BG_COLOR, avctx->width);
145  s->x = s->y = 0;
146 }
147 
151 static void draw_char(AVCodecContext *avctx, int c)
152 {
153  AnsiContext *s = avctx->priv_data;
154  int fg = s->fg;
155  int bg = s->bg;
156 
157  if ((s->attributes & ATTR_BOLD))
158  fg += 8;
159  if ((s->attributes & ATTR_BLINK))
160  bg += 8;
161  if ((s->attributes & ATTR_REVERSE))
162  FFSWAP(int, fg, bg);
163  if ((s->attributes & ATTR_CONCEALED))
164  fg = bg;
165  ff_draw_pc_font(s->frame.data[0] + s->y * s->frame.linesize[0] + s->x,
166  s->frame.linesize[0], s->font, s->font_height, c, fg, bg);
167  s->x += FONT_WIDTH;
168  if (s->x > avctx->width - FONT_WIDTH) {
169  s->x = 0;
170  hscroll(avctx);
171  }
172 }
173 
178 static int execute_code(AVCodecContext * avctx, int c)
179 {
180  AnsiContext *s = avctx->priv_data;
181  int ret, i, width, height;
182  switch(c) {
183  case 'A': //Cursor Up
184  s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0);
185  break;
186  case 'B': //Cursor Down
187  s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height);
188  break;
189  case 'C': //Cursor Right
190  s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width - FONT_WIDTH);
191  break;
192  case 'D': //Cursor Left
193  s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0);
194  break;
195  case 'H': //Cursor Position
196  case 'f': //Horizontal and Vertical Position
197  s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0;
198  s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH, 0, avctx->width - FONT_WIDTH) : 0;
199  break;
200  case 'h': //set creen mode
201  case 'l': //reset screen mode
202  if (s->nb_args < 2)
203  s->args[0] = DEFAULT_SCREEN_MODE;
204  width = avctx->width;
205  height = avctx->height;
206  switch(s->args[0]) {
207  case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows)
208  s->font = avpriv_cga_font;
209  s->font_height = 8;
210  width = 40<<3;
211  height = 25<<3;
212  break;
213  case 2: case 3: //640x400 (25 rows)
214  s->font = avpriv_vga16_font;
215  s->font_height = 16;
216  width = 80<<3;
217  height = 25<<4;
218  break;
219  case 6: case 14: //640x200 (25 rows)
220  s->font = avpriv_cga_font;
221  s->font_height = 8;
222  width = 80<<3;
223  height = 25<<3;
224  break;
225  case 7: //set line wrapping
226  break;
227  case 15: case 16: //640x350 (43 rows)
228  s->font = avpriv_cga_font;
229  s->font_height = 8;
230  width = 80<<3;
231  height = 43<<3;
232  break;
233  case 17: case 18: //640x480 (60 rows)
234  s->font = avpriv_cga_font;
235  s->font_height = 8;
236  width = 80<<3;
237  height = 60<<4;
238  break;
239  default:
240  av_log_ask_for_sample(avctx, "unsupported screen mode\n");
241  }
242  s->x = av_clip(s->x, 0, width - FONT_WIDTH);
243  s->y = av_clip(s->y, 0, height - s->font_height);
244  if (width != avctx->width || height != avctx->height) {
245  if (s->frame.data[0])
246  avctx->release_buffer(avctx, &s->frame);
247  avcodec_set_dimensions(avctx, width, height);
248  ret = ff_get_buffer(avctx, &s->frame);
249  if (ret < 0) {
250  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
251  return ret;
252  }
254  s->frame.palette_has_changed = 1;
255  set_palette((uint32_t *)s->frame.data[1]);
256  erase_screen(avctx);
257  } else if (c == 'l') {
258  erase_screen(avctx);
259  }
260  break;
261  case 'J': //Erase in Page
262  switch (s->args[0]) {
263  case 0:
264  erase_line(avctx, s->x, avctx->width - s->x);
265  if (s->y < avctx->height - s->font_height)
266  memset(s->frame.data[0] + (s->y + s->font_height)*s->frame.linesize[0],
267  DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame.linesize[0]);
268  break;
269  case 1:
270  erase_line(avctx, 0, s->x);
271  if (s->y > 0)
272  memset(s->frame.data[0], DEFAULT_BG_COLOR, s->y * s->frame.linesize[0]);
273  break;
274  case 2:
275  erase_screen(avctx);
276  }
277  break;
278  case 'K': //Erase in Line
279  switch(s->args[0]) {
280  case 0:
281  erase_line(avctx, s->x, avctx->width - s->x);
282  break;
283  case 1:
284  erase_line(avctx, 0, s->x);
285  break;
286  case 2:
287  erase_line(avctx, 0, avctx->width);
288  }
289  break;
290  case 'm': //Select Graphics Rendition
291  if (s->nb_args == 0) {
292  s->nb_args = 1;
293  s->args[0] = 0;
294  }
295  for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) {
296  int m = s->args[i];
297  if (m == 0) {
298  s->attributes = 0;
299  s->fg = DEFAULT_FG_COLOR;
300  s->bg = DEFAULT_BG_COLOR;
301  } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) {
302  s->attributes |= 1 << (m - 1);
303  } else if (m >= 30 && m <= 37) {
304  s->fg = ansi_to_cga[m - 30];
305  } else if (m == 38 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {
306  int index = s->args[i + 2];
307  s->fg = index < 16 ? ansi_to_cga[index] : index;
308  i += 2;
309  } else if (m == 39) {
311  } else if (m >= 40 && m <= 47) {
312  s->bg = ansi_to_cga[m - 40];
313  } else if (m == 48 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {
314  int index = s->args[i + 2];
315  s->bg = index < 16 ? ansi_to_cga[index] : index;
316  i += 2;
317  } else if (m == 49) {
319  } else {
320  av_log_ask_for_sample(avctx, "unsupported rendition parameter\n");
321  }
322  }
323  break;
324  case 'n': //Device Status Report
325  case 'R': //report current line and column
326  /* ignore */
327  break;
328  case 's': //Save Cursor Position
329  s->sx = s->x;
330  s->sy = s->y;
331  break;
332  case 'u': //Restore Cursor Position
333  s->x = av_clip(s->sx, 0, avctx->width - FONT_WIDTH);
334  s->y = av_clip(s->sy, 0, avctx->height - s->font_height);
335  break;
336  default:
337  av_log_ask_for_sample(avctx, "unsupported escape code\n");
338  break;
339  }
340  s->x = av_clip(s->x, 0, avctx->width - FONT_WIDTH);
341  s->y = av_clip(s->y, 0, avctx->height - s->font_height);
342  return 0;
343 }
344 
345 static int decode_frame(AVCodecContext *avctx,
346  void *data, int *got_frame,
347  AVPacket *avpkt)
348 {
349  AnsiContext *s = avctx->priv_data;
350  uint8_t *buf = avpkt->data;
351  int buf_size = avpkt->size;
352  const uint8_t *buf_end = buf+buf_size;
353  int ret, i, count;
354 
355  ret = avctx->reget_buffer(avctx, &s->frame);
356  if (ret < 0){
357  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
358  return ret;
359  }
360  if (!avctx->frame_number) {
361  for (i=0; i<avctx->height; i++)
362  memset(s->frame.data[0]+ i*s->frame.linesize[0], 0, avctx->width);
363  memset(s->frame.data[1], 0, AVPALETTE_SIZE);
364  }
365 
367  s->frame.palette_has_changed = 1;
368  set_palette((uint32_t *)s->frame.data[1]);
369  if (!s->first_frame) {
370  erase_screen(avctx);
371  s->first_frame = 1;
372  }
373 
374  while(buf < buf_end) {
375  switch(s->state) {
376  case STATE_NORMAL:
377  switch (buf[0]) {
378  case 0x00: //NUL
379  case 0x07: //BEL
380  case 0x1A: //SUB
381  /* ignore */
382  break;
383  case 0x08: //BS
384  s->x = FFMAX(s->x - 1, 0);
385  break;
386  case 0x09: //HT
387  i = s->x / FONT_WIDTH;
388  count = ((i + 8) & ~7) - i;
389  for (i = 0; i < count; i++)
390  draw_char(avctx, ' ');
391  break;
392  case 0x0A: //LF
393  hscroll(avctx);
394  case 0x0D: //CR
395  s->x = 0;
396  break;
397  case 0x0C: //FF
398  erase_screen(avctx);
399  break;
400  case 0x1B: //ESC
401  s->state = STATE_ESCAPE;
402  break;
403  default:
404  draw_char(avctx, buf[0]);
405  }
406  break;
407  case STATE_ESCAPE:
408  if (buf[0] == '[') {
409  s->state = STATE_CODE;
410  s->nb_args = 0;
411  s->args[0] = -1;
412  } else {
413  s->state = STATE_NORMAL;
414  draw_char(avctx, 0x1B);
415  continue;
416  }
417  break;
418  case STATE_CODE:
419  switch(buf[0]) {
420  case '0': case '1': case '2': case '3': case '4':
421  case '5': case '6': case '7': case '8': case '9':
422  if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] < 6553)
423  s->args[s->nb_args] = FFMAX(s->args[s->nb_args], 0) * 10 + buf[0] - '0';
424  break;
425  case ';':
426  s->nb_args++;
427  if (s->nb_args < MAX_NB_ARGS)
428  s->args[s->nb_args] = 0;
429  break;
430  case 'M':
431  s->state = STATE_MUSIC_PREAMBLE;
432  break;
433  case '=': case '?':
434  /* ignore */
435  break;
436  default:
437  if (s->nb_args > MAX_NB_ARGS)
438  av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args);
439  if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] >= 0)
440  s->nb_args++;
441  if ((ret = execute_code(avctx, buf[0])) < 0)
442  return ret;
443  s->state = STATE_NORMAL;
444  }
445  break;
446  case STATE_MUSIC_PREAMBLE:
447  if (buf[0] == 0x0E || buf[0] == 0x1B)
448  s->state = STATE_NORMAL;
449  /* ignore music data */
450  break;
451  }
452  buf++;
453  }
454 
455  *got_frame = 1;
456  *(AVFrame*)data = s->frame;
457  return buf_size;
458 }
459 
461 {
462  AnsiContext *s = avctx->priv_data;
463  if (s->frame.data[0])
464  avctx->release_buffer(avctx, &s->frame);
465  return 0;
466 }
467 
469  .name = "ansi",
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  .long_name = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"),
478 };