| 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 | ff_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; |
| 186 | int width = avctx->width; |
| 187 | int height = avctx->height; |
| 188 | |
| 189 | switch(c) { |
| 190 | case 'A': //Cursor Up |
| 191 | s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0); |
| 192 | break; |
| 193 | case 'B': //Cursor Down |
| 194 | s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height); |
| 195 | break; |
| 196 | case 'C': //Cursor Right |
| 197 | s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width - FONT_WIDTH); |
| 198 | break; |
| 199 | case 'D': //Cursor Left |
| 200 | s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0); |
| 201 | break; |
| 202 | case 'H': //Cursor Position |
| 203 | case 'f': //Horizontal and Vertical Position |
| 204 | s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0; |
| 205 | s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH, 0, avctx->width - FONT_WIDTH) : 0; |
| 206 | break; |
| 207 | case 'h': //set creen mode |
| 208 | case 'l': //reset screen mode |
| 209 | if (s->nb_args < 2) |
| 210 | s->args[0] = DEFAULT_SCREEN_MODE; |
| 211 | switch(s->args[0]) { |
| 212 | case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows) |
| 213 | s->font = avpriv_cga_font; |
| 214 | s->font_height = 8; |
| 215 | width = 40<<3; |
| 216 | height = 25<<3; |
| 217 | break; |
| 218 | case 2: case 3: //640x400 (25 rows) |
| 219 | s->font = avpriv_vga16_font; |
| 220 | s->font_height = 16; |
| 221 | width = 80<<3; |
| 222 | height = 25<<4; |
| 223 | break; |
| 224 | case 6: case 14: //640x200 (25 rows) |
| 225 | s->font = avpriv_cga_font; |
| 226 | s->font_height = 8; |
| 227 | width = 80<<3; |
| 228 | height = 25<<3; |
| 229 | break; |
| 230 | case 7: //set line wrapping |
| 231 | break; |
| 232 | case 15: case 16: //640x350 (43 rows) |
| 233 | s->font = avpriv_cga_font; |
| 234 | s->font_height = 8; |
| 235 | width = 80<<3; |
| 236 | height = 43<<3; |
| 237 | break; |
| 238 | case 17: case 18: //640x480 (60 rows) |
| 239 | s->font = avpriv_cga_font; |
| 240 | s->font_height = 8; |
| 241 | width = 80<<3; |
| 242 | height = 60<<4; |
| 243 | break; |
| 244 | default: |
| 245 | avpriv_request_sample(avctx, "Unsupported screen mode"); |
| 246 | } |
| 247 | s->x = av_clip(s->x, 0, width - FONT_WIDTH); |
| 248 | s->y = av_clip(s->y, 0, height - s->font_height); |
| 249 | if (width != avctx->width || height != avctx->height) { |
| 250 | av_frame_unref(s->frame); |
| 251 | ret = ff_set_dimensions(avctx, width, height); |
| 252 | if (ret < 0) |
| 253 | return ret; |
| 254 | if ((ret = ff_get_buffer(avctx, s->frame, |
| 255 | AV_GET_BUFFER_FLAG_REF)) < 0) |
| 256 | return ret; |
| 257 | s->frame->pict_type = AV_PICTURE_TYPE_I; |
| 258 | s->frame->palette_has_changed = 1; |
| 259 | set_palette((uint32_t *)s->frame->data[1]); |
| 260 | erase_screen(avctx); |
| 261 | } else if (c == 'l') { |
| 262 | erase_screen(avctx); |
| 263 | } |
| 264 | break; |
| 265 | case 'J': //Erase in Page |
| 266 | switch (s->args[0]) { |
| 267 | case 0: |
| 268 | erase_line(avctx, s->x, avctx->width - s->x); |
| 269 | if (s->y < avctx->height - s->font_height) |
| 270 | memset(s->frame->data[0] + (s->y + s->font_height)*s->frame->linesize[0], |
| 271 | DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame->linesize[0]); |
| 272 | break; |
| 273 | case 1: |
| 274 | erase_line(avctx, 0, s->x); |
| 275 | if (s->y > 0) |
| 276 | memset(s->frame->data[0], DEFAULT_BG_COLOR, s->y * s->frame->linesize[0]); |
| 277 | break; |
| 278 | case 2: |
| 279 | erase_screen(avctx); |
| 280 | } |
| 281 | break; |
| 282 | case 'K': //Erase in Line |
| 283 | switch(s->args[0]) { |
| 284 | case 0: |
| 285 | erase_line(avctx, s->x, avctx->width - s->x); |
| 286 | break; |
| 287 | case 1: |
| 288 | erase_line(avctx, 0, s->x); |
| 289 | break; |
| 290 | case 2: |
| 291 | erase_line(avctx, 0, avctx->width); |
| 292 | } |
| 293 | break; |
| 294 | case 'm': //Select Graphics Rendition |
| 295 | if (s->nb_args == 0) { |
| 296 | s->nb_args = 1; |
| 297 | s->args[0] = 0; |
| 298 | } |
| 299 | for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) { |
| 300 | int m = s->args[i]; |
| 301 | if (m == 0) { |
| 302 | s->attributes = 0; |
| 303 | s->fg = DEFAULT_FG_COLOR; |
| 304 | s->bg = DEFAULT_BG_COLOR; |
| 305 | } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) { |
| 306 | s->attributes |= 1 << (m - 1); |
| 307 | } else if (m >= 30 && m <= 37) { |
| 308 | s->fg = ansi_to_cga[m - 30]; |
| 309 | } else if (m == 38 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) { |
| 310 | int index = s->args[i + 2]; |
| 311 | s->fg = index < 16 ? ansi_to_cga[index] : index; |
| 312 | i += 2; |
| 313 | } else if (m == 39) { |
| 314 | s->fg = ansi_to_cga[DEFAULT_FG_COLOR]; |
| 315 | } else if (m >= 40 && m <= 47) { |
| 316 | s->bg = ansi_to_cga[m - 40]; |
| 317 | } else if (m == 48 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) { |
| 318 | int index = s->args[i + 2]; |
| 319 | s->bg = index < 16 ? ansi_to_cga[index] : index; |
| 320 | i += 2; |
| 321 | } else if (m == 49) { |
| 322 | s->fg = ansi_to_cga[DEFAULT_BG_COLOR]; |
| 323 | } else { |
| 324 | avpriv_request_sample(avctx, "Unsupported rendition parameter"); |
| 325 | } |
| 326 | } |
| 327 | break; |
| 328 | case 'n': //Device Status Report |
| 329 | case 'R': //report current line and column |
| 330 | /* ignore */ |
| 331 | break; |
| 332 | case 's': //Save Cursor Position |
| 333 | s->sx = s->x; |
| 334 | s->sy = s->y; |
| 335 | break; |
| 336 | case 'u': //Restore Cursor Position |
| 337 | s->x = av_clip(s->sx, 0, avctx->width - FONT_WIDTH); |
| 338 | s->y = av_clip(s->sy, 0, avctx->height - s->font_height); |
| 339 | break; |
| 340 | default: |
| 341 | avpriv_request_sample(avctx, "Unknown escape code"); |
| 342 | break; |
| 343 | } |
| 344 | s->x = av_clip(s->x, 0, avctx->width - FONT_WIDTH); |
| 345 | s->y = av_clip(s->y, 0, avctx->height - s->font_height); |
| 346 | return 0; |
| 347 | } |
| 348 | |
| 349 | static int decode_frame(AVCodecContext *avctx, |
| 350 | void *data, int *got_frame, |
| 351 | AVPacket *avpkt) |
| 352 | { |
| 353 | AnsiContext *s = avctx->priv_data; |
| 354 | uint8_t *buf = avpkt->data; |
| 355 | int buf_size = avpkt->size; |
| 356 | const uint8_t *buf_end = buf+buf_size; |
| 357 | int ret, i, count; |
| 358 | |
| 359 | if ((ret = ff_reget_buffer(avctx, s->frame)) < 0) |
| 360 | return ret; |
| 361 | if (!avctx->frame_number) { |
| 362 | for (i=0; i<avctx->height; i++) |
| 363 | memset(s->frame->data[0]+ i*s->frame->linesize[0], 0, avctx->width); |
| 364 | memset(s->frame->data[1], 0, AVPALETTE_SIZE); |
| 365 | } |
| 366 | |
| 367 | s->frame->pict_type = AV_PICTURE_TYPE_I; |
| 368 | s->frame->palette_has_changed = 1; |
| 369 | set_palette((uint32_t *)s->frame->data[1]); |
| 370 | if (!s->first_frame) { |
| 371 | erase_screen(avctx); |
| 372 | s->first_frame = 1; |
| 373 | } |
| 374 | |
| 375 | while(buf < buf_end) { |
| 376 | switch(s->state) { |
| 377 | case STATE_NORMAL: |
| 378 | switch (buf[0]) { |
| 379 | case 0x00: //NUL |
| 380 | case 0x07: //BEL |
| 381 | case 0x1A: //SUB |
| 382 | /* ignore */ |
| 383 | break; |
| 384 | case 0x08: //BS |
| 385 | s->x = FFMAX(s->x - 1, 0); |
| 386 | break; |
| 387 | case 0x09: //HT |
| 388 | i = s->x / FONT_WIDTH; |
| 389 | count = ((i + 8) & ~7) - i; |
| 390 | for (i = 0; i < count; i++) |
| 391 | draw_char(avctx, ' '); |
| 392 | break; |
| 393 | case 0x0A: //LF |
| 394 | hscroll(avctx); |
| 395 | case 0x0D: //CR |
| 396 | s->x = 0; |
| 397 | break; |
| 398 | case 0x0C: //FF |
| 399 | erase_screen(avctx); |
| 400 | break; |
| 401 | case 0x1B: //ESC |
| 402 | s->state = STATE_ESCAPE; |
| 403 | break; |
| 404 | default: |
| 405 | draw_char(avctx, buf[0]); |
| 406 | } |
| 407 | break; |
| 408 | case STATE_ESCAPE: |
| 409 | if (buf[0] == '[') { |
| 410 | s->state = STATE_CODE; |
| 411 | s->nb_args = 0; |
| 412 | s->args[0] = -1; |
| 413 | } else { |
| 414 | s->state = STATE_NORMAL; |
| 415 | draw_char(avctx, 0x1B); |
| 416 | continue; |
| 417 | } |
| 418 | break; |
| 419 | case STATE_CODE: |
| 420 | switch(buf[0]) { |
| 421 | case '0': case '1': case '2': case '3': case '4': |
| 422 | case '5': case '6': case '7': case '8': case '9': |
| 423 | if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] < 6553) |
| 424 | s->args[s->nb_args] = FFMAX(s->args[s->nb_args], 0) * 10 + buf[0] - '0'; |
| 425 | break; |
| 426 | case ';': |
| 427 | s->nb_args++; |
| 428 | if (s->nb_args < MAX_NB_ARGS) |
| 429 | s->args[s->nb_args] = 0; |
| 430 | break; |
| 431 | case 'M': |
| 432 | s->state = STATE_MUSIC_PREAMBLE; |
| 433 | break; |
| 434 | case '=': case '?': |
| 435 | /* ignore */ |
| 436 | break; |
| 437 | default: |
| 438 | if (s->nb_args > MAX_NB_ARGS) |
| 439 | av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args); |
| 440 | if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] >= 0) |
| 441 | s->nb_args++; |
| 442 | if ((ret = execute_code(avctx, buf[0])) < 0) |
| 443 | return ret; |
| 444 | s->state = STATE_NORMAL; |
| 445 | } |
| 446 | break; |
| 447 | case STATE_MUSIC_PREAMBLE: |
| 448 | if (buf[0] == 0x0E || buf[0] == 0x1B) |
| 449 | s->state = STATE_NORMAL; |
| 450 | /* ignore music data */ |
| 451 | break; |
| 452 | } |
| 453 | buf++; |
| 454 | } |
| 455 | |
| 456 | *got_frame = 1; |
| 457 | if ((ret = av_frame_ref(data, s->frame)) < 0) |
| 458 | return ret; |
| 459 | return buf_size; |
| 460 | } |
| 461 | |
| 462 | static av_cold int decode_close(AVCodecContext *avctx) |
| 463 | { |
| 464 | AnsiContext *s = avctx->priv_data; |
| 465 | |
| 466 | av_frame_free(&s->frame); |
| 467 | return 0; |
| 468 | } |
| 469 | |
| 470 | AVCodec ff_ansi_decoder = { |
| 471 | .name = "ansi", |
| 472 | .long_name = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"), |
| 473 | .type = AVMEDIA_TYPE_VIDEO, |
| 474 | .id = AV_CODEC_ID_ANSI, |
| 475 | .priv_data_size = sizeof(AnsiContext), |
| 476 | .init = decode_init, |
| 477 | .close = decode_close, |
| 478 | .decode = decode_frame, |
| 479 | .capabilities = CODEC_CAP_DR1, |
| 480 | }; |