| 1 | /* |
| 2 | * DVD subtitle encoding |
| 3 | * Copyright (c) 2005 Wolfram Gloger |
| 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 | #include "avcodec.h" |
| 22 | #include "bytestream.h" |
| 23 | #include "internal.h" |
| 24 | #include "libavutil/avassert.h" |
| 25 | #include "libavutil/bprint.h" |
| 26 | #include "libavutil/imgutils.h" |
| 27 | #include "libavutil/opt.h" |
| 28 | |
| 29 | typedef struct { |
| 30 | AVClass *class; |
| 31 | uint32_t global_palette[16]; |
| 32 | int even_rows_fix; |
| 33 | } DVDSubtitleContext; |
| 34 | |
| 35 | // ncnt is the nibble counter |
| 36 | #define PUTNIBBLE(val)\ |
| 37 | do {\ |
| 38 | if (ncnt++ & 1)\ |
| 39 | *q++ = bitbuf | ((val) & 0x0f);\ |
| 40 | else\ |
| 41 | bitbuf = (val) << 4;\ |
| 42 | } while(0) |
| 43 | |
| 44 | static void dvd_encode_rle(uint8_t **pq, |
| 45 | const uint8_t *bitmap, int linesize, |
| 46 | int w, int h, |
| 47 | const int cmap[256]) |
| 48 | { |
| 49 | uint8_t *q; |
| 50 | unsigned int bitbuf = 0; |
| 51 | int ncnt; |
| 52 | int x, y, len, color; |
| 53 | |
| 54 | q = *pq; |
| 55 | |
| 56 | for (y = 0; y < h; ++y) { |
| 57 | ncnt = 0; |
| 58 | for(x = 0; x < w; x += len) { |
| 59 | color = bitmap[x]; |
| 60 | for (len=1; x+len < w; ++len) |
| 61 | if (bitmap[x+len] != color) |
| 62 | break; |
| 63 | color = cmap[color]; |
| 64 | av_assert0(color < 4); |
| 65 | if (len < 0x04) { |
| 66 | PUTNIBBLE((len << 2)|color); |
| 67 | } else if (len < 0x10) { |
| 68 | PUTNIBBLE(len >> 2); |
| 69 | PUTNIBBLE((len << 2)|color); |
| 70 | } else if (len < 0x40) { |
| 71 | PUTNIBBLE(0); |
| 72 | PUTNIBBLE(len >> 2); |
| 73 | PUTNIBBLE((len << 2)|color); |
| 74 | } else if (x+len == w) { |
| 75 | PUTNIBBLE(0); |
| 76 | PUTNIBBLE(0); |
| 77 | PUTNIBBLE(0); |
| 78 | PUTNIBBLE(color); |
| 79 | } else { |
| 80 | if (len > 0xff) |
| 81 | len = 0xff; |
| 82 | PUTNIBBLE(0); |
| 83 | PUTNIBBLE(len >> 6); |
| 84 | PUTNIBBLE(len >> 2); |
| 85 | PUTNIBBLE((len << 2)|color); |
| 86 | } |
| 87 | } |
| 88 | /* end of line */ |
| 89 | if (ncnt & 1) |
| 90 | PUTNIBBLE(0); |
| 91 | bitmap += linesize; |
| 92 | } |
| 93 | |
| 94 | *pq = q; |
| 95 | } |
| 96 | |
| 97 | static int color_distance(uint32_t a, uint32_t b) |
| 98 | { |
| 99 | int r = 0, d, i; |
| 100 | int alpha_a = 8, alpha_b = 8; |
| 101 | |
| 102 | for (i = 24; i >= 0; i -= 8) { |
| 103 | d = alpha_a * (int)((a >> i) & 0xFF) - |
| 104 | alpha_b * (int)((b >> i) & 0xFF); |
| 105 | r += d * d; |
| 106 | alpha_a = a >> 28; |
| 107 | alpha_b = b >> 28; |
| 108 | } |
| 109 | return r; |
| 110 | } |
| 111 | |
| 112 | /** |
| 113 | * Count colors used in a rectangle, quantizing alpha and grouping by |
| 114 | * nearest global palette entry. |
| 115 | */ |
| 116 | static void count_colors(AVCodecContext *avctx, unsigned hits[33], |
| 117 | const AVSubtitleRect *r) |
| 118 | { |
| 119 | DVDSubtitleContext *dvdc = avctx->priv_data; |
| 120 | unsigned count[256] = { 0 }; |
| 121 | uint32_t *palette = (uint32_t *)r->pict.data[1]; |
| 122 | uint32_t color; |
| 123 | int x, y, i, j, match, d, best_d, av_uninit(best_j); |
| 124 | uint8_t *p = r->pict.data[0]; |
| 125 | |
| 126 | for (y = 0; y < r->h; y++) { |
| 127 | for (x = 0; x < r->w; x++) |
| 128 | count[*(p++)]++; |
| 129 | p += r->pict.linesize[0] - r->w; |
| 130 | } |
| 131 | for (i = 0; i < 256; i++) { |
| 132 | if (!count[i]) /* avoid useless search */ |
| 133 | continue; |
| 134 | color = palette[i]; |
| 135 | /* 0: transparent, 1-16: semi-transparent, 17-33 opaque */ |
| 136 | match = color < 0x33000000 ? 0 : color < 0xCC000000 ? 1 : 17; |
| 137 | if (match) { |
| 138 | best_d = INT_MAX; |
| 139 | for (j = 0; j < 16; j++) { |
| 140 | d = color_distance(0xFF000000 | color, |
| 141 | 0xFF000000 | dvdc->global_palette[j]); |
| 142 | if (d < best_d) { |
| 143 | best_d = d; |
| 144 | best_j = j; |
| 145 | } |
| 146 | } |
| 147 | match += best_j; |
| 148 | } |
| 149 | hits[match] += count[i]; |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | static void select_palette(AVCodecContext *avctx, int out_palette[4], |
| 154 | int out_alpha[4], unsigned hits[33]) |
| 155 | { |
| 156 | DVDSubtitleContext *dvdc = avctx->priv_data; |
| 157 | int i, j, bright, mult; |
| 158 | uint32_t color; |
| 159 | int selected[4] = { 0 }; |
| 160 | uint32_t pseudopal[33] = { 0 }; |
| 161 | uint32_t refcolor[3] = { 0x00000000, 0xFFFFFFFF, 0xFF000000 }; |
| 162 | |
| 163 | /* Bonus for transparent: if the rectangle fits tightly the text, the |
| 164 | background color can be quite rare, but it would be ugly without it */ |
| 165 | hits[0] *= 16; |
| 166 | /* Bonus for bright colors */ |
| 167 | for (i = 0; i < 16; i++) { |
| 168 | if (!(hits[1 + i] + hits[17 + i])) |
| 169 | continue; /* skip unused colors to gain time */ |
| 170 | color = dvdc->global_palette[i]; |
| 171 | bright = 0; |
| 172 | for (j = 0; j < 3; j++, color >>= 8) |
| 173 | bright += (color & 0xFF) < 0x40 || (color & 0xFF) >= 0xC0; |
| 174 | mult = 2 + FFMIN(bright, 2); |
| 175 | hits[ 1 + i] *= mult; |
| 176 | hits[17 + i] *= mult; |
| 177 | } |
| 178 | |
| 179 | /* Select four most frequent colors */ |
| 180 | for (i = 0; i < 4; i++) { |
| 181 | for (j = 0; j < 33; j++) |
| 182 | if (hits[j] > hits[selected[i]]) |
| 183 | selected[i] = j; |
| 184 | hits[selected[i]] = 0; |
| 185 | } |
| 186 | |
| 187 | /* Order the colors like in most DVDs: |
| 188 | 0: background, 1: foreground, 2: outline */ |
| 189 | for (i = 0; i < 16; i++) { |
| 190 | pseudopal[ 1 + i] = 0x80000000 | dvdc->global_palette[i]; |
| 191 | pseudopal[17 + i] = 0xFF000000 | dvdc->global_palette[i]; |
| 192 | } |
| 193 | for (i = 0; i < 3; i++) { |
| 194 | int best_d = color_distance(refcolor[i], pseudopal[selected[i]]); |
| 195 | for (j = i + 1; j < 4; j++) { |
| 196 | int d = color_distance(refcolor[i], pseudopal[selected[j]]); |
| 197 | if (d < best_d) { |
| 198 | FFSWAP(int, selected[i], selected[j]); |
| 199 | best_d = d; |
| 200 | } |
| 201 | } |
| 202 | } |
| 203 | |
| 204 | /* Output */ |
| 205 | for (i = 0; i < 4; i++) { |
| 206 | out_palette[i] = selected[i] ? (selected[i] - 1) & 0xF : 0; |
| 207 | out_alpha [i] = !selected[i] ? 0 : selected[i] < 17 ? 0x80 : 0xFF; |
| 208 | } |
| 209 | } |
| 210 | |
| 211 | static void build_color_map(AVCodecContext *avctx, int cmap[], |
| 212 | const uint32_t palette[], |
| 213 | const int out_palette[], unsigned int const out_alpha[]) |
| 214 | { |
| 215 | DVDSubtitleContext *dvdc = avctx->priv_data; |
| 216 | int i, j, d, best_d; |
| 217 | uint32_t pseudopal[4]; |
| 218 | |
| 219 | for (i = 0; i < 4; i++) |
| 220 | pseudopal[i] = (out_alpha[i] << 24) | |
| 221 | dvdc->global_palette[out_palette[i]]; |
| 222 | for (i = 0; i < 256; i++) { |
| 223 | best_d = INT_MAX; |
| 224 | for (j = 0; j < 4; j++) { |
| 225 | d = color_distance(pseudopal[j], palette[i]); |
| 226 | if (d < best_d) { |
| 227 | cmap[i] = j; |
| 228 | best_d = d; |
| 229 | } |
| 230 | } |
| 231 | } |
| 232 | } |
| 233 | |
| 234 | static void copy_rectangle(AVSubtitleRect *dst, AVSubtitleRect *src, int cmap[]) |
| 235 | { |
| 236 | int x, y; |
| 237 | uint8_t *p, *q; |
| 238 | |
| 239 | p = src->pict.data[0]; |
| 240 | q = dst->pict.data[0] + (src->x - dst->x) + |
| 241 | (src->y - dst->y) * dst->pict.linesize[0]; |
| 242 | for (y = 0; y < src->h; y++) { |
| 243 | for (x = 0; x < src->w; x++) |
| 244 | *(q++) = cmap[*(p++)]; |
| 245 | p += src->pict.linesize[0] - src->w; |
| 246 | q += dst->pict.linesize[0] - src->w; |
| 247 | } |
| 248 | } |
| 249 | |
| 250 | static int encode_dvd_subtitles(AVCodecContext *avctx, |
| 251 | uint8_t *outbuf, int outbuf_size, |
| 252 | const AVSubtitle *h) |
| 253 | { |
| 254 | DVDSubtitleContext *dvdc = avctx->priv_data; |
| 255 | uint8_t *q, *qq; |
| 256 | int offset1, offset2; |
| 257 | int i, rects = h->num_rects, ret; |
| 258 | unsigned global_palette_hits[33] = { 0 }; |
| 259 | int cmap[256]; |
| 260 | int out_palette[4]; |
| 261 | int out_alpha[4]; |
| 262 | AVSubtitleRect vrect; |
| 263 | uint8_t *vrect_data = NULL; |
| 264 | int x2, y2; |
| 265 | int forced = 0; |
| 266 | |
| 267 | if (rects == 0 || !h->rects) |
| 268 | return AVERROR(EINVAL); |
| 269 | for (i = 0; i < rects; i++) |
| 270 | if (h->rects[i]->type != SUBTITLE_BITMAP) { |
| 271 | av_log(avctx, AV_LOG_ERROR, "Bitmap subtitle required\n"); |
| 272 | return AVERROR(EINVAL); |
| 273 | } |
| 274 | /* Mark this subtitle forced if any of the rectangles is forced. */ |
| 275 | for (i = 0; i < rects; i++) |
| 276 | if ((h->rects[i]->flags & AV_SUBTITLE_FLAG_FORCED) != 0) { |
| 277 | forced = 1; |
| 278 | break; |
| 279 | } |
| 280 | vrect = *h->rects[0]; |
| 281 | |
| 282 | if (rects > 1) { |
| 283 | /* DVD subtitles can have only one rectangle: build a virtual |
| 284 | rectangle containing all actual rectangles. |
| 285 | The data of the rectangles will be copied later, when the palette |
| 286 | is decided, because the rectangles may have different palettes. */ |
| 287 | int xmin = h->rects[0]->x, xmax = xmin + h->rects[0]->w; |
| 288 | int ymin = h->rects[0]->y, ymax = ymin + h->rects[0]->h; |
| 289 | for (i = 1; i < rects; i++) { |
| 290 | xmin = FFMIN(xmin, h->rects[i]->x); |
| 291 | ymin = FFMIN(ymin, h->rects[i]->y); |
| 292 | xmax = FFMAX(xmax, h->rects[i]->x + h->rects[i]->w); |
| 293 | ymax = FFMAX(ymax, h->rects[i]->y + h->rects[i]->h); |
| 294 | } |
| 295 | vrect.x = xmin; |
| 296 | vrect.y = ymin; |
| 297 | vrect.w = xmax - xmin; |
| 298 | vrect.h = ymax - ymin; |
| 299 | if ((ret = av_image_check_size(vrect.w, vrect.h, 0, avctx)) < 0) |
| 300 | return ret; |
| 301 | |
| 302 | /* Count pixels outside the virtual rectangle as transparent */ |
| 303 | global_palette_hits[0] = vrect.w * vrect.h; |
| 304 | for (i = 0; i < rects; i++) |
| 305 | global_palette_hits[0] -= h->rects[i]->w * h->rects[i]->h; |
| 306 | } |
| 307 | |
| 308 | for (i = 0; i < rects; i++) |
| 309 | count_colors(avctx, global_palette_hits, h->rects[i]); |
| 310 | select_palette(avctx, out_palette, out_alpha, global_palette_hits); |
| 311 | |
| 312 | if (rects > 1) { |
| 313 | if (!(vrect_data = av_calloc(vrect.w, vrect.h))) |
| 314 | return AVERROR(ENOMEM); |
| 315 | vrect.pict.data [0] = vrect_data; |
| 316 | vrect.pict.linesize[0] = vrect.w; |
| 317 | for (i = 0; i < rects; i++) { |
| 318 | build_color_map(avctx, cmap, (uint32_t *)h->rects[i]->pict.data[1], |
| 319 | out_palette, out_alpha); |
| 320 | copy_rectangle(&vrect, h->rects[i], cmap); |
| 321 | } |
| 322 | for (i = 0; i < 4; i++) |
| 323 | cmap[i] = i; |
| 324 | } else { |
| 325 | build_color_map(avctx, cmap, (uint32_t *)h->rects[0]->pict.data[1], |
| 326 | out_palette, out_alpha); |
| 327 | } |
| 328 | |
| 329 | av_log(avctx, AV_LOG_DEBUG, "Selected palette:"); |
| 330 | for (i = 0; i < 4; i++) |
| 331 | av_log(avctx, AV_LOG_DEBUG, " 0x%06x@@%02x (0x%x,0x%x)", |
| 332 | dvdc->global_palette[out_palette[i]], out_alpha[i], |
| 333 | out_palette[i], out_alpha[i] >> 4); |
| 334 | av_log(avctx, AV_LOG_DEBUG, "\n"); |
| 335 | |
| 336 | // encode data block |
| 337 | q = outbuf + 4; |
| 338 | offset1 = q - outbuf; |
| 339 | // worst case memory requirement: 1 nibble per pixel.. |
| 340 | if ((q - outbuf) + vrect.w * vrect.h / 2 + 17 + 21 > outbuf_size) { |
| 341 | av_log(NULL, AV_LOG_ERROR, "dvd_subtitle too big\n"); |
| 342 | ret = AVERROR_BUFFER_TOO_SMALL; |
| 343 | goto fail; |
| 344 | } |
| 345 | dvd_encode_rle(&q, vrect.pict.data[0], vrect.w * 2, |
| 346 | vrect.w, (vrect.h + 1) >> 1, cmap); |
| 347 | offset2 = q - outbuf; |
| 348 | dvd_encode_rle(&q, vrect.pict.data[0] + vrect.w, vrect.w * 2, |
| 349 | vrect.w, vrect.h >> 1, cmap); |
| 350 | |
| 351 | if (dvdc->even_rows_fix && (vrect.h & 1)) { |
| 352 | // Work-around for some players that want the height to be even. |
| 353 | vrect.h++; |
| 354 | *q++ = 0x00; // 0x00 0x00 == empty row, i.e. fully transparent |
| 355 | *q++ = 0x00; |
| 356 | } |
| 357 | |
| 358 | // set data packet size |
| 359 | qq = outbuf + 2; |
| 360 | bytestream_put_be16(&qq, q - outbuf); |
| 361 | |
| 362 | // send start display command |
| 363 | bytestream_put_be16(&q, (h->start_display_time*90) >> 10); |
| 364 | bytestream_put_be16(&q, (q - outbuf) /*- 2 */ + 8 + 12 + 2); |
| 365 | *q++ = 0x03; // palette - 4 nibbles |
| 366 | *q++ = (out_palette[3] << 4) | out_palette[2]; |
| 367 | *q++ = (out_palette[1] << 4) | out_palette[0]; |
| 368 | *q++ = 0x04; // alpha - 4 nibbles |
| 369 | *q++ = (out_alpha[3] & 0xF0) | (out_alpha[2] >> 4); |
| 370 | *q++ = (out_alpha[1] & 0xF0) | (out_alpha[0] >> 4); |
| 371 | |
| 372 | // 12 bytes per rect |
| 373 | x2 = vrect.x + vrect.w - 1; |
| 374 | y2 = vrect.y + vrect.h - 1; |
| 375 | |
| 376 | *q++ = 0x05; |
| 377 | // x1 x2 -> 6 nibbles |
| 378 | *q++ = vrect.x >> 4; |
| 379 | *q++ = (vrect.x << 4) | ((x2 >> 8) & 0xf); |
| 380 | *q++ = x2; |
| 381 | // y1 y2 -> 6 nibbles |
| 382 | *q++ = vrect.y >> 4; |
| 383 | *q++ = (vrect.y << 4) | ((y2 >> 8) & 0xf); |
| 384 | *q++ = y2; |
| 385 | |
| 386 | *q++ = 0x06; |
| 387 | // offset1, offset2 |
| 388 | bytestream_put_be16(&q, offset1); |
| 389 | bytestream_put_be16(&q, offset2); |
| 390 | |
| 391 | *q++ = forced ? 0x00 : 0x01; // start command |
| 392 | *q++ = 0xff; // terminating command |
| 393 | |
| 394 | // send stop display command last |
| 395 | bytestream_put_be16(&q, (h->end_display_time*90) >> 10); |
| 396 | bytestream_put_be16(&q, (q - outbuf) - 2 /*+ 4*/); |
| 397 | *q++ = 0x02; // set end |
| 398 | *q++ = 0xff; // terminating command |
| 399 | |
| 400 | qq = outbuf; |
| 401 | bytestream_put_be16(&qq, q - outbuf); |
| 402 | |
| 403 | av_log(NULL, AV_LOG_DEBUG, "subtitle_packet size=%"PTRDIFF_SPECIFIER"\n", q - outbuf); |
| 404 | ret = q - outbuf; |
| 405 | |
| 406 | fail: |
| 407 | av_free(vrect_data); |
| 408 | return ret; |
| 409 | } |
| 410 | |
| 411 | static int dvdsub_init(AVCodecContext *avctx) |
| 412 | { |
| 413 | DVDSubtitleContext *dvdc = avctx->priv_data; |
| 414 | static const uint32_t default_palette[16] = { |
| 415 | 0x000000, 0x0000FF, 0x00FF00, 0xFF0000, |
| 416 | 0xFFFF00, 0xFF00FF, 0x00FFFF, 0xFFFFFF, |
| 417 | 0x808000, 0x8080FF, 0x800080, 0x80FF80, |
| 418 | 0x008080, 0xFF8080, 0x555555, 0xAAAAAA, |
| 419 | }; |
| 420 | AVBPrint extradata; |
| 421 | int i, ret; |
| 422 | |
| 423 | av_assert0(sizeof(dvdc->global_palette) == sizeof(default_palette)); |
| 424 | memcpy(dvdc->global_palette, default_palette, sizeof(dvdc->global_palette)); |
| 425 | |
| 426 | av_bprint_init(&extradata, 0, 1); |
| 427 | if (avctx->width && avctx->height) |
| 428 | av_bprintf(&extradata, "size: %dx%d\n", avctx->width, avctx->height); |
| 429 | av_bprintf(&extradata, "palette:"); |
| 430 | for (i = 0; i < 16; i++) |
| 431 | av_bprintf(&extradata, " %06"PRIx32"%c", |
| 432 | dvdc->global_palette[i] & 0xFFFFFF, i < 15 ? ',' : '\n'); |
| 433 | |
| 434 | ret = avpriv_bprint_to_extradata(avctx, &extradata); |
| 435 | if (ret < 0) |
| 436 | return ret; |
| 437 | |
| 438 | return 0; |
| 439 | } |
| 440 | |
| 441 | static int dvdsub_encode(AVCodecContext *avctx, |
| 442 | unsigned char *buf, int buf_size, |
| 443 | const AVSubtitle *sub) |
| 444 | { |
| 445 | //DVDSubtitleContext *s = avctx->priv_data; |
| 446 | int ret; |
| 447 | |
| 448 | ret = encode_dvd_subtitles(avctx, buf, buf_size, sub); |
| 449 | return ret; |
| 450 | } |
| 451 | |
| 452 | #define OFFSET(x) offsetof(DVDSubtitleContext, x) |
| 453 | #define SE AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_ENCODING_PARAM |
| 454 | static const AVOption options[] = { |
| 455 | {"even_rows_fix", "Make number of rows even (workaround for some players)", OFFSET(even_rows_fix), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SE}, |
| 456 | { NULL }, |
| 457 | }; |
| 458 | |
| 459 | static const AVClass dvdsubenc_class = { |
| 460 | .class_name = "VOBSUB subtitle encoder", |
| 461 | .item_name = av_default_item_name, |
| 462 | .option = options, |
| 463 | .version = LIBAVUTIL_VERSION_INT, |
| 464 | }; |
| 465 | |
| 466 | AVCodec ff_dvdsub_encoder = { |
| 467 | .name = "dvdsub", |
| 468 | .long_name = NULL_IF_CONFIG_SMALL("DVD subtitles"), |
| 469 | .type = AVMEDIA_TYPE_SUBTITLE, |
| 470 | .id = AV_CODEC_ID_DVD_SUBTITLE, |
| 471 | .init = dvdsub_init, |
| 472 | .encode_sub = dvdsub_encode, |
| 473 | .priv_class = &dvdsubenc_class, |
| 474 | .priv_data_size = sizeof(DVDSubtitleContext), |
| 475 | }; |