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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 | }; |