0ba11c2c3fb0792df424ec45ecf241340802403f
[libav.git] / libavcodec / dvdsubdec.c
1 /*
2 * DVD subtitle decoding for ffmpeg
3 * Copyright (c) 2005 Fabrice Bellard.
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 "bitstream.h"
23 #include "colorspace.h"
24 #include "dsputil.h"
25
26 //#define DEBUG
27
28 static void yuv_a_to_rgba(const uint8_t *ycbcr, const uint8_t *alpha, uint32_t *rgba, int num_values)
29 {
30 uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
31 uint8_t r, g, b;
32 int i, y, cb, cr;
33 int r_add, g_add, b_add;
34
35 for (i = num_values; i > 0; i--) {
36 y = *ycbcr++;
37 cb = *ycbcr++;
38 cr = *ycbcr++;
39 YUV_TO_RGB1_CCIR(cb, cr);
40 YUV_TO_RGB2_CCIR(r, g, b, y);
41 *rgba++ = (*alpha++ << 24) | (r << 16) | (g << 8) | b;
42 }
43 }
44
45 static int decode_run_2bit(GetBitContext *gb, int *color)
46 {
47 unsigned int v, t;
48
49 v = 0;
50 for (t = 1; v < t && t <= 0x40; t <<= 2)
51 v = (v << 4) | get_bits(gb, 4);
52 *color = v & 3;
53 if (v < 4) { /* Code for fill rest of line */
54 return INT_MAX;
55 }
56 return v >> 2;
57 }
58
59 static int decode_run_8bit(GetBitContext *gb, int *color)
60 {
61 int len;
62 int has_run = get_bits1(gb);
63 if (get_bits1(gb))
64 *color = get_bits(gb, 8);
65 else
66 *color = get_bits(gb, 2);
67 if (has_run) {
68 if (get_bits1(gb)) {
69 len = get_bits(gb, 7);
70 if (len == 0)
71 len = INT_MAX;
72 else
73 len += 9;
74 } else
75 len = get_bits(gb, 3) + 2;
76 } else
77 len = 1;
78 return len;
79 }
80
81 static int decode_rle(uint8_t *bitmap, int linesize, int w, int h,
82 const uint8_t *buf, int start, int buf_size, int is_8bit)
83 {
84 GetBitContext gb;
85 int bit_len;
86 int x, y, len, color;
87 uint8_t *d;
88
89 bit_len = (buf_size - start) * 8;
90 init_get_bits(&gb, buf + start, bit_len);
91
92 x = 0;
93 y = 0;
94 d = bitmap;
95 for(;;) {
96 if (get_bits_count(&gb) > bit_len)
97 return -1;
98 if (is_8bit)
99 len = decode_run_8bit(&gb, &color);
100 else
101 len = decode_run_2bit(&gb, &color);
102 len = FFMIN(len, w - x);
103 memset(d + x, color, len);
104 x += len;
105 if (x >= w) {
106 y++;
107 if (y >= h)
108 break;
109 d += linesize;
110 x = 0;
111 /* byte align */
112 align_get_bits(&gb);
113 }
114 }
115 return 0;
116 }
117
118 static void guess_palette(uint32_t *rgba_palette,
119 uint8_t *colormap,
120 uint8_t *alpha,
121 uint32_t subtitle_color)
122 {
123 uint8_t color_used[16];
124 int nb_opaque_colors, i, level, j, r, g, b;
125
126 for(i = 0; i < 4; i++)
127 rgba_palette[i] = 0;
128
129 memset(color_used, 0, 16);
130 nb_opaque_colors = 0;
131 for(i = 0; i < 4; i++) {
132 if (alpha[i] != 0 && !color_used[colormap[i]]) {
133 color_used[colormap[i]] = 1;
134 nb_opaque_colors++;
135 }
136 }
137
138 if (nb_opaque_colors == 0)
139 return;
140
141 j = nb_opaque_colors;
142 memset(color_used, 0, 16);
143 for(i = 0; i < 4; i++) {
144 if (alpha[i] != 0) {
145 if (!color_used[colormap[i]]) {
146 level = (0xff * j) / nb_opaque_colors;
147 r = (((subtitle_color >> 16) & 0xff) * level) >> 8;
148 g = (((subtitle_color >> 8) & 0xff) * level) >> 8;
149 b = (((subtitle_color >> 0) & 0xff) * level) >> 8;
150 rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);
151 color_used[colormap[i]] = (i + 1);
152 j--;
153 } else {
154 rgba_palette[i] = (rgba_palette[color_used[colormap[i]] - 1] & 0x00ffffff) |
155 ((alpha[i] * 17) << 24);
156 }
157 }
158 }
159 }
160
161 #define READ_OFFSET(a) (big_offsets ? AV_RB32(a) : AV_RB16(a))
162
163 static int decode_dvd_subtitles(AVSubtitle *sub_header,
164 const uint8_t *buf, int buf_size)
165 {
166 int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;
167 int big_offsets, offset_size, is_8bit = 0;
168 const uint8_t *yuv_palette = 0;
169 uint8_t colormap[4], alpha[256];
170 int date;
171 int i;
172 int is_menu = 0;
173
174 if (buf_size < 10)
175 return -1;
176 sub_header->rects = NULL;
177 sub_header->num_rects = 0;
178 sub_header->start_display_time = 0;
179 sub_header->end_display_time = 0;
180
181 if (AV_RB16(buf) == 0) { /* HD subpicture with 4-byte offsets */
182 big_offsets = 1;
183 offset_size = 4;
184 cmd_pos = 6;
185 } else {
186 big_offsets = 0;
187 offset_size = 2;
188 cmd_pos = 2;
189 }
190
191 cmd_pos = READ_OFFSET(buf + cmd_pos);
192
193 while ((cmd_pos + 2 + offset_size) < buf_size) {
194 date = AV_RB16(buf + cmd_pos);
195 next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2);
196 #ifdef DEBUG
197 av_log(NULL, AV_LOG_INFO, "cmd_pos=0x%04x next=0x%04x date=%d\n",
198 cmd_pos, next_cmd_pos, date);
199 #endif
200 pos = cmd_pos + 2 + offset_size;
201 offset1 = -1;
202 offset2 = -1;
203 x1 = y1 = x2 = y2 = 0;
204 while (pos < buf_size) {
205 cmd = buf[pos++];
206 #ifdef DEBUG
207 av_log(NULL, AV_LOG_INFO, "cmd=%02x\n", cmd);
208 #endif
209 switch(cmd) {
210 case 0x00:
211 /* menu subpicture */
212 is_menu = 1;
213 break;
214 case 0x01:
215 /* set start date */
216 sub_header->start_display_time = (date << 10) / 90;
217 break;
218 case 0x02:
219 /* set end date */
220 sub_header->end_display_time = (date << 10) / 90;
221 break;
222 case 0x03:
223 /* set colormap */
224 if ((buf_size - pos) < 2)
225 goto fail;
226 colormap[3] = buf[pos] >> 4;
227 colormap[2] = buf[pos] & 0x0f;
228 colormap[1] = buf[pos + 1] >> 4;
229 colormap[0] = buf[pos + 1] & 0x0f;
230 pos += 2;
231 break;
232 case 0x04:
233 /* set alpha */
234 if ((buf_size - pos) < 2)
235 goto fail;
236 alpha[3] = buf[pos] >> 4;
237 alpha[2] = buf[pos] & 0x0f;
238 alpha[1] = buf[pos + 1] >> 4;
239 alpha[0] = buf[pos + 1] & 0x0f;
240 pos += 2;
241 #ifdef DEBUG
242 av_log(NULL, AV_LOG_INFO, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
243 #endif
244 break;
245 case 0x05:
246 case 0x85:
247 if ((buf_size - pos) < 6)
248 goto fail;
249 x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
250 x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
251 y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
252 y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
253 if (cmd & 0x80)
254 is_8bit = 1;
255 #ifdef DEBUG
256 av_log(NULL, AV_LOG_INFO, "x1=%d x2=%d y1=%d y2=%d\n",
257 x1, x2, y1, y2);
258 #endif
259 pos += 6;
260 break;
261 case 0x06:
262 if ((buf_size - pos) < 4)
263 goto fail;
264 offset1 = AV_RB16(buf + pos);
265 offset2 = AV_RB16(buf + pos + 2);
266 #ifdef DEBUG
267 av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
268 #endif
269 pos += 4;
270 break;
271 case 0x86:
272 if ((buf_size - pos) < 8)
273 goto fail;
274 offset1 = AV_RB32(buf + pos);
275 offset2 = AV_RB32(buf + pos + 4);
276 #ifdef DEBUG
277 av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
278 #endif
279 pos += 8;
280 break;
281
282 case 0x83:
283 /* HD set palette */
284 if ((buf_size - pos) < 768)
285 goto fail;
286 yuv_palette = buf + pos;
287 pos += 768;
288 break;
289 case 0x84:
290 /* HD set contrast (alpha) */
291 if ((buf_size - pos) < 256)
292 goto fail;
293 for (i = 0; i < 256; i++)
294 alpha[i] = 0xFF - buf[pos+i];
295 pos += 256;
296 break;
297
298 case 0xff:
299 goto the_end;
300 default:
301 #ifdef DEBUG
302 av_log(NULL, AV_LOG_INFO, "unrecognised subpicture command 0x%x\n", cmd);
303 #endif
304 goto the_end;
305 }
306 }
307 the_end:
308 if (offset1 >= 0) {
309 int w, h;
310 uint8_t *bitmap;
311
312 /* decode the bitmap */
313 w = x2 - x1 + 1;
314 if (w < 0)
315 w = 0;
316 h = y2 - y1;
317 if (h < 0)
318 h = 0;
319 if (w > 0 && h > 0) {
320 if (sub_header->rects != NULL) {
321 for (i = 0; i < sub_header->num_rects; i++) {
322 av_freep(&sub_header->rects[i]->bitmap);
323 av_freep(&sub_header->rects[i]->rgba_palette);
324 av_freep(&sub_header->rects[i]);
325 }
326 av_freep(&sub_header->rects);
327 sub_header->num_rects = 0;
328 }
329
330 bitmap = av_malloc(w * h);
331 sub_header->rects = av_mallocz(sizeof(*sub_header->rects));
332 sub_header->rects[0] = av_mallocz(sizeof(AVSubtitleRect));
333 sub_header->num_rects = 1;
334 sub_header->rects[0]->bitmap = bitmap;
335 decode_rle(bitmap, w * 2, w, (h + 1) / 2,
336 buf, offset1, buf_size, is_8bit);
337 decode_rle(bitmap + w, w * 2, w, h / 2,
338 buf, offset2, buf_size, is_8bit);
339 if (is_8bit) {
340 if (yuv_palette == 0)
341 goto fail;
342 sub_header->rects[0]->rgba_palette = av_malloc(256 * 4);
343 sub_header->rects[0]->nb_colors = 256;
344 yuv_a_to_rgba(yuv_palette, alpha, sub_header->rects[0]->rgba_palette, 256);
345 } else {
346 sub_header->rects[0]->rgba_palette = av_malloc(4 * 4);
347 sub_header->rects[0]->nb_colors = 4;
348 guess_palette(sub_header->rects[0]->rgba_palette,
349 colormap, alpha, 0xffff00);
350 }
351 sub_header->rects[0]->x = x1;
352 sub_header->rects[0]->y = y1;
353 sub_header->rects[0]->w = w;
354 sub_header->rects[0]->h = h;
355 sub_header->rects[0]->linesize = w;
356 }
357 }
358 if (next_cmd_pos == cmd_pos)
359 break;
360 cmd_pos = next_cmd_pos;
361 }
362 if (sub_header->num_rects > 0)
363 return is_menu;
364 fail:
365 if (sub_header->rects != NULL) {
366 for (i = 0; i < sub_header->num_rects; i++) {
367 av_freep(&sub_header->rects[i]->bitmap);
368 av_freep(&sub_header->rects[i]->rgba_palette);
369 av_freep(&sub_header->rects[i]);
370 }
371 av_freep(&sub_header->rects);
372 sub_header->num_rects = 0;
373 }
374 return -1;
375 }
376
377 static int is_transp(const uint8_t *buf, int pitch, int n,
378 const uint8_t *transp_color)
379 {
380 int i;
381 for(i = 0; i < n; i++) {
382 if (!transp_color[*buf])
383 return 0;
384 buf += pitch;
385 }
386 return 1;
387 }
388
389 /* return 0 if empty rectangle, 1 if non empty */
390 static int find_smallest_bounding_rectangle(AVSubtitle *s)
391 {
392 uint8_t transp_color[256];
393 int y1, y2, x1, x2, y, w, h, i;
394 uint8_t *bitmap;
395
396 if (s->num_rects == 0 || s->rects == NULL || s->rects[0]->w <= 0 || s->rects[0]->h <= 0)
397 return 0;
398
399 memset(transp_color, 0, 256);
400 for(i = 0; i < s->rects[0]->nb_colors; i++) {
401 if ((s->rects[0]->rgba_palette[i] >> 24) == 0)
402 transp_color[i] = 1;
403 }
404 y1 = 0;
405 while (y1 < s->rects[0]->h && is_transp(s->rects[0]->bitmap + y1 * s->rects[0]->linesize,
406 1, s->rects[0]->w, transp_color))
407 y1++;
408 if (y1 == s->rects[0]->h) {
409 av_freep(&s->rects[0]->bitmap);
410 s->rects[0]->w = s->rects[0]->h = 0;
411 return 0;
412 }
413
414 y2 = s->rects[0]->h - 1;
415 while (y2 > 0 && is_transp(s->rects[0]->bitmap + y2 * s->rects[0]->linesize, 1,
416 s->rects[0]->w, transp_color))
417 y2--;
418 x1 = 0;
419 while (x1 < (s->rects[0]->w - 1) && is_transp(s->rects[0]->bitmap + x1, s->rects[0]->linesize,
420 s->rects[0]->h, transp_color))
421 x1++;
422 x2 = s->rects[0]->w - 1;
423 while (x2 > 0 && is_transp(s->rects[0]->bitmap + x2, s->rects[0]->linesize, s->rects[0]->h,
424 transp_color))
425 x2--;
426 w = x2 - x1 + 1;
427 h = y2 - y1 + 1;
428 bitmap = av_malloc(w * h);
429 if (!bitmap)
430 return 1;
431 for(y = 0; y < h; y++) {
432 memcpy(bitmap + w * y, s->rects[0]->bitmap + x1 + (y1 + y) * s->rects[0]->linesize, w);
433 }
434 av_freep(&s->rects[0]->bitmap);
435 s->rects[0]->bitmap = bitmap;
436 s->rects[0]->linesize = w;
437 s->rects[0]->w = w;
438 s->rects[0]->h = h;
439 s->rects[0]->x += x1;
440 s->rects[0]->y += y1;
441 return 1;
442 }
443
444 #ifdef DEBUG
445 #undef fprintf
446 #undef perror
447 #undef exit
448 static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
449 uint32_t *rgba_palette)
450 {
451 int x, y, v;
452 FILE *f;
453
454 f = fopen(filename, "w");
455 if (!f) {
456 perror(filename);
457 exit(1);
458 }
459 fprintf(f, "P6\n"
460 "%d %d\n"
461 "%d\n",
462 w, h, 255);
463 for(y = 0; y < h; y++) {
464 for(x = 0; x < w; x++) {
465 v = rgba_palette[bitmap[y * w + x]];
466 putc((v >> 16) & 0xff, f);
467 putc((v >> 8) & 0xff, f);
468 putc((v >> 0) & 0xff, f);
469 }
470 }
471 fclose(f);
472 }
473 #endif
474
475 static int dvdsub_decode(AVCodecContext *avctx,
476 void *data, int *data_size,
477 const uint8_t *buf, int buf_size)
478 {
479 AVSubtitle *sub = (void *)data;
480 int is_menu;
481
482 is_menu = decode_dvd_subtitles(sub, buf, buf_size);
483
484 if (is_menu < 0) {
485 no_subtitle:
486 *data_size = 0;
487
488 return buf_size;
489 }
490 if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
491 goto no_subtitle;
492
493 #if defined(DEBUG)
494 av_log(NULL, AV_LOG_INFO, "start=%d ms end =%d ms\n",
495 sub->start_display_time,
496 sub->end_display_time);
497 ppm_save("/tmp/a.ppm", sub->rects[0]->bitmap,
498 sub->rects[0]->w, sub->rects[0]->h, sub->rects[0]->rgba_palette);
499 #endif
500
501 *data_size = 1;
502 return buf_size;
503 }
504
505 AVCodec dvdsub_decoder = {
506 "dvdsub",
507 CODEC_TYPE_SUBTITLE,
508 CODEC_ID_DVD_SUBTITLE,
509 0,
510 NULL,
511 NULL,
512 NULL,
513 dvdsub_decode,
514 .long_name = NULL_IF_CONFIG_SMALL("DVD subtitles"),
515 };