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source: vbox/trunk/src/libs/ffmpeg-20060710/libavcodec/dvdsub.c@ 9441

Last change on this file since 9441 was 5776, checked in by vboxsync, 17 years ago

ffmpeg: exported to OSE
File size: 13.9 KB
Line 
1/*
2 * DVD subtitle decoding for ffmpeg
3 * Copyright (c) 2005 Fabrice Bellard.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19#include "avcodec.h"
20
21//#define DEBUG
22
23typedef struct DVDSubContext {
24} DVDSubContext;
25
26static int dvdsub_init_decoder(AVCodecContext *avctx)
27{
28 return 0;
29}
30
31static uint16_t getbe16(const uint8_t *p)
32{
33 return (p[0] << 8) | p[1];
34}
35
36static int get_nibble(const uint8_t *buf, int nibble_offset)
37{
38 return (buf[nibble_offset >> 1] >> ((1 - (nibble_offset & 1)) << 2)) & 0xf;
39}
40
41static int decode_rle(uint8_t *bitmap, int linesize, int w, int h,
42 const uint8_t *buf, int nibble_offset, int buf_size)
43{
44 unsigned int v;
45 int x, y, len, color, nibble_end;
46 uint8_t *d;
47
48 nibble_end = buf_size * 2;
49 x = 0;
50 y = 0;
51 d = bitmap;
52 for(;;) {
53 if (nibble_offset >= nibble_end)
54 return -1;
55 v = get_nibble(buf, nibble_offset++);
56 if (v < 0x4) {
57 v = (v << 4) | get_nibble(buf, nibble_offset++);
58 if (v < 0x10) {
59 v = (v << 4) | get_nibble(buf, nibble_offset++);
60 if (v < 0x040) {
61 v = (v << 4) | get_nibble(buf, nibble_offset++);
62 if (v < 4) {
63 v |= (w - x) << 2;
64 }
65 }
66 }
67 }
68 len = v >> 2;
69 if (len > (w - x))
70 len = (w - x);
71 color = v & 0x03;
72 memset(d + x, color, len);
73 x += len;
74 if (x >= w) {
75 y++;
76 if (y >= h)
77 break;
78 d += linesize;
79 x = 0;
80 /* byte align */
81 nibble_offset += (nibble_offset & 1);
82 }
83 }
84 return 0;
85}
86
87static void guess_palette(uint32_t *rgba_palette,
88 uint8_t *palette,
89 uint8_t *alpha,
90 uint32_t subtitle_color)
91{
92 uint8_t color_used[16];
93 int nb_opaque_colors, i, level, j, r, g, b;
94
95 for(i = 0; i < 4; i++)
96 rgba_palette[i] = 0;
97
98 memset(color_used, 0, 16);
99 nb_opaque_colors = 0;
100 for(i = 0; i < 4; i++) {
101 if (alpha[i] != 0 && !color_used[palette[i]]) {
102 color_used[palette[i]] = 1;
103 nb_opaque_colors++;
104 }
105 }
106
107 if (nb_opaque_colors == 0)
108 return;
109
110 j = nb_opaque_colors;
111 memset(color_used, 0, 16);
112 for(i = 0; i < 4; i++) {
113 if (alpha[i] != 0) {
114 if (!color_used[palette[i]]) {
115 level = (0xff * j) / nb_opaque_colors;
116 r = (((subtitle_color >> 16) & 0xff) * level) >> 8;
117 g = (((subtitle_color >> 8) & 0xff) * level) >> 8;
118 b = (((subtitle_color >> 0) & 0xff) * level) >> 8;
119 rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);
120 color_used[palette[i]] = (i + 1);
121 j--;
122 } else {
123 rgba_palette[i] = (rgba_palette[color_used[palette[i]] - 1] & 0x00ffffff) |
124 ((alpha[i] * 17) << 24);
125 }
126 }
127 }
128}
129
130static int decode_dvd_subtitles(AVSubtitle *sub_header,
131 const uint8_t *buf, int buf_size)
132{
133 int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;
134 uint8_t palette[4], alpha[4];
135 int date;
136 int i;
137 int is_menu = 0;
138
139 if (buf_size < 4)
140 return -1;
141 sub_header->rects = NULL;
142 sub_header->num_rects = 0;
143 sub_header->start_display_time = 0;
144 sub_header->end_display_time = 0;
145
146 cmd_pos = getbe16(buf + 2);
147 while ((cmd_pos + 4) < buf_size) {
148 date = getbe16(buf + cmd_pos);
149 next_cmd_pos = getbe16(buf + cmd_pos + 2);
150#ifdef DEBUG
151 av_log(NULL, AV_LOG_INFO, "cmd_pos=0x%04x next=0x%04x date=%d\n",
152 cmd_pos, next_cmd_pos, date);
153#endif
154 pos = cmd_pos + 4;
155 offset1 = -1;
156 offset2 = -1;
157 x1 = y1 = x2 = y2 = 0;
158 while (pos < buf_size) {
159 cmd = buf[pos++];
160#ifdef DEBUG
161 av_log(NULL, AV_LOG_INFO, "cmd=%02x\n", cmd);
162#endif
163 switch(cmd) {
164 case 0x00:
165 /* menu subpicture */
166 is_menu = 1;
167 break;
168 case 0x01:
169 /* set start date */
170 sub_header->start_display_time = (date << 10) / 90;
171 break;
172 case 0x02:
173 /* set end date */
174 sub_header->end_display_time = (date << 10) / 90;
175 break;
176 case 0x03:
177 /* set palette */
178 if ((buf_size - pos) < 2)
179 goto fail;
180 palette[3] = buf[pos] >> 4;
181 palette[2] = buf[pos] & 0x0f;
182 palette[1] = buf[pos + 1] >> 4;
183 palette[0] = buf[pos + 1] & 0x0f;
184 pos += 2;
185 break;
186 case 0x04:
187 /* set alpha */
188 if ((buf_size - pos) < 2)
189 goto fail;
190 alpha[3] = buf[pos] >> 4;
191 alpha[2] = buf[pos] & 0x0f;
192 alpha[1] = buf[pos + 1] >> 4;
193 alpha[0] = buf[pos + 1] & 0x0f;
194 pos += 2;
195#ifdef DEBUG
196 av_log(NULL, AV_LOG_INFO, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
197#endif
198 break;
199 case 0x05:
200 if ((buf_size - pos) < 6)
201 goto fail;
202 x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
203 x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
204 y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
205 y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
206#ifdef DEBUG
207 av_log(NULL, AV_LOG_INFO, "x1=%d x2=%d y1=%d y2=%d\n",
208 x1, x2, y1, y2);
209#endif
210 pos += 6;
211 break;
212 case 0x06:
213 if ((buf_size - pos) < 4)
214 goto fail;
215 offset1 = getbe16(buf + pos);
216 offset2 = getbe16(buf + pos + 2);
217#ifdef DEBUG
218 av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
219#endif
220 pos += 4;
221 break;
222 case 0xff:
223 default:
224 goto the_end;
225 }
226 }
227 the_end:
228 if (offset1 >= 0) {
229 int w, h;
230 uint8_t *bitmap;
231
232 /* decode the bitmap */
233 w = x2 - x1 + 1;
234 if (w < 0)
235 w = 0;
236 h = y2 - y1;
237 if (h < 0)
238 h = 0;
239 if (w > 0 && h > 0) {
240 if (sub_header->rects != NULL) {
241 for (i = 0; i < sub_header->num_rects; i++) {
242 av_free(sub_header->rects[i].bitmap);
243 av_free(sub_header->rects[i].rgba_palette);
244 }
245 av_freep(&sub_header->rects);
246 sub_header->num_rects = 0;
247 }
248
249 bitmap = av_malloc(w * h);
250 sub_header->rects = av_mallocz(sizeof(AVSubtitleRect));
251 sub_header->num_rects = 1;
252 sub_header->rects[0].rgba_palette = av_malloc(4 * 4);
253 decode_rle(bitmap, w * 2, w, h / 2,
254 buf, offset1 * 2, buf_size);
255 decode_rle(bitmap + w, w * 2, w, h / 2,
256 buf, offset2 * 2, buf_size);
257 guess_palette(sub_header->rects[0].rgba_palette,
258 palette, alpha, 0xffff00);
259 sub_header->rects[0].x = x1;
260 sub_header->rects[0].y = y1;
261 sub_header->rects[0].w = w;
262 sub_header->rects[0].h = h;
263 sub_header->rects[0].nb_colors = 4;
264 sub_header->rects[0].linesize = w;
265 sub_header->rects[0].bitmap = bitmap;
266 }
267 }
268 if (next_cmd_pos == cmd_pos)
269 break;
270 cmd_pos = next_cmd_pos;
271 }
272 if (sub_header->num_rects > 0)
273 return is_menu;
274 fail:
275 return -1;
276}
277
278static int is_transp(const uint8_t *buf, int pitch, int n,
279 const uint8_t *transp_color)
280{
281 int i;
282 for(i = 0; i < n; i++) {
283 if (!transp_color[*buf])
284 return 0;
285 buf += pitch;
286 }
287 return 1;
288}
289
290/* return 0 if empty rectangle, 1 if non empty */
291static int find_smallest_bounding_rectangle(AVSubtitle *s)
292{
293 uint8_t transp_color[256];
294 int y1, y2, x1, x2, y, w, h, i;
295 uint8_t *bitmap;
296
297 if (s->num_rects == 0 || s->rects == NULL || s->rects[0].w <= 0 || s->rects[0].h <= 0)
298 return 0;
299
300 memset(transp_color, 0, 256);
301 for(i = 0; i < s->rects[0].nb_colors; i++) {
302 if ((s->rects[0].rgba_palette[i] >> 24) == 0)
303 transp_color[i] = 1;
304 }
305 y1 = 0;
306 while (y1 < s->rects[0].h && is_transp(s->rects[0].bitmap + y1 * s->rects[0].linesize,
307 1, s->rects[0].w, transp_color))
308 y1++;
309 if (y1 == s->rects[0].h) {
310 av_freep(&s->rects[0].bitmap);
311 s->rects[0].w = s->rects[0].h = 0;
312 return 0;
313 }
314
315 y2 = s->rects[0].h - 1;
316 while (y2 > 0 && is_transp(s->rects[0].bitmap + y2 * s->rects[0].linesize, 1,
317 s->rects[0].w, transp_color))
318 y2--;
319 x1 = 0;
320 while (x1 < (s->rects[0].w - 1) && is_transp(s->rects[0].bitmap + x1, s->rects[0].linesize,
321 s->rects[0].h, transp_color))
322 x1++;
323 x2 = s->rects[0].w - 1;
324 while (x2 > 0 && is_transp(s->rects[0].bitmap + x2, s->rects[0].linesize, s->rects[0].h,
325 transp_color))
326 x2--;
327 w = x2 - x1 + 1;
328 h = y2 - y1 + 1;
329 bitmap = av_malloc(w * h);
330 if (!bitmap)
331 return 1;
332 for(y = 0; y < h; y++) {
333 memcpy(bitmap + w * y, s->rects[0].bitmap + x1 + (y1 + y) * s->rects[0].linesize, w);
334 }
335 av_freep(&s->rects[0].bitmap);
336 s->rects[0].bitmap = bitmap;
337 s->rects[0].linesize = w;
338 s->rects[0].w = w;
339 s->rects[0].h = h;
340 s->rects[0].x += x1;
341 s->rects[0].y += y1;
342 return 1;
343}
344
345static int dvdsub_close_decoder(AVCodecContext *avctx)
346{
347 return 0;
348}
349
350#ifdef DEBUG
351#undef fprintf
352static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
353 uint32_t *rgba_palette)
354{
355 int x, y, v;
356 FILE *f;
357
358 f = fopen(filename, "w");
359 if (!f) {
360 perror(filename);
361 exit(1);
362 }
363 fprintf(f, "P6\n"
364 "%d %d\n"
365 "%d\n",
366 w, h, 255);
367 for(y = 0; y < h; y++) {
368 for(x = 0; x < w; x++) {
369 v = rgba_palette[bitmap[y * w + x]];
370 putc((v >> 16) & 0xff, f);
371 putc((v >> 8) & 0xff, f);
372 putc((v >> 0) & 0xff, f);
373 }
374 }
375 fclose(f);
376}
377#endif
378
379static int dvdsub_decode(AVCodecContext *avctx,
380 void *data, int *data_size,
381 uint8_t *buf, int buf_size)
382{
383 AVSubtitle *sub = (void *)data;
384 int is_menu;
385
386 is_menu = decode_dvd_subtitles(sub, buf, buf_size);
387
388 if (is_menu < 0) {
389 no_subtitle:
390 *data_size = 0;
391
392 return buf_size;
393 }
394 if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
395 goto no_subtitle;
396
397#if defined(DEBUG)
398 av_log(NULL, AV_LOG_INFO, "start=%d ms end =%d ms\n",
399 sub->start_display_time,
400 sub->end_display_time);
401 ppm_save("/tmp/a.ppm", sub->rects[0].bitmap,
402 sub->rects[0].w, sub->rects[0].h, sub->rects[0].rgba_palette);
403#endif
404
405 *data_size = 1;
406 return buf_size;
407}
408
409AVCodec dvdsub_decoder = {
410 "dvdsub",
411 CODEC_TYPE_SUBTITLE,
412 CODEC_ID_DVD_SUBTITLE,
413 sizeof(DVDSubContext),
414 dvdsub_init_decoder,
415 NULL,
416 dvdsub_close_decoder,
417 dvdsub_decode,
418};
419
420/* parser definition */
421typedef struct DVDSubParseContext {
422 uint8_t *packet;
423 int packet_len;
424 int packet_index;
425} DVDSubParseContext;
426
427static int dvdsub_parse_init(AVCodecParserContext *s)
428{
429 return 0;
430}
431
432static int dvdsub_parse(AVCodecParserContext *s,
433 AVCodecContext *avctx,
434 uint8_t **poutbuf, int *poutbuf_size,
435 const uint8_t *buf, int buf_size)
436{
437 DVDSubParseContext *pc = s->priv_data;
438
439 if (pc->packet_index == 0) {
440 if (buf_size < 2)
441 return 0;
442 pc->packet_len = (buf[0] << 8) | buf[1];
443 av_freep(&pc->packet);
444 pc->packet = av_malloc(pc->packet_len);
445 }
446 if (pc->packet) {
447 if (pc->packet_index + buf_size <= pc->packet_len) {
448 memcpy(pc->packet + pc->packet_index, buf, buf_size);
449 pc->packet_index += buf_size;
450 if (pc->packet_index >= pc->packet_len) {
451 *poutbuf = pc->packet;
452 *poutbuf_size = pc->packet_len;
453 pc->packet_index = 0;
454 return buf_size;
455 }
456 } else {
457 /* erroneous size */
458 pc->packet_index = 0;
459 }
460 }
461 *poutbuf = NULL;
462 *poutbuf_size = 0;
463 return buf_size;
464}
465
466static void dvdsub_parse_close(AVCodecParserContext *s)
467{
468 DVDSubParseContext *pc = s->priv_data;
469 av_freep(&pc->packet);
470}
471
472AVCodecParser dvdsub_parser = {
473 { CODEC_ID_DVD_SUBTITLE },
474 sizeof(DVDSubParseContext),
475 dvdsub_parse_init,
476 dvdsub_parse,
477 dvdsub_parse_close,
478};
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