1 /*
2 * DVB subtitle encoding
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 "bytestream.h"
23 #include "libavutil/colorspace.h"
24
25 typedef struct DVBSubtitleContext {
26 int object_version;
27 } DVBSubtitleContext;
28
29 #define PUTBITS2(val)\
30 {\
31 bitbuf |= (val) << bitcnt;\
32 bitcnt -= 2;\
33 if (bitcnt < 0) {\
34 bitcnt = 6;\
35 *q++ = bitbuf;\
36 bitbuf = 0;\
37 }\
38 }
39
dvb_encode_rle2(uint8_t ** pq,int buf_size,const uint8_t * bitmap,int linesize,int w,int h)40 static int dvb_encode_rle2(uint8_t **pq, int buf_size,
41 const uint8_t *bitmap, int linesize,
42 int w, int h)
43 {
44 uint8_t *q, *line_begin;
45 unsigned int bitbuf;
46 int bitcnt;
47 int x, y, len, x1, v, color;
48
49 q = *pq;
50
51 for(y = 0; y < h; y++) {
52 // Worst case line is 3 bits per value + 4 bytes overhead
53 if (buf_size * 8 < w * 3 + 32)
54 return AVERROR_BUFFER_TOO_SMALL;
55 line_begin = q;
56 *q++ = 0x10;
57 bitbuf = 0;
58 bitcnt = 6;
59
60 x = 0;
61 while (x < w) {
62 x1 = x;
63 color = bitmap[x1++];
64 while (x1 < w && bitmap[x1] == color)
65 x1++;
66 len = x1 - x;
67 if (color == 0 && len == 2) {
68 PUTBITS2(0);
69 PUTBITS2(0);
70 PUTBITS2(1);
71 } else if (len >= 3 && len <= 10) {
72 v = len - 3;
73 PUTBITS2(0);
74 PUTBITS2((v >> 2) | 2);
75 PUTBITS2(v & 3);
76 PUTBITS2(color);
77 } else if (len >= 12 && len <= 27) {
78 v = len - 12;
79 PUTBITS2(0);
80 PUTBITS2(0);
81 PUTBITS2(2);
82 PUTBITS2(v >> 2);
83 PUTBITS2(v & 3);
84 PUTBITS2(color);
85 } else if (len >= 29) {
86 /* length = 29 ... 284 */
87 if (len > 284)
88 len = 284;
89 v = len - 29;
90 PUTBITS2(0);
91 PUTBITS2(0);
92 PUTBITS2(3);
93 PUTBITS2((v >> 6));
94 PUTBITS2((v >> 4) & 3);
95 PUTBITS2((v >> 2) & 3);
96 PUTBITS2(v & 3);
97 PUTBITS2(color);
98 } else {
99 PUTBITS2(color);
100 if (color == 0) {
101 PUTBITS2(1);
102 }
103 len = 1;
104 }
105 x += len;
106 }
107 /* end of line */
108 PUTBITS2(0);
109 PUTBITS2(0);
110 PUTBITS2(0);
111 if (bitcnt != 6) {
112 *q++ = bitbuf;
113 }
114 *q++ = 0xf0;
115 bitmap += linesize;
116 buf_size -= q - line_begin;
117 }
118 len = q - *pq;
119 *pq = q;
120 return len;
121 }
122
123 #define PUTBITS4(val)\
124 {\
125 bitbuf |= (val) << bitcnt;\
126 bitcnt -= 4;\
127 if (bitcnt < 0) {\
128 bitcnt = 4;\
129 *q++ = bitbuf;\
130 bitbuf = 0;\
131 }\
132 }
133
134 /* some DVB decoders only implement 4 bits/pixel */
dvb_encode_rle4(uint8_t ** pq,int buf_size,const uint8_t * bitmap,int linesize,int w,int h)135 static int dvb_encode_rle4(uint8_t **pq, int buf_size,
136 const uint8_t *bitmap, int linesize,
137 int w, int h)
138 {
139 uint8_t *q, *line_begin;
140 unsigned int bitbuf;
141 int bitcnt;
142 int x, y, len, x1, v, color;
143
144 q = *pq;
145
146 for(y = 0; y < h; y++) {
147 // Worst case line is 6 bits per value, + 4 bytes overhead
148 if (buf_size * 8 < w * 6 + 32)
149 return AVERROR_BUFFER_TOO_SMALL;
150 line_begin = q;
151 *q++ = 0x11;
152 bitbuf = 0;
153 bitcnt = 4;
154
155 x = 0;
156 while (x < w) {
157 x1 = x;
158 color = bitmap[x1++];
159 while (x1 < w && bitmap[x1] == color)
160 x1++;
161 len = x1 - x;
162 if (color == 0 && len == 2) {
163 PUTBITS4(0);
164 PUTBITS4(0xd);
165 } else if (color == 0 && (len >= 3 && len <= 9)) {
166 PUTBITS4(0);
167 PUTBITS4(len - 2);
168 } else if (len >= 4 && len <= 7) {
169 PUTBITS4(0);
170 PUTBITS4(8 + len - 4);
171 PUTBITS4(color);
172 } else if (len >= 9 && len <= 24) {
173 PUTBITS4(0);
174 PUTBITS4(0xe);
175 PUTBITS4(len - 9);
176 PUTBITS4(color);
177 } else if (len >= 25) {
178 if (len > 280)
179 len = 280;
180 v = len - 25;
181 PUTBITS4(0);
182 PUTBITS4(0xf);
183 PUTBITS4(v >> 4);
184 PUTBITS4(v & 0xf);
185 PUTBITS4(color);
186 } else {
187 PUTBITS4(color);
188 if (color == 0) {
189 PUTBITS4(0xc);
190 }
191 len = 1;
192 }
193 x += len;
194 }
195 /* end of line */
196 PUTBITS4(0);
197 PUTBITS4(0);
198 if (bitcnt != 4) {
199 *q++ = bitbuf;
200 }
201 *q++ = 0xf0;
202 bitmap += linesize;
203 buf_size -= q - line_begin;
204 }
205 len = q - *pq;
206 *pq = q;
207 return len;
208 }
209
dvb_encode_rle8(uint8_t ** pq,int buf_size,const uint8_t * bitmap,int linesize,int w,int h)210 static int dvb_encode_rle8(uint8_t **pq, int buf_size,
211 const uint8_t *bitmap, int linesize,
212 int w, int h)
213 {
214 uint8_t *q, *line_begin;
215 int x, y, len, x1, color;
216
217 q = *pq;
218
219 for (y = 0; y < h; y++) {
220 // Worst case line is 12 bits per value, + 3 bytes overhead
221 if (buf_size * 8 < w * 12 + 24)
222 return AVERROR_BUFFER_TOO_SMALL;
223 line_begin = q;
224 *q++ = 0x12;
225
226 x = 0;
227 while (x < w) {
228 x1 = x;
229 color = bitmap[x1++];
230 while (x1 < w && bitmap[x1] == color)
231 x1++;
232 len = x1 - x;
233 if (len == 1 && color) {
234 // 00000001 to 11111111 1 pixel in colour x
235 *q++ = color;
236 } else {
237 if (color == 0x00) {
238 // 00000000 0LLLLLLL L pixels (1-127) in colour 0 (L > 0)
239 len = FFMIN(len, 127);
240 *q++ = 0x00;
241 *q++ = len;
242 } else if (len > 2) {
243 // 00000000 1LLLLLLL CCCCCCCC L pixels (3-127) in colour C (L > 2)
244 len = FFMIN(len, 127);
245 *q++ = 0x00;
246 *q++ = 0x80+len;
247 *q++ = color;
248 }
249 else if (len == 2) {
250 *q++ = color;
251 *q++ = color;
252 } else {
253 *q++ = color;
254 len = 1;
255 }
256 }
257 x += len;
258 }
259 /* end of line */
260 // 00000000 end of 8-bit/pixel_code_string
261 *q++ = 0x00;
262 *q++ = 0xf0;
263 bitmap += linesize;
264 buf_size -= q - line_begin;
265 }
266 len = q - *pq;
267 *pq = q;
268 return len;
269 }
270
encode_dvb_subtitles(AVCodecContext * avctx,uint8_t * outbuf,int buf_size,const AVSubtitle * h)271 static int encode_dvb_subtitles(AVCodecContext *avctx,
272 uint8_t *outbuf, int buf_size,
273 const AVSubtitle *h)
274 {
275 DVBSubtitleContext *s = avctx->priv_data;
276 uint8_t *q, *pseg_len;
277 int page_id, region_id, clut_id, object_id, i, bpp_index, page_state;
278
279
280 q = outbuf;
281
282 page_id = 1;
283
284 if (h->num_rects && !h->rects)
285 return AVERROR(EINVAL);
286
287 if (avctx->width > 0 && avctx->height > 0) {
288 if (buf_size < 11)
289 return AVERROR_BUFFER_TOO_SMALL;
290 /* display definition segment */
291 *q++ = 0x0f; /* sync_byte */
292 *q++ = 0x14; /* segment_type */
293 bytestream_put_be16(&q, page_id);
294 pseg_len = q;
295 q += 2; /* segment length */
296 *q++ = 0x00; /* dds version number & display window flag */
297 bytestream_put_be16(&q, avctx->width - 1); /* display width */
298 bytestream_put_be16(&q, avctx->height - 1); /* display height */
299 bytestream_put_be16(&pseg_len, q - pseg_len - 2);
300 buf_size -= 11;
301 }
302
303 /* page composition segment */
304
305 if (buf_size < 8 + h->num_rects * 6)
306 return AVERROR_BUFFER_TOO_SMALL;
307 *q++ = 0x0f; /* sync_byte */
308 *q++ = 0x10; /* segment_type */
309 bytestream_put_be16(&q, page_id);
310 pseg_len = q;
311 q += 2; /* segment length */
312 *q++ = 30; /* page_timeout (seconds) */
313 page_state = 2; /* mode change */
314 /* page_version = 0 + page_state */
315 *q++ = (s->object_version << 4) | (page_state << 2) | 3;
316
317 for (region_id = 0; region_id < h->num_rects; region_id++) {
318 *q++ = region_id;
319 *q++ = 0xff; /* reserved */
320 bytestream_put_be16(&q, h->rects[region_id]->x); /* left pos */
321 bytestream_put_be16(&q, h->rects[region_id]->y); /* top pos */
322 }
323
324 bytestream_put_be16(&pseg_len, q - pseg_len - 2);
325 buf_size -= 8 + h->num_rects * 6;
326
327 if (h->num_rects) {
328 for (clut_id = 0; clut_id < h->num_rects; clut_id++) {
329 if (buf_size < 6 + h->rects[clut_id]->nb_colors * 6)
330 return AVERROR_BUFFER_TOO_SMALL;
331
332 /* CLUT segment */
333
334 if (h->rects[clut_id]->nb_colors <= 4) {
335 /* 2 bpp, some decoders do not support it correctly */
336 bpp_index = 0;
337 } else if (h->rects[clut_id]->nb_colors <= 16) {
338 /* 4 bpp, standard encoding */
339 bpp_index = 1;
340 } else if (h->rects[clut_id]->nb_colors <= 256) {
341 /* 8 bpp, standard encoding */
342 bpp_index = 2;
343 } else {
344 return AVERROR(EINVAL);
345 }
346
347
348 /* CLUT segment */
349 *q++ = 0x0f; /* sync byte */
350 *q++ = 0x12; /* CLUT definition segment */
351 bytestream_put_be16(&q, page_id);
352 pseg_len = q;
353 q += 2; /* segment length */
354 *q++ = clut_id;
355 *q++ = (0 << 4) | 0xf; /* version = 0 */
356
357 for(i = 0; i < h->rects[clut_id]->nb_colors; i++) {
358 *q++ = i; /* clut_entry_id */
359 *q++ = (1 << (7 - bpp_index)) | (0xf << 1) | 1; /* 2 bits/pixel full range */
360 {
361 int a, r, g, b;
362 uint32_t x= ((uint32_t*)h->rects[clut_id]->data[1])[i];
363 a = (x >> 24) & 0xff;
364 r = (x >> 16) & 0xff;
365 g = (x >> 8) & 0xff;
366 b = (x >> 0) & 0xff;
367
368 *q++ = RGB_TO_Y_CCIR(r, g, b);
369 *q++ = RGB_TO_V_CCIR(r, g, b, 0);
370 *q++ = RGB_TO_U_CCIR(r, g, b, 0);
371 *q++ = 255 - a;
372 }
373 }
374
375 bytestream_put_be16(&pseg_len, q - pseg_len - 2);
376 buf_size -= 6 + h->rects[clut_id]->nb_colors * 6;
377 }
378 }
379
380 if (buf_size < h->num_rects * 22)
381 return AVERROR_BUFFER_TOO_SMALL;
382 for (region_id = 0; region_id < h->num_rects; region_id++) {
383
384 /* region composition segment */
385
386 if (h->rects[region_id]->nb_colors <= 4) {
387 /* 2 bpp, some decoders do not support it correctly */
388 bpp_index = 0;
389 } else if (h->rects[region_id]->nb_colors <= 16) {
390 /* 4 bpp, standard encoding */
391 bpp_index = 1;
392 } else if (h->rects[region_id]->nb_colors <= 256) {
393 /* 8 bpp, standard encoding */
394 bpp_index = 2;
395 } else {
396 return AVERROR(EINVAL);
397 }
398
399 *q++ = 0x0f; /* sync_byte */
400 *q++ = 0x11; /* segment_type */
401 bytestream_put_be16(&q, page_id);
402 pseg_len = q;
403 q += 2; /* segment length */
404 *q++ = region_id;
405 *q++ = (s->object_version << 4) | (0 << 3) | 0x07; /* version , no fill */
406 bytestream_put_be16(&q, h->rects[region_id]->w); /* region width */
407 bytestream_put_be16(&q, h->rects[region_id]->h); /* region height */
408 *q++ = ((1 + bpp_index) << 5) | ((1 + bpp_index) << 2) | 0x03;
409 *q++ = region_id; /* clut_id == region_id */
410 *q++ = 0; /* 8 bit fill colors */
411 *q++ = 0x03; /* 4 bit and 2 bit fill colors */
412
413 bytestream_put_be16(&q, region_id); /* object_id == region_id */
414 *q++ = (0 << 6) | (0 << 4);
415 *q++ = 0;
416 *q++ = 0xf0;
417 *q++ = 0;
418
419 bytestream_put_be16(&pseg_len, q - pseg_len - 2);
420 }
421 buf_size -= h->num_rects * 22;
422
423 if (h->num_rects) {
424
425 for (object_id = 0; object_id < h->num_rects; object_id++) {
426 int (*dvb_encode_rle)(uint8_t **pq, int buf_size,
427 const uint8_t *bitmap, int linesize,
428 int w, int h);
429
430 if (buf_size < 13)
431 return AVERROR_BUFFER_TOO_SMALL;
432
433 /* bpp_index maths */
434 if (h->rects[object_id]->nb_colors <= 4) {
435 /* 2 bpp, some decoders do not support it correctly */
436 dvb_encode_rle = dvb_encode_rle2;
437 } else if (h->rects[object_id]->nb_colors <= 16) {
438 /* 4 bpp, standard encoding */
439 dvb_encode_rle = dvb_encode_rle4;
440 } else if (h->rects[object_id]->nb_colors <= 256) {
441 /* 8 bpp, standard encoding */
442 dvb_encode_rle = dvb_encode_rle8;
443 } else {
444 return AVERROR(EINVAL);
445 }
446
447 /* Object Data segment */
448 *q++ = 0x0f; /* sync byte */
449 *q++ = 0x13;
450 bytestream_put_be16(&q, page_id);
451 pseg_len = q;
452 q += 2; /* segment length */
453
454 bytestream_put_be16(&q, object_id);
455 *q++ = (s->object_version << 4) | (0 << 2) | (0 << 1) | 1; /* version = 0,
456 onject_coding_method,
457 non_modifying_color_flag */
458 {
459 uint8_t *ptop_field_len, *pbottom_field_len, *top_ptr, *bottom_ptr;
460 int ret;
461
462 ptop_field_len = q;
463 q += 2;
464 pbottom_field_len = q;
465 q += 2;
466 buf_size -= 13;
467
468 top_ptr = q;
469 ret = dvb_encode_rle(&q, buf_size,
470 h->rects[object_id]->data[0],
471 h->rects[object_id]->w * 2,
472 h->rects[object_id]->w,
473 h->rects[object_id]->h >> 1);
474 if (ret < 0)
475 return ret;
476 buf_size -= ret;
477 bottom_ptr = q;
478 ret = dvb_encode_rle(&q, buf_size,
479 h->rects[object_id]->data[0] + h->rects[object_id]->w,
480 h->rects[object_id]->w * 2,
481 h->rects[object_id]->w,
482 h->rects[object_id]->h >> 1);
483 if (ret < 0)
484 return ret;
485 buf_size -= ret;
486
487 bytestream_put_be16(&ptop_field_len, bottom_ptr - top_ptr);
488 bytestream_put_be16(&pbottom_field_len, q - bottom_ptr);
489 }
490
491 bytestream_put_be16(&pseg_len, q - pseg_len - 2);
492 }
493 }
494
495 /* end of display set segment */
496
497 if (buf_size < 6)
498 return AVERROR_BUFFER_TOO_SMALL;
499 *q++ = 0x0f; /* sync_byte */
500 *q++ = 0x80; /* segment_type */
501 bytestream_put_be16(&q, page_id);
502 pseg_len = q;
503 q += 2; /* segment length */
504
505 bytestream_put_be16(&pseg_len, q - pseg_len - 2);
506 buf_size -= 6;
507
508 s->object_version = (s->object_version + 1) & 0xf;
509 return q - outbuf;
510 }
511
dvbsub_encode(AVCodecContext * avctx,unsigned char * buf,int buf_size,const AVSubtitle * sub)512 static int dvbsub_encode(AVCodecContext *avctx,
513 unsigned char *buf, int buf_size,
514 const AVSubtitle *sub)
515 {
516 int ret;
517
518 ret = encode_dvb_subtitles(avctx, buf, buf_size, sub);
519 return ret;
520 }
521
522 AVCodec ff_dvbsub_encoder = {
523 .name = "dvbsub",
524 .long_name = NULL_IF_CONFIG_SMALL("DVB subtitles"),
525 .type = AVMEDIA_TYPE_SUBTITLE,
526 .id = AV_CODEC_ID_DVB_SUBTITLE,
527 .priv_data_size = sizeof(DVBSubtitleContext),
528 .encode_sub = dvbsub_encode,
529 };
530