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