libavcodec/dvbsub.c

   1 /*
   2  * DVB subtitle encoding 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 "bytestream.h"
  23 #include "colorspace.h"
  24
  25 typedef struct DVBSubtitleContext {
  26     int hide_state;
  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
  41 static void dvb_encode_rle2(uint8_t **pq,
  42                             const uint8_t *bitmap, int linesize,
  43                             int w, int h)
  44 {
  45     uint8_t *q;
  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         *q++ = 0x10;
  54         bitbuf = 0;
  55         bitcnt = 6;
  56
  57         x = 0;
  58         while (x < w) {
  59             x1 = x;
  60             color = bitmap[x1++];
  61             while (x1 < w && bitmap[x1] == color)
  62                 x1++;
  63             len = x1 - x;
  64             if (color == 0 && len == 2) {
  65                 PUTBITS2(0);
  66                 PUTBITS2(0);
  67                 PUTBITS2(1);
  68             } else if (len >= 3 && len <= 10) {
  69                 v = len - 3;
  70                 PUTBITS2(0);
  71                 PUTBITS2((v >> 2) | 2);
  72                 PUTBITS2(v & 3);
  73                 PUTBITS2(color);
  74             } else if (len >= 12 && len <= 27) {
  75                 v = len - 12;
  76                 PUTBITS2(0);
  77                 PUTBITS2(0);
  78                 PUTBITS2(2);
  79                 PUTBITS2(v >> 2);
  80                 PUTBITS2(v & 3);
  81                 PUTBITS2(color);
  82             } else if (len >= 29) {
  83                 /* length = 29 ... 284 */
  84                 if (len > 284)
  85                     len = 284;
  86                 v = len - 29;
  87                 PUTBITS2(0);
  88                 PUTBITS2(0);
  89                 PUTBITS2(3);
  90                 PUTBITS2((v >> 6));
  91                 PUTBITS2((v >> 4) & 3);
  92                 PUTBITS2((v >> 2) & 3);
  93                 PUTBITS2(v & 3);
  94                 PUTBITS2(color);
  95             } else {
  96                 PUTBITS2(color);
  97                 if (color == 0) {
  98                     PUTBITS2(1);
  99                 }
 100                 len = 1;
 101             }
 102             x += len;
 103         }
 104         /* end of line */
 105         PUTBITS2(0);
 106         PUTBITS2(0);
 107         PUTBITS2(0);
 108         if (bitcnt != 6) {
 109             *q++ = bitbuf;
 110         }
 111         *q++ = 0xf0;
 112         bitmap += linesize;
 113     }
 114     *pq = q;
 115 }
 116
 117 #define PUTBITS4(val)\
 118 {\
 119     bitbuf |= (val) << bitcnt;\
 120     bitcnt -= 4;\
 121     if (bitcnt < 0) {\
 122         bitcnt = 4;\
 123         *q++ = bitbuf;\
 124         bitbuf = 0;\
 125     }\
 126 }
 127
 128 /* some DVB decoders only implement 4 bits/pixel */
 129 static void dvb_encode_rle4(uint8_t **pq,
 130                             const uint8_t *bitmap, int linesize,
 131                             int w, int h)
 132 {
 133     uint8_t *q;
 134     unsigned int bitbuf;
 135     int bitcnt;
 136     int x, y, len, x1, v, color;
 137
 138     q = *pq;
 139
 140     for(y = 0; y < h; y++) {
 141         *q++ = 0x11;
 142         bitbuf = 0;
 143         bitcnt = 4;
 144
 145         x = 0;
 146         while (x < w) {
 147             x1 = x;
 148             color = bitmap[x1++];
 149             while (x1 < w && bitmap[x1] == color)
 150                 x1++;
 151             len = x1 - x;
 152             if (color == 0 && len == 2) {
 153                 PUTBITS4(0);
 154                 PUTBITS4(0xd);
 155             } else if (color == 0 && (len >= 3 && len <= 9)) {
 156                 PUTBITS4(0);
 157                 PUTBITS4(len - 2);
 158             } else if (len >= 4 && len <= 7) {
 159                 PUTBITS4(0);
 160                 PUTBITS4(8 + len - 4);
 161                 PUTBITS4(color);
 162             } else if (len >= 9 && len <= 24) {
 163                 PUTBITS4(0);
 164                 PUTBITS4(0xe);
 165                 PUTBITS4(len - 9);
 166                 PUTBITS4(color);
 167             } else if (len >= 25) {
 168                 if (len > 280)
 169                     len = 280;
 170                 v = len - 25;
 171                 PUTBITS4(0);
 172                 PUTBITS4(0xf);
 173                 PUTBITS4(v >> 4);
 174                 PUTBITS4(v & 0xf);
 175                 PUTBITS4(color);
 176             } else {
 177                 PUTBITS4(color);
 178                 if (color == 0) {
 179                     PUTBITS4(0xc);
 180                 }
 181                 len = 1;
 182             }
 183             x += len;
 184         }
 185         /* end of line */
 186         PUTBITS4(0);
 187         PUTBITS4(0);
 188         if (bitcnt != 4) {
 189             *q++ = bitbuf;
 190         }
 191         *q++ = 0xf0;
 192         bitmap += linesize;
 193     }
 194     *pq = q;
 195 }
 196
 197 static int encode_dvb_subtitles(DVBSubtitleContext *s,
 198                                 uint8_t *outbuf, AVSubtitle *h)
 199 {
 200     uint8_t *q, *pseg_len;
 201     int page_id, region_id, clut_id, object_id, i, bpp_index, page_state;
 202
 203
 204     q = outbuf;
 205
 206     page_id = 1;
 207
 208     if (h->num_rects == 0 || h->rects == NULL)
 209         return -1;
 210
 211     *q++ = 0x00; /* subtitle_stream_id */
 212
 213     /* page composition segment */
 214
 215     *q++ = 0x0f; /* sync_byte */
 216     *q++ = 0x10; /* segment_type */
 217     bytestream_put_be16(&q, page_id);
 218     pseg_len = q;
 219     q += 2; /* segment length */
 220     *q++ = 30; /* page_timeout (seconds) */
 221     if (s->hide_state)
 222         page_state = 0; /* normal case */
 223     else
 224         page_state = 2; /* mode change */
 225     /* page_version = 0 + page_state */
 226     *q++ = s->object_version | (page_state << 2) | 3;
 227
 228     for (region_id = 0; region_id < h->num_rects; region_id++) {
 229         *q++ = region_id;
 230         *q++ = 0xff; /* reserved */
 231         bytestream_put_be16(&q, h->rects[region_id]->x); /* left pos */
 232         bytestream_put_be16(&q, h->rects[region_id]->y); /* top pos */
 233     }
 234
 235     bytestream_put_be16(&pseg_len, q - pseg_len - 2);
 236
 237     if (!s->hide_state) {
 238         for (clut_id = 0; clut_id < h->num_rects; clut_id++) {
 239
 240             /* CLUT segment */
 241
 242             if (h->rects[clut_id]->nb_colors <= 4) {
 243                 /* 2 bpp, some decoders do not support it correctly */
 244                 bpp_index = 0;
 245             } else if (h->rects[clut_id]->nb_colors <= 16) {
 246                 /* 4 bpp, standard encoding */
 247                 bpp_index = 1;
 248             } else {
 249                 return -1;
 250             }
 251
 252             *q++ = 0x0f; /* sync byte */
 253             *q++ = 0x12; /* CLUT definition segment */
 254             bytestream_put_be16(&q, page_id);
 255             pseg_len = q;
 256             q += 2; /* segment length */
 257             *q++ = clut_id;
 258             *q++ = (0 << 4) | 0xf; /* version = 0 */
 259
 260             for(i = 0; i < h->rects[clut_id]->nb_colors; i++) {
 261                 *q++ = i; /* clut_entry_id */
 262                 *q++ = (1 << (7 - bpp_index)) | (0xf << 1) | 1; /* 2 bits/pixel full range */
 263                 {
 264                     int a, r, g, b;
 265                     uint32_t x= ((uint32_t*)h->rects[clut_id]->pict.data[1])[i];
 266                     a = (x >> 24) & 0xff;
 267                     r = (x >> 16) & 0xff;
 268                     g = (x >>  8) & 0xff;
 269                     b = (x >>  0) & 0xff;
 270
 271                     *q++ = RGB_TO_Y_CCIR(r, g, b);
 272                     *q++ = RGB_TO_V_CCIR(r, g, b, 0);
 273                     *q++ = RGB_TO_U_CCIR(r, g, b, 0);
 274                     *q++ = 255 - a;
 275                 }
 276             }
 277
 278             bytestream_put_be16(&pseg_len, q - pseg_len - 2);
 279         }
 280     }
 281
 282     for (region_id = 0; region_id < h->num_rects; region_id++) {
 283
 284         /* region composition segment */
 285
 286         if (h->rects[region_id]->nb_colors <= 4) {
 287             /* 2 bpp, some decoders do not support it correctly */
 288             bpp_index = 0;
 289         } else if (h->rects[region_id]->nb_colors <= 16) {
 290             /* 4 bpp, standard encoding */
 291             bpp_index = 1;
 292         } else {
 293             return -1;
 294         }
 295
 296         *q++ = 0x0f; /* sync_byte */
 297         *q++ = 0x11; /* segment_type */
 298         bytestream_put_be16(&q, page_id);
 299         pseg_len = q;
 300         q += 2; /* segment length */
 301         *q++ = region_id;
 302         *q++ = (s->object_version << 4) | (0 << 3) | 0x07; /* version , no fill */
 303         bytestream_put_be16(&q, h->rects[region_id]->w); /* region width */
 304         bytestream_put_be16(&q, h->rects[region_id]->h); /* region height */
 305         *q++ = ((1 + bpp_index) << 5) | ((1 + bpp_index) << 2) | 0x03;
 306         *q++ = region_id; /* clut_id == region_id */
 307         *q++ = 0; /* 8 bit fill colors */
 308         *q++ = 0x03; /* 4 bit and 2 bit fill colors */
 309
 310         if (!s->hide_state) {
 311             bytestream_put_be16(&q, region_id); /* object_id == region_id */
 312             *q++ = (0 << 6) | (0 << 4);
 313             *q++ = 0;
 314             *q++ = 0xf0;
 315             *q++ = 0;
 316         }
 317
 318         bytestream_put_be16(&pseg_len, q - pseg_len - 2);
 319     }
 320
 321     if (!s->hide_state) {
 322
 323         for (object_id = 0; object_id < h->num_rects; object_id++) {
 324             /* Object Data segment */
 325
 326             if (h->rects[object_id]->nb_colors <= 4) {
 327                 /* 2 bpp, some decoders do not support it correctly */
 328                 bpp_index = 0;
 329             } else if (h->rects[object_id]->nb_colors <= 16) {
 330                 /* 4 bpp, standard encoding */
 331                 bpp_index = 1;
 332             } else {
 333                 return -1;
 334             }
 335
 336             *q++ = 0x0f; /* sync byte */
 337             *q++ = 0x13;
 338             bytestream_put_be16(&q, page_id);
 339             pseg_len = q;
 340             q += 2; /* segment length */
 341
 342             bytestream_put_be16(&q, object_id);
 343             *q++ = (s->object_version << 4) | (0 << 2) | (0 << 1) | 1; /* version = 0,
 344                                                                        onject_coding_method,
 345                                                                        non_modifying_color_flag */
 346             {
 347                 uint8_t *ptop_field_len, *pbottom_field_len, *top_ptr, *bottom_ptr;
 348                 void (*dvb_encode_rle)(uint8_t **pq,
 349                                         const uint8_t *bitmap, int linesize,
 350                                         int w, int h);
 351                 ptop_field_len = q;
 352                 q += 2;
 353                 pbottom_field_len = q;
 354                 q += 2;
 355
 356                 if (bpp_index == 0)
 357                     dvb_encode_rle = dvb_encode_rle2;
 358                 else
 359                     dvb_encode_rle = dvb_encode_rle4;
 360
 361                 top_ptr = q;
 362                 dvb_encode_rle(&q, h->rects[object_id]->pict.data[0], h->rects[object_id]->w * 2,
 363                                     h->rects[object_id]->w, h->rects[object_id]->h >> 1);
 364                 bottom_ptr = q;
 365                 dvb_encode_rle(&q, h->rects[object_id]->pict.data[0] + h->rects[object_id]->w,
 366                                     h->rects[object_id]->w * 2, h->rects[object_id]->w,
 367                                     h->rects[object_id]->h >> 1);
 368
 369                 bytestream_put_be16(&ptop_field_len, bottom_ptr - top_ptr);
 370                 bytestream_put_be16(&pbottom_field_len, q - bottom_ptr);
 371             }
 372
 373             bytestream_put_be16(&pseg_len, q - pseg_len - 2);
 374         }
 375     }
 376
 377     /* end of display set segment */
 378
 379     *q++ = 0x0f; /* sync_byte */
 380     *q++ = 0x80; /* segment_type */
 381     bytestream_put_be16(&q, page_id);
 382     pseg_len = q;
 383     q += 2; /* segment length */
 384
 385     bytestream_put_be16(&pseg_len, q - pseg_len - 2);
 386
 387     *q++ = 0xff; /* end of PES data */
 388
 389     s->object_version = (s->object_version + 1) & 0xf;
 390     s->hide_state = !s->hide_state;
 391     return q - outbuf;
 392 }
 393
 394 static int dvbsub_encode(AVCodecContext *avctx,
 395                        unsigned char *buf, int buf_size, void *data)
 396 {
 397     DVBSubtitleContext *s = avctx->priv_data;
 398     AVSubtitle *sub = data;
 399     int ret;
 400
 401     ret = encode_dvb_subtitles(s, buf, sub);
 402     return ret;
 403 }
 404
 405 AVCodec dvbsub_encoder = {
 406     "dvbsub",
 407     CODEC_TYPE_SUBTITLE,
 408     CODEC_ID_DVB_SUBTITLE,
 409     sizeof(DVBSubtitleContext),
 410     NULL,
 411     dvbsub_encode,
 412     .long_name = NULL_IF_CONFIG_SMALL("DVB subtitles"),
 413 };