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                     a = (h->rects[clut_id].rgba_palette[i] >> 24) & 0xff;
 266                     r = (h->rects[clut_id].rgba_palette[i] >> 16) & 0xff;
 267                     g = (h->rects[clut_id].rgba_palette[i] >> 8) & 0xff;
 268                     b = (h->rects[clut_id].rgba_palette[i] >> 0) & 0xff;
 269
 270                     *q++ = RGB_TO_Y_CCIR(r, g, b);
 271                     *q++ = RGB_TO_V_CCIR(r, g, b, 0);
 272                     *q++ = RGB_TO_U_CCIR(r, g, b, 0);
 273                     *q++ = 255 - a;
 274                 }
 275             }
 276
 277             bytestream_put_be16(&pseg_len, q - pseg_len - 2);
 278         }
 279     }
 280
 281     for (region_id = 0; region_id < h->num_rects; region_id++) {
 282
 283         /* region composition segment */
 284
 285         if (h->rects[region_id].nb_colors <= 4) {
 286             /* 2 bpp, some decoders do not support it correctly */
 287             bpp_index = 0;
 288         } else if (h->rects[region_id].nb_colors <= 16) {
 289             /* 4 bpp, standard encoding */
 290             bpp_index = 1;
 291         } else {
 292             return -1;
 293         }
 294
 295         *q++ = 0x0f; /* sync_byte */
 296         *q++ = 0x11; /* segment_type */
 297         bytestream_put_be16(&q, page_id);
 298         pseg_len = q;
 299         q += 2; /* segment length */
 300         *q++ = region_id;
 301         *q++ = (s->object_version << 4) | (0 << 3) | 0x07; /* version , no fill */
 302         bytestream_put_be16(&q, h->rects[region_id].w); /* region width */
 303         bytestream_put_be16(&q, h->rects[region_id].h); /* region height */
 304         *q++ = ((1 + bpp_index) << 5) | ((1 + bpp_index) << 2) | 0x03;
 305         *q++ = region_id; /* clut_id == region_id */
 306         *q++ = 0; /* 8 bit fill colors */
 307         *q++ = 0x03; /* 4 bit and 2 bit fill colors */
 308
 309         if (!s->hide_state) {
 310             bytestream_put_be16(&q, region_id); /* object_id == region_id */
 311             *q++ = (0 << 6) | (0 << 4);
 312             *q++ = 0;
 313             *q++ = 0xf0;
 314             *q++ = 0;
 315         }
 316
 317         bytestream_put_be16(&pseg_len, q - pseg_len - 2);
 318     }
 319
 320     if (!s->hide_state) {
 321
 322         for (object_id = 0; object_id < h->num_rects; object_id++) {
 323             /* Object Data segment */
 324
 325             if (h->rects[object_id].nb_colors <= 4) {
 326                 /* 2 bpp, some decoders do not support it correctly */
 327                 bpp_index = 0;
 328             } else if (h->rects[object_id].nb_colors <= 16) {
 329                 /* 4 bpp, standard encoding */
 330                 bpp_index = 1;
 331             } else {
 332                 return -1;
 333             }
 334
 335             *q++ = 0x0f; /* sync byte */
 336             *q++ = 0x13;
 337             bytestream_put_be16(&q, page_id);
 338             pseg_len = q;
 339             q += 2; /* segment length */
 340
 341             bytestream_put_be16(&q, object_id);
 342             *q++ = (s->object_version << 4) | (0 << 2) | (0 << 1) | 1; /* version = 0,
 343                                                                        onject_coding_method,
 344                                                                        non_modifying_color_flag */
 345             {
 346                 uint8_t *ptop_field_len, *pbottom_field_len, *top_ptr, *bottom_ptr;
 347                 void (*dvb_encode_rle)(uint8_t **pq,
 348                                         const uint8_t *bitmap, int linesize,
 349                                         int w, int h);
 350                 ptop_field_len = q;
 351                 q += 2;
 352                 pbottom_field_len = q;
 353                 q += 2;
 354
 355                 if (bpp_index == 0)
 356                     dvb_encode_rle = dvb_encode_rle2;
 357                 else
 358                     dvb_encode_rle = dvb_encode_rle4;
 359
 360                 top_ptr = q;
 361                 dvb_encode_rle(&q, h->rects[object_id].bitmap, h->rects[object_id].w * 2,
 362                                     h->rects[object_id].w, h->rects[object_id].h >> 1);
 363                 bottom_ptr = q;
 364                 dvb_encode_rle(&q, h->rects[object_id].bitmap + h->rects[object_id].w,
 365                                     h->rects[object_id].w * 2, h->rects[object_id].w,
 366                                     h->rects[object_id].h >> 1);
 367
 368                 bytestream_put_be16(&ptop_field_len, bottom_ptr - top_ptr);
 369                 bytestream_put_be16(&pbottom_field_len, q - bottom_ptr);
 370             }
 371
 372             bytestream_put_be16(&pseg_len, q - pseg_len - 2);
 373         }
 374     }
 375
 376     /* end of display set segment */
 377
 378     *q++ = 0x0f; /* sync_byte */
 379     *q++ = 0x80; /* segment_type */
 380     bytestream_put_be16(&q, page_id);
 381     pseg_len = q;
 382     q += 2; /* segment length */
 383
 384     bytestream_put_be16(&pseg_len, q - pseg_len - 2);
 385
 386     *q++ = 0xff; /* end of PES data */
 387
 388     s->object_version = (s->object_version + 1) & 0xf;
 389     s->hide_state = !s->hide_state;
 390     return q - outbuf;
 391 }
 392
 393 static int dvbsub_encode(AVCodecContext *avctx,
 394                        unsigned char *buf, int buf_size, void *data)
 395 {
 396     DVBSubtitleContext *s = avctx->priv_data;
 397     AVSubtitle *sub = data;
 398     int ret;
 399
 400     ret = encode_dvb_subtitles(s, buf, sub);
 401     return ret;
 402 }
 403
 404 AVCodec dvbsub_encoder = {
 405     "dvbsub",
 406     CODEC_TYPE_SUBTITLE,
 407     CODEC_ID_DVB_SUBTITLE,
 408     sizeof(DVBSubtitleContext),
 409     NULL,
 410     dvbsub_encode,
 411     .long_name = NULL_IF_CONFIG_SMALL("DVB subtitles"),
 412 };