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
  23 typedef struct DVBSubtitleContext {
  24     int hide_state;
  25     int object_version;
  26 } DVBSubtitleContext;
  27
  28 #define PUTBITS2(val)\
  29 {\
  30     bitbuf |= (val) << bitcnt;\
  31     bitcnt -= 2;\
  32     if (bitcnt < 0) {\
  33         bitcnt = 6;\
  34         *q++ = bitbuf;\
  35         bitbuf = 0;\
  36     }\
  37 }
  38
  39 static void dvb_encode_rle2(uint8_t **pq,
  40                             const uint8_t *bitmap, int linesize,
  41                             int w, int h)
  42 {
  43     uint8_t *q;
  44     unsigned int bitbuf;
  45     int bitcnt;
  46     int x, y, len, x1, v, color;
  47
  48     q = *pq;
  49
  50     for(y = 0; y < h; y++) {
  51         *q++ = 0x10;
  52         bitbuf = 0;
  53         bitcnt = 6;
  54
  55         x = 0;
  56         while (x < w) {
  57             x1 = x;
  58             color = bitmap[x1++];
  59             while (x1 < w && bitmap[x1] == color)
  60                 x1++;
  61             len = x1 - x;
  62             if (color == 0 && len == 2) {
  63                 PUTBITS2(0);
  64                 PUTBITS2(0);
  65                 PUTBITS2(1);
  66             } else if (len >= 3 && len <= 10) {
  67                 v = len - 3;
  68                 PUTBITS2(0);
  69                 PUTBITS2((v >> 2) | 2);
  70                 PUTBITS2(v & 3);
  71                 PUTBITS2(color);
  72             } else if (len >= 12 && len <= 27) {
  73                 v = len - 12;
  74                 PUTBITS2(0);
  75                 PUTBITS2(0);
  76                 PUTBITS2(2);
  77                 PUTBITS2(v >> 2);
  78                 PUTBITS2(v & 3);
  79                 PUTBITS2(color);
  80             } else if (len >= 29) {
  81                 /* length = 29 ... 284 */
  82                 if (len > 284)
  83                     len = 284;
  84                 v = len - 29;
  85                 PUTBITS2(0);
  86                 PUTBITS2(0);
  87                 PUTBITS2(3);
  88                 PUTBITS2((v >> 6));
  89                 PUTBITS2((v >> 4) & 3);
  90                 PUTBITS2((v >> 2) & 3);
  91                 PUTBITS2(v & 3);
  92                 PUTBITS2(color);
  93             } else {
  94                 PUTBITS2(color);
  95                 if (color == 0) {
  96                     PUTBITS2(1);
  97                 }
  98                 len = 1;
  99             }
 100             x += len;
 101         }
 102         /* end of line */
 103         PUTBITS2(0);
 104         PUTBITS2(0);
 105         PUTBITS2(0);
 106         if (bitcnt != 6) {
 107             *q++ = bitbuf;
 108         }
 109         *q++ = 0xf0;
 110         bitmap += linesize;
 111     }
 112     *pq = q;
 113 }
 114
 115 #define PUTBITS4(val)\
 116 {\
 117     bitbuf |= (val) << bitcnt;\
 118     bitcnt -= 4;\
 119     if (bitcnt < 0) {\
 120         bitcnt = 4;\
 121         *q++ = bitbuf;\
 122         bitbuf = 0;\
 123     }\
 124 }
 125
 126 /* some DVB decoders only implement 4 bits/pixel */
 127 static void dvb_encode_rle4(uint8_t **pq,
 128                             const uint8_t *bitmap, int linesize,
 129                             int w, int h)
 130 {
 131     uint8_t *q;
 132     unsigned int bitbuf;
 133     int bitcnt;
 134     int x, y, len, x1, v, color;
 135
 136     q = *pq;
 137
 138     for(y = 0; y < h; y++) {
 139         *q++ = 0x11;
 140         bitbuf = 0;
 141         bitcnt = 4;
 142
 143         x = 0;
 144         while (x < w) {
 145             x1 = x;
 146             color = bitmap[x1++];
 147             while (x1 < w && bitmap[x1] == color)
 148                 x1++;
 149             len = x1 - x;
 150             if (color == 0 && len == 2) {
 151                 PUTBITS4(0);
 152                 PUTBITS4(0xd);
 153             } else if (color == 0 && (len >= 3 && len <= 9)) {
 154                 PUTBITS4(0);
 155                 PUTBITS4(len - 2);
 156             } else if (len >= 4 && len <= 7) {
 157                 PUTBITS4(0);
 158                 PUTBITS4(8 + len - 4);
 159                 PUTBITS4(color);
 160             } else if (len >= 9 && len <= 24) {
 161                 PUTBITS4(0);
 162                 PUTBITS4(0xe);
 163                 PUTBITS4(len - 9);
 164                 PUTBITS4(color);
 165             } else if (len >= 25) {
 166                 if (len > 280)
 167                     len = 280;
 168                 v = len - 25;
 169                 PUTBITS4(0);
 170                 PUTBITS4(0xf);
 171                 PUTBITS4(v >> 4);
 172                 PUTBITS4(v & 0xf);
 173                 PUTBITS4(color);
 174             } else {
 175                 PUTBITS4(color);
 176                 if (color == 0) {
 177                     PUTBITS4(0xc);
 178                 }
 179                 len = 1;
 180             }
 181             x += len;
 182         }
 183         /* end of line */
 184         PUTBITS4(0);
 185         PUTBITS4(0);
 186         if (bitcnt != 4) {
 187             *q++ = bitbuf;
 188         }
 189         *q++ = 0xf0;
 190         bitmap += linesize;
 191     }
 192     *pq = q;
 193 }
 194
 195 #define SCALEBITS 10
 196 #define ONE_HALF  (1 << (SCALEBITS - 1))
 197 #define FIX(x)    ((int) ((x) * (1<<SCALEBITS) + 0.5))
 198
 199 #define RGB_TO_Y_CCIR(r, g, b) \
 200 ((FIX(0.29900*219.0/255.0) * (r) + FIX(0.58700*219.0/255.0) * (g) + \
 201   FIX(0.11400*219.0/255.0) * (b) + (ONE_HALF + (16 << SCALEBITS))) >> SCALEBITS)
 202
 203 #define RGB_TO_U_CCIR(r1, g1, b1, shift)\
 204 (((- FIX(0.16874*224.0/255.0) * r1 - FIX(0.33126*224.0/255.0) * g1 +         \
 205      FIX(0.50000*224.0/255.0) * b1 + (ONE_HALF << shift) - 1) >> (SCALEBITS + shift)) + 128)
 206
 207 #define RGB_TO_V_CCIR(r1, g1, b1, shift)\
 208 (((FIX(0.50000*224.0/255.0) * r1 - FIX(0.41869*224.0/255.0) * g1 -           \
 209    FIX(0.08131*224.0/255.0) * b1 + (ONE_HALF << shift) - 1) >> (SCALEBITS + shift)) + 128)
 210
 211 static inline void putbe16(uint8_t **pq, uint16_t v)
 212 {
 213     uint8_t *q;
 214     q = *pq;
 215     *q++ = v >> 8;
 216     *q++ = v;
 217     *pq = q;
 218 }
 219
 220 static int encode_dvb_subtitles(DVBSubtitleContext *s,
 221                                 uint8_t *outbuf, AVSubtitle *h)
 222 {
 223     uint8_t *q, *pseg_len;
 224     int page_id, region_id, clut_id, object_id, i, bpp_index, page_state;
 225
 226
 227     q = outbuf;
 228
 229     page_id = 1;
 230
 231     if (h->num_rects == 0 || h->rects == NULL)
 232         return -1;
 233
 234     *q++ = 0x00; /* subtitle_stream_id */
 235
 236     /* page composition segment */
 237
 238     *q++ = 0x0f; /* sync_byte */
 239     *q++ = 0x10; /* segment_type */
 240     putbe16(&q, page_id);
 241     pseg_len = q;
 242     q += 2; /* segment length */
 243     *q++ = 30; /* page_timeout (seconds) */
 244     if (s->hide_state)
 245         page_state = 0; /* normal case */
 246     else
 247         page_state = 2; /* mode change */
 248     /* page_version = 0 + page_state */
 249     *q++ = s->object_version | (page_state << 2) | 3;
 250
 251     for (region_id = 0; region_id < h->num_rects; region_id++) {
 252         *q++ = region_id;
 253         *q++ = 0xff; /* reserved */
 254         putbe16(&q, h->rects[region_id].x); /* left pos */
 255         putbe16(&q, h->rects[region_id].y); /* top pos */
 256     }
 257
 258     putbe16(&pseg_len, q - pseg_len - 2);
 259
 260     if (!s->hide_state) {
 261         for (clut_id = 0; clut_id < h->num_rects; clut_id++) {
 262
 263             /* CLUT segment */
 264
 265             if (h->rects[clut_id].nb_colors <= 4) {
 266                 /* 2 bpp, some decoders do not support it correctly */
 267                 bpp_index = 0;
 268             } else if (h->rects[clut_id].nb_colors <= 16) {
 269                 /* 4 bpp, standard encoding */
 270                 bpp_index = 1;
 271             } else {
 272                 return -1;
 273             }
 274
 275             *q++ = 0x0f; /* sync byte */
 276             *q++ = 0x12; /* CLUT definition segment */
 277             putbe16(&q, page_id);
 278             pseg_len = q;
 279             q += 2; /* segment length */
 280             *q++ = clut_id;
 281             *q++ = (0 << 4) | 0xf; /* version = 0 */
 282
 283             for(i = 0; i < h->rects[clut_id].nb_colors; i++) {
 284                 *q++ = i; /* clut_entry_id */
 285                 *q++ = (1 << (7 - bpp_index)) | (0xf << 1) | 1; /* 2 bits/pixel full range */
 286                 {
 287                     int a, r, g, b;
 288                     a = (h->rects[clut_id].rgba_palette[i] >> 24) & 0xff;
 289                     r = (h->rects[clut_id].rgba_palette[i] >> 16) & 0xff;
 290                     g = (h->rects[clut_id].rgba_palette[i] >> 8) & 0xff;
 291                     b = (h->rects[clut_id].rgba_palette[i] >> 0) & 0xff;
 292
 293                     *q++ = RGB_TO_Y_CCIR(r, g, b);
 294                     *q++ = RGB_TO_V_CCIR(r, g, b, 0);
 295                     *q++ = RGB_TO_U_CCIR(r, g, b, 0);
 296                     *q++ = 255 - a;
 297                 }
 298             }
 299
 300             putbe16(&pseg_len, q - pseg_len - 2);
 301         }
 302     }
 303
 304     for (region_id = 0; region_id < h->num_rects; region_id++) {
 305
 306         /* region composition segment */
 307
 308         if (h->rects[region_id].nb_colors <= 4) {
 309             /* 2 bpp, some decoders do not support it correctly */
 310             bpp_index = 0;
 311         } else if (h->rects[region_id].nb_colors <= 16) {
 312             /* 4 bpp, standard encoding */
 313             bpp_index = 1;
 314         } else {
 315             return -1;
 316         }
 317
 318         *q++ = 0x0f; /* sync_byte */
 319         *q++ = 0x11; /* segment_type */
 320         putbe16(&q, page_id);
 321         pseg_len = q;
 322         q += 2; /* segment length */
 323         *q++ = region_id;
 324         *q++ = (s->object_version << 4) | (0 << 3) | 0x07; /* version , no fill */
 325         putbe16(&q, h->rects[region_id].w); /* region width */
 326         putbe16(&q, h->rects[region_id].h); /* region height */
 327         *q++ = ((1 + bpp_index) << 5) | ((1 + bpp_index) << 2) | 0x03;
 328         *q++ = region_id; /* clut_id == region_id */
 329         *q++ = 0; /* 8 bit fill colors */
 330         *q++ = 0x03; /* 4 bit and 2 bit fill colors */
 331
 332         if (!s->hide_state) {
 333             putbe16(&q, region_id); /* object_id == region_id */
 334             *q++ = (0 << 6) | (0 << 4);
 335             *q++ = 0;
 336             *q++ = 0xf0;
 337             *q++ = 0;
 338         }
 339
 340         putbe16(&pseg_len, q - pseg_len - 2);
 341     }
 342
 343     if (!s->hide_state) {
 344
 345         for (object_id = 0; object_id < h->num_rects; object_id++) {
 346             /* Object Data segment */
 347
 348             if (h->rects[object_id].nb_colors <= 4) {
 349                 /* 2 bpp, some decoders do not support it correctly */
 350                 bpp_index = 0;
 351             } else if (h->rects[object_id].nb_colors <= 16) {
 352                 /* 4 bpp, standard encoding */
 353                 bpp_index = 1;
 354             } else {
 355                 return -1;
 356             }
 357
 358             *q++ = 0x0f; /* sync byte */
 359             *q++ = 0x13;
 360             putbe16(&q, page_id);
 361             pseg_len = q;
 362             q += 2; /* segment length */
 363
 364             putbe16(&q, object_id);
 365             *q++ = (s->object_version << 4) | (0 << 2) | (0 << 1) | 1; /* version = 0,
 366                                                                        onject_coding_method,
 367                                                                        non_modifying_color_flag */
 368             {
 369                 uint8_t *ptop_field_len, *pbottom_field_len, *top_ptr, *bottom_ptr;
 370                 void (*dvb_encode_rle)(uint8_t **pq,
 371                                         const uint8_t *bitmap, int linesize,
 372                                         int w, int h);
 373                 ptop_field_len = q;
 374                 q += 2;
 375                 pbottom_field_len = q;
 376                 q += 2;
 377
 378                 if (bpp_index == 0)
 379                     dvb_encode_rle = dvb_encode_rle2;
 380                 else
 381                     dvb_encode_rle = dvb_encode_rle4;
 382
 383                 top_ptr = q;
 384                 dvb_encode_rle(&q, h->rects[object_id].bitmap, h->rects[object_id].w * 2,
 385                                     h->rects[object_id].w, h->rects[object_id].h >> 1);
 386                 bottom_ptr = q;
 387                 dvb_encode_rle(&q, h->rects[object_id].bitmap + h->rects[object_id].w,
 388                                     h->rects[object_id].w * 2, h->rects[object_id].w,
 389                                     h->rects[object_id].h >> 1);
 390
 391                 putbe16(&ptop_field_len, bottom_ptr - top_ptr);
 392                 putbe16(&pbottom_field_len, q - bottom_ptr);
 393             }
 394
 395             putbe16(&pseg_len, q - pseg_len - 2);
 396         }
 397     }
 398
 399     /* end of display set segment */
 400
 401     *q++ = 0x0f; /* sync_byte */
 402     *q++ = 0x80; /* segment_type */
 403     putbe16(&q, page_id);
 404     pseg_len = q;
 405     q += 2; /* segment length */
 406
 407     putbe16(&pseg_len, q - pseg_len - 2);
 408
 409     *q++ = 0xff; /* end of PES data */
 410
 411     s->object_version = (s->object_version + 1) & 0xf;
 412     s->hide_state = !s->hide_state;
 413     return q - outbuf;
 414 }
 415
 416 static int dvbsub_init_decoder(AVCodecContext *avctx)
 417 {
 418     return 0;
 419 }
 420
 421 static int dvbsub_close_decoder(AVCodecContext *avctx)
 422 {
 423     return 0;
 424 }
 425
 426 static int dvbsub_encode(AVCodecContext *avctx,
 427                        unsigned char *buf, int buf_size, void *data)
 428 {
 429     DVBSubtitleContext *s = avctx->priv_data;
 430     AVSubtitle *sub = data;
 431     int ret;
 432
 433     ret = encode_dvb_subtitles(s, buf, sub);
 434     return ret;
 435 }
 436
 437 AVCodec dvbsub_encoder = {
 438     "dvbsub",
 439     CODEC_TYPE_SUBTITLE,
 440     CODEC_ID_DVB_SUBTITLE,
 441     sizeof(DVBSubtitleContext),
 442     dvbsub_init_decoder,
 443     dvbsub_encode,
 444     dvbsub_close_decoder,
 445 };