modules/codec/scte27.c

   1 /*****************************************************************************
   2  * scte27.c : SCTE-27 subtitles decoder
   3  *****************************************************************************
   4  * Copyright (C) Laurent Aimar
   5  * $Id$
   6  *
   7  * Authors: Laurent Aimar <fenrir _AT_ videolan _DOT_ org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software Foundation,
  21  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 #ifdef HAVE_CONFIG_H
  25 # include "config.h"
  26 #endif
  27
  28 #include <vlc_common.h>
  29 #include <vlc_plugin.h>
  30 #include <vlc_codec.h>
  31 #include <vlc_bits.h>
  32
  33 #include <assert.h>
  34
  35 /*****************************************************************************
  36  * Module descriptor.
  37  *****************************************************************************/
  38 static int  Open (vlc_object_t *);
  39 static void Close(vlc_object_t *);
  40
  41 vlc_module_begin ()
  42     set_description(N_("SCTE-27 decoder"))
  43     set_shortname(N_("SCTE-27"))
  44     set_capability( "decoder", 51)
  45     set_category(CAT_INPUT)
  46     set_subcategory(SUBCAT_INPUT_SCODEC)
  47     set_callbacks(Open, Close)
  48 vlc_module_end ()
  49
  50 /****************************************************************************
  51  * Local prototypes
  52  ****************************************************************************/
  53 struct decoder_sys_t {
  54     int     segment_id;
  55     int     segment_size;
  56     uint8_t *segment_buffer;
  57     mtime_t segment_date;
  58 };
  59
  60 typedef struct {
  61     uint8_t y, u, v;
  62     uint8_t alpha;
  63 } scte27_color_t;
  64
  65 static const scte27_color_t scte27_color_transparent = {
  66     .y     = 0x00,
  67     .u     = 0x80,
  68     .v     = 0x80,
  69     .alpha = 0x00,
  70 };
  71
  72 static scte27_color_t bs_read_color(bs_t *bs)
  73 {
  74     scte27_color_t color;
  75
  76     /* XXX it's unclear if a value of 0 in Y/U/V means a transparent pixel */
  77     color.y     = bs_read(bs, 5) << 3;
  78     color.alpha = bs_read1(bs) ? 0xff : 0x80;
  79     color.u     = bs_read(bs, 5) << 3;
  80     color.v     = bs_read(bs, 5) << 3;
  81
  82     return color;
  83 }
  84
  85 static inline void SetYUVPPixel(picture_t *picture, int x, int y, int value)
  86 {
  87     picture->p->p_pixels[y * picture->p->i_pitch + x] = value;
  88 }
  89
  90 static subpicture_region_t *DecodeSimpleBitmap(decoder_t *dec,
  91                                                const uint8_t *data, int size)
  92 {
  93     VLC_UNUSED(dec);
  94     /* Parse the bitmap and its properties */
  95     bs_t bs;
  96     bs_init(&bs, data, size);
  97
  98     bs_skip(&bs, 5);
  99     int is_framed = bs_read(&bs, 1);
 100     int outline_style = bs_read(&bs, 2);
 101     scte27_color_t character_color = bs_read_color(&bs);
 102     int top_h = bs_read(&bs, 12);
 103     int top_v = bs_read(&bs, 12);
 104     int bottom_h = bs_read(&bs, 12);
 105     int bottom_v = bs_read(&bs, 12);
 106     if (top_h >= bottom_h || top_v >= bottom_v)
 107         return NULL;
 108     int frame_top_h = top_h;
 109     int frame_top_v = top_v;
 110     int frame_bottom_h = bottom_h;
 111     int frame_bottom_v = bottom_v;
 112     scte27_color_t frame_color = scte27_color_transparent;
 113     if (is_framed) {
 114         frame_top_h = bs_read(&bs, 12);
 115         frame_top_v = bs_read(&bs, 12);
 116         frame_bottom_h = bs_read(&bs, 12);
 117         frame_bottom_v = bs_read(&bs, 12);
 118         frame_color = bs_read_color(&bs);
 119         if (frame_top_h > top_h ||
 120             frame_top_v > top_v ||
 121             frame_bottom_h < bottom_h ||
 122             frame_bottom_v < bottom_v)
 123             return NULL;
 124     }
 125     int outline_thickness = 0;
 126     scte27_color_t outline_color = scte27_color_transparent;
 127     int shadow_right = 0;
 128     int shadow_bottom = 0;
 129     scte27_color_t shadow_color = scte27_color_transparent;
 130     if (outline_style == 1) {
 131         bs_skip(&bs, 4);
 132         outline_thickness = bs_read(&bs, 4);
 133         outline_color = bs_read_color(&bs);
 134     } else if (outline_style == 2) {
 135         shadow_right = bs_read(&bs, 4);
 136         shadow_bottom = bs_read(&bs, 4);
 137         shadow_color = bs_read_color(&bs);
 138     } else if (outline_style == 3) {
 139         bs_skip(&bs, 24);
 140     }
 141     bs_skip(&bs, 16); // bitmap_compressed_length
 142     int bitmap_h = bottom_h - top_h;
 143     int bitmap_v = bottom_v - top_v;
 144     int bitmap_size = bitmap_h * bitmap_v;
 145     bool *bitmap = malloc(bitmap_size * sizeof(*bitmap));
 146     if (!bitmap)
 147         return NULL;
 148     for (int position = 0; position < bitmap_size;) {
 149         if (bs_eof(&bs)) {
 150             for (; position < bitmap_size; position++)
 151                 bitmap[position] = false;
 152             break;
 153         }
 154
 155         int run_on_length = 0;
 156         int run_off_length = 0;
 157         if (!bs_read1(&bs)) {
 158             if (!bs_read1(&bs)) {
 159                 if (!bs_read1(&bs)) {
 160                     if (bs_read(&bs, 2) == 1) {
 161                         int next = __MIN((position / bitmap_h + 1) * bitmap_h,
 162                                          bitmap_size);
 163                         for (; position < next; position++)
 164                             bitmap[position] = false;
 165                     }
 166                 } else {
 167                     run_on_length = 4;
 168                 }
 169             } else {
 170                 run_off_length = 6;
 171             }
 172         } else {
 173             run_on_length = 3;
 174             run_off_length = 5;
 175         }
 176
 177         if (run_on_length > 0) {
 178             int run = bs_read(&bs, run_on_length);
 179             if (!run)
 180                 run = 1 << run_on_length;
 181             for (; position < bitmap_size && run > 0; position++, run--)
 182                 bitmap[position] = true;
 183         }
 184         if (run_off_length > 0) {
 185             int run = bs_read(&bs, run_off_length);
 186             if (!run)
 187                 run = 1 << run_off_length;
 188             for (; position < bitmap_size && run > 0; position++, run--)
 189                 bitmap[position] = false;
 190         }
 191     }
 192
 193     /* Render the bitmap into a subpicture_region_t */
 194
 195     /* Reserve the place for the style
 196      * FIXME It's unclear if it is needed or if the bitmap should already include
 197      * the needed margin (I think the samples I have do both). */
 198     int margin_h = 0;
 199     int margin_v = 0;
 200     if (outline_style == 1) {
 201         margin_h =
 202         margin_v = outline_thickness;
 203     } else if (outline_style == 2) {
 204         margin_h = shadow_right;
 205         margin_v = shadow_bottom;
 206     }
 207     frame_top_h -= margin_h;
 208     frame_top_v -= margin_v;
 209     frame_bottom_h += margin_h;
 210     frame_bottom_v += margin_v;
 211
 212     const int frame_h = frame_bottom_h - frame_top_h;
 213     const int frame_v = frame_bottom_v - frame_top_v;
 214     const int bitmap_oh = top_h - frame_top_h;
 215     const int bitmap_ov = top_v - frame_top_v;
 216
 217     enum {
 218         COLOR_FRAME,
 219         COLOR_CHARACTER,
 220         COLOR_OUTLINE,
 221         COLOR_SHADOW,
 222     };
 223     video_palette_t palette = {
 224         .i_entries = 4,
 225         .palette = {
 226             [COLOR_FRAME] = {
 227                 frame_color.y,
 228                 frame_color.u,
 229                 frame_color.v,
 230                 frame_color.alpha
 231             },
 232             [COLOR_CHARACTER] = {
 233                 character_color.y,
 234                 character_color.u,
 235                 character_color.v,
 236                 character_color.alpha
 237             },
 238             [COLOR_OUTLINE] = {
 239                 outline_color.y,
 240                 outline_color.u,
 241                 outline_color.v,
 242                 outline_color.alpha
 243             },
 244             [COLOR_SHADOW] = {
 245                 shadow_color.y,
 246                 shadow_color.u,
 247                 shadow_color.v,
 248                 shadow_color.alpha
 249             },
 250         },
 251     };
 252     video_format_t fmt = {
 253         .i_chroma = VLC_CODEC_YUVP,
 254         .i_width = frame_h,
 255         .i_visible_width = frame_h,
 256         .i_height = frame_v,
 257         .i_visible_height = frame_v,
 258         .i_sar_num = 0, /* Use video AR */
 259         .i_sar_den = 1,
 260         .p_palette = &palette,
 261     };
 262     subpicture_region_t *r = subpicture_region_New(&fmt);
 263     if (!r) {
 264         free(bitmap);
 265         return NULL;
 266     }
 267     r->i_x = frame_top_h;
 268     r->i_y = frame_top_v;
 269
 270     /* Fill up with frame (background) color */
 271     for (int y = 0; y < frame_v; y++)
 272         memset(&r->p_picture->p->p_pixels[y * r->p_picture->p->i_pitch],
 273                COLOR_FRAME,
 274                frame_h);
 275
 276     /* Draw the outline/shadow if requested */
 277     if (outline_style == 1) {
 278         /* Draw an outline
 279          * XXX simple but slow and of low quality (no anti-aliasing) */
 280         bool circle[16][16];
 281         for (int dy = 0; dy <= 15; dy++) {
 282             for (int dx = 0; dx <= 15; dx++)
 283                 circle[dy][dx] = (dx > 0 || dy > 0) &&
 284                                  dx * dx + dy * dy <= outline_thickness * outline_thickness;
 285         }
 286         for (int by = 0; by < bitmap_v; by++) {
 287             for (int bx = 0; bx < bitmap_h; bx++) {
 288                 if (!bitmap[by * bitmap_h + bx])
 289                     continue;
 290                 for (int dy = 0; dy <= outline_thickness; dy++) {
 291                     for (int dx = 0; dx <= outline_thickness; dx++) {
 292                         if (circle[dy][dx]) {
 293                             SetYUVPPixel(r->p_picture,
 294                                          bx + bitmap_oh + dx, by + bitmap_ov + dy, COLOR_OUTLINE);
 295                             SetYUVPPixel(r->p_picture,
 296                                          bx + bitmap_oh - dx, by + bitmap_ov + dy, COLOR_OUTLINE);
 297                             SetYUVPPixel(r->p_picture,
 298                                          bx + bitmap_oh + dx, by + bitmap_ov - dy, COLOR_OUTLINE);
 299                             SetYUVPPixel(r->p_picture,
 300                                          bx + bitmap_oh - dx, by + bitmap_ov - dy, COLOR_OUTLINE);
 301                         }
 302                     }
 303                 }
 304             }
 305         }
 306     } else if (outline_style == 2) {
 307         /* Draw a shadow by drawing the character shifted by shaddow right/bottom */
 308         for (int by = 0; by < bitmap_v; by++) {
 309             for (int bx = 0; bx < bitmap_h; bx++) {
 310                 if (bitmap[by * bitmap_h + bx])
 311                     SetYUVPPixel(r->p_picture,
 312                                  bx + bitmap_oh + shadow_right,
 313                                  by + bitmap_ov + shadow_bottom,
 314                                  COLOR_SHADOW);
 315             }
 316         }
 317     }
 318
 319     /* Draw the character */
 320     for (int by = 0; by < bitmap_v; by++) {
 321         for (int bx = 0; bx < bitmap_h; bx++) {
 322             if (bitmap[by * bitmap_h + bx])
 323                 SetYUVPPixel(r->p_picture,
 324                              bx + bitmap_oh, by + bitmap_ov, COLOR_CHARACTER);
 325         }
 326     }
 327     free(bitmap);
 328     return r;
 329 }
 330
 331 static subpicture_t *DecodeSubtitleMessage(decoder_t *dec,
 332                                            const uint8_t *data, int size,
 333                                            mtime_t date)
 334 {
 335     if (size < 12)
 336         goto error;
 337
 338     /* Parse the header */
 339     bool pre_clear_display = data[3] & 0x80;
 340     int  display_standard = data[3] & 0x1f;
 341     int subtitle_type = data[8] >> 4;
 342     int display_duration = ((data[8] & 0x07) << 8) | data[9];
 343     int block_length = GetWBE(&data[10]);
 344
 345     size -= 12;
 346     data += 12;
 347
 348     if (block_length > size)
 349         goto error;
 350
 351     if (subtitle_type == 1) {
 352         subpicture_region_t *region = DecodeSimpleBitmap(dec, data, block_length);
 353         if (!region)
 354             goto error;
 355         subpicture_t *sub = decoder_NewSubpicture(dec, NULL);
 356         if (!sub) {
 357             subpicture_region_Delete(region);
 358             return NULL;
 359         }
 360         int frame_duration;
 361         switch (display_standard) {
 362         case 0:
 363             sub->i_original_picture_width  = 720;
 364             sub->i_original_picture_height = 480;
 365             frame_duration = 33367;
 366             break;
 367         case 1:
 368             sub->i_original_picture_width  = 720;
 369             sub->i_original_picture_height = 576;
 370             frame_duration = 40000;
 371             break;
 372         case 2:
 373             sub->i_original_picture_width  = 1280;
 374             sub->i_original_picture_height =  720;
 375             frame_duration = 16683;
 376             break;
 377         case 3:
 378             sub->i_original_picture_width  = 1920;
 379             sub->i_original_picture_height = 1080;
 380             frame_duration = 16683;
 381             break;
 382         default:
 383             msg_Warn(dec, "Unknown display standard");
 384             sub->i_original_picture_width  = 0;
 385             sub->i_original_picture_height = 0;
 386             frame_duration = 40000;
 387             break;
 388         }
 389         sub->b_absolute = true;
 390         if (!pre_clear_display)
 391             msg_Warn(dec, "SCTE-27 subtitles without pre_clear_display flag are not well supported");
 392         sub->b_ephemer = true;
 393         sub->i_start = date;
 394         sub->i_stop = date + display_duration * frame_duration;
 395         sub->p_region = region;
 396
 397         return sub;
 398     } else {
 399         /* Reserved */
 400         return NULL;
 401     }
 402
 403 error:
 404     msg_Err(dec, "corrupted subtitle_message");
 405     return NULL;
 406 }
 407
 408 static subpicture_t *Decode(decoder_t *dec, block_t **block)
 409 {
 410     decoder_sys_t *sys = dec->p_sys;
 411
 412     if (block == NULL || *block == NULL)
 413         return NULL;
 414     block_t *b = *block; *block = NULL;
 415
 416     subpicture_t *sub_first = NULL;
 417     subpicture_t **sub_last = &sub_first;
 418
 419     if (b->i_flags & (BLOCK_FLAG_CORRUPTED))
 420         goto exit;
 421
 422     while (b->i_buffer > 3) {
 423         const int table_id =  b->p_buffer[0];
 424         if (table_id != 0xc6) {
 425             //if (table_id != 0xff)
 426             //    msg_Err(dec, "Invalid SCTE-27 table id (0x%x)", table_id);
 427             break;
 428         }
 429         const int section_length = ((b->p_buffer[1] & 0xf) << 8) | b->p_buffer[2];
 430         if (section_length <= 1 + 4 || b->i_buffer < 3 + (unsigned)section_length) {
 431             msg_Err(dec, "Invalid SCTE-27 section length");
 432             break;
 433         }
 434         const int protocol_version = b->p_buffer[3] & 0x3f;
 435         if (protocol_version != 0) {
 436             msg_Err(dec, "Unsupported SCTE-27 protocol version (%d)", protocol_version);
 437             break;
 438         }
 439         const bool segmentation_overlay = b->p_buffer[3] & 0x40;
 440
 441         subpicture_t *sub = NULL;
 442         if (segmentation_overlay) {
 443             if (section_length < 1 + 5 + 4)
 444                 break;
 445             int id = GetWBE(&b->p_buffer[4]);
 446             int last = (b->p_buffer[6] << 4) | (b->p_buffer[7] >> 4);
 447             int index = ((b->p_buffer[7] & 0x0f) << 8) | b->p_buffer[8];
 448             if (index > last)
 449                 break;
 450             if (index == 0) {
 451                 sys->segment_id = id;
 452                 sys->segment_size = 0;
 453                 sys->segment_date = b->i_pts > VLC_TS_INVALID ? b->i_pts : b->i_dts;
 454             } else {
 455                 if (sys->segment_id != id || sys->segment_size <= 0) {
 456                     sys->segment_id = -1;
 457                     break;
 458                 }
 459             }
 460
 461             int segment_size = section_length - 1 - 5 - 4;
 462
 463             sys->segment_buffer = xrealloc(sys->segment_buffer,
 464                                            sys->segment_size + segment_size);
 465             memcpy(&sys->segment_buffer[sys->segment_size],
 466                    &b->p_buffer[9], segment_size);
 467             sys->segment_size += segment_size;
 468
 469             if (index == last) {
 470                 sub = DecodeSubtitleMessage(dec,
 471                                             sys->segment_buffer,
 472                                             sys->segment_size,
 473                                             sys->segment_date);
 474                 sys->segment_size = 0;
 475             }
 476         } else {
 477             sub = DecodeSubtitleMessage(dec,
 478                                         &b->p_buffer[4],
 479                                         section_length - 1 - 4,
 480                                         b->i_pts > VLC_TS_INVALID ? b->i_pts : b->i_dts);
 481         }
 482         *sub_last = sub;
 483         if (*sub_last)
 484             sub_last = &(*sub_last)->p_next;
 485
 486         b->i_buffer -= 3 + section_length;
 487         b->p_buffer += 3 + section_length;
 488         break;
 489     }
 490
 491 exit:
 492     block_Release(b);
 493     return sub_first;
 494 }
 495
 496 static int Open(vlc_object_t *object)
 497 {
 498     decoder_t *dec = (decoder_t *)object;
 499
 500     if (dec->fmt_in.i_codec != VLC_CODEC_SCTE_27)
 501         return VLC_EGENERIC;
 502
 503     decoder_sys_t *sys = dec->p_sys = malloc(sizeof(*sys));
 504     if (!sys)
 505         return VLC_ENOMEM;
 506     sys->segment_id = -1;
 507     sys->segment_size = 0;
 508     sys->segment_buffer = NULL;
 509
 510     dec->pf_decode_sub = Decode;
 511     es_format_Init(&dec->fmt_out, SPU_ES, VLC_CODEC_SPU);
 512     dec->fmt_out.video.i_chroma = VLC_CODEC_YUVP;
 513
 514     return VLC_SUCCESS;
 515 }
 516
 517 static void Close(vlc_object_t *object)
 518 {
 519     decoder_t *dec = (decoder_t *)object;
 520     decoder_sys_t *sys = dec->p_sys;
 521
 522     free(sys->segment_buffer);
 523     free(sys);
 524 }
 525