modules/codec/cvdsub.c

   1 /*****************************************************************************
   2  * cvd.c : CVD Subtitle decoder
   3  *****************************************************************************
   4  * Copyright (C) 2003, 2004 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Rocky Bernstein
   8  *          Gildas Bazin <gbazin@videolan.org>
   9  *          Julio Sanchez Fernandez (http://subhandler.sourceforge.net)
  10  *          Laurent Aimar <fenrir@via.ecp.fr>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  25  *****************************************************************************/
  26
  27 /*****************************************************************************
  28  * Preamble
  29  *****************************************************************************/
  30 #ifdef HAVE_CONFIG_H
  31 # include "config.h"
  32 #endif
  33
  34 #include <vlc_common.h>
  35 #include <vlc_plugin.h>
  36 #include <vlc_vout.h>
  37 #include <vlc_codec.h>
  38
  39 #include "vlc_bits.h"
  40
  41 #define DEBUG_CVDSUB 1
  42
  43 /*****************************************************************************
  44  * Module descriptor.
  45  *****************************************************************************/
  46 static int  DecoderOpen   ( vlc_object_t * );
  47 static int  PacketizerOpen( vlc_object_t * );
  48 static void DecoderClose  ( vlc_object_t * );
  49
  50 vlc_module_begin ()
  51     set_description( N_("CVD subtitle decoder") )
  52     set_capability( "decoder", 50 )
  53     set_callbacks( DecoderOpen, DecoderClose )
  54
  55     add_submodule ()
  56     set_description( N_("Chaoji VCD subtitle packetizer") )
  57     set_capability( "packetizer", 50 )
  58     set_callbacks( PacketizerOpen, DecoderClose )
  59 vlc_module_end ()
  60
  61 /*****************************************************************************
  62  * Local prototypes
  63  *****************************************************************************/
  64 static subpicture_t *Decode( decoder_t *, block_t ** );
  65 static block_t *Packetize  ( decoder_t *, block_t ** );
  66 static block_t *Reassemble ( decoder_t *, block_t * );
  67 static void ParseMetaInfo  ( decoder_t *, block_t * );
  68 static void ParseHeader    ( decoder_t *, block_t * );
  69 static subpicture_t *DecodePacket( decoder_t *, block_t * );
  70 static void RenderImage( decoder_t *, block_t *, subpicture_region_t * );
  71
  72 #define SUBTITLE_BLOCK_EMPTY 0
  73 #define SUBTITLE_BLOCK_PARTIAL 1
  74 #define SUBTITLE_BLOCK_COMPLETE 2
  75
  76 struct decoder_sys_t
  77 {
  78   int      b_packetizer;
  79
  80   int      i_state;    /* data-gathering state for this subtitle */
  81
  82   block_t  *p_spu;   /* Bytes of the packet. */
  83
  84   size_t   i_spu_size;     /* goal for subtitle_data_pos while gathering,
  85                              size of used subtitle_data later */
  86
  87   uint16_t i_image_offset;      /* offset from subtitle_data to compressed
  88                                    image data */
  89   size_t i_image_length;           /* size of the compressed image data */
  90   size_t first_field_offset;       /* offset of even raster lines */
  91   size_t second_field_offset;      /* offset of odd raster lines */
  92   size_t metadata_offset;          /* offset to data describing the image */
  93   size_t metadata_length;          /* length of metadata */
  94
  95   mtime_t i_duration;   /* how long to display the image, 0 stands
  96                            for "until next subtitle" */
  97
  98   uint16_t i_x_start, i_y_start; /* position of top leftmost pixel of
  99                                     image when displayed */
 100   uint16_t i_width, i_height;    /* dimensions in pixels of image */
 101
 102   uint8_t p_palette[4][4];       /* Palette of colors used in subtitle */
 103   uint8_t p_palette_highlight[4][4];
 104 };
 105
 106 /*****************************************************************************
 107  * DecoderOpen: open/initialize the cvdsub decoder.
 108  *****************************************************************************/
 109 static int DecoderOpen( vlc_object_t *p_this )
 110 {
 111     decoder_t     *p_dec = (decoder_t*)p_this;
 112     decoder_sys_t *p_sys;
 113
 114     if( p_dec->fmt_in.i_codec != VLC_FOURCC( 'c','v','d',' ' ) )
 115     {
 116         return VLC_EGENERIC;
 117     }
 118
 119     p_dec->p_sys = p_sys = malloc( sizeof( decoder_sys_t ) );
 120     if( !p_sys )
 121         return VLC_ENOMEM;
 122
 123     p_sys->b_packetizer  = false;
 124
 125     p_sys->i_state = SUBTITLE_BLOCK_EMPTY;
 126     p_sys->p_spu   = NULL;
 127
 128     es_format_Init( &p_dec->fmt_out, SPU_ES, VLC_FOURCC( 'c','v','d',' ' ) );
 129
 130     p_dec->pf_decode_sub = Decode;
 131     p_dec->pf_packetize  = Packetize;
 132
 133     return VLC_SUCCESS;
 134 }
 135
 136 /*****************************************************************************
 137  * PacketizerOpen: open/initialize the cvdsub packetizer.
 138  *****************************************************************************/
 139 static int PacketizerOpen( vlc_object_t *p_this )
 140 {
 141     decoder_t *p_dec = (decoder_t*)p_this;
 142
 143     if( DecoderOpen( p_this ) != VLC_SUCCESS ) return VLC_EGENERIC;
 144
 145     p_dec->p_sys->b_packetizer = true;
 146
 147     return VLC_SUCCESS;
 148 }
 149
 150 /*****************************************************************************
 151  * DecoderClose: closes the cvdsub decoder/packetizer.
 152  *****************************************************************************/
 153 void DecoderClose( vlc_object_t *p_this )
 154 {
 155     decoder_t     *p_dec = (decoder_t*)p_this;
 156     decoder_sys_t *p_sys = p_dec->p_sys;
 157
 158     if( p_sys->p_spu ) block_ChainRelease( p_sys->p_spu );
 159     free( p_sys );
 160 }
 161
 162 /*****************************************************************************
 163  * Decode:
 164  *****************************************************************************/
 165 static subpicture_t *Decode( decoder_t *p_dec, block_t **pp_block )
 166 {
 167     block_t *p_block, *p_spu;
 168
 169     if( pp_block == NULL || *pp_block == NULL ) return NULL;
 170
 171     p_block = *pp_block;
 172     *pp_block = NULL;
 173
 174     if( !(p_spu = Reassemble( p_dec, p_block )) ) return NULL;
 175
 176     /* Parse and decode */
 177     return DecodePacket( p_dec, p_spu );
 178 }
 179
 180 /*****************************************************************************
 181  * Packetize:
 182  *****************************************************************************/
 183 static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
 184 {
 185     block_t *p_block, *p_spu;
 186
 187     if( pp_block == NULL || *pp_block == NULL ) return NULL;
 188
 189     p_block = *pp_block;
 190     *pp_block = NULL;
 191
 192     if( !(p_spu = Reassemble( p_dec, p_block )) ) return NULL;
 193
 194     p_spu->i_dts = p_spu->i_pts;
 195     p_spu->i_length = 0;
 196
 197     return p_spu;
 198 }
 199
 200
 201 /*****************************************************************************
 202  Reassemble:
 203
 204  Data for single screen subtitle may come in several non-contiguous
 205  packets of a stream. This routine is called when the next packet in
 206  the stream comes in. The job of this routine is to parse the header,
 207  if this is the beginning, and combine the packets into one complete
 208  subtitle unit.
 209
 210  If everything is complete, we will return a block. Otherwise return
 211  NULL.
 212
 213  *****************************************************************************/
 214 #define SPU_HEADER_LEN 1
 215
 216 static block_t *Reassemble( decoder_t *p_dec, block_t *p_block )
 217 {
 218     decoder_sys_t *p_sys = p_dec->p_sys;
 219     uint8_t *p_buffer;
 220
 221     if( p_block->i_buffer < SPU_HEADER_LEN )
 222     {
 223         msg_Dbg( p_dec, "invalid packet header (size %zu < %u)" ,
 224                  p_block->i_buffer, SPU_HEADER_LEN );
 225         block_Release( p_block );
 226         return NULL;
 227     }
 228
 229     p_buffer = p_block->p_buffer;
 230
 231     /* From the scant data on the format, there is only only way known
 232      * to detect the first packet in a subtitle.  The first packet
 233      * seems to have a valid PTS while later packets for the same
 234      * image don't. */
 235     if( p_sys->i_state == SUBTITLE_BLOCK_EMPTY && p_block->i_pts == 0 )
 236     {
 237         msg_Warn( p_dec, "first packet expected but no PTS present");
 238         return NULL;
 239     }
 240
 241     p_block->p_buffer += SPU_HEADER_LEN;
 242     p_block->i_buffer -= SPU_HEADER_LEN;
 243
 244     /* First packet in the subtitle block */
 245     if( p_sys->i_state == SUBTITLE_BLOCK_EMPTY ) ParseHeader( p_dec, p_block );
 246
 247     block_ChainAppend( &p_sys->p_spu, p_block );
 248     p_sys->p_spu = block_ChainGather( p_sys->p_spu );
 249
 250     if( p_sys->p_spu->i_buffer >= p_sys->i_spu_size )
 251     {
 252         block_t *p_spu = p_sys->p_spu;
 253
 254         if( p_spu->i_buffer != p_sys->i_spu_size )
 255         {
 256             msg_Warn( p_dec, "SPU packets size=%zu should be %zu",
 257                       p_spu->i_buffer, p_sys->i_spu_size );
 258         }
 259
 260         msg_Dbg( p_dec, "subtitle packet complete, size=%zuu", p_spu->i_buffer);
 261
 262         ParseMetaInfo( p_dec, p_spu );
 263
 264         p_sys->i_state = SUBTITLE_BLOCK_EMPTY;
 265         p_sys->p_spu = 0;
 266         return p_spu;
 267     }
 268     else
 269     {
 270         /* Not last block in subtitle, so wait for another. */
 271         p_sys->i_state = SUBTITLE_BLOCK_PARTIAL;
 272     }
 273
 274     return NULL;
 275 }
 276
 277 /*
 278   We do not have information on the subtitle format used on CVD's
 279   except the submux sample code and a couple of samples of dubious
 280   origin. Thus, this is the result of reading some code whose
 281   correctness is not known and some experimentation.
 282
 283   CVD subtitles are different in several ways from SVCD OGT subtitles.
 284   Image comes first and metadata is at the end.  So that the metadata
 285   can be found easily, the subtitle packet starts with two bytes
 286   (everything is big-endian again) that give the total size of the
 287   subtitle data and the offset to the metadata - i.e. size of the
 288   image data plus the four bytes at the beginning.
 289
 290   Image data comes interlaced is run-length encoded.  Each field is a
 291   four-bit nibble. Each nibble contains a two-bit repeat count and a
 292   two-bit color number so that up to three pixels can be described in
 293   four bits.  The function of a 0 repeat count is unknown; it might be
 294   used for RLE extension.  However when the full nibble is zero, the
 295   rest of the line is filled with the color value in the next nibble.
 296   It is unknown what happens if the color value is greater than three.
 297   The rest seems to use a 4-entries palette.  It is not impossible
 298   that the fill-line complete case above is not as described and the
 299   zero repeat count means fill line.  The sample code never produces
 300   this, so it may be untested.
 301 */
 302
 303 static void ParseHeader( decoder_t *p_dec, block_t *p_block )
 304 {
 305     decoder_sys_t *p_sys = p_dec->p_sys;
 306     uint8_t *p = p_block->p_buffer;
 307
 308     p_sys->i_spu_size = (p[0] << 8) + p[1] + 4; p += 2;
 309
 310     /* FIXME: check data sanity */
 311     p_sys->metadata_offset = (p[0] <<  8) +   p[1]; p +=2;
 312     p_sys->metadata_length = p_sys->i_spu_size - p_sys->metadata_offset;
 313
 314     p_sys->i_image_offset = 4;
 315     p_sys->i_image_length = p_sys->metadata_offset - p_sys->i_image_offset;
 316
 317 #ifdef DEBUG_CVDSUB
 318     msg_Dbg( p_dec, "total size: %zu  image size: %zu",
 319              p_sys->i_spu_size, p_sys->i_image_length );
 320 #endif
 321 }
 322
 323 /*
 324   We parse the metadata information here.
 325
 326   Although metadata information does not have to come in a fixed field
 327   order, every metadata field consists of a tag byte followed by
 328   parameters. In all cases known, the size including tag byte is
 329   exactly four bytes in length.
 330 */
 331
 332 #define ExtractXY(x, y) x = ((p[1]&0x0f)<<6) + (p[2]>>2); \
 333                         y = ((p[2]&0x03)<<8) + p[3];
 334
 335 static void ParseMetaInfo( decoder_t *p_dec, block_t *p_spu  )
 336 {
 337     /* Last packet in subtitle block. */
 338
 339     decoder_sys_t *p_sys = p_dec->p_sys;
 340     uint8_t       *p     = p_spu->p_buffer + p_sys->metadata_offset;
 341     uint8_t       *p_end = p + p_sys->metadata_length;
 342
 343     for( ; p < p_end; p += 4 )
 344     {
 345         switch( p[0] )
 346         {
 347         case 0x04: /* subtitle duration in 1/90000ths of a second */
 348             p_sys->i_duration = (p[1]<<16) + (p[2]<<8) + p[3];
 349
 350 #ifdef DEBUG_CVDSUB
 351             msg_Dbg( p_dec, "subtitle display duration %lu secs",
 352                      (long unsigned int)(p_sys->i_duration / 90000) );
 353 #endif
 354             p_sys->i_duration *= 100 / 9;
 355             break;
 356
 357         case 0x0c: /* unknown */
 358 #ifdef DEBUG_CVDSUB
 359             msg_Dbg( p_dec, "subtitle command unknown 0x%0x 0x%0x 0x%0x 0x%0x",
 360                      (int)p[0], (int)p[1], (int)p[2], (int)p[3] );
 361 #endif
 362             break;
 363
 364         case 0x17: /* coordinates of subtitle upper left x, y position */
 365             ExtractXY(p_sys->i_x_start, p_sys->i_y_start);
 366
 367 #ifdef DEBUG_CVDSUB
 368             msg_Dbg( p_dec, "start position (%d,%d)",
 369                      p_sys->i_x_start, p_sys->i_y_start );
 370 #endif
 371             break;
 372
 373         case 0x1f: /* coordinates of subtitle bottom right x, y position */
 374         {
 375             int lastx;
 376             int lasty;
 377             ExtractXY(lastx, lasty);
 378             p_sys->i_width  = lastx - p_sys->i_x_start + 1;
 379             p_sys->i_height = lasty - p_sys->i_y_start + 1;
 380
 381 #ifdef DEBUG_CVDSUB
 382             msg_Dbg( p_dec, "end position (%d,%d), w x h: %dx%d",
 383                      lastx, lasty, p_sys->i_width, p_sys->i_height );
 384 #endif
 385             break;
 386         }
 387
 388         case 0x24:
 389         case 0x25:
 390         case 0x26:
 391         case 0x27:
 392         {
 393             uint8_t v = p[0] - 0x24;
 394
 395 #ifdef DEBUG_CVDSUB
 396             /* Primary Palette */
 397             msg_Dbg( p_dec, "primary palette %d (y,u,v): (0x%0x,0x%0x,0x%0x)",
 398                      (int)v, (int)p[1], (int)p[2], (int)p[3] );
 399 #endif
 400
 401             p_sys->p_palette[v][0] = p[1]; /* Y */
 402             p_sys->p_palette[v][1] = p[3]; /* Cr / V */
 403             p_sys->p_palette[v][2] = p[2]; /* Cb / U */
 404             break;
 405         }
 406
 407         case 0x2c:
 408         case 0x2d:
 409         case 0x2e:
 410         case 0x2f:
 411         {
 412             uint8_t v = p[0] - 0x2c;
 413
 414 #ifdef DEBUG_CVDSUB
 415             msg_Dbg( p_dec,"highlight palette %d (y,u,v): (0x%0x,0x%0x,0x%0x)",
 416                      (int)v, (int)p[1], (int)p[2], (int)p[3] );
 417 #endif
 418
 419             /* Highlight Palette */
 420             p_sys->p_palette_highlight[v][0] = p[1]; /* Y */
 421             p_sys->p_palette_highlight[v][1] = p[3]; /* Cr / V */
 422             p_sys->p_palette_highlight[v][2] = p[2]; /* Cb / U */
 423             break;
 424         }
 425
 426         case 0x37:
 427             /* transparency for primary palette */
 428             p_sys->p_palette[0][3] = (p[3] & 0x0f) << 4;
 429             p_sys->p_palette[1][3] = (p[3] >> 4) << 4;
 430             p_sys->p_palette[2][3] = (p[2] & 0x0f) << 4;
 431             p_sys->p_palette[3][3] = (p[2] >> 4) << 4;
 432
 433 #ifdef DEBUG_CVDSUB
 434             msg_Dbg( p_dec, "transparency for primary palette 0..3: "
 435                      "0x%0x 0x%0x 0x%0x 0x%0x",
 436                      (int)p_sys->p_palette[0][3], (int)p_sys->p_palette[1][3],
 437                      (int)p_sys->p_palette[2][3], (int)p_sys->p_palette[3][3]);
 438 #endif
 439             break;
 440
 441         case 0x3f:
 442             /* transparency for highlight palette */
 443             p_sys->p_palette_highlight[0][3] = (p[2] & 0x0f) << 4;
 444             p_sys->p_palette_highlight[1][3] = (p[2] >> 4) << 4;
 445             p_sys->p_palette_highlight[2][3] = (p[1] & 0x0f) << 4;
 446             p_sys->p_palette_highlight[3][3] = (p[1] >> 4) << 4;
 447
 448 #ifdef DEBUG_CVDSUB
 449             msg_Dbg( p_dec, "transparency for highlight palette 0..3: "
 450                      "0x%0x 0x%0x 0x%0x 0x%0x",
 451                      (int)p_sys->p_palette_highlight[0][3],
 452                      (int)p_sys->p_palette_highlight[1][3],
 453                      (int)p_sys->p_palette_highlight[2][3],
 454                      (int)p_sys->p_palette_highlight[3][3] );
 455 #endif
 456             break;
 457
 458         case 0x47:
 459             /* offset to start of even rows of interlaced image, we correct
 460              * to make it relative to i_image_offset (usually 4) */
 461             p_sys->first_field_offset =
 462                 (p[2] << 8) + p[3] - p_sys->i_image_offset;
 463 #ifdef DEBUG_CVDSUB
 464             msg_Dbg( p_dec, "1st_field_offset %zu",
 465                      p_sys->first_field_offset );
 466 #endif
 467             break;
 468
 469         case 0x4f:
 470             /* offset to start of odd rows of interlaced image, we correct
 471              * to make it relative to i_image_offset (usually 4) */
 472             p_sys->second_field_offset =
 473                 (p[2] << 8) + p[3] - p_sys->i_image_offset;
 474 #ifdef DEBUG_CVDSUB
 475             msg_Dbg( p_dec, "2nd_field_offset %zu",
 476                      p_sys->second_field_offset);
 477 #endif
 478             break;
 479
 480         default:
 481 #ifdef DEBUG_CVDSUB
 482             msg_Warn( p_dec, "unknown sequence in control header "
 483                       "0x%0x 0x%0x 0x%0x 0x%0x", p[0], p[1], p[2], p[3]);
 484 #endif
 485         }
 486     }
 487 }
 488
 489 /*****************************************************************************
 490  * DecodePacket: parse and decode an SPU packet
 491  *****************************************************************************
 492  * This function parses and decodes an SPU packet and, if valid, returns a
 493  * subpicture.
 494  *****************************************************************************/
 495 static subpicture_t *DecodePacket( decoder_t *p_dec, block_t *p_data )
 496 {
 497     decoder_sys_t *p_sys = p_dec->p_sys;
 498     subpicture_t  *p_spu;
 499     subpicture_region_t *p_region;
 500     video_format_t fmt;
 501     video_palette_t palette;
 502     int i;
 503
 504     /* Allocate the subpicture internal data. */
 505     p_spu = decoder_NewSubpicture( p_dec );
 506     if( !p_spu ) return NULL;
 507
 508     p_spu->i_start = p_data->i_pts;
 509     p_spu->i_stop  = p_data->i_pts + p_sys->i_duration;
 510     p_spu->b_ephemer = true;
 511
 512     /* Create new SPU region */
 513     memset( &fmt, 0, sizeof(video_format_t) );
 514     fmt.i_chroma = VLC_FOURCC('Y','U','V','P');
 515     fmt.i_aspect = VOUT_ASPECT_FACTOR;
 516     fmt.i_width = fmt.i_visible_width = p_sys->i_width;
 517     fmt.i_height = fmt.i_visible_height = p_sys->i_height;
 518     fmt.i_x_offset = fmt.i_y_offset = 0;
 519     fmt.p_palette = &palette;
 520     fmt.p_palette->i_entries = 4;
 521     for( i = 0; i < fmt.p_palette->i_entries; i++ )
 522     {
 523         fmt.p_palette->palette[i][0] = p_sys->p_palette[i][0];
 524         fmt.p_palette->palette[i][1] = p_sys->p_palette[i][1];
 525         fmt.p_palette->palette[i][2] = p_sys->p_palette[i][2];
 526         fmt.p_palette->palette[i][3] = p_sys->p_palette[i][3];
 527     }
 528
 529     p_region = subpicture_region_New( &fmt );
 530     if( !p_region )
 531     {
 532         msg_Err( p_dec, "cannot allocate SPU region" );
 533         decoder_DeleteSubpicture( p_dec, p_spu );
 534         return NULL;
 535     }
 536
 537     p_spu->p_region = p_region;
 538     p_region->i_x = p_sys->i_x_start;
 539     p_region->i_x = p_region->i_x * 3 / 4; /* FIXME: use aspect ratio for x? */
 540     p_region->i_y = p_sys->i_y_start;
 541
 542     RenderImage( p_dec, p_data, p_region );
 543
 544     return p_spu;
 545 }
 546
 547 /*****************************************************************************
 548  * ParseImage: parse and render the image part of the subtitle
 549  *****************************************************************************
 550  This part parses the subtitle graphical data and renders it.
 551
 552  Image data comes interlaced and is run-length encoded (RLE). Each
 553  field is a four-bit nibbles that is further subdivided in a two-bit
 554  repeat count and a two-bit color number - up to three pixels can be
 555  described in four bits.  What a 0 repeat count means is unknown.  It
 556  might be used for RLE extension.  There is a special case of a 0
 557  repeat count though.  When the full nibble is zero, the rest of the
 558  line is filled with the color value in the next nibble.  It is
 559  unknown what happens if the color value is greater than three.  The
 560  rest seems to use a 4-entries palette.  It is not impossible that the
 561  fill-line complete case above is not as described and the zero repeat
 562  count means fill line.  The sample code never produces this, so it
 563  may be untested.
 564
 565  However we'll transform this so that that the RLE is expanded and
 566  interlacing will also be removed. On output each pixel entry will by
 567  a 4-bit alpha (filling 8 bits), and 8-bit y, u, and v entry.
 568
 569  *****************************************************************************/
 570 static void RenderImage( decoder_t *p_dec, block_t *p_data,
 571                          subpicture_region_t *p_region )
 572 {
 573     decoder_sys_t *p_sys = p_dec->p_sys;
 574     uint8_t *p_dest = p_region->p_picture->Y_PIXELS;
 575     int i_field;            /* The subtitles are interlaced */
 576     int i_row, i_column;    /* scanline row/column number */
 577     uint8_t i_color, i_count;
 578     bs_t bs;
 579
 580     bs_init( &bs, p_data->p_buffer + p_sys->i_image_offset,
 581              p_data->i_buffer - p_sys->i_image_offset );
 582
 583     for( i_field = 0; i_field < 2; i_field++ )
 584     {
 585         for( i_row = i_field; i_row < p_sys->i_height; i_row += 2 )
 586         {
 587             for( i_column = 0; i_column < p_sys->i_width; i_column++ )
 588             {
 589                 uint8_t i_val = bs_read( &bs, 4 );
 590
 591                 if( i_val == 0 )
 592                 {
 593                     /* Fill the rest of the line with next color */
 594                     i_color = bs_read( &bs, 4 );
 595
 596                     memset( &p_dest[i_row * p_region->p_picture->Y_PITCH +
 597                                     i_column], i_color,
 598                             p_sys->i_width - i_column );
 599                     i_column = p_sys->i_width;
 600                     continue;
 601                 }
 602                 else
 603                 {
 604                     /* Normal case: get color and repeat count */
 605                     i_count = (i_val >> 2);
 606                     i_color = i_val & 0x3;
 607
 608                     i_count = __MIN( i_count, p_sys->i_width - i_column );
 609
 610                     memset( &p_dest[i_row * p_region->p_picture->Y_PITCH +
 611                                     i_column], i_color, i_count );
 612                     i_column += i_count - 1;
 613                     continue;
 614                 }
 615             }
 616
 617             bs_align( &bs );
 618         }
 619     }
 620 }