1 /*****************************************************************************
2 * cvdsub.c : CVD Subtitle decoder
3 *****************************************************************************
4 * Copyright (C) 2003, 2004 VLC authors and VideoLAN
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>
12 * This program is free software; you can redistribute it and/or modify it
13 * under the terms of the GNU Lesser General Public License as published by
14 * the Free Software Foundation; either version 2.1 of the License, or
15 * (at your option) any later version.
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 Lesser General Public License for more details.
22 * You should have received a copy of the GNU Lesser General Public License
23 * along with this program; if not, write to the Free Software Foundation,
24 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
25 *****************************************************************************/
27 /*****************************************************************************
29 *****************************************************************************/
34 #include <vlc_common.h>
35 #include <vlc_plugin.h>
36 #include <vlc_codec.h>
40 #define DEBUG_CVDSUB 1
42 /*****************************************************************************
44 *****************************************************************************/
45 static int DecoderOpen ( vlc_object_t * );
46 static int PacketizerOpen( vlc_object_t * );
47 static void DecoderClose ( vlc_object_t * );
50 set_description( N_("CVD subtitle decoder") )
51 set_capability( "decoder", 50 )
52 set_callbacks( DecoderOpen, DecoderClose )
55 set_description( N_("Chaoji VCD subtitle packetizer") )
56 set_capability( "packetizer", 50 )
57 set_callbacks( PacketizerOpen, DecoderClose )
60 /*****************************************************************************
62 *****************************************************************************/
63 static subpicture_t *Decode( decoder_t *, block_t ** );
64 static block_t *Packetize ( decoder_t *, block_t ** );
65 static block_t *Reassemble ( decoder_t *, block_t * );
66 static void ParseMetaInfo ( decoder_t *, block_t * );
67 static void ParseHeader ( decoder_t *, block_t * );
68 static subpicture_t *DecodePacket( decoder_t *, block_t * );
69 static void RenderImage( decoder_t *, block_t *, subpicture_region_t * );
71 #define SUBTITLE_BLOCK_EMPTY 0
72 #define SUBTITLE_BLOCK_PARTIAL 1
73 #define SUBTITLE_BLOCK_COMPLETE 2
79 int i_state; /* data-gathering state for this subtitle */
81 block_t *p_spu; /* Bytes of the packet. */
83 size_t i_spu_size; /* goal for subtitle_data_pos while gathering,
84 size of used subtitle_data later */
86 uint16_t i_image_offset; /* offset from subtitle_data to compressed
88 size_t i_image_length; /* size of the compressed image data */
89 size_t first_field_offset; /* offset of even raster lines */
90 size_t second_field_offset; /* offset of odd raster lines */
91 size_t metadata_offset; /* offset to data describing the image */
92 size_t metadata_length; /* length of metadata */
94 mtime_t i_duration; /* how long to display the image, 0 stands
95 for "until next subtitle" */
97 uint16_t i_x_start, i_y_start; /* position of top leftmost pixel of
98 image when displayed */
99 uint16_t i_width, i_height; /* dimensions in pixels of image */
101 uint8_t p_palette[4][4]; /* Palette of colors used in subtitle */
102 uint8_t p_palette_highlight[4][4];
105 /*****************************************************************************
106 * DecoderOpen: open/initialize the cvdsub decoder.
107 *****************************************************************************/
108 static int DecoderOpen( vlc_object_t *p_this )
110 decoder_t *p_dec = (decoder_t*)p_this;
111 decoder_sys_t *p_sys;
113 if( p_dec->fmt_in.i_codec != VLC_CODEC_CVD )
116 p_dec->p_sys = p_sys = malloc( sizeof( decoder_sys_t ) );
120 p_sys->b_packetizer = false;
122 p_sys->i_state = SUBTITLE_BLOCK_EMPTY;
125 p_dec->pf_decode_sub = Decode;
126 p_dec->pf_packetize = Packetize;
128 p_dec->fmt_out.i_cat = SPU_ES;
129 p_dec->fmt_out.i_codec = VLC_CODEC_YUVP;
134 /*****************************************************************************
135 * PacketizerOpen: open/initialize the cvdsub packetizer.
136 *****************************************************************************/
137 static int PacketizerOpen( vlc_object_t *p_this )
139 decoder_t *p_dec = (decoder_t*)p_this;
141 if( DecoderOpen( p_this ) != VLC_SUCCESS ) return VLC_EGENERIC;
143 p_dec->p_sys->b_packetizer = true;
148 /*****************************************************************************
149 * DecoderClose: closes the cvdsub decoder/packetizer.
150 *****************************************************************************/
151 void DecoderClose( vlc_object_t *p_this )
153 decoder_t *p_dec = (decoder_t*)p_this;
154 decoder_sys_t *p_sys = p_dec->p_sys;
156 if( p_sys->p_spu ) block_ChainRelease( p_sys->p_spu );
160 /*****************************************************************************
162 *****************************************************************************/
163 static subpicture_t *Decode( decoder_t *p_dec, block_t **pp_block )
165 block_t *p_block, *p_spu;
167 if( pp_block == NULL || *pp_block == NULL ) return NULL;
172 if( !(p_spu = Reassemble( p_dec, p_block )) ) return NULL;
174 /* Parse and decode */
175 return DecodePacket( p_dec, p_spu );
178 /*****************************************************************************
180 *****************************************************************************/
181 static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
183 block_t *p_block, *p_spu;
185 if( pp_block == NULL || *pp_block == NULL ) return NULL;
190 if( !(p_spu = Reassemble( p_dec, p_block )) ) return NULL;
192 p_spu->i_dts = p_spu->i_pts;
199 /*****************************************************************************
202 Data for single screen subtitle may come in several non-contiguous
203 packets of a stream. This routine is called when the next packet in
204 the stream comes in. The job of this routine is to parse the header,
205 if this is the beginning, and combine the packets into one complete
208 If everything is complete, we will return a block. Otherwise return
211 *****************************************************************************/
212 #define SPU_HEADER_LEN 1
214 static block_t *Reassemble( decoder_t *p_dec, block_t *p_block )
216 decoder_sys_t *p_sys = p_dec->p_sys;
218 if( p_block->i_buffer < SPU_HEADER_LEN )
220 msg_Dbg( p_dec, "invalid packet header (size %zu < %u)" ,
221 p_block->i_buffer, SPU_HEADER_LEN );
222 block_Release( p_block );
226 /* From the scant data on the format, there is only only way known
227 * to detect the first packet in a subtitle. The first packet
228 * seems to have a valid PTS while later packets for the same
230 if( p_sys->i_state == SUBTITLE_BLOCK_EMPTY && p_block->i_pts <= VLC_TS_INVALID )
232 msg_Warn( p_dec, "first packet expected but no PTS present");
236 p_block->p_buffer += SPU_HEADER_LEN;
237 p_block->i_buffer -= SPU_HEADER_LEN;
239 /* First packet in the subtitle block */
240 if( p_sys->i_state == SUBTITLE_BLOCK_EMPTY ) ParseHeader( p_dec, p_block );
242 block_ChainAppend( &p_sys->p_spu, p_block );
243 p_sys->p_spu = block_ChainGather( p_sys->p_spu );
245 if( p_sys->p_spu->i_buffer >= p_sys->i_spu_size )
247 block_t *p_spu = p_sys->p_spu;
249 if( p_spu->i_buffer != p_sys->i_spu_size )
251 msg_Warn( p_dec, "SPU packets size=%zu should be %zu",
252 p_spu->i_buffer, p_sys->i_spu_size );
255 msg_Dbg( p_dec, "subtitle packet complete, size=%zuu", p_spu->i_buffer);
257 ParseMetaInfo( p_dec, p_spu );
259 p_sys->i_state = SUBTITLE_BLOCK_EMPTY;
265 /* Not last block in subtitle, so wait for another. */
266 p_sys->i_state = SUBTITLE_BLOCK_PARTIAL;
273 We do not have information on the subtitle format used on CVD's
274 except the submux sample code and a couple of samples of dubious
275 origin. Thus, this is the result of reading some code whose
276 correctness is not known and some experimentation.
278 CVD subtitles are different in several ways from SVCD OGT subtitles.
279 Image comes first and metadata is at the end. So that the metadata
280 can be found easily, the subtitle packet starts with two bytes
281 (everything is big-endian again) that give the total size of the
282 subtitle data and the offset to the metadata - i.e. size of the
283 image data plus the four bytes at the beginning.
285 Image data comes interlaced is run-length encoded. Each field is a
286 four-bit nibble. Each nibble contains a two-bit repeat count and a
287 two-bit color number so that up to three pixels can be described in
288 four bits. The function of a 0 repeat count is unknown; it might be
289 used for RLE extension. However when the full nibble is zero, the
290 rest of the line is filled with the color value in the next nibble.
291 It is unknown what happens if the color value is greater than three.
292 The rest seems to use a 4-entries palette. It is not impossible
293 that the fill-line complete case above is not as described and the
294 zero repeat count means fill line. The sample code never produces
295 this, so it may be untested.
298 static void ParseHeader( decoder_t *p_dec, block_t *p_block )
300 decoder_sys_t *p_sys = p_dec->p_sys;
301 uint8_t *p = p_block->p_buffer;
303 p_sys->i_spu_size = (p[0] << 8) + p[1] + 4; p += 2;
305 /* FIXME: check data sanity */
306 p_sys->metadata_offset = (p[0] << 8) + p[1]; p +=2;
307 p_sys->metadata_length = p_sys->i_spu_size - p_sys->metadata_offset;
309 p_sys->i_image_offset = 4;
310 p_sys->i_image_length = p_sys->metadata_offset - p_sys->i_image_offset;
313 msg_Dbg( p_dec, "total size: %zu image size: %zu",
314 p_sys->i_spu_size, p_sys->i_image_length );
319 We parse the metadata information here.
321 Although metadata information does not have to come in a fixed field
322 order, every metadata field consists of a tag byte followed by
323 parameters. In all cases known, the size including tag byte is
324 exactly four bytes in length.
327 #define ExtractXY(x, y) x = ((p[1]&0x0f)<<6) + (p[2]>>2); \
328 y = ((p[2]&0x03)<<8) + p[3];
330 static void ParseMetaInfo( decoder_t *p_dec, block_t *p_spu )
332 /* Last packet in subtitle block. */
334 decoder_sys_t *p_sys = p_dec->p_sys;
335 uint8_t *p = p_spu->p_buffer + p_sys->metadata_offset;
336 uint8_t *p_end = p + p_sys->metadata_length;
338 for( ; p < p_end; p += 4 )
342 case 0x04: /* subtitle duration in 1/90000ths of a second */
343 p_sys->i_duration = (p[1]<<16) + (p[2]<<8) + p[3];
346 msg_Dbg( p_dec, "subtitle display duration %lu secs",
347 (long unsigned int)(p_sys->i_duration / 90000) );
349 p_sys->i_duration *= 100 / 9;
352 case 0x0c: /* unknown */
354 msg_Dbg( p_dec, "subtitle command unknown 0x%0x 0x%0x 0x%0x 0x%0x",
355 (int)p[0], (int)p[1], (int)p[2], (int)p[3] );
359 case 0x17: /* coordinates of subtitle upper left x, y position */
360 ExtractXY(p_sys->i_x_start, p_sys->i_y_start);
363 msg_Dbg( p_dec, "start position (%d,%d)",
364 p_sys->i_x_start, p_sys->i_y_start );
368 case 0x1f: /* coordinates of subtitle bottom right x, y position */
372 ExtractXY(lastx, lasty);
373 p_sys->i_width = lastx - p_sys->i_x_start + 1;
374 p_sys->i_height = lasty - p_sys->i_y_start + 1;
377 msg_Dbg( p_dec, "end position (%d,%d), w x h: %dx%d",
378 lastx, lasty, p_sys->i_width, p_sys->i_height );
388 uint8_t v = p[0] - 0x24;
391 /* Primary Palette */
392 msg_Dbg( p_dec, "primary palette %d (y,u,v): (0x%0x,0x%0x,0x%0x)",
393 (int)v, (int)p[1], (int)p[2], (int)p[3] );
396 p_sys->p_palette[v][0] = p[1]; /* Y */
397 p_sys->p_palette[v][1] = p[3]; /* Cr / V */
398 p_sys->p_palette[v][2] = p[2]; /* Cb / U */
407 uint8_t v = p[0] - 0x2c;
410 msg_Dbg( p_dec,"highlight palette %d (y,u,v): (0x%0x,0x%0x,0x%0x)",
411 (int)v, (int)p[1], (int)p[2], (int)p[3] );
414 /* Highlight Palette */
415 p_sys->p_palette_highlight[v][0] = p[1]; /* Y */
416 p_sys->p_palette_highlight[v][1] = p[3]; /* Cr / V */
417 p_sys->p_palette_highlight[v][2] = p[2]; /* Cb / U */
422 /* transparency for primary palette */
423 p_sys->p_palette[0][3] = (p[3] & 0x0f) << 4;
424 p_sys->p_palette[1][3] = (p[3] >> 4) << 4;
425 p_sys->p_palette[2][3] = (p[2] & 0x0f) << 4;
426 p_sys->p_palette[3][3] = (p[2] >> 4) << 4;
429 msg_Dbg( p_dec, "transparency for primary palette 0..3: "
430 "0x%0x 0x%0x 0x%0x 0x%0x",
431 (int)p_sys->p_palette[0][3], (int)p_sys->p_palette[1][3],
432 (int)p_sys->p_palette[2][3], (int)p_sys->p_palette[3][3]);
437 /* transparency for highlight palette */
438 p_sys->p_palette_highlight[0][3] = (p[2] & 0x0f) << 4;
439 p_sys->p_palette_highlight[1][3] = (p[2] >> 4) << 4;
440 p_sys->p_palette_highlight[2][3] = (p[1] & 0x0f) << 4;
441 p_sys->p_palette_highlight[3][3] = (p[1] >> 4) << 4;
444 msg_Dbg( p_dec, "transparency for highlight palette 0..3: "
445 "0x%0x 0x%0x 0x%0x 0x%0x",
446 (int)p_sys->p_palette_highlight[0][3],
447 (int)p_sys->p_palette_highlight[1][3],
448 (int)p_sys->p_palette_highlight[2][3],
449 (int)p_sys->p_palette_highlight[3][3] );
454 /* offset to start of even rows of interlaced image, we correct
455 * to make it relative to i_image_offset (usually 4) */
456 p_sys->first_field_offset =
457 (p[2] << 8) + p[3] - p_sys->i_image_offset;
459 msg_Dbg( p_dec, "1st_field_offset %zu",
460 p_sys->first_field_offset );
465 /* offset to start of odd rows of interlaced image, we correct
466 * to make it relative to i_image_offset (usually 4) */
467 p_sys->second_field_offset =
468 (p[2] << 8) + p[3] - p_sys->i_image_offset;
470 msg_Dbg( p_dec, "2nd_field_offset %zu",
471 p_sys->second_field_offset);
477 msg_Warn( p_dec, "unknown sequence in control header "
478 "0x%0x 0x%0x 0x%0x 0x%0x", p[0], p[1], p[2], p[3]);
484 /*****************************************************************************
485 * DecodePacket: parse and decode an SPU packet
486 *****************************************************************************
487 * This function parses and decodes an SPU packet and, if valid, returns a
489 *****************************************************************************/
490 static subpicture_t *DecodePacket( decoder_t *p_dec, block_t *p_data )
492 decoder_sys_t *p_sys = p_dec->p_sys;
494 subpicture_region_t *p_region;
496 video_palette_t palette;
499 /* Allocate the subpicture internal data. */
500 p_spu = decoder_NewSubpicture( p_dec, NULL );
501 if( !p_spu ) return NULL;
503 p_spu->i_start = p_data->i_pts;
504 p_spu->i_stop = p_data->i_pts + p_sys->i_duration;
505 p_spu->b_ephemer = true;
507 /* Create new SPU region */
508 memset( &fmt, 0, sizeof(video_format_t) );
509 fmt.i_chroma = VLC_CODEC_YUVP;
512 fmt.i_width = fmt.i_visible_width = p_sys->i_width;
513 fmt.i_height = fmt.i_visible_height = p_sys->i_height;
514 fmt.i_x_offset = fmt.i_y_offset = 0;
515 fmt.p_palette = &palette;
516 fmt.p_palette->i_entries = 4;
517 for( i = 0; i < fmt.p_palette->i_entries; i++ )
519 fmt.p_palette->palette[i][0] = p_sys->p_palette[i][0];
520 fmt.p_palette->palette[i][1] = p_sys->p_palette[i][1];
521 fmt.p_palette->palette[i][2] = p_sys->p_palette[i][2];
522 fmt.p_palette->palette[i][3] = p_sys->p_palette[i][3];
525 p_region = subpicture_region_New( &fmt );
528 msg_Err( p_dec, "cannot allocate SPU region" );
529 decoder_DeleteSubpicture( p_dec, p_spu );
533 p_spu->p_region = p_region;
534 p_region->i_x = p_sys->i_x_start;
535 p_region->i_x = p_region->i_x * 3 / 4; /* FIXME: use aspect ratio for x? */
536 p_region->i_y = p_sys->i_y_start;
538 RenderImage( p_dec, p_data, p_region );
543 /*****************************************************************************
544 * ParseImage: parse and render the image part of the subtitle
545 *****************************************************************************
546 This part parses the subtitle graphical data and renders it.
548 Image data comes interlaced and is run-length encoded (RLE). Each
549 field is a four-bit nibbles that is further subdivided in a two-bit
550 repeat count and a two-bit color number - up to three pixels can be
551 described in four bits. What a 0 repeat count means is unknown. It
552 might be used for RLE extension. There is a special case of a 0
553 repeat count though. When the full nibble is zero, the rest of the
554 line is filled with the color value in the next nibble. It is
555 unknown what happens if the color value is greater than three. The
556 rest seems to use a 4-entries palette. It is not impossible that the
557 fill-line complete case above is not as described and the zero repeat
558 count means fill line. The sample code never produces this, so it
561 However we'll transform this so that that the RLE is expanded and
562 interlacing will also be removed. On output each pixel entry will by
563 a 4-bit alpha (filling 8 bits), and 8-bit y, u, and v entry.
565 *****************************************************************************/
566 static void RenderImage( decoder_t *p_dec, block_t *p_data,
567 subpicture_region_t *p_region )
569 decoder_sys_t *p_sys = p_dec->p_sys;
570 uint8_t *p_dest = p_region->p_picture->Y_PIXELS;
571 int i_field; /* The subtitles are interlaced */
572 int i_row, i_column; /* scanline row/column number */
573 uint8_t i_color, i_count;
576 bs_init( &bs, p_data->p_buffer + p_sys->i_image_offset,
577 p_data->i_buffer - p_sys->i_image_offset );
579 for( i_field = 0; i_field < 2; i_field++ )
581 for( i_row = i_field; i_row < p_sys->i_height; i_row += 2 )
583 for( i_column = 0; i_column < p_sys->i_width; i_column++ )
585 uint8_t i_val = bs_read( &bs, 4 );
589 /* Fill the rest of the line with next color */
590 i_color = bs_read( &bs, 4 );
592 memset( &p_dest[i_row * p_region->p_picture->Y_PITCH +
594 p_sys->i_width - i_column );
595 i_column = p_sys->i_width;
600 /* Normal case: get color and repeat count */
601 i_count = (i_val >> 2);
602 i_color = i_val & 0x3;
604 i_count = __MIN( i_count, p_sys->i_width - i_column );
606 memset( &p_dest[i_row * p_region->p_picture->Y_PITCH +
607 i_column], i_color, i_count );
608 i_column += i_count - 1;