1 /*****************************************************************************
2 * svcdsub.c : Overlay Graphics Text (SVCD subtitles) decoder
3 *****************************************************************************
4 * Copyright (C) 2003, 2004 the VideoLAN team
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
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.
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.
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 *****************************************************************************/
27 /*****************************************************************************
29 *****************************************************************************/
31 #include <vlc/decoder.h>
35 /*****************************************************************************
37 *****************************************************************************/
38 static int DecoderOpen ( vlc_object_t * );
39 static int PacketizerOpen( vlc_object_t * );
40 static void DecoderClose ( vlc_object_t * );
45 #define DEBUG_LONGTEXT \
46 "This integer when viewed in binary is a debugging mask\n" \
48 "packet assembly info 2\n"
51 set_description( _("Philips OGT (SVCD subtitle) decoder") );
52 set_shortname( N_("SVCD subtitles"));
53 set_category( CAT_INPUT );
54 set_subcategory( SUBCAT_INPUT_SCODEC );
55 set_capability( "decoder", 50 );
56 set_callbacks( DecoderOpen, DecoderClose );
58 add_integer ( MODULE_STRING "-debug", 0, NULL,
59 DEBUG_TEXT, DEBUG_LONGTEXT, VLC_TRUE );
62 set_description( _("Philips OGT (SVCD subtitle) packetizer") );
63 set_capability( "packetizer", 50 );
64 set_callbacks( PacketizerOpen, DecoderClose );
67 /*****************************************************************************
69 *****************************************************************************/
70 static subpicture_t *Decode( decoder_t *, block_t ** );
71 static block_t *Packetize ( decoder_t *, block_t ** );
72 static block_t *Reassemble ( decoder_t *, block_t * );
73 static void ParseHeader( decoder_t *, block_t * );
74 static subpicture_t *DecodePacket( decoder_t *, block_t * );
75 static void SVCDSubRenderImage( decoder_t *, block_t *, subpicture_region_t * );
77 #define DECODE_DBG_CALL 1 /* calls */
78 #define DECODE_DBG_PACKET 2 /* packet assembly info */
80 #define GETINT16(p) ( (p[0] << 8) + p[1] ) ; p +=2;
82 #define GETINT32(p) ( (p[0] << 24) + (p[1] << 16) + \
83 (p[2] << 8) + (p[3]) ) ; p += 4;
86 SUBTITLE_BLOCK_EMPTY = 0,
87 SUBTITLE_BLOCK_PARTIAL = 1,
88 SUBTITLE_BLOCK_COMPLETE = 2
92 #define DECODE_DEBUG 1
95 #define dbg_print(mask, s, args...) \
96 if (p_sys && p_sys->i_debug & mask) \
97 msg_Dbg(p_dec, "%s: "s, __func__ , ##args)
99 #define dbg_print(mask, s, args...)
104 int i_debug; /* debugging mask */
106 packet_state_t i_state; /* data-gathering state for this subtitle */
108 block_t *p_spu; /* Bytes of the packet. */
110 uint16_t i_image; /* image number in the subtitle stream */
111 uint8_t i_packet; /* packet number for above image number */
113 int i_spu_size; /* goal for subtitle_data_pos while gathering,
114 size of used subtitle_data later */
116 uint16_t i_image_offset; /* offset from subtitle_data to compressed
118 int i_image_length; /* size of the compressed image data */
119 int second_field_offset; /* offset of odd raster lines */
120 int metadata_offset; /* offset to data describing the image */
121 int metadata_length; /* length of metadata */
123 mtime_t i_duration; /* how long to display the image, 0 stands
124 for "until next subtitle" */
126 uint16_t i_x_start, i_y_start; /* position of top leftmost pixel of
127 image when displayed */
128 uint16_t i_width, i_height; /* dimensions in pixels of image */
130 uint8_t p_palette[4][4]; /* Palette of colors used in subtitle */
133 /*****************************************************************************
134 * DecoderOpen: open/initialize the svcdsub decoder.
135 *****************************************************************************/
136 static int DecoderOpen( vlc_object_t *p_this )
138 decoder_t *p_dec = (decoder_t*)p_this;
139 decoder_sys_t *p_sys;
141 if( p_dec->fmt_in.i_codec != VLC_FOURCC( 'o','g','t',' ' ) )
146 p_dec->p_sys = p_sys = calloc( 1, sizeof( decoder_sys_t ) );
147 p_sys->i_debug = config_GetInt( p_this, MODULE_STRING "-debug" );
151 p_sys->i_state = SUBTITLE_BLOCK_EMPTY;
154 es_format_Init( &p_dec->fmt_out, SPU_ES, VLC_FOURCC( 'o','g','t',' ' ) );
156 p_dec->pf_decode_sub = Decode;
157 p_dec->pf_packetize = Packetize;
159 dbg_print( (DECODE_DBG_CALL) , "");
163 /*****************************************************************************
164 * PacketizerOpen: open/initialize the svcdsub packetizer.
165 *****************************************************************************/
166 static int PacketizerOpen( vlc_object_t *p_this )
168 if( DecoderOpen( p_this ) != VLC_SUCCESS ) return VLC_EGENERIC;
173 /*****************************************************************************
174 * DecoderClose: closes the svcdsub decoder/packetizer.
175 *****************************************************************************/
176 void DecoderClose( vlc_object_t *p_this )
178 decoder_t *p_dec = (decoder_t*)p_this;
179 decoder_sys_t *p_sys = p_dec->p_sys;
181 if( p_sys->p_spu ) block_ChainRelease( p_sys->p_spu );
185 /*****************************************************************************
187 *****************************************************************************/
188 static subpicture_t *Decode( decoder_t *p_dec, block_t **pp_block )
190 block_t *p_block, *p_spu;
191 decoder_sys_t *p_sys = p_dec->p_sys;
193 dbg_print( (DECODE_DBG_CALL) , "");
195 if( pp_block == NULL || *pp_block == NULL ) return NULL;
200 if( !(p_spu = Reassemble( p_dec, p_block )) ) return NULL;
202 /* Parse and decode */
203 return DecodePacket( p_dec, p_spu );
206 /*****************************************************************************
208 *****************************************************************************/
209 static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
211 block_t *p_block, *p_spu;
213 if( pp_block == NULL || *pp_block == NULL ) return NULL;
218 if( !(p_spu = Reassemble( p_dec, p_block )) ) return NULL;
220 p_spu->i_dts = p_spu->i_pts;
226 /*****************************************************************************
229 The data for single screen subtitle may come in one of many
230 non-contiguous packets of a stream. This routine is called when the
231 next packet in the stream comes in. The job of this routine is to
232 parse the header, if this is the beginning, and combine the packets
233 into one complete subtitle unit.
235 If everything is complete, we will return a block. Otherwise return
239 The format of the beginning of the subtitle packet that is used here.
242 -------------------------------------------
243 byte subtitle channel (0..7) in bits 0-3
244 byte subtitle packet number of this subtitle image 0-N,
245 if the subtitle packet is complete, the top bit of the byte is 1.
246 uint16 subtitle image number
248 *****************************************************************************/
249 #define SPU_HEADER_LEN 5
251 static block_t *Reassemble( decoder_t *p_dec, block_t *p_block )
253 decoder_sys_t *p_sys = p_dec->p_sys;
255 uint16_t i_expected_image;
256 uint8_t i_packet, i_expected_packet;
258 if( p_block->i_buffer < SPU_HEADER_LEN )
260 msg_Dbg( p_dec, "invalid packet header (size %d < %d)" ,
261 p_block->i_buffer, SPU_HEADER_LEN );
262 block_Release( p_block );
266 p_buffer = p_block->p_buffer;
268 /* Attach to our input thread and see if subtitle is selected. */
270 vlc_object_t * p_input;
273 p_input = vlc_object_find( p_dec, VLC_OBJECT_INPUT, FIND_PARENT );
275 if( !p_input ) return NULL;
277 if( var_Get( p_input, "sub-track", &val ) )
279 vlc_object_release( p_input );
283 vlc_object_release( p_input );
284 dbg_print( (DECODE_DBG_PACKET),
285 "val.i_int %x p_buffer[i] %x", val.i_int, p_buffer[1]);
287 /* The dummy ES that the menu selection uses has an 0x70 at
288 the head which we need to strip off. */
289 if( val.i_int == -1 || (val.i_int & 0x03) != p_buffer[1] )
291 dbg_print( DECODE_DBG_PACKET, "subtitle not for us.\n");
296 if( p_sys->i_state == SUBTITLE_BLOCK_EMPTY )
298 i_expected_image = p_sys->i_image + 1;
299 i_expected_packet = 0;
303 i_expected_image = p_sys->i_image;
304 i_expected_packet = p_sys->i_packet + 1;
309 if( *p_buffer & 0x80 )
311 p_sys->i_state = SUBTITLE_BLOCK_COMPLETE;
312 i_packet = *p_buffer++ & 0x7F;
316 p_sys->i_state = SUBTITLE_BLOCK_PARTIAL;
317 i_packet = *p_buffer++;
320 p_sys->i_image = GETINT16(p_buffer);
322 if( p_sys->i_image != i_expected_image )
324 msg_Warn( p_dec, "expected subtitle image %u but found %u",
325 i_expected_image, p_sys->i_image );
328 if( i_packet != i_expected_packet )
330 msg_Warn( p_dec, "expected subtitle image packet %u but found %u",
331 i_expected_packet, i_packet );
334 p_block->p_buffer += SPU_HEADER_LEN;
335 p_block->i_buffer -= SPU_HEADER_LEN;
337 p_sys->i_packet = i_packet;
338 /* First packet in the subtitle block */
339 if( !p_sys->i_packet ) ParseHeader( p_dec, p_block );
341 block_ChainAppend( &p_sys->p_spu, p_block );
343 if( p_sys->i_state == SUBTITLE_BLOCK_COMPLETE )
345 block_t *p_spu = block_ChainGather( p_sys->p_spu );
347 if( p_spu->i_buffer != p_sys->i_spu_size )
349 msg_Warn( p_dec, "subtitle packets size=%d should be %d",
350 p_spu->i_buffer, p_sys->i_spu_size );
353 dbg_print( (DECODE_DBG_PACKET),
354 "subtitle packet complete, size=%d", p_spu->i_buffer );
356 p_sys->i_state = SUBTITLE_BLOCK_EMPTY;
364 /******************************************************************************
365 The format is roughly as follows (everything is big-endian):
368 -------------------------------------------
369 byte subtitle channel (0..7) in bits 0-3
370 byte subtitle packet number of this subtitle image 0-N,
371 if the subtitle packet is complete, the top bit of the byte is 1.
372 u_int16 subtitle image number
373 u_int16 length in bytes of the rest
374 byte option flags, unknown meaning except bit 3 (0x08) indicates
375 presence of the duration field
377 u_int32 duration in 1/90000ths of a second (optional), start time
378 is as indicated by the PTS in the PES header
381 u_int32 width (must be even)
382 u_int32 height (must be even)
383 byte[16] palette, 4 palette entries, each contains values for
384 Y, U, V and transparency, 0 standing for transparent
386 cmd>>6==1 indicates shift
387 (cmd>>4)&3 is direction from, (0=top,1=left,2=right,3=bottom)
388 u_int32 shift duration in 1/90000ths of a second
389 u_int16 offset of odd-numbered scanlines - subtitle images are
390 given in interlace order
391 byte[] limited RLE image data in interlace order (0,2,4... 1,3,5) with
392 2-bits per palette number
393 ******************************************************************************/
394 static void ParseHeader( decoder_t *p_dec, block_t *p_block )
396 decoder_sys_t *p_sys = p_dec->p_sys;
397 uint8_t *p = p_block->p_buffer;
398 uint8_t i_options, i_options2, i_cmd, i_cmd_arg;
401 p_sys->i_spu_size = GETINT16(p);
405 if( i_options & 0x08 ) { p_sys->i_duration = GETINT32(p); }
406 else p_sys->i_duration = 0; /* Ephemer subtitle */
407 p_sys->i_duration *= 100 / 9;
409 p_sys->i_x_start = GETINT16(p);
410 p_sys->i_y_start = GETINT16(p);
411 p_sys->i_width = GETINT16(p);
412 p_sys->i_height = GETINT16(p);
414 for( i = 0; i < 4; i++ )
416 p_sys->p_palette[i][0] = *p++; /* Y */
417 p_sys->p_palette[i][2] = *p++; /* Cr / V */
418 p_sys->p_palette[i][1] = *p++; /* Cb / U */
419 p_sys->p_palette[i][3] = *p++; /* T */
423 /* We do not really know this, FIXME */
424 if( i_cmd ) {i_cmd_arg = GETINT32(p);}
426 /* Actually, this is measured against a different origin, so we have to
428 p_sys->second_field_offset = GETINT16(p);
429 p_sys->i_image_offset = p - p_block->p_buffer;
430 p_sys->i_image_length = p_sys->i_spu_size - p_sys->i_image_offset;
431 p_sys->metadata_length = p_sys->i_image_offset;
433 if (p_sys && p_sys->i_debug & DECODE_DBG_PACKET)
435 msg_Dbg( p_dec, "x-start: %d, y-start: %d, width: %d, height %d, "
436 "spu size: %d, duration: %lu (d:%d p:%d)",
437 p_sys->i_x_start, p_sys->i_y_start,
438 p_sys->i_width, p_sys->i_height,
439 p_sys->i_spu_size, (long unsigned int) p_sys->i_duration,
440 p_sys->i_image_length, p_sys->i_image_offset);
442 for( i = 0; i < 4; i++ )
444 msg_Dbg( p_dec, "palette[%d]= T: %2x, Y: %2x, u: %2x, v: %2x", i,
445 p_sys->p_palette[i][3], p_sys->p_palette[i][0],
446 p_sys->p_palette[i][1], p_sys->p_palette[i][2] );
451 /*****************************************************************************
452 * DecodePacket: parse and decode an subtitle packet
453 *****************************************************************************
454 * This function parses and decodes an SPU packet and, if valid, returns a
456 *****************************************************************************/
457 static subpicture_t *DecodePacket( decoder_t *p_dec, block_t *p_data )
459 decoder_sys_t *p_sys = p_dec->p_sys;
461 subpicture_region_t *p_region;
465 /* Allocate the subpicture internal data. */
466 p_spu = p_dec->pf_spu_buffer_new( p_dec );
467 if( !p_spu ) return NULL;
469 p_spu->b_pausable = VLC_TRUE;
471 p_spu->i_x = p_sys->i_x_start;
472 p_spu->i_y = p_sys->i_y_start;
473 p_spu->i_start = p_data->i_pts;
474 p_spu->i_stop = p_data->i_pts + p_sys->i_duration;
475 p_spu->b_ephemer = VLC_TRUE;
477 /* Create new subtitle region */
478 memset( &fmt, 0, sizeof(video_format_t) );
479 fmt.i_chroma = VLC_FOURCC('Y','U','V','P');
482 The video on which the subtitle sits, is scaled, probably
483 4:3. However subtitle bitmaps assume an 1:1 aspect ratio.
485 FIXME: We should get the video aspect ratio from somewhere.
486 Two candidates are the video and the other possibility would be
489 fmt.i_aspect = VOUT_ASPECT_FACTOR;
491 fmt.i_width = fmt.i_visible_width = p_sys->i_width;
492 fmt.i_height = fmt.i_visible_height = p_sys->i_height;
493 fmt.i_x_offset = fmt.i_y_offset = 0;
494 p_region = p_spu->pf_create_region( VLC_OBJECT(p_dec), &fmt );
497 msg_Err( p_dec, "cannot allocate SVCD subtitle region" );
501 p_region->fmt.i_aspect = VOUT_ASPECT_FACTOR;
503 p_spu->p_region = p_region;
504 p_region->i_x = p_region->i_y = 0;
507 fmt.p_palette->i_entries = 4;
508 for( i = 0; i < fmt.p_palette->i_entries; i++ )
510 fmt.p_palette->palette[i][0] = p_sys->p_palette[i][0];
511 fmt.p_palette->palette[i][1] = p_sys->p_palette[i][1];
512 fmt.p_palette->palette[i][2] = p_sys->p_palette[i][2];
513 fmt.p_palette->palette[i][3] = p_sys->p_palette[i][3];
516 SVCDSubRenderImage( p_dec, p_data, p_region );
521 /*****************************************************************************
522 * SVCDSubRenderImage: reorders bytes of image data in subpicture region.
523 *****************************************************************************
525 The image is encoded using two bits per pixel that select a palette
526 entry except that value 0 starts a limited run-length encoding for
527 color 0. When 0 is seen, the next two bits encode one less than the
528 number of pixels, so we can encode run lengths from 1 to 4. These get
529 filled with the color in palette entry 0.
531 The encoding of each line is padded to a whole number of bytes. The
532 first field is padded to an even byte length and the complete subtitle
533 is padded to a 4-byte multiple that always include one zero byte at
536 However we'll transform this so that that the RLE is expanded and
537 interlacing will also be removed.
538 *****************************************************************************/
539 static void SVCDSubRenderImage( decoder_t *p_dec, block_t *p_data,
540 subpicture_region_t *p_region )
542 decoder_sys_t *p_sys = p_dec->p_sys;
543 uint8_t *p_dest = p_region->picture.Y_PIXELS;
544 int i_field; /* The subtitles are interlaced */
545 int i_row, i_column; /* scanline row/column number */
546 uint8_t i_color, i_count;
549 bs_init( &bs, p_data->p_buffer + p_sys->i_image_offset,
550 p_data->i_buffer - p_sys->i_image_offset );
552 for( i_field = 0; i_field < 2; i_field++ )
554 for( i_row = i_field; i_row < p_sys->i_height; i_row += 2 )
556 for( i_column = 0; i_column < p_sys->i_width; i_column++ )
558 i_color = bs_read( &bs, 2 );
559 if( i_color == 0 && (i_count = bs_read( &bs, 2 )) )
561 i_count = __MIN( i_count, p_sys->i_width - i_column );
562 memset( &p_dest[i_row * p_region->picture.Y_PITCH +
563 i_column], 0, i_count + 1 );
568 p_dest[i_row * p_region->picture.Y_PITCH + i_column] = i_color;
575 bs_init( &bs, p_data->p_buffer + p_sys->i_image_offset +
576 p_sys->second_field_offset,
577 p_data->i_buffer - p_sys->i_image_offset -
578 p_sys->second_field_offset );