1 /*****************************************************************************
2 * svcdsub.c : Overlay Graphics Text (SVCD subtitles) decoder
3 *****************************************************************************
4 * Copyright (C) 2003, 2004 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
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., 59 Temple Place - Suite 330, Boston, MA 02111, 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 * );
42 #define DEBUG_TEXT N_( \
43 "If nonzero, this gives additional debug information." \
46 #define DEBUG_LONGTEXT N_( \
47 "This integer when viewed in binary is a debugging mask\n" \
49 "packet assembly info 2\n" )
52 set_description( _("Philips OGT (SVCD subtitle) decoder") );
53 set_shortname( N_("SVCD subtitles"));
54 set_category( CAT_INPUT );
55 set_subcategory( SUBCAT_INPUT_SCODEC );
56 set_capability( "decoder", 50 );
57 set_callbacks( DecoderOpen, DecoderClose );
59 add_integer ( MODULE_STRING "-debug", 0, NULL,
60 DEBUG_TEXT, DEBUG_LONGTEXT, VLC_TRUE );
63 set_description( _("Philips OGT (SVCD subtitle) packetizer") );
64 set_capability( "packetizer", 50 );
65 set_callbacks( PacketizerOpen, DecoderClose );
68 /*****************************************************************************
70 *****************************************************************************/
71 static subpicture_t *Decode( decoder_t *, block_t ** );
72 static block_t *Packetize ( decoder_t *, block_t ** );
73 static block_t *Reassemble ( decoder_t *, block_t * );
74 static void ParseHeader( decoder_t *, block_t * );
75 static subpicture_t *DecodePacket( decoder_t *, block_t * );
76 static void SVCDSubRenderImage( decoder_t *, block_t *, subpicture_region_t * );
78 #define DECODE_DBG_CALL 1 /* calls */
79 #define DECODE_DBG_PACKET 2 /* packet assembly info */
81 #define GETINT16(p) ( (p[0] << 8) + p[1] ) ; p +=2;
83 #define GETINT32(p) ( (p[0] << 24) + (p[1] << 16) + \
84 (p[2] << 8) + (p[3]) ) ; p += 4;
87 SUBTITLE_BLOCK_EMPTY = 0,
88 SUBTITLE_BLOCK_PARTIAL = 1,
89 SUBTITLE_BLOCK_COMPLETE = 2
93 #define DECODE_DEBUG 1
96 #define dbg_print(mask, s, args...) \
97 if (p_sys && p_sys->i_debug & mask) \
98 msg_Dbg(p_dec, "%s: "s, __func__ , ##args)
100 #define dbg_print(mask, s, args...)
105 int i_debug; /* debugging mask */
107 packet_state_t i_state; /* data-gathering state for this subtitle */
109 block_t *p_spu; /* Bytes of the packet. */
111 uint16_t i_image; /* image number in the subtitle stream */
112 uint8_t i_packet; /* packet number for above image number */
114 int i_spu_size; /* goal for subtitle_data_pos while gathering,
115 size of used subtitle_data later */
117 uint16_t i_image_offset; /* offset from subtitle_data to compressed
119 int i_image_length; /* size of the compressed image data */
120 int second_field_offset; /* offset of odd raster lines */
121 int metadata_offset; /* offset to data describing the image */
122 int metadata_length; /* length of metadata */
124 mtime_t i_duration; /* how long to display the image, 0 stands
125 for "until next subtitle" */
127 uint16_t i_x_start, i_y_start; /* position of top leftmost pixel of
128 image when displayed */
129 uint16_t i_width, i_height; /* dimensions in pixels of image */
131 uint8_t p_palette[4][4]; /* Palette of colors used in subtitle */
134 /*****************************************************************************
135 * DecoderOpen: open/initialize the svcdsub decoder.
136 *****************************************************************************/
137 static int DecoderOpen( vlc_object_t *p_this )
139 decoder_t *p_dec = (decoder_t*)p_this;
140 decoder_sys_t *p_sys;
142 if( p_dec->fmt_in.i_codec != VLC_FOURCC( 'o','g','t',' ' ) )
147 p_dec->p_sys = p_sys = calloc( 1, sizeof( decoder_sys_t ) );
148 p_sys->i_debug = config_GetInt( p_this, MODULE_STRING "-debug" );
152 p_sys->i_state = SUBTITLE_BLOCK_EMPTY;
155 es_format_Init( &p_dec->fmt_out, SPU_ES, VLC_FOURCC( 'o','g','t',' ' ) );
157 p_dec->pf_decode_sub = Decode;
158 p_dec->pf_packetize = Packetize;
160 dbg_print( (DECODE_DBG_CALL) , "");
164 /*****************************************************************************
165 * PacketizerOpen: open/initialize the svcdsub packetizer.
166 *****************************************************************************/
167 static int PacketizerOpen( vlc_object_t *p_this )
169 if( DecoderOpen( p_this ) != VLC_SUCCESS ) return VLC_EGENERIC;
174 /*****************************************************************************
175 * DecoderClose: closes the svcdsub decoder/packetizer.
176 *****************************************************************************/
177 void DecoderClose( vlc_object_t *p_this )
179 decoder_t *p_dec = (decoder_t*)p_this;
180 decoder_sys_t *p_sys = p_dec->p_sys;
182 if( p_sys->p_spu ) block_ChainRelease( p_sys->p_spu );
186 /*****************************************************************************
188 *****************************************************************************/
189 static subpicture_t *Decode( decoder_t *p_dec, block_t **pp_block )
191 block_t *p_block, *p_spu;
192 decoder_sys_t *p_sys = p_dec->p_sys;
194 dbg_print( (DECODE_DBG_CALL) , "");
196 if( pp_block == NULL || *pp_block == NULL ) return NULL;
201 if( !(p_spu = Reassemble( p_dec, p_block )) ) return NULL;
203 /* Parse and decode */
204 return DecodePacket( p_dec, p_spu );
207 /*****************************************************************************
209 *****************************************************************************/
210 static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
212 block_t *p_block, *p_spu;
214 if( pp_block == NULL || *pp_block == NULL ) return NULL;
219 if( !(p_spu = Reassemble( p_dec, p_block )) ) return NULL;
221 p_spu->i_dts = p_spu->i_pts;
227 /*****************************************************************************
230 The data for single screen subtitle may come in one of many
231 non-contiguous packets of a stream. This routine is called when the
232 next packet in the stream comes in. The job of this routine is to
233 parse the header, if this is the beginning, and combine the packets
234 into one complete subtitle unit.
236 If everything is complete, we will return a block. Otherwise return
240 The format of the beginning of the subtitle packet that is used here.
243 -------------------------------------------
244 byte subtitle channel (0..7) in bits 0-3
245 byte subtitle packet number of this subtitle image 0-N,
246 if the subtitle packet is complete, the top bit of the byte is 1.
247 uint16 subtitle image number
249 *****************************************************************************/
250 #define SPU_HEADER_LEN 5
252 static block_t *Reassemble( decoder_t *p_dec, block_t *p_block )
254 decoder_sys_t *p_sys = p_dec->p_sys;
256 uint16_t i_expected_image;
257 uint8_t i_packet, i_expected_packet;
259 if( p_block->i_buffer < SPU_HEADER_LEN )
261 msg_Dbg( p_dec, "invalid packet header (size %d < %d)" ,
262 p_block->i_buffer, SPU_HEADER_LEN );
263 block_Release( p_block );
267 p_buffer = p_block->p_buffer;
269 /* Attach to our input thread and see if subtitle is selected. */
271 vlc_object_t * p_input;
274 p_input = vlc_object_find( p_dec, VLC_OBJECT_INPUT, FIND_PARENT );
276 if( !p_input ) return NULL;
278 if( var_Get( p_input, "sub-track", &val ) )
280 vlc_object_release( p_input );
284 vlc_object_release( p_input );
285 dbg_print( (DECODE_DBG_PACKET),
286 "val.i_int %x p_buffer[i] %x", val.i_int, p_buffer[1]);
288 /* The dummy ES that the menu selection uses has an 0x70 at
289 the head which we need to strip off. */
290 if( val.i_int == -1 || (val.i_int & 0x03) != p_buffer[1] )
292 dbg_print( DECODE_DBG_PACKET, "subtitle not for us.\n");
297 if( p_sys->i_state == SUBTITLE_BLOCK_EMPTY )
299 i_expected_image = p_sys->i_image + 1;
300 i_expected_packet = 0;
304 i_expected_image = p_sys->i_image;
305 i_expected_packet = p_sys->i_packet + 1;
310 if( *p_buffer & 0x80 )
312 p_sys->i_state = SUBTITLE_BLOCK_COMPLETE;
313 i_packet = *p_buffer++ & 0x7F;
317 p_sys->i_state = SUBTITLE_BLOCK_PARTIAL;
318 i_packet = *p_buffer++;
321 p_sys->i_image = GETINT16(p_buffer);
323 if( p_sys->i_image != i_expected_image )
325 msg_Warn( p_dec, "expected subtitle image %u but found %u",
326 i_expected_image, p_sys->i_image );
329 if( i_packet != i_expected_packet )
331 msg_Warn( p_dec, "expected subtitle image packet %u but found %u",
332 i_expected_packet, i_packet );
335 p_block->p_buffer += SPU_HEADER_LEN;
336 p_block->i_buffer -= SPU_HEADER_LEN;
338 p_sys->i_packet = i_packet;
339 /* First packet in the subtitle block */
340 if( !p_sys->i_packet ) ParseHeader( p_dec, p_block );
342 block_ChainAppend( &p_sys->p_spu, p_block );
344 if( p_sys->i_state == SUBTITLE_BLOCK_COMPLETE )
346 block_t *p_spu = block_ChainGather( p_sys->p_spu );
348 if( p_spu->i_buffer != p_sys->i_spu_size )
350 msg_Warn( p_dec, "subtitle packets size=%d should be %d",
351 p_spu->i_buffer, p_sys->i_spu_size );
354 dbg_print( (DECODE_DBG_PACKET),
355 "subtitle packet complete, size=%d", p_spu->i_buffer );
357 p_sys->i_state = SUBTITLE_BLOCK_EMPTY;
365 /******************************************************************************
366 The format is roughly as follows (everything is big-endian):
369 -------------------------------------------
370 byte subtitle channel (0..7) in bits 0-3
371 byte subtitle packet number of this subtitle image 0-N,
372 if the subtitle packet is complete, the top bit of the byte is 1.
373 u_int16 subtitle image number
374 u_int16 length in bytes of the rest
375 byte option flags, unknown meaning except bit 3 (0x08) indicates
376 presence of the duration field
378 u_int32 duration in 1/90000ths of a second (optional), start time
379 is as indicated by the PTS in the PES header
382 u_int32 width (must be even)
383 u_int32 height (must be even)
384 byte[16] palette, 4 palette entries, each contains values for
385 Y, U, V and transparency, 0 standing for transparent
387 cmd>>6==1 indicates shift
388 (cmd>>4)&3 is direction from, (0=top,1=left,2=right,3=bottom)
389 u_int32 shift duration in 1/90000ths of a second
390 u_int16 offset of odd-numbered scanlines - subtitle images are
391 given in interlace order
392 byte[] limited RLE image data in interlace order (0,2,4... 1,3,5) with
393 2-bits per palette number
394 ******************************************************************************/
395 static void ParseHeader( decoder_t *p_dec, block_t *p_block )
397 decoder_sys_t *p_sys = p_dec->p_sys;
398 uint8_t *p = p_block->p_buffer;
399 uint8_t i_options, i_options2, i_cmd, i_cmd_arg;
402 p_sys->i_spu_size = GETINT16(p);
406 if( i_options & 0x08 ) { p_sys->i_duration = GETINT32(p); }
407 else p_sys->i_duration = 0; /* Ephemer subtitle */
408 p_sys->i_duration *= 100 / 9;
410 p_sys->i_x_start = GETINT16(p);
411 p_sys->i_y_start = GETINT16(p);
412 p_sys->i_width = GETINT16(p);
413 p_sys->i_height = GETINT16(p);
415 for( i = 0; i < 4; i++ )
417 p_sys->p_palette[i][0] = *p++; /* Y */
418 p_sys->p_palette[i][2] = *p++; /* Cr / V */
419 p_sys->p_palette[i][1] = *p++; /* Cb / U */
420 p_sys->p_palette[i][3] = *p++; /* T */
424 /* We do not really know this, FIXME */
425 if( i_cmd ) {i_cmd_arg = GETINT32(p);}
427 /* Actually, this is measured against a different origin, so we have to
429 p_sys->second_field_offset = GETINT16(p);
430 p_sys->i_image_offset = p - p_block->p_buffer;
431 p_sys->i_image_length = p_sys->i_spu_size - p_sys->i_image_offset;
432 p_sys->metadata_length = p_sys->i_image_offset;
434 if (p_sys && p_sys->i_debug & DECODE_DBG_PACKET)
436 msg_Dbg( p_dec, "x-start: %d, y-start: %d, width: %d, height %d, "
437 "spu size: %d, duration: %lu (d:%d p:%d)",
438 p_sys->i_x_start, p_sys->i_y_start,
439 p_sys->i_width, p_sys->i_height,
440 p_sys->i_spu_size, (long unsigned int) p_sys->i_duration,
441 p_sys->i_image_length, p_sys->i_image_offset);
443 for( i = 0; i < 4; i++ )
445 msg_Dbg( p_dec, "palette[%d]= T: %2x, Y: %2x, u: %2x, v: %2x", i,
446 p_sys->p_palette[i][3], p_sys->p_palette[i][0],
447 p_sys->p_palette[i][1], p_sys->p_palette[i][2] );
452 /*****************************************************************************
453 * DecodePacket: parse and decode an subtitle packet
454 *****************************************************************************
455 * This function parses and decodes an SPU packet and, if valid, returns a
457 *****************************************************************************/
458 static subpicture_t *DecodePacket( decoder_t *p_dec, block_t *p_data )
460 decoder_sys_t *p_sys = p_dec->p_sys;
462 subpicture_region_t *p_region;
466 /* Allocate the subpicture internal data. */
467 p_spu = p_dec->pf_spu_buffer_new( p_dec );
468 if( !p_spu ) return NULL;
470 p_spu->i_x = p_sys->i_x_start;
471 p_spu->i_y = p_sys->i_y_start;
472 p_spu->i_start = p_data->i_pts;
473 p_spu->i_stop = p_data->i_pts + p_sys->i_duration;
474 p_spu->b_ephemer = VLC_TRUE;
476 /* Create new subtitle region */
477 memset( &fmt, 0, sizeof(video_format_t) );
478 fmt.i_chroma = VLC_FOURCC('Y','U','V','P');
481 The video on which the subtitle sits, is scaled, probably
482 4:3. However subtitle bitmaps assume an 1:1 aspect ratio.
484 FIXME: We should get the video aspect ratio from somewhere.
485 Two candidates are the video and the other possibility would be
488 fmt.i_aspect = VOUT_ASPECT_FACTOR;
490 fmt.i_width = fmt.i_visible_width = p_sys->i_width;
491 fmt.i_height = fmt.i_visible_height = p_sys->i_height;
492 fmt.i_x_offset = fmt.i_y_offset = 0;
493 p_region = p_spu->pf_create_region( VLC_OBJECT(p_dec), &fmt );
496 msg_Err( p_dec, "cannot allocate SVCD subtitle region" );
500 p_region->fmt.i_aspect = VOUT_ASPECT_FACTOR;
502 p_spu->p_region = p_region;
503 p_region->i_x = p_region->i_y = 0;
506 fmt.p_palette->i_entries = 4;
507 for( i = 0; i < fmt.p_palette->i_entries; i++ )
509 fmt.p_palette->palette[i][0] = p_sys->p_palette[i][0];
510 fmt.p_palette->palette[i][1] = p_sys->p_palette[i][1];
511 fmt.p_palette->palette[i][2] = p_sys->p_palette[i][2];
512 fmt.p_palette->palette[i][3] = p_sys->p_palette[i][3];
515 SVCDSubRenderImage( p_dec, p_data, p_region );
520 /*****************************************************************************
521 * SVCDSubRenderImage: reorders bytes of image data in subpicture region.
522 *****************************************************************************
524 The image is encoded using two bits per pixel that select a palette
525 entry except that value 0 starts a limited run-length encoding for
526 color 0. When 0 is seen, the next two bits encode one less than the
527 number of pixels, so we can encode run lengths from 1 to 4. These get
528 filled with the color in palette entry 0.
530 The encoding of each line is padded to a whole number of bytes. The
531 first field is padded to an even byte length and the complete subtitle
532 is padded to a 4-byte multiple that always include one zero byte at
535 However we'll transform this so that that the RLE is expanded and
536 interlacing will also be removed.
537 *****************************************************************************/
538 static void SVCDSubRenderImage( decoder_t *p_dec, block_t *p_data,
539 subpicture_region_t *p_region )
541 decoder_sys_t *p_sys = p_dec->p_sys;
542 uint8_t *p_dest = p_region->picture.Y_PIXELS;
543 int i_field; /* The subtitles are interlaced */
544 int i_row, i_column; /* scanline row/column number */
545 uint8_t i_color, i_count;
548 bs_init( &bs, p_data->p_buffer + p_sys->i_image_offset,
549 p_data->i_buffer - p_sys->i_image_offset );
551 for( i_field = 0; i_field < 2; i_field++ )
553 for( i_row = i_field; i_row < p_sys->i_height; i_row += 2 )
555 for( i_column = 0; i_column < p_sys->i_width; i_column++ )
557 i_color = bs_read( &bs, 2 );
558 if( i_color == 0 && (i_count = bs_read( &bs, 2 )) )
560 i_count = __MIN( i_count, p_sys->i_width - i_column );
561 memset( &p_dest[i_row * p_region->picture.Y_PITCH +
562 i_column], 0, i_count + 1 );
567 p_dest[i_row * p_region->picture.Y_PITCH + i_column] = i_color;
574 bs_init( &bs, p_data->p_buffer + p_sys->i_image_offset +
575 p_sys->second_field_offset,
576 p_data->i_buffer - p_sys->i_image_offset -
577 p_sys->second_field_offset );