1 /*****************************************************************************
2 * svcdsub.c : Overlay Graphics Text (SVCD subtitles) 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>
39 /*****************************************************************************
41 *****************************************************************************/
42 static int DecoderOpen ( vlc_object_t
* );
43 static int PacketizerOpen( vlc_object_t
* );
44 static void DecoderClose ( vlc_object_t
* );
47 set_description( N_("Philips OGT (SVCD subtitle) decoder") )
48 set_shortname( N_("SVCD subtitles") )
49 set_category( CAT_INPUT
)
50 set_subcategory( SUBCAT_INPUT_SCODEC
)
51 set_capability( "spu decoder", 50 )
52 set_callbacks( DecoderOpen
, DecoderClose
)
54 add_obsolete_integer ( "svcdsub-debug" )
57 set_description( N_("Philips OGT (SVCD subtitle) packetizer") )
58 set_capability( "packetizer", 50 )
59 set_callbacks( PacketizerOpen
, DecoderClose
)
62 /*****************************************************************************
64 *****************************************************************************/
65 static int Decode( decoder_t
*, block_t
* );
66 static block_t
*Packetize ( decoder_t
*, block_t
** );
67 static block_t
*Reassemble ( decoder_t
*, block_t
* );
68 static void ParseHeader( decoder_t
*, block_t
* );
69 static subpicture_t
*DecodePacket( decoder_t
*, block_t
* );
70 static void SVCDSubRenderImage( decoder_t
*, block_t
*, subpicture_region_t
* );
72 #define GETINT16(p) GetWBE(p) ; p +=2;
74 #define GETINT32(p) GetDWBE(p) ; p += 4;
77 SUBTITLE_BLOCK_EMPTY
= 0,
78 SUBTITLE_BLOCK_PARTIAL
= 1,
79 SUBTITLE_BLOCK_COMPLETE
= 2
84 packet_state_t i_state
; /* data-gathering state for this subtitle */
86 block_t
*p_spu
; /* Bytes of the packet. */
88 uint16_t i_image
; /* image number in the subtitle stream */
89 uint8_t i_packet
; /* packet number for above image number */
91 size_t i_spu_size
; /* goal for subtitle_data_pos while gathering,
92 size of used subtitle_data later */
94 uint16_t i_image_offset
; /* offset from subtitle_data to compressed
96 size_t i_image_length
; /* size of the compressed image data */
97 size_t second_field_offset
; /* offset of odd raster lines */
98 size_t metadata_offset
; /* offset to data describing the image */
99 size_t metadata_length
; /* length of metadata */
101 mtime_t i_duration
; /* how long to display the image, 0 stands
102 for "until next subtitle" */
104 uint16_t i_x_start
, i_y_start
; /* position of top leftmost pixel of
105 image when displayed */
106 uint16_t i_width
, i_height
; /* dimensions in pixels of image */
108 uint8_t p_palette
[4][4]; /* Palette of colors used in subtitle */
111 /*****************************************************************************
112 * DecoderOpen: open/initialize the svcdsub decoder.
113 *****************************************************************************/
114 static int DecoderOpen( vlc_object_t
*p_this
)
116 decoder_t
*p_dec
= (decoder_t
*)p_this
;
117 decoder_sys_t
*p_sys
;
119 if( p_dec
->fmt_in
.i_codec
!= VLC_CODEC_OGT
)
122 p_dec
->p_sys
= p_sys
= calloc( 1, sizeof( decoder_sys_t
) );
129 p_sys
->i_state
= SUBTITLE_BLOCK_EMPTY
;
132 p_dec
->fmt_out
.i_codec
= VLC_CODEC_OGT
;
134 p_dec
->pf_decode
= Decode
;
135 p_dec
->pf_packetize
= Packetize
;
140 /*****************************************************************************
141 * PacketizerOpen: open/initialize the svcdsub packetizer.
142 *****************************************************************************/
143 static int PacketizerOpen( vlc_object_t
*p_this
)
145 if( DecoderOpen( p_this
) != VLC_SUCCESS
) return VLC_EGENERIC
;
150 /*****************************************************************************
151 * DecoderClose: closes the svcdsub decoder/packetizer.
152 *****************************************************************************/
153 void DecoderClose( vlc_object_t
*p_this
)
155 decoder_t
*p_dec
= (decoder_t
*)p_this
;
156 decoder_sys_t
*p_sys
= p_dec
->p_sys
;
158 if( p_sys
->p_spu
) block_ChainRelease( p_sys
->p_spu
);
162 /*****************************************************************************
164 *****************************************************************************/
165 static int Decode( decoder_t
*p_dec
, block_t
*p_block
)
168 msg_Dbg( p_dec
, "Decode" );
171 if( p_block
== NULL
) /* No Drain */
172 return VLCDEC_SUCCESS
;
174 if( !(p_block
= Reassemble( p_dec
, p_block
)) )
175 return VLCDEC_SUCCESS
;
177 /* Parse and decode */
178 subpicture_t
*p_spu
= DecodePacket( p_dec
, p_block
);
180 decoder_QueueSub( p_dec
, p_spu
);
181 return VLCDEC_SUCCESS
;
184 /*****************************************************************************
186 *****************************************************************************/
187 static block_t
*Packetize( decoder_t
*p_dec
, block_t
**pp_block
)
189 block_t
*p_block
, *p_spu
;
191 if( pp_block
== NULL
|| *pp_block
== NULL
) return NULL
;
196 if( !(p_spu
= Reassemble( p_dec
, p_block
)) ) return NULL
;
198 p_spu
->i_dts
= p_spu
->i_pts
;
204 /*****************************************************************************
207 The data for single screen subtitle may come in one of many
208 non-contiguous packets of a stream. This routine is called when the
209 next packet in the stream comes in. The job of this routine is to
210 parse the header, if this is the beginning, and combine the packets
211 into one complete subtitle unit.
213 If everything is complete, we will return a block. Otherwise return
217 The format of the beginning of the subtitle packet that is used here.
220 -------------------------------------------
221 byte subtitle channel (0..7) in bits 0-3
222 byte subtitle packet number of this subtitle image 0-N,
223 if the subtitle packet is complete, the top bit of the byte is 1.
224 uint16 subtitle image number
226 *****************************************************************************/
227 #define SPU_HEADER_LEN 5
229 static block_t
*Reassemble( decoder_t
*p_dec
, block_t
*p_block
)
231 decoder_sys_t
*p_sys
= p_dec
->p_sys
;
233 uint16_t i_expected_image
;
234 uint8_t i_packet
, i_expected_packet
;
236 if( p_block
->i_flags
& (BLOCK_FLAG_CORRUPTED
) )
238 block_Release( p_block
);
242 if( p_block
->i_buffer
< SPU_HEADER_LEN
)
244 msg_Dbg( p_dec
, "invalid packet header (size %zu < %u)" ,
245 p_block
->i_buffer
, SPU_HEADER_LEN
);
246 block_Release( p_block
);
250 p_buffer
= p_block
->p_buffer
;
252 if( p_sys
->i_state
== SUBTITLE_BLOCK_EMPTY
)
254 i_expected_image
= p_sys
->i_image
+ 1;
255 i_expected_packet
= 0;
259 i_expected_image
= p_sys
->i_image
;
260 i_expected_packet
= p_sys
->i_packet
+ 1;
263 /* The dummy ES that the menu selection uses has an 0x70 at
264 the head which we need to strip off. */
267 if( *p_buffer
& 0x80 )
269 p_sys
->i_state
= SUBTITLE_BLOCK_COMPLETE
;
270 i_packet
= *p_buffer
++ & 0x7F;
274 p_sys
->i_state
= SUBTITLE_BLOCK_PARTIAL
;
275 i_packet
= *p_buffer
++;
278 p_sys
->i_image
= GETINT16(p_buffer
);
280 if( p_sys
->i_image
!= i_expected_image
)
282 msg_Warn( p_dec
, "expected subtitle image %u but found %u",
283 i_expected_image
, p_sys
->i_image
);
286 if( i_packet
!= i_expected_packet
)
288 msg_Warn( p_dec
, "expected subtitle image packet %u but found %u",
289 i_expected_packet
, i_packet
);
292 p_block
->p_buffer
+= SPU_HEADER_LEN
;
293 p_block
->i_buffer
-= SPU_HEADER_LEN
;
295 p_sys
->i_packet
= i_packet
;
296 /* First packet in the subtitle block */
297 if( !p_sys
->i_packet
) ParseHeader( p_dec
, p_block
);
299 block_ChainAppend( &p_sys
->p_spu
, p_block
);
301 if( p_sys
->i_state
== SUBTITLE_BLOCK_COMPLETE
)
303 block_t
*p_spu
= block_ChainGather( p_sys
->p_spu
);
305 if( unlikely( !p_spu
) )
307 block_ChainRelease( p_sys
->p_spu
);
308 p_sys
->i_state
= SUBTITLE_BLOCK_EMPTY
;
311 msg_Warn( p_dec
, "unable to assemble blocks, discarding" );
315 if( p_spu
->i_buffer
!= p_sys
->i_spu_size
)
317 msg_Warn( p_dec
, "subtitle packets size=%zu should be %zu",
318 p_spu
->i_buffer
, p_sys
->i_spu_size
);
321 msg_Dbg( p_dec
, "subtitle packet complete, size=%zu", p_spu
->i_buffer
);
323 p_sys
->i_state
= SUBTITLE_BLOCK_EMPTY
;
331 /******************************************************************************
332 The format is roughly as follows (everything is big-endian):
335 -------------------------------------------
336 byte subtitle channel (0..7) in bits 0-3
337 byte subtitle packet number of this subtitle image 0-N,
338 if the subtitle packet is complete, the top bit of the byte is 1.
339 u_int16 subtitle image number
340 u_int16 length in bytes of the rest
341 byte option flags, unknown meaning except bit 3 (0x08) indicates
342 presence of the duration field
344 u_int32 duration in 1/90000ths of a second (optional), start time
345 is as indicated by the PTS in the PES header
348 u_int32 width (must be even)
349 u_int32 height (must be even)
350 byte[16] palette, 4 palette entries, each contains values for
351 Y, U, V and transparency, 0 standing for transparent
353 cmd>>6==1 indicates shift
354 (cmd>>4)&3 is direction from, (0=top,1=left,2=right,3=bottom)
355 u_int32 shift duration in 1/90000ths of a second
356 u_int16 offset of odd-numbered scanlines - subtitle images are
357 given in interlace order
358 byte[] limited RLE image data in interlace order (0,2,4... 1,3,5) with
359 2-bits per palette number
360 ******************************************************************************/
361 static void ParseHeader( decoder_t
*p_dec
, block_t
*p_block
)
363 decoder_sys_t
*p_sys
= p_dec
->p_sys
;
364 uint8_t *p
= p_block
->p_buffer
;
365 uint8_t i_options
, i_cmd
;
368 p_sys
->i_spu_size
= GETINT16(p
);
370 // Skip over unused value
373 if( i_options
& 0x08 ) { p_sys
->i_duration
= GETINT32(p
); }
374 else p_sys
->i_duration
= 0; /* Ephemer subtitle */
375 p_sys
->i_duration
*= 100 / 9;
377 p_sys
->i_x_start
= GETINT16(p
);
378 p_sys
->i_y_start
= GETINT16(p
);
379 p_sys
->i_width
= GETINT16(p
);
380 p_sys
->i_height
= GETINT16(p
);
382 for( i
= 0; i
< 4; i
++ )
384 p_sys
->p_palette
[i
][0] = *p
++; /* Y */
385 p_sys
->p_palette
[i
][2] = *p
++; /* Cr / V */
386 p_sys
->p_palette
[i
][1] = *p
++; /* Cb / U */
387 p_sys
->p_palette
[i
][3] = *p
++; /* T */
391 /* We do not really know this, FIXME */
392 if( i_cmd
) { p
+= 4; }
394 /* Actually, this is measured against a different origin, so we have to
396 p_sys
->second_field_offset
= GETINT16(p
);
397 p_sys
->i_image_offset
= p
- p_block
->p_buffer
;
398 p_sys
->i_image_length
= p_sys
->i_spu_size
- p_sys
->i_image_offset
;
399 p_sys
->metadata_length
= p_sys
->i_image_offset
;
402 msg_Dbg( p_dec
, "x-start: %d, y-start: %d, width: %d, height %d, "
403 "spu size: %zu, duration: %"PRIu64
" (d:%zu p:%"PRIu16
")",
404 p_sys
->i_x_start
, p_sys
->i_y_start
,
405 p_sys
->i_width
, p_sys
->i_height
,
406 p_sys
->i_spu_size
, p_sys
->i_duration
,
407 p_sys
->i_image_length
, p_sys
->i_image_offset
);
409 for( i
= 0; i
< 4; i
++ )
411 msg_Dbg( p_dec
, "palette[%d]= T: %2x, Y: %2x, u: %2x, v: %2x", i
,
412 p_sys
->p_palette
[i
][3], p_sys
->p_palette
[i
][0],
413 p_sys
->p_palette
[i
][1], p_sys
->p_palette
[i
][2] );
418 /*****************************************************************************
419 * DecodePacket: parse and decode an subtitle packet
420 *****************************************************************************
421 * This function parses and decodes an SPU packet and, if valid, returns a
423 *****************************************************************************/
424 static subpicture_t
*DecodePacket( decoder_t
*p_dec
, block_t
*p_data
)
426 decoder_sys_t
*p_sys
= p_dec
->p_sys
;
428 subpicture_region_t
*p_region
;
430 video_palette_t palette
;
433 /* Allocate the subpicture internal data. */
434 p_spu
= decoder_NewSubpicture( p_dec
, NULL
);
435 if( !p_spu
) return NULL
;
437 p_spu
->i_start
= p_data
->i_pts
;
438 p_spu
->i_stop
= p_data
->i_pts
+ p_sys
->i_duration
;
439 p_spu
->b_ephemer
= true;
441 /* Create new subtitle region */
442 video_format_Init( &fmt
, VLC_CODEC_YUVP
);
445 The video on which the subtitle sits, is scaled, probably
446 4:3. However subtitle bitmaps assume an 1:1 aspect ratio.
448 FIXME: We should get the video aspect ratio from somewhere.
449 Two candidates are the video and the other possibility would be
452 fmt
.i_sar_num
= p_sys
->i_height
;
453 fmt
.i_sar_den
= p_sys
->i_width
;
455 fmt
.i_width
= fmt
.i_visible_width
= p_sys
->i_width
;
456 fmt
.i_height
= fmt
.i_visible_height
= p_sys
->i_height
;
457 fmt
.i_x_offset
= fmt
.i_y_offset
= 0;
458 fmt
.p_palette
= &palette
;
459 fmt
.p_palette
->i_entries
= 4;
460 for( i
= 0; i
< fmt
.p_palette
->i_entries
; i
++ )
462 fmt
.p_palette
->palette
[i
][0] = p_sys
->p_palette
[i
][0];
463 fmt
.p_palette
->palette
[i
][1] = p_sys
->p_palette
[i
][1];
464 fmt
.p_palette
->palette
[i
][2] = p_sys
->p_palette
[i
][2];
465 fmt
.p_palette
->palette
[i
][3] = p_sys
->p_palette
[i
][3];
468 p_region
= subpicture_region_New( &fmt
);
469 fmt
.p_palette
= NULL
;
470 video_format_Clean( &fmt
);
473 msg_Err( p_dec
, "cannot allocate SVCD subtitle region" );
474 subpicture_Delete( p_spu
);
478 p_spu
->p_region
= p_region
;
479 p_region
->i_x
= p_sys
->i_x_start
;
480 p_region
->i_y
= p_sys
->i_y_start
;
482 SVCDSubRenderImage( p_dec
, p_data
, p_region
);
487 /*****************************************************************************
488 * SVCDSubRenderImage: reorders bytes of image data in subpicture region.
489 *****************************************************************************
491 The image is encoded using two bits per pixel that select a palette
492 entry except that value 0 starts a limited run-length encoding for
493 color 0. When 0 is seen, the next two bits encode one less than the
494 number of pixels, so we can encode run lengths from 1 to 4. These get
495 filled with the color in palette entry 0.
497 The encoding of each line is padded to a whole number of bytes. The
498 first field is padded to an even byte length and the complete subtitle
499 is padded to a 4-byte multiple that always include one zero byte at
502 However we'll transform this so that that the RLE is expanded and
503 interlacing will also be removed.
504 *****************************************************************************/
505 static void SVCDSubRenderImage( decoder_t
*p_dec
, block_t
*p_data
,
506 subpicture_region_t
*p_region
)
508 decoder_sys_t
*p_sys
= p_dec
->p_sys
;
509 uint8_t *p_dest
= p_region
->p_picture
->Y_PIXELS
;
510 int i_field
; /* The subtitles are interlaced */
511 int i_row
, i_column
; /* scanline row/column number */
512 uint8_t i_color
, i_count
;
515 bs_init( &bs
, p_data
->p_buffer
+ p_sys
->i_image_offset
,
516 p_data
->i_buffer
- p_sys
->i_image_offset
);
518 for( i_field
= 0; i_field
< 2; i_field
++ )
520 for( i_row
= i_field
; i_row
< p_sys
->i_height
; i_row
+= 2 )
522 for( i_column
= 0; i_column
< p_sys
->i_width
; i_column
++ )
524 i_color
= bs_read( &bs
, 2 );
525 if( i_color
== 0 && (i_count
= bs_read( &bs
, 2 )) )
527 i_count
= __MIN( i_count
, p_sys
->i_width
- i_column
);
528 memset( &p_dest
[i_row
* p_region
->p_picture
->Y_PITCH
+
529 i_column
], 0, i_count
+ 1 );
534 p_dest
[i_row
* p_region
->p_picture
->Y_PITCH
+ i_column
] = i_color
;
541 bs_init( &bs
, p_data
->p_buffer
+ p_sys
->i_image_offset
+
542 p_sys
->second_field_offset
,
543 p_data
->i_buffer
- p_sys
->i_image_offset
-
544 p_sys
->second_field_offset
);