Converted globalhotkeys to XCB.
[vlc.git] / modules / packetizer / mpegvideo.c
1 /*****************************************************************************
2  * mpegvideo.c: parse and packetize an MPEG1/2 video stream
3  *****************************************************************************
4  * Copyright (C) 2001-2006 the VideoLAN team
5  * $Id$
6  *
7  * Authors: Laurent Aimar <fenrir@via.ecp.fr>
8  *          Eric Petit <titer@videolan.org>
9  *          Gildas Bazin <gbazin@videolan.org>
10  *          Jean-Paul Saman <jpsaman #_at_# m2x dot nl>
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  * Problem with this implementation:
29  *
30  * Although we should time-stamp each picture with a PTS, this isn't possible
31  * with the current implementation.
32  * The problem comes from the fact that for non-low-delay streams we can't
33  * calculate the PTS of pictures used as backward reference. Even the temporal
34  * reference number doesn't help here because all the pictures don't
35  * necessarily have the same duration (eg. 3:2 pulldown).
36  *
37  * However this doesn't really matter as far as the MPEG muxers are concerned
38  * because they allow having empty PTS fields. --gibalou
39  *****************************************************************************/
40
41 /*****************************************************************************
42  * Preamble
43  *****************************************************************************/
44
45 #ifdef HAVE_CONFIG_H
46 # include "config.h"
47 #endif
48
49 #include <vlc_common.h>
50 #include <vlc_plugin.h>
51 #include <vlc_block.h>
52 #include <vlc_codec.h>
53 #include <vlc_block_helper.h>
54 #include "../codec/cc.h"
55
56 #define SYNC_INTRAFRAME_TEXT N_("Sync on Intra Frame")
57 #define SYNC_INTRAFRAME_LONGTEXT N_("Normally the packetizer would " \
58     "sync on the next full frame. This flags instructs the packetizer " \
59     "to sync on the first Intra Frame found.")
60
61 /*****************************************************************************
62  * Module descriptor
63  *****************************************************************************/
64 static int  Open ( vlc_object_t * );
65 static void Close( vlc_object_t * );
66
67 vlc_module_begin ()
68     set_category( CAT_SOUT )
69     set_subcategory( SUBCAT_SOUT_PACKETIZER )
70     set_description( N_("MPEG-I/II video packetizer") )
71     set_shortname( N_("MPEG Video") )
72     set_capability( "packetizer", 50 )
73     set_callbacks( Open, Close )
74
75     add_bool( "packetizer-mpegvideo-sync-iframe", 0, NULL, SYNC_INTRAFRAME_TEXT,
76               SYNC_INTRAFRAME_LONGTEXT, true )
77 vlc_module_end ()
78
79 /*****************************************************************************
80  * Local prototypes
81  *****************************************************************************/
82 static block_t *Packetize( decoder_t *, block_t ** );
83 static block_t *ParseMPEGBlock( decoder_t *, block_t * );
84 static block_t *GetCc( decoder_t *p_dec, bool pb_present[4] );
85
86 struct decoder_sys_t
87 {
88     /*
89      * Input properties
90      */
91     block_bytestream_t bytestream;
92     int i_state;
93     size_t i_offset;
94     uint8_t p_startcode[3];
95
96     /* Sequence header and extension */
97     block_t *p_seq;
98     block_t *p_ext;
99
100     /* Current frame being built */
101     block_t    *p_frame;
102     block_t    **pp_last;
103
104     bool b_frame_slice;
105     mtime_t i_pts;
106     mtime_t i_dts;
107
108     /* Sequence properties */
109     int         i_frame_rate;
110     int         i_frame_rate_base;
111     bool  b_seq_progressive;
112     bool  b_low_delay;
113     int         i_aspect_ratio_info;
114     bool  b_inited;
115
116     /* Picture properties */
117     int i_temporal_ref;
118     int i_picture_type;
119     int i_picture_structure;
120     int i_top_field_first;
121     int i_repeat_first_field;
122     int i_progressive_frame;
123
124     mtime_t i_interpolated_dts;
125     mtime_t i_last_ref_pts;
126     bool b_second_field;
127
128     /* Number of pictures since last sequence header */
129     int i_seq_old;
130
131     /* Sync behaviour */
132     bool  b_sync_on_intra_frame;
133     bool  b_discontinuity;
134
135     /* */
136     bool b_cc_reset;
137     uint32_t i_cc_flags;
138     mtime_t i_cc_pts;
139     mtime_t i_cc_dts;
140     cc_data_t cc;
141 };
142
143 enum {
144     STATE_NOSYNC,
145     STATE_NEXT_SYNC
146 };
147
148 /*****************************************************************************
149  * Open:
150  *****************************************************************************/
151 static int Open( vlc_object_t *p_this )
152 {
153     decoder_t *p_dec = (decoder_t*)p_this;
154     decoder_sys_t *p_sys;
155
156     if( p_dec->fmt_in.i_codec != VLC_FOURCC( 'm', 'p', 'g', '1' ) &&
157         p_dec->fmt_in.i_codec != VLC_FOURCC( 'm', 'p', 'g', '2' ) &&
158         p_dec->fmt_in.i_codec != VLC_FOURCC( 'm', 'p', 'g', 'v' ) )
159     {
160         return VLC_EGENERIC;
161     }
162
163     es_format_Init( &p_dec->fmt_out, VIDEO_ES, VLC_FOURCC('m','p','g','v') );
164     p_dec->pf_packetize = Packetize;
165     p_dec->pf_get_cc = GetCc;
166
167     p_dec->p_sys = p_sys = malloc( sizeof( decoder_sys_t ) );
168     if( !p_dec->p_sys )
169         return VLC_ENOMEM;
170     memset( p_dec->p_sys, 0, sizeof( decoder_sys_t ) );
171
172     /* Misc init */
173     p_sys->i_state = STATE_NOSYNC;
174     p_sys->bytestream = block_BytestreamInit();
175     p_sys->p_startcode[0] = 0;
176     p_sys->p_startcode[1] = 0;
177     p_sys->p_startcode[2] = 1;
178     p_sys->i_offset = 0;
179
180     p_sys->p_seq = NULL;
181     p_sys->p_ext = NULL;
182     p_sys->p_frame = NULL;
183     p_sys->pp_last = &p_sys->p_frame;
184     p_sys->b_frame_slice = false;
185
186     p_sys->i_dts = p_sys->i_pts = 0;
187
188     p_sys->i_frame_rate = 1;
189     p_sys->i_frame_rate_base = 1;
190     p_sys->b_seq_progressive = true;
191     p_sys->b_low_delay = true;
192     p_sys->i_seq_old = 0;
193
194     p_sys->i_temporal_ref = 0;
195     p_sys->i_picture_type = 0;
196     p_sys->i_picture_structure = 0x03; /* frame */
197     p_sys->i_top_field_first = 0;
198     p_sys->i_repeat_first_field = 0;
199     p_sys->i_progressive_frame = 0;
200     p_sys->b_inited = 0;
201
202     p_sys->i_interpolated_dts = 0;
203     p_sys->i_last_ref_pts = 0;
204     p_sys->b_second_field = 0;
205
206     p_sys->b_discontinuity = false;
207     p_sys->b_sync_on_intra_frame = var_CreateGetBool( p_dec, "packetizer-mpegvideo-sync-iframe" );
208     if( p_sys->b_sync_on_intra_frame )
209         msg_Dbg( p_dec, "syncing on intra frame now" );
210
211     p_sys->b_cc_reset = false;
212     p_sys->i_cc_pts = 0;
213     p_sys->i_cc_dts = 0;
214     p_sys->i_cc_flags = 0;
215     cc_Init( &p_sys->cc );
216
217     return VLC_SUCCESS;
218 }
219
220 /*****************************************************************************
221  * Close:
222  *****************************************************************************/
223 static void Close( vlc_object_t *p_this )
224 {
225     decoder_t     *p_dec = (decoder_t*)p_this;
226     decoder_sys_t *p_sys = p_dec->p_sys;
227
228     block_BytestreamRelease( &p_sys->bytestream );
229
230     if( p_sys->p_seq )
231     {
232         block_Release( p_sys->p_seq );
233     }
234     if( p_sys->p_ext )
235     {
236         block_Release( p_sys->p_ext );
237     }
238     if( p_sys->p_frame )
239     {
240         block_ChainRelease( p_sys->p_frame );
241     }
242
243     var_Destroy( p_dec, "packetizer-mpegvideo-sync-iframe" );
244
245     free( p_sys );
246 }
247
248 /*****************************************************************************
249  * Packetize:
250  *****************************************************************************/
251 static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
252 {
253     decoder_sys_t *p_sys = p_dec->p_sys;
254     block_t       *p_pic;
255
256     if( pp_block == NULL || *pp_block == NULL )
257     {
258         return NULL;
259     }
260
261     if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
262     {
263         if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
264         {
265             p_sys->i_state = STATE_NOSYNC;
266             block_BytestreamEmpty( &p_sys->bytestream );
267
268             p_sys->b_discontinuity = true;
269             if( p_sys->p_frame )
270                 block_ChainRelease( p_sys->p_frame );
271             p_sys->p_frame = NULL;
272             p_sys->pp_last = &p_sys->p_frame;
273             p_sys->b_frame_slice = false;
274         }
275         p_sys->i_dts = 0;
276         p_sys->i_pts = 0;
277         p_sys->i_interpolated_dts = 0;
278         p_sys->i_last_ref_pts = 0;
279
280         block_Release( *pp_block );
281         return NULL;
282     }
283
284
285     block_BytestreamPush( &p_sys->bytestream, *pp_block );
286
287     while( 1 )
288     {
289         switch( p_sys->i_state )
290         {
291
292         case STATE_NOSYNC:
293             if( block_FindStartcodeFromOffset( &p_sys->bytestream,
294                     &p_sys->i_offset, p_sys->p_startcode, 3 ) == VLC_SUCCESS )
295             {
296                 p_sys->i_state = STATE_NEXT_SYNC;
297             }
298
299             if( p_sys->i_offset )
300             {
301                 block_SkipBytes( &p_sys->bytestream, p_sys->i_offset );
302                 p_sys->i_offset = 0;
303                 block_BytestreamFlush( &p_sys->bytestream );
304             }
305
306             if( p_sys->i_state != STATE_NEXT_SYNC )
307             {
308                 /* Need more data */
309                 return NULL;
310             }
311
312             p_sys->i_offset = 1; /* To find next startcode */
313
314         case STATE_NEXT_SYNC:
315             /* TODO: If p_block == NULL, flush the buffer without checking the
316              * next sync word */
317
318             /* Find the next startcode */
319             if( block_FindStartcodeFromOffset( &p_sys->bytestream,
320                     &p_sys->i_offset, p_sys->p_startcode, 3 ) != VLC_SUCCESS )
321             {
322                 /* Need more data */
323                 return NULL;
324             }
325
326             /* Get the new fragment and set the pts/dts */
327             p_pic = block_New( p_dec, p_sys->i_offset );
328             block_BytestreamFlush( &p_sys->bytestream );
329             p_pic->i_pts = p_sys->bytestream.p_block->i_pts;
330             p_pic->i_dts = p_sys->bytestream.p_block->i_dts;
331
332             block_GetBytes( &p_sys->bytestream, p_pic->p_buffer,
333                             p_pic->i_buffer );
334
335             /* don't reuse the same timestamps several times */
336             if( p_pic->i_buffer >= 4 && p_pic->p_buffer[3] == 0x00 )
337             {
338                 /* We have a picture start code */
339                 p_sys->bytestream.p_block->i_pts = 0;
340                 p_sys->bytestream.p_block->i_dts = 0;
341             }
342
343             p_sys->i_offset = 0;
344
345             /* Get picture if any */
346             if( !( p_pic = ParseMPEGBlock( p_dec, p_pic ) ) )
347             {
348                 p_sys->i_state = STATE_NOSYNC;
349                 break;
350             }
351
352             /* If a discontinuity has been encountered, then wait till
353              * the next Intra frame before continuing with packetizing */
354             if( p_sys->b_discontinuity &&
355                 p_sys->b_sync_on_intra_frame )
356             {
357                 if( p_pic->i_flags & BLOCK_FLAG_TYPE_I )
358                 {
359                     msg_Dbg( p_dec, "synced on intra frame" );
360                     p_sys->b_discontinuity = false;
361                     p_pic->i_flags |= BLOCK_FLAG_DISCONTINUITY;
362                 }
363                 else
364                 {
365                     msg_Dbg( p_dec, "waiting on intra frame" );
366                     p_sys->i_state = STATE_NOSYNC;
367                     block_Release( p_pic );
368                     break;
369                 }
370             }
371
372             /* We've just started the stream, wait for the first PTS.
373              * We discard here so we can still get the sequence header. */
374             if( p_sys->i_dts <= 0 && p_sys->i_pts <= 0 &&
375                 p_sys->i_interpolated_dts <= 0 )
376             {
377                 msg_Dbg( p_dec, "need a starting pts/dts" );
378                 p_sys->i_state = STATE_NOSYNC;
379                 block_Release( p_pic );
380                 break;
381             }
382
383             /* When starting the stream we can have the first frame with
384              * a null DTS (i_interpolated_pts is initialized to 0) */
385             if( !p_pic->i_dts ) p_pic->i_dts = p_pic->i_pts;
386
387             /* So p_block doesn't get re-added several times */
388             *pp_block = block_BytestreamPop( &p_sys->bytestream );
389
390             p_sys->i_state = STATE_NOSYNC;
391
392             return p_pic;
393         }
394     }
395 }
396
397 /*****************************************************************************
398  * GetCc:
399  *****************************************************************************/
400 static block_t *GetCc( decoder_t *p_dec, bool pb_present[4] )
401 {
402     decoder_sys_t *p_sys = p_dec->p_sys;
403     block_t *p_cc;
404     int i;
405
406     for( i = 0; i < 4; i++ )
407         pb_present[i] = p_sys->cc.pb_present[i];
408
409     if( p_sys->cc.i_data <= 0 )
410         return NULL;
411
412     p_cc = block_New( p_dec, p_sys->cc.i_data);
413     if( p_cc )
414     {
415         memcpy( p_cc->p_buffer, p_sys->cc.p_data, p_sys->cc.i_data );
416         p_cc->i_dts = 
417         p_cc->i_pts = p_sys->cc.b_reorder ? p_sys->i_cc_pts : p_sys->i_cc_dts;
418         p_cc->i_flags = ( p_sys->cc.b_reorder  ? p_sys->i_cc_flags : BLOCK_FLAG_TYPE_P ) & ( BLOCK_FLAG_TYPE_I|BLOCK_FLAG_TYPE_P|BLOCK_FLAG_TYPE_B);
419     }
420     cc_Flush( &p_sys->cc );
421     return p_cc;
422 }
423
424 /*****************************************************************************
425  * ParseMPEGBlock: Re-assemble fragments into a block containing a picture
426  *****************************************************************************/
427 static block_t *ParseMPEGBlock( decoder_t *p_dec, block_t *p_frag )
428 {
429     decoder_sys_t *p_sys = p_dec->p_sys;
430     block_t *p_pic = NULL;
431
432     /*
433      * Check if previous picture is finished
434      */
435     if( ( p_sys->b_frame_slice &&
436           (p_frag->p_buffer[3] == 0x00 || p_frag->p_buffer[3] > 0xaf) ) &&
437           p_sys->p_seq == NULL )
438     {
439         /* We have a picture but without a sequence header we can't
440          * do anything */
441         msg_Dbg( p_dec, "waiting for sequence start" );
442         if( p_sys->p_frame ) block_ChainRelease( p_sys->p_frame );
443         p_sys->p_frame = NULL;
444         p_sys->pp_last = &p_sys->p_frame;
445         p_sys->b_frame_slice = false;
446
447     }
448     else if( p_sys->b_frame_slice &&
449              (p_frag->p_buffer[3] == 0x00 || p_frag->p_buffer[3] > 0xaf) )
450     {
451         const bool b_eos = p_frag->p_buffer[3] == 0xb7;
452
453         mtime_t i_duration;
454
455         if( b_eos )
456         {
457             block_ChainLastAppend( &p_sys->pp_last, p_frag );
458             p_frag = NULL;
459         }
460
461         p_pic = block_ChainGather( p_sys->p_frame );
462
463         if( b_eos )
464             p_pic->i_flags |= BLOCK_FLAG_END_OF_SEQUENCE;
465
466         i_duration = (mtime_t)( 1000000 * p_sys->i_frame_rate_base /
467                                 p_sys->i_frame_rate );
468
469         if( !p_sys->b_seq_progressive && p_sys->i_picture_structure != 0x03 )
470         {
471             i_duration /= 2;
472         }
473
474         if( p_sys->b_seq_progressive )
475         {
476             if( p_sys->i_top_field_first == 0 &&
477                 p_sys->i_repeat_first_field == 1 )
478             {
479                 i_duration *= 2;
480             }
481             else if( p_sys->i_top_field_first == 1 &&
482                      p_sys->i_repeat_first_field == 1 )
483             {
484                 i_duration *= 3;
485             }
486         }
487         else
488         {
489             if( p_sys->i_picture_structure == 0x03 )
490             {
491                 if( p_sys->i_progressive_frame && p_sys->i_repeat_first_field )
492                 {
493                     i_duration += i_duration / 2;
494                 }
495             }
496         }
497
498         if( p_sys->b_low_delay || p_sys->i_picture_type == 0x03 )
499         {
500             /* Trivial case (DTS == PTS) */
501             /* Correct interpolated dts when we receive a new pts/dts */
502             if( p_sys->i_pts > 0 ) p_sys->i_interpolated_dts = p_sys->i_pts;
503             if( p_sys->i_dts > 0 ) p_sys->i_interpolated_dts = p_sys->i_dts;
504         }
505         else
506         {
507             /* Correct interpolated dts when we receive a new pts/dts */
508             if( p_sys->i_last_ref_pts > 0 && !p_sys->b_second_field )
509                 p_sys->i_interpolated_dts = p_sys->i_last_ref_pts;
510             if( p_sys->i_dts > 0 ) p_sys->i_interpolated_dts = p_sys->i_dts;
511
512             if( !p_sys->b_second_field )
513                 p_sys->i_last_ref_pts = p_sys->i_pts;
514         }
515
516         p_pic->i_dts = p_sys->i_interpolated_dts;
517         p_sys->i_interpolated_dts += i_duration;
518
519         /* Set PTS only if we have a B frame or if it comes from the stream */
520         if( p_sys->i_pts > 0 )
521         {
522             p_pic->i_pts = p_sys->i_pts;
523         }
524         else if( p_sys->i_picture_type == 0x03 )
525         {
526             p_pic->i_pts = p_pic->i_dts;
527         }
528         else
529         {
530             p_pic->i_pts = 0;
531         }
532
533         switch ( p_sys->i_picture_type )
534         {
535         case 0x01:
536             p_pic->i_flags |= BLOCK_FLAG_TYPE_I;
537             break;
538         case 0x02:
539             p_pic->i_flags |= BLOCK_FLAG_TYPE_P;
540             break;
541         case 0x03:
542             p_pic->i_flags |= BLOCK_FLAG_TYPE_B;
543             break;
544         }
545
546         p_pic->i_length = p_sys->i_interpolated_dts - p_pic->i_dts;
547
548 #if 0
549         msg_Dbg( p_dec, "pic: type=%d dts=%"PRId64" pts-dts=%"PRId64,
550         p_sys->i_picture_type, p_pic->i_dts, p_pic->i_pts - p_pic->i_dts);
551 #endif
552
553         /* Reset context */
554         p_sys->p_frame = NULL;
555         p_sys->pp_last = &p_sys->p_frame;
556         p_sys->b_frame_slice = false;
557
558         if( p_sys->i_picture_structure != 0x03 )
559         {
560             p_sys->b_second_field = !p_sys->b_second_field;
561         }
562         else
563         {
564             p_sys->b_second_field = 0;
565         }
566
567         /* CC */
568         p_sys->b_cc_reset = true;
569         p_sys->i_cc_pts = p_pic->i_pts;
570         p_sys->i_cc_dts = p_pic->i_dts;
571         p_sys->i_cc_flags = p_pic->i_flags;
572     }
573
574     if( !p_pic && p_sys->b_cc_reset )
575     {
576         p_sys->b_cc_reset = false;
577         cc_Flush( &p_sys->cc );
578     }
579
580     if( !p_frag )
581         return p_pic;
582     /*
583      * Check info of current fragment
584      */
585     if( p_frag->p_buffer[3] == 0xb8 )
586     {
587         /* Group start code */
588         if( p_sys->p_seq &&
589             p_sys->i_seq_old > p_sys->i_frame_rate/p_sys->i_frame_rate_base )
590         {
591             /* Usefull for mpeg1: repeat sequence header every second */
592             block_ChainLastAppend( &p_sys->pp_last, block_Duplicate( p_sys->p_seq ) );
593             if( p_sys->p_ext )
594             {
595                 block_ChainLastAppend( &p_sys->pp_last, block_Duplicate( p_sys->p_ext ) );
596             }
597
598             p_sys->i_seq_old = 0;
599         }
600     }
601     else if( p_frag->p_buffer[3] == 0xb3 && p_frag->i_buffer >= 8 )
602     {
603         /* Sequence header code */
604         static const int code_to_frame_rate[16][2] =
605         {
606             { 1, 1 },  /* invalid */
607             { 24000, 1001 }, { 24, 1 }, { 25, 1 },       { 30000, 1001 },
608             { 30, 1 },       { 50, 1 }, { 60000, 1001 }, { 60, 1 },
609             /* Unofficial 15fps from Xing*/
610             { 15, 1001 },
611             /* Unofficial economy rates from libmpeg3 */
612             { 5, 1001 }, { 10, 1001 }, { 12, 1001 }, { 15, 1001 },
613             { 1, 1 },  { 1, 1 }  /* invalid */
614         };
615
616         if( p_sys->p_seq ) block_Release( p_sys->p_seq );
617         if( p_sys->p_ext ) block_Release( p_sys->p_ext );
618
619         p_sys->p_seq = block_Duplicate( p_frag );
620         p_sys->i_seq_old = 0;
621         p_sys->p_ext = NULL;
622
623         p_dec->fmt_out.video.i_width =
624             ( p_frag->p_buffer[4] << 4)|(p_frag->p_buffer[5] >> 4 );
625         p_dec->fmt_out.video.i_height =
626             ( (p_frag->p_buffer[5]&0x0f) << 8 )|p_frag->p_buffer[6];
627         p_sys->i_aspect_ratio_info = p_frag->p_buffer[7] >> 4;
628
629         /* TODO: MPEG1 aspect ratio */
630
631         p_sys->i_frame_rate = code_to_frame_rate[p_frag->p_buffer[7]&0x0f][0];
632         p_sys->i_frame_rate_base =
633             code_to_frame_rate[p_frag->p_buffer[7]&0x0f][1];
634
635         p_dec->fmt_out.video.i_frame_rate = p_sys->i_frame_rate;
636         p_dec->fmt_out.video.i_frame_rate_base = p_sys->i_frame_rate_base;
637
638         p_sys->b_seq_progressive = true;
639         p_sys->b_low_delay = true;
640
641         if ( !p_sys->b_inited )
642         {
643             msg_Dbg( p_dec, "size %dx%d fps=%.3f",
644                  p_dec->fmt_out.video.i_width, p_dec->fmt_out.video.i_height,
645                  p_sys->i_frame_rate / (float)p_sys->i_frame_rate_base );
646             p_sys->b_inited = 1;
647         }
648     }
649     else if( p_frag->p_buffer[3] == 0xb5 )
650     {
651         int i_type = p_frag->p_buffer[4] >> 4;
652
653         /* Extension start code */
654         if( i_type == 0x01 )
655         {
656 #if 0
657             static const int mpeg2_aspect[16][2] =
658             {
659                 {0,1}, {1,1}, {4,3}, {16,9}, {221,100},
660                 {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1},
661                 {0,1}, {0,1}
662             };
663 #endif
664
665             /* sequence extension */
666             if( p_sys->p_ext) block_Release( p_sys->p_ext );
667             p_sys->p_ext = block_Duplicate( p_frag );
668
669             if( p_frag->i_buffer >= 10 )
670             {
671                 p_sys->b_seq_progressive =
672                     p_frag->p_buffer[5]&0x08 ? true : false;
673                 p_sys->b_low_delay =
674                     p_frag->p_buffer[9]&0x80 ? true : false;
675             }
676
677             /* Do not set aspect ratio : in case we're transcoding,
678              * transcode will take our fmt_out as a fmt_in to libmpeg2.
679              * libmpeg2.c will then believe that the user has requested
680              * a specific aspect ratio, which she hasn't. Thus in case
681              * of aspect ratio change, we're screwed. --Meuuh
682              */
683 #if 0
684             p_dec->fmt_out.video.i_aspect =
685                 mpeg2_aspect[p_sys->i_aspect_ratio_info][0] *
686                 VOUT_ASPECT_FACTOR /
687                 mpeg2_aspect[p_sys->i_aspect_ratio_info][1];
688 #endif
689
690         }
691         else if( i_type == 0x08 )
692         {
693             /* picture extension */
694             p_sys->i_picture_structure = p_frag->p_buffer[6]&0x03;
695             p_sys->i_top_field_first   = p_frag->p_buffer[7] >> 7;
696             p_sys->i_repeat_first_field= (p_frag->p_buffer[7]>>1)&0x01;
697             p_sys->i_progressive_frame = p_frag->p_buffer[8] >> 7;
698         }
699     }
700     else if( p_frag->p_buffer[3] == 0xb2 && p_frag->i_buffer > 4 )
701     {
702         cc_Extract( &p_sys->cc, &p_frag->p_buffer[4], p_frag->i_buffer - 4 );
703     }
704     else if( p_frag->p_buffer[3] == 0x00 )
705     {
706         /* Picture start code */
707         p_sys->i_seq_old++;
708
709         if( p_frag->i_buffer >= 6 )
710         {
711             p_sys->i_temporal_ref =
712                 ( p_frag->p_buffer[4] << 2 )|(p_frag->p_buffer[5] >> 6);
713             p_sys->i_picture_type = ( p_frag->p_buffer[5] >> 3 ) & 0x03;
714         }
715
716         p_sys->i_dts = p_frag->i_dts;
717         p_sys->i_pts = p_frag->i_pts;
718     }
719     else if( p_frag->p_buffer[3] >= 0x01 && p_frag->p_buffer[3] <= 0xaf )
720     {
721         /* Slice start code */
722         p_sys->b_frame_slice = true;
723     }
724
725     /* Append the block */
726     block_ChainLastAppend( &p_sys->pp_last, p_frag );
727
728     return p_pic;
729 }