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