git.sesse.net Git - vlc/blob - modules/codec/libmpeg2.c

   1 /*****************************************************************************
   2  * libmpeg2.c: mpeg2 video decoder module making use of libmpeg2.
   3  *****************************************************************************
   4  * Copyright (C) 1999-2001 VideoLAN
   5  * $Id$
   6  *
   7  * Authors: Gildas Bazin <gbazin@netcourrier.com>
   8  *          Christophe Massiot <massiot@via.ecp.fr>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  23  *****************************************************************************/
  24
  25 /*****************************************************************************
  26  * Preamble
  27  *****************************************************************************/
  28 #include <vlc/vlc.h>
  29 #include <vlc/vout.h>
  30 #include <vlc/decoder.h>
  31
  32 #include <mpeg2dec/mpeg2.h>
  33
  34 #include "vout_synchro.h"
  35
  36 /* Aspect ratio (ISO/IEC 13818-2 section 6.3.3, table 6-3) */
  37 #define AR_SQUARE_PICTURE       1                           /* square pixels */
  38 #define AR_3_4_PICTURE          2                        /* 3:4 picture (TV) */
  39 #define AR_16_9_PICTURE         3              /* 16:9 picture (wide screen) */
  40 #define AR_221_1_PICTURE        4                  /* 2.21:1 picture (movie) */
  41
  42 /*****************************************************************************
  43  * decoder_sys_t : libmpeg2 decoder descriptor
  44  *****************************************************************************/
  45 struct decoder_sys_t
  46 {
  47     /*
  48      * libmpeg2 properties
  49      */
  50     mpeg2dec_t          *p_mpeg2dec;
  51     const mpeg2_info_t  *p_info;
  52     vlc_bool_t          b_skip;
  53
  54     /*
  55      * Input properties
  56      */
  57     pes_packet_t     *p_pes;                  /* current PES we are decoding */
  58     mtime_t          i_pts;
  59     mtime_t          i_previous_pts;
  60     mtime_t          i_current_pts;
  61     int              i_current_rate;
  62     picture_t *      p_picture_to_destroy;
  63     vlc_bool_t       b_garbage_pic;
  64     vlc_bool_t       b_after_sequence_header; /* is it the next frame after
  65                                                * the sequence header ?    */
  66     vlc_bool_t       b_slice_i;             /* intra-slice refresh stream */
  67
  68     /*
  69      * Output properties
  70      */
  71     vout_synchro_t *p_synchro;
  72     int i_aspect;
  73
  74 };
  75
  76 /*****************************************************************************
  77  * Local prototypes
  78  *****************************************************************************/
  79 static int  OpenDecoder( vlc_object_t * );
  80 static void CloseDecoder( vlc_object_t * );
  81
  82 static picture_t *DecodeBlock( decoder_t *, block_t ** );
  83
  84 static picture_t *GetNewPicture( decoder_t *, uint8_t ** );
  85
  86 /*****************************************************************************
  87  * Module descriptor
  88  *****************************************************************************/
  89 vlc_module_begin();
  90     set_description( _("MPEG I/II video decoder (using libmpeg2)") );
  91     set_capability( "decoder", 150 );
  92     set_callbacks( OpenDecoder, CloseDecoder );
  93     add_shortcut( "libmpeg2" );
  94 vlc_module_end();
  95
  96 /*****************************************************************************
  97  * OpenDecoder: probe the decoder and return score
  98  *****************************************************************************/
  99 static int OpenDecoder( vlc_object_t *p_this )
 100 {
 101     decoder_t *p_dec = (decoder_t*)p_this;
 102     decoder_sys_t *p_sys;
 103     uint32_t i_accel = 0;
 104
 105     if( p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','g','v') &&
 106         p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','g','1') &&
 107         /* Pinnacle hardware-mpeg1 */
 108         p_dec->fmt_in.i_codec != VLC_FOURCC('P','I','M','1') &&
 109         /* ATI Video */
 110         p_dec->fmt_in.i_codec != VLC_FOURCC('V','C','R','2') &&
 111         p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','g','2') )
 112     {
 113         return VLC_EGENERIC;
 114     }
 115
 116     /* Allocate the memory needed to store the decoder's structure */
 117     if( ( p_dec->p_sys = p_sys =
 118           (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
 119     {
 120         msg_Err( p_dec, "out of memory" );
 121         return VLC_EGENERIC;
 122     }
 123
 124     /* Initialize the thread properties */
 125     memset( p_sys, 0, sizeof(decoder_sys_t) );
 126     p_sys->p_pes      = NULL;
 127     p_sys->p_mpeg2dec = NULL;
 128     p_sys->p_synchro  = NULL;
 129     p_sys->p_info     = NULL;
 130     p_sys->i_pts      = mdate() + DEFAULT_PTS_DELAY;
 131     p_sys->i_current_pts  = 0;
 132     p_sys->i_previous_pts = 0;
 133     p_sys->p_picture_to_destroy = NULL;
 134     p_sys->b_garbage_pic = 0;
 135     p_sys->b_slice_i  = 0;
 136     p_sys->b_skip     = 0;
 137
 138 #if defined( __i386__ )
 139     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_MMX )
 140     {
 141         i_accel |= MPEG2_ACCEL_X86_MMX;
 142     }
 143
 144     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_3DNOW )
 145     {
 146         i_accel |= MPEG2_ACCEL_X86_3DNOW;
 147     }
 148
 149     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_MMXEXT )
 150     {
 151         i_accel |= MPEG2_ACCEL_X86_MMXEXT;
 152     }
 153
 154 #elif defined( __powerpc__ ) || defined( SYS_DARWIN )
 155     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_ALTIVEC )
 156     {
 157         i_accel |= MPEG2_ACCEL_PPC_ALTIVEC;
 158     }
 159
 160 #else
 161     /* If we do not know this CPU, trust libmpeg2's feature detection */
 162     i_accel = MPEG2_ACCEL_DETECT;
 163
 164 #endif
 165
 166     /* Set CPU acceleration features */
 167     mpeg2_accel( i_accel );
 168
 169     /* Initialize decoder */
 170     p_sys->p_mpeg2dec = mpeg2_init();
 171     if( p_sys->p_mpeg2dec == NULL)
 172     {
 173         msg_Err( p_dec, "mpeg2_init() failed" );
 174         free( p_sys );
 175         return VLC_EGENERIC;
 176     }
 177
 178     p_sys->p_info = mpeg2_info( p_sys->p_mpeg2dec );
 179
 180     p_dec->pf_decode_video = DecodeBlock;
 181
 182     return VLC_SUCCESS;
 183 }
 184
 185 /*****************************************************************************
 186  * RunDecoder: the libmpeg2 decoder
 187  *****************************************************************************/
 188 static picture_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
 189 {
 190     decoder_sys_t   *p_sys = p_dec->p_sys;
 191     mpeg2_state_t   state;
 192     picture_t       *p_pic;
 193
 194     block_t *p_block;
 195
 196     if( !pp_block || !*pp_block ) return NULL;
 197
 198     p_block = *pp_block;
 199
 200     while( 1 )
 201     {
 202         state = mpeg2_parse( p_sys->p_mpeg2dec );
 203
 204         switch( state )
 205         {
 206         case STATE_BUFFER:
 207             if( !p_block->i_buffer )
 208             {
 209                 block_Release( p_block );
 210                 return NULL;
 211             }
 212
 213             if( (p_block->i_flags&BLOCK_FLAG_DISCONTINUITY) &&
 214                 p_sys->p_synchro &&
 215                 p_sys->p_info->sequence &&
 216                 p_sys->p_info->sequence->width != (unsigned)-1 )
 217             {
 218                 vout_SynchroReset( p_sys->p_synchro );
 219                 if( p_sys->p_info->current_fbuf != NULL
 220                     && p_sys->p_info->current_fbuf->id != NULL )
 221                 {
 222                     p_sys->b_garbage_pic = 1;
 223                     p_pic = p_sys->p_info->current_fbuf->id;
 224                 }
 225                 else
 226                 {
 227                     uint8_t *buf[3];
 228                     buf[0] = buf[1] = buf[2] = NULL;
 229                     if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 230                         break;
 231                     mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 232                 }
 233                 p_sys->p_picture_to_destroy = p_pic;
 234
 235                 if ( p_sys->b_slice_i )
 236                 {
 237                     vout_SynchroNewPicture( p_sys->p_synchro,
 238                         I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate );
 239                     vout_SynchroDecode( p_sys->p_synchro );
 240                     vout_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 241                 }
 242             }
 243
 244             if( p_block->i_pts )
 245             {
 246 #ifdef PIC_FLAG_PTS
 247                 mpeg2_pts( p_sys->p_mpeg2dec, (uint32_t)p_block->i_pts );
 248
 249 #else /* New interface */
 250                 mpeg2_tag_picture( p_sys->p_mpeg2dec,
 251                                    (uint32_t)p_block->i_pts, 0/*dts*/ );
 252 #endif
 253                 p_sys->i_previous_pts = p_sys->i_current_pts;
 254                 p_sys->i_current_pts = p_block->i_pts;
 255             }
 256
 257             p_sys->i_current_rate = p_block->i_rate;
 258
 259             mpeg2_buffer( p_sys->p_mpeg2dec, p_block->p_buffer,
 260                           p_block->p_buffer + p_block->i_buffer );
 261
 262             p_block->i_buffer = 0;
 263             break;
 264
 265         case STATE_SEQUENCE:
 266         {
 267             /* Initialize video output */
 268             uint8_t *buf[3];
 269             buf[0] = buf[1] = buf[2] = NULL;
 270
 271             /* Check whether the input gave a particular aspect ratio */
 272             if( p_dec->fmt_in.video.i_aspect )
 273             {
 274                 p_sys->i_aspect = p_dec->fmt_in.video.i_aspect;
 275                 if( p_sys->i_aspect <= AR_221_1_PICTURE )
 276                 switch( p_sys->i_aspect )
 277                 {
 278                 case AR_3_4_PICTURE:
 279                     p_sys->i_aspect = VOUT_ASPECT_FACTOR * 4 / 3;
 280                     break;
 281                 case AR_16_9_PICTURE:
 282                     p_sys->i_aspect = VOUT_ASPECT_FACTOR * 16 / 9;
 283                     break;
 284                 case AR_221_1_PICTURE:
 285                     p_sys->i_aspect = VOUT_ASPECT_FACTOR * 221 / 100;
 286                     break;
 287                 case AR_SQUARE_PICTURE:
 288                     p_sys->i_aspect = VOUT_ASPECT_FACTOR *
 289                                    p_sys->p_info->sequence->width /
 290                                    p_sys->p_info->sequence->height;
 291                     break;
 292                 }
 293             }
 294             else
 295             {
 296                 /* Use the value provided in the MPEG sequence header */
 297                 if( p_sys->p_info->sequence->pixel_height > 0 )
 298                 {
 299                     p_sys->i_aspect =
 300                         ((uint64_t)p_sys->p_info->sequence->display_width) *
 301                         p_sys->p_info->sequence->pixel_width *
 302                         VOUT_ASPECT_FACTOR /
 303                         p_sys->p_info->sequence->display_height /
 304                         p_sys->p_info->sequence->pixel_height;
 305                 }
 306                 else
 307                 {
 308                     /* Invalid aspect, assume 4:3.
 309                      * This shouldn't happen and if it does it is a bug
 310                      * in libmpeg2 (likely triggered by an invalid stream) */
 311                     p_sys->i_aspect = VOUT_ASPECT_FACTOR * 4 / 3;
 312                 }
 313             }
 314
 315             msg_Dbg( p_dec, "%dx%d, aspect %d, %u.%03u fps",
 316                      p_sys->p_info->sequence->width,
 317                      p_sys->p_info->sequence->height, p_sys->i_aspect,
 318                      (uint32_t)((uint64_t)1001000000 * 27 /
 319                          p_sys->p_info->sequence->frame_period / 1001),
 320                      (uint32_t)((uint64_t)1001000000 * 27 /
 321                          p_sys->p_info->sequence->frame_period % 1001) );
 322
 323             mpeg2_custom_fbuf( p_sys->p_mpeg2dec, 1 );
 324
 325             /* Set the first 2 reference frames */
 326             mpeg2_set_buf( p_sys->p_mpeg2dec, buf, NULL );
 327
 328             if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 329             {
 330                 block_Release( p_block );
 331                 return NULL;
 332             }
 333
 334             mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 335
 336             /* This picture will never go through display_picture. */
 337             p_pic->date = 0;
 338
 339             /* For some reason, libmpeg2 will put this pic twice in
 340              * discard_picture. This can be considered a bug in libmpeg2. */
 341             p_dec->pf_picture_link( p_dec, p_pic );
 342
 343             if( p_sys->p_synchro )
 344             {
 345                 vout_SynchroRelease( p_sys->p_synchro );
 346             }
 347             p_sys->p_synchro = vout_SynchroInit( p_dec,
 348                 (uint32_t)((uint64_t)1001000000 * 27 /
 349                 p_sys->p_info->sequence->frame_period) );
 350             p_sys->b_after_sequence_header = 1;
 351         }
 352         break;
 353
 354         case STATE_PICTURE_2ND:
 355             vout_SynchroNewPicture( p_sys->p_synchro,
 356                 p_sys->p_info->current_picture->flags & PIC_MASK_CODING_TYPE,
 357                 p_sys->p_info->current_picture->nb_fields,
 358                 0, 0, p_sys->i_current_rate );
 359
 360             if( p_sys->b_skip )
 361             {
 362                 vout_SynchroTrash( p_sys->p_synchro );
 363             }
 364             else
 365             {
 366                 vout_SynchroDecode( p_sys->p_synchro );
 367             }
 368             break;
 369
 370         case STATE_PICTURE:
 371         {
 372             uint8_t *buf[3];
 373             mtime_t i_pts;
 374             buf[0] = buf[1] = buf[2] = NULL;
 375
 376             if ( p_sys->b_after_sequence_header &&
 377                  ((p_sys->p_info->current_picture->flags &
 378                        PIC_MASK_CODING_TYPE) == PIC_FLAG_CODING_TYPE_P) )
 379             {
 380                 /* Intra-slice refresh. Simulate a blank I picture. */
 381                 msg_Dbg( p_dec, "intra-slice refresh stream" );
 382                 vout_SynchroNewPicture( p_sys->p_synchro,
 383                     I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate );
 384                 vout_SynchroDecode( p_sys->p_synchro );
 385                 vout_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 386                 p_sys->b_slice_i = 1;
 387             }
 388             p_sys->b_after_sequence_header = 0;
 389
 390 #ifdef PIC_FLAG_PTS
 391             i_pts = p_sys->p_info->current_picture->flags & PIC_FLAG_PTS ?
 392                 ( ( p_sys->p_info->current_picture->pts ==
 393                     (uint32_t)p_sys->i_current_pts ) ?
 394                   p_sys->i_current_pts : p_sys->i_previous_pts ) : 0;
 395
 396 #else /* New interface */
 397
 398             i_pts = p_sys->p_info->current_picture->flags & PIC_FLAG_TAGS ?
 399                 ( ( p_sys->p_info->current_picture->tag ==
 400                     (uint32_t)p_sys->i_current_pts ) ?
 401                   p_sys->i_current_pts : p_sys->i_previous_pts ) : 0;
 402 #endif
 403
 404             /* Hack to handle demuxers which only have DTS timestamps */
 405             if( !i_pts && !p_block->i_pts && p_block->i_dts > 0 )
 406             {
 407                 if( p_sys->p_info->sequence->flags & SEQ_FLAG_LOW_DELAY ||
 408                     (p_sys->p_info->current_picture->flags &
 409                       PIC_MASK_CODING_TYPE) == PIC_FLAG_CODING_TYPE_B )
 410                 {
 411                     i_pts = p_block->i_dts;
 412                 }
 413             }
 414             p_block->i_pts = p_block->i_dts = 0;
 415             /* End hack */
 416
 417             vout_SynchroNewPicture( p_sys->p_synchro,
 418                 p_sys->p_info->current_picture->flags & PIC_MASK_CODING_TYPE,
 419                 p_sys->p_info->current_picture->nb_fields, i_pts,
 420                 0, p_sys->i_current_rate );
 421
 422             if ( !(p_sys->b_slice_i
 423                    && ((p_sys->p_info->current_picture->flags
 424                          & PIC_MASK_CODING_TYPE) == P_CODING_TYPE))
 425                    && !vout_SynchroChoose( p_sys->p_synchro,
 426                               p_sys->p_info->current_picture->flags
 427                                 & PIC_MASK_CODING_TYPE,
 428                               /*p_sys->p_vout->render_time*/ 0 /*FIXME*/ ) )
 429             {
 430                 mpeg2_skip( p_sys->p_mpeg2dec, 1 );
 431                 p_sys->b_skip = 1;
 432                 vout_SynchroTrash( p_sys->p_synchro );
 433                 mpeg2_set_buf( p_sys->p_mpeg2dec, buf, NULL );
 434             }
 435             else
 436             {
 437                 mpeg2_skip( p_sys->p_mpeg2dec, 0 );
 438                 p_sys->b_skip = 0;
 439                 vout_SynchroDecode( p_sys->p_synchro );
 440
 441                 if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 442                 {
 443                     block_Release( p_block );
 444                     return NULL;
 445                 }
 446
 447                 mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 448             }
 449         }
 450         break;
 451
 452         case STATE_END:
 453         case STATE_SLICE:
 454             p_pic = NULL;
 455             if( p_sys->p_info->display_fbuf
 456                 && p_sys->p_info->display_fbuf->id )
 457             {
 458                 p_pic = (picture_t *)p_sys->p_info->display_fbuf->id;
 459
 460                 vout_SynchroEnd( p_sys->p_synchro,
 461                             p_sys->p_info->display_picture->flags
 462                              & PIC_MASK_CODING_TYPE,
 463                             p_sys->b_garbage_pic );
 464                 p_sys->b_garbage_pic = 0;
 465
 466                 if ( p_sys->p_picture_to_destroy != p_pic )
 467                 {
 468                     p_pic->date = vout_SynchroDate( p_sys->p_synchro );
 469                 }
 470                 else
 471                 {
 472                     p_sys->p_picture_to_destroy = NULL;
 473                     p_pic->date = 0;
 474                 }
 475             }
 476
 477             if( p_sys->p_info->discard_fbuf &&
 478                 p_sys->p_info->discard_fbuf->id )
 479             {
 480                 p_dec->pf_picture_unlink( p_dec,
 481                                           p_sys->p_info->discard_fbuf->id );
 482             }
 483
 484             if( p_pic ) return p_pic;
 485
 486             break;
 487
 488         case STATE_INVALID:
 489         {
 490             uint8_t *buf[3];
 491             buf[0] = buf[1] = buf[2] = NULL;
 492
 493             msg_Warn( p_dec, "invalid picture encountered" );
 494             if ( ( p_sys->p_info->current_picture == NULL ) ||
 495                ( ( p_sys->p_info->current_picture->flags &
 496                    PIC_MASK_CODING_TYPE) != B_CODING_TYPE ) )
 497             {
 498                 if( p_sys->p_synchro ) vout_SynchroReset( p_sys->p_synchro );
 499             }
 500             mpeg2_skip( p_sys->p_mpeg2dec, 1 );
 501             p_sys->b_skip = 1;
 502
 503             if( p_sys->p_info->current_fbuf &&
 504                 p_sys->p_info->current_fbuf->id )
 505             {
 506                 p_sys->b_garbage_pic = 1;
 507                 p_pic = p_sys->p_info->current_fbuf->id;
 508             }
 509             else if( !p_sys->p_info->sequence )
 510             {
 511                 break;
 512             }
 513             else
 514             {
 515                 if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 516                     break;
 517                 mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 518             }
 519             p_sys->p_picture_to_destroy = p_pic;
 520
 521             memset( p_pic->p[0].p_pixels, 0,
 522                     p_sys->p_info->sequence->width
 523                      * p_sys->p_info->sequence->height );
 524             memset( p_pic->p[1].p_pixels, 0x80,
 525                     p_sys->p_info->sequence->width
 526                      * p_sys->p_info->sequence->height / 4 );
 527             memset( p_pic->p[2].p_pixels, 0x80,
 528                     p_sys->p_info->sequence->width
 529                      * p_sys->p_info->sequence->height / 4 );
 530
 531             if( p_sys->b_slice_i )
 532             {
 533                 vout_SynchroNewPicture( p_sys->p_synchro,
 534                             I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate );
 535                 vout_SynchroDecode( p_sys->p_synchro );
 536                 vout_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 537             }
 538             break;
 539         }
 540
 541         default:
 542             break;
 543         }
 544     }
 545
 546     /* Never reached */
 547     return NULL;
 548 }
 549
 550 /*****************************************************************************
 551  * CloseDecoder: libmpeg2 decoder destruction
 552  *****************************************************************************/
 553 static void CloseDecoder( vlc_object_t *p_this )
 554 {
 555     decoder_t *p_dec = (decoder_t *)p_this;
 556     decoder_sys_t *p_sys = p_dec->p_sys;
 557
 558     if( p_sys->p_synchro ) vout_SynchroRelease( p_sys->p_synchro );
 559
 560     if( p_sys->p_mpeg2dec ) mpeg2_close( p_sys->p_mpeg2dec );
 561
 562     free( p_sys );
 563 }
 564
 565 /*****************************************************************************
 566  * GetNewPicture: Get a new picture from the vout and set the buf struct
 567  *****************************************************************************/
 568 static picture_t *GetNewPicture( decoder_t *p_dec, uint8_t **pp_buf )
 569 {
 570     decoder_sys_t *p_sys = p_dec->p_sys;
 571     picture_t *p_pic;
 572
 573     p_dec->fmt_out.video.i_width = p_sys->p_info->sequence->width;
 574     p_dec->fmt_out.video.i_height = p_sys->p_info->sequence->height;
 575     p_dec->fmt_out.video.i_aspect = p_sys->i_aspect;
 576
 577     p_dec->fmt_out.i_codec =
 578         ( p_sys->p_info->sequence->chroma_height <
 579           p_sys->p_info->sequence->height ) ?
 580         VLC_FOURCC('I','4','2','0') : VLC_FOURCC('I','4','2','2');
 581
 582     /* Get a new picture */
 583     p_pic = p_dec->pf_vout_buffer_new( p_dec );
 584
 585     if( p_pic == NULL ) return NULL;
 586
 587     p_pic->b_progressive = p_sys->p_info->current_picture != NULL ?
 588         p_sys->p_info->current_picture->flags & PIC_FLAG_PROGRESSIVE_FRAME : 1;
 589     p_pic->b_top_field_first = p_sys->p_info->current_picture != NULL ?
 590         p_sys->p_info->current_picture->flags & PIC_FLAG_TOP_FIELD_FIRST : 1;
 591     p_pic->i_nb_fields = p_sys->p_info->current_picture != NULL ?
 592         p_sys->p_info->current_picture->nb_fields : 2;
 593
 594     p_dec->pf_picture_link( p_dec, p_pic );
 595
 596     pp_buf[0] = p_pic->p[0].p_pixels;
 597     pp_buf[1] = p_pic->p[1].p_pixels;
 598     pp_buf[2] = p_pic->p[2].p_pixels;
 599
 600     return p_pic;
 601 }