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 * VOUT_ASPECT_FACTOR /
 302                         p_sys->p_info->sequence->display_height /
 303                         p_sys->p_info->sequence->pixel_height;
 304                 }
 305                 else
 306                 {
 307                     /* Handle invalid aspect as square */
 308                     p_sys->i_aspect = VOUT_ASPECT_FACTOR *
 309                                       p_sys->p_info->sequence->width /
 310                                       p_sys->p_info->sequence->height;
 311                 }
 312             }
 313
 314             msg_Dbg( p_dec, "%dx%d, aspect %d, %u.%03u fps",
 315                      p_sys->p_info->sequence->width,
 316                      p_sys->p_info->sequence->height, p_sys->i_aspect,
 317                      (uint32_t)((uint64_t)1001000000 * 27 /
 318                          p_sys->p_info->sequence->frame_period / 1001),
 319                      (uint32_t)((uint64_t)1001000000 * 27 /
 320                          p_sys->p_info->sequence->frame_period % 1001) );
 321
 322             mpeg2_custom_fbuf( p_sys->p_mpeg2dec, 1 );
 323
 324             /* Set the first 2 reference frames */
 325             mpeg2_set_buf( p_sys->p_mpeg2dec, buf, NULL );
 326
 327             if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 328             {
 329                 block_Release( p_block );
 330                 return NULL;
 331             }
 332
 333             mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 334
 335             /* This picture will never go through display_picture. */
 336             p_pic->date = 0;
 337
 338             /* For some reason, libmpeg2 will put this pic twice in
 339              * discard_picture. This can be considered a bug in libmpeg2. */
 340             p_dec->pf_picture_link( p_dec, p_pic );
 341
 342             if( p_sys->p_synchro )
 343             {
 344                 vout_SynchroRelease( p_sys->p_synchro );
 345             }
 346             p_sys->p_synchro = vout_SynchroInit( p_dec,
 347                 (uint32_t)((uint64_t)1001000000 * 27 /
 348                 p_sys->p_info->sequence->frame_period) );
 349             p_sys->b_after_sequence_header = 1;
 350         }
 351         break;
 352
 353         case STATE_PICTURE_2ND:
 354             vout_SynchroNewPicture( p_sys->p_synchro,
 355                 p_sys->p_info->current_picture->flags & PIC_MASK_CODING_TYPE,
 356                 p_sys->p_info->current_picture->nb_fields,
 357                 0, 0, p_sys->i_current_rate );
 358
 359             if( p_sys->b_skip )
 360             {
 361                 vout_SynchroTrash( p_sys->p_synchro );
 362             }
 363             else
 364             {
 365                 vout_SynchroDecode( p_sys->p_synchro );
 366             }
 367             break;
 368
 369         case STATE_PICTURE:
 370         {
 371             uint8_t *buf[3];
 372             mtime_t i_pts;
 373             buf[0] = buf[1] = buf[2] = NULL;
 374
 375             if ( p_sys->b_after_sequence_header &&
 376                  ((p_sys->p_info->current_picture->flags &
 377                        PIC_MASK_CODING_TYPE) == PIC_FLAG_CODING_TYPE_P) )
 378             {
 379                 /* Intra-slice refresh. Simulate a blank I picture. */
 380                 msg_Dbg( p_dec, "intra-slice refresh stream" );
 381                 vout_SynchroNewPicture( p_sys->p_synchro,
 382                     I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate );
 383                 vout_SynchroDecode( p_sys->p_synchro );
 384                 vout_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 385                 p_sys->b_slice_i = 1;
 386             }
 387             p_sys->b_after_sequence_header = 0;
 388
 389 #ifdef PIC_FLAG_PTS
 390             i_pts = p_sys->p_info->current_picture->flags & PIC_FLAG_PTS ?
 391                 ( ( p_sys->p_info->current_picture->pts ==
 392                     (uint32_t)p_sys->i_current_pts ) ?
 393                   p_sys->i_current_pts : p_sys->i_previous_pts ) : 0;
 394
 395 #else /* New interface */
 396
 397             i_pts = p_sys->p_info->current_picture->flags & PIC_FLAG_TAGS ?
 398                 ( ( p_sys->p_info->current_picture->tag ==
 399                     (uint32_t)p_sys->i_current_pts ) ?
 400                   p_sys->i_current_pts : p_sys->i_previous_pts ) : 0;
 401 #endif
 402
 403             /* Hack to handle demuxers which only have DTS timestamps */
 404             if( !i_pts && !p_block->i_pts && p_block->i_dts > 0 )
 405             {
 406                 if( p_sys->p_info->sequence->flags & SEQ_FLAG_LOW_DELAY ||
 407                     (p_sys->p_info->current_picture->flags &
 408                       PIC_MASK_CODING_TYPE) == PIC_FLAG_CODING_TYPE_B )
 409                 {
 410                     i_pts = p_block->i_dts;
 411                 }
 412             }
 413             p_block->i_pts = p_block->i_dts = 0;
 414             /* End hack */
 415
 416             vout_SynchroNewPicture( p_sys->p_synchro,
 417                 p_sys->p_info->current_picture->flags & PIC_MASK_CODING_TYPE,
 418                 p_sys->p_info->current_picture->nb_fields, i_pts,
 419                 0, p_sys->i_current_rate );
 420
 421             if ( !(p_sys->b_slice_i
 422                    && ((p_sys->p_info->current_picture->flags
 423                          & PIC_MASK_CODING_TYPE) == P_CODING_TYPE))
 424                    && !vout_SynchroChoose( p_sys->p_synchro,
 425                               p_sys->p_info->current_picture->flags
 426                                 & PIC_MASK_CODING_TYPE,
 427                               /*p_sys->p_vout->render_time*/ 0 /*FIXME*/ ) )
 428             {
 429                 mpeg2_skip( p_sys->p_mpeg2dec, 1 );
 430                 p_sys->b_skip = 1;
 431                 vout_SynchroTrash( p_sys->p_synchro );
 432                 mpeg2_set_buf( p_sys->p_mpeg2dec, buf, NULL );
 433             }
 434             else
 435             {
 436                 mpeg2_skip( p_sys->p_mpeg2dec, 0 );
 437                 p_sys->b_skip = 0;
 438                 vout_SynchroDecode( p_sys->p_synchro );
 439
 440                 if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 441                 {
 442                     block_Release( p_block );
 443                     return NULL;
 444                 }
 445
 446                 mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 447             }
 448         }
 449         break;
 450
 451         case STATE_END:
 452         case STATE_SLICE:
 453             p_pic = NULL;
 454             if( p_sys->p_info->display_fbuf
 455                 && p_sys->p_info->display_fbuf->id )
 456             {
 457                 p_pic = (picture_t *)p_sys->p_info->display_fbuf->id;
 458
 459                 vout_SynchroEnd( p_sys->p_synchro,
 460                             p_sys->p_info->display_picture->flags
 461                              & PIC_MASK_CODING_TYPE,
 462                             p_sys->b_garbage_pic );
 463                 p_sys->b_garbage_pic = 0;
 464
 465                 if ( p_sys->p_picture_to_destroy != p_pic )
 466                 {
 467                     p_pic->date = vout_SynchroDate( p_sys->p_synchro );
 468                 }
 469                 else
 470                 {
 471                     p_sys->p_picture_to_destroy = NULL;
 472                     p_pic->date = 0;
 473                 }
 474             }
 475
 476             if( p_sys->p_info->discard_fbuf &&
 477                 p_sys->p_info->discard_fbuf->id )
 478             {
 479                 p_dec->pf_picture_unlink( p_dec,
 480                                           p_sys->p_info->discard_fbuf->id );
 481             }
 482
 483             if( p_pic ) return p_pic;
 484
 485             break;
 486
 487         case STATE_INVALID:
 488         {
 489             uint8_t *buf[3];
 490             buf[0] = buf[1] = buf[2] = NULL;
 491
 492             msg_Warn( p_dec, "invalid picture encountered" );
 493             if ( ( p_sys->p_info->current_picture == NULL ) ||
 494                ( ( p_sys->p_info->current_picture->flags &
 495                    PIC_MASK_CODING_TYPE) != B_CODING_TYPE ) )
 496             {
 497                 if( p_sys->p_synchro ) vout_SynchroReset( p_sys->p_synchro );
 498             }
 499             mpeg2_skip( p_sys->p_mpeg2dec, 1 );
 500             p_sys->b_skip = 1;
 501
 502             if( p_sys->p_info->current_fbuf &&
 503                 p_sys->p_info->current_fbuf->id )
 504             {
 505                 p_sys->b_garbage_pic = 1;
 506                 p_pic = p_sys->p_info->current_fbuf->id;
 507             }
 508             else if( !p_sys->p_info->sequence )
 509             {
 510                 break;
 511             }
 512             else
 513             {
 514                 if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 515                     break;
 516                 mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 517             }
 518             p_sys->p_picture_to_destroy = p_pic;
 519
 520             memset( p_pic->p[0].p_pixels, 0,
 521                     p_sys->p_info->sequence->width
 522                      * p_sys->p_info->sequence->height );
 523             memset( p_pic->p[1].p_pixels, 0x80,
 524                     p_sys->p_info->sequence->width
 525                      * p_sys->p_info->sequence->height / 4 );
 526             memset( p_pic->p[2].p_pixels, 0x80,
 527                     p_sys->p_info->sequence->width
 528                      * p_sys->p_info->sequence->height / 4 );
 529
 530             if( p_sys->b_slice_i )
 531             {
 532                 vout_SynchroNewPicture( p_sys->p_synchro,
 533                             I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate );
 534                 vout_SynchroDecode( p_sys->p_synchro );
 535                 vout_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 536             }
 537             break;
 538         }
 539
 540         default:
 541             break;
 542         }
 543     }
 544
 545     /* Never reached */
 546     return NULL;
 547 }
 548
 549 /*****************************************************************************
 550  * CloseDecoder: libmpeg2 decoder destruction
 551  *****************************************************************************/
 552 static void CloseDecoder( vlc_object_t *p_this )
 553 {
 554     decoder_t *p_dec = (decoder_t *)p_this;
 555     decoder_sys_t *p_sys = p_dec->p_sys;
 556
 557     if( p_sys->p_synchro ) vout_SynchroRelease( p_sys->p_synchro );
 558
 559     if( p_sys->p_mpeg2dec ) mpeg2_close( p_sys->p_mpeg2dec );
 560
 561     free( p_sys );
 562 }
 563
 564 /*****************************************************************************
 565  * GetNewPicture: Get a new picture from the vout and set the buf struct
 566  *****************************************************************************/
 567 static picture_t *GetNewPicture( decoder_t *p_dec, uint8_t **pp_buf )
 568 {
 569     decoder_sys_t *p_sys = p_dec->p_sys;
 570     picture_t *p_pic;
 571
 572     p_dec->fmt_out.video.i_width = p_sys->p_info->sequence->width;
 573     p_dec->fmt_out.video.i_height = p_sys->p_info->sequence->height;
 574     p_dec->fmt_out.video.i_aspect = p_sys->i_aspect;
 575
 576     p_dec->fmt_out.i_codec =
 577         ( p_sys->p_info->sequence->chroma_height <
 578           p_sys->p_info->sequence->height ) ?
 579         VLC_FOURCC('I','4','2','0') : VLC_FOURCC('I','4','2','2');
 580
 581     /* Get a new picture */
 582     p_pic = p_dec->pf_vout_buffer_new( p_dec );
 583
 584     if( p_pic == NULL ) return NULL;
 585
 586     p_pic->b_progressive = p_sys->p_info->current_picture != NULL ?
 587         p_sys->p_info->current_picture->flags & PIC_FLAG_PROGRESSIVE_FRAME : 1;
 588     p_pic->b_top_field_first = p_sys->p_info->current_picture != NULL ?
 589         p_sys->p_info->current_picture->flags & PIC_FLAG_TOP_FIELD_FIRST : 1;
 590     p_pic->i_nb_fields = p_sys->p_info->current_picture != NULL ?
 591         p_sys->p_info->current_picture->nb_fields : 2;
 592
 593     p_dec->pf_picture_link( p_dec, p_pic );
 594
 595     pp_buf[0] = p_pic->p[0].p_pixels;
 596     pp_buf[1] = p_pic->p[1].p_pixels;
 597     pp_buf[2] = p_pic->p[2].p_pixels;
 598
 599     return p_pic;
 600 }