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     mtime_t          i_pts;
  58     mtime_t          i_previous_pts;
  59     mtime_t          i_current_pts;
  60     int              i_current_rate;
  61     picture_t *      p_picture_to_destroy;
  62     vlc_bool_t       b_garbage_pic;
  63     vlc_bool_t       b_after_sequence_header; /* is it the next frame after
  64                                                * the sequence header ?    */
  65     vlc_bool_t       b_slice_i;             /* intra-slice refresh stream */
  66
  67     /*
  68      * Output properties
  69      */
  70     vout_synchro_t *p_synchro;
  71     int            i_aspect;
  72     mtime_t        i_last_frame_pts;
  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_mpeg2dec = NULL;
 127     p_sys->p_synchro  = NULL;
 128     p_sys->p_info     = NULL;
 129     p_sys->i_pts      = mdate() + DEFAULT_PTS_DELAY;
 130     p_sys->i_current_pts  = 0;
 131     p_sys->i_previous_pts = 0;
 132     p_sys->p_picture_to_destroy = NULL;
 133     p_sys->b_garbage_pic = 0;
 134     p_sys->b_slice_i  = 0;
 135     p_sys->b_skip     = 0;
 136
 137 #if defined( __i386__ )
 138     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_MMX )
 139     {
 140         i_accel |= MPEG2_ACCEL_X86_MMX;
 141     }
 142
 143     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_3DNOW )
 144     {
 145         i_accel |= MPEG2_ACCEL_X86_3DNOW;
 146     }
 147
 148     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_MMXEXT )
 149     {
 150         i_accel |= MPEG2_ACCEL_X86_MMXEXT;
 151     }
 152
 153 #elif defined( __powerpc__ ) || defined( SYS_DARWIN )
 154     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_ALTIVEC )
 155     {
 156         i_accel |= MPEG2_ACCEL_PPC_ALTIVEC;
 157     }
 158
 159 #else
 160     /* If we do not know this CPU, trust libmpeg2's feature detection */
 161     i_accel = MPEG2_ACCEL_DETECT;
 162
 163 #endif
 164
 165     /* Set CPU acceleration features */
 166     mpeg2_accel( i_accel );
 167
 168     /* Initialize decoder */
 169     p_sys->p_mpeg2dec = mpeg2_init();
 170     if( p_sys->p_mpeg2dec == NULL)
 171     {
 172         msg_Err( p_dec, "mpeg2_init() failed" );
 173         free( p_sys );
 174         return VLC_EGENERIC;
 175     }
 176
 177     p_sys->p_info = mpeg2_info( p_sys->p_mpeg2dec );
 178
 179     p_dec->pf_decode_video = DecodeBlock;
 180
 181     return VLC_SUCCESS;
 182 }
 183
 184 /*****************************************************************************
 185  * RunDecoder: the libmpeg2 decoder
 186  *****************************************************************************/
 187 static picture_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
 188 {
 189     decoder_sys_t   *p_sys = p_dec->p_sys;
 190     mpeg2_state_t   state;
 191     picture_t       *p_pic;
 192
 193     block_t *p_block;
 194
 195     if( !pp_block || !*pp_block ) return NULL;
 196
 197     p_block = *pp_block;
 198
 199     while( 1 )
 200     {
 201         state = mpeg2_parse( p_sys->p_mpeg2dec );
 202
 203         switch( state )
 204         {
 205         case STATE_BUFFER:
 206             if( !p_block->i_buffer )
 207             {
 208                 block_Release( p_block );
 209                 return NULL;
 210             }
 211
 212             if( (p_block->i_flags&BLOCK_FLAG_DISCONTINUITY) &&
 213                 p_sys->p_synchro &&
 214                 p_sys->p_info->sequence &&
 215                 p_sys->p_info->sequence->width != (unsigned)-1 )
 216             {
 217                 vout_SynchroReset( p_sys->p_synchro );
 218                 if( p_sys->p_info->current_fbuf != NULL
 219                     && p_sys->p_info->current_fbuf->id != NULL )
 220                 {
 221                     p_sys->b_garbage_pic = 1;
 222                     p_pic = p_sys->p_info->current_fbuf->id;
 223                 }
 224                 else
 225                 {
 226                     uint8_t *buf[3];
 227                     buf[0] = buf[1] = buf[2] = NULL;
 228                     if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 229                         break;
 230                     mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 231                 }
 232                 p_sys->p_picture_to_destroy = p_pic;
 233
 234                 if ( p_sys->b_slice_i )
 235                 {
 236                     vout_SynchroNewPicture( p_sys->p_synchro,
 237                         I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate );
 238                     vout_SynchroDecode( p_sys->p_synchro );
 239                     vout_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 240                 }
 241             }
 242
 243             if( p_block->i_pts )
 244             {
 245 #ifdef PIC_FLAG_PTS
 246                 mpeg2_pts( p_sys->p_mpeg2dec, (uint32_t)p_block->i_pts );
 247
 248 #else /* New interface */
 249                 mpeg2_tag_picture( p_sys->p_mpeg2dec,
 250                                    (uint32_t)p_block->i_pts, 0/*dts*/ );
 251 #endif
 252                 p_sys->i_previous_pts = p_sys->i_current_pts;
 253                 p_sys->i_current_pts = p_block->i_pts;
 254             }
 255
 256             p_sys->i_current_rate = p_block->i_rate;
 257
 258             mpeg2_buffer( p_sys->p_mpeg2dec, p_block->p_buffer,
 259                           p_block->p_buffer + p_block->i_buffer );
 260
 261             p_block->i_buffer = 0;
 262             break;
 263
 264         case STATE_SEQUENCE:
 265         {
 266             /* Initialize video output */
 267             uint8_t *buf[3];
 268             buf[0] = buf[1] = buf[2] = NULL;
 269
 270             /* Check whether the input gave a particular aspect ratio */
 271             if( p_dec->fmt_in.video.i_aspect )
 272             {
 273                 p_sys->i_aspect = p_dec->fmt_in.video.i_aspect;
 274                 if( p_sys->i_aspect <= AR_221_1_PICTURE )
 275                 switch( p_sys->i_aspect )
 276                 {
 277                 case AR_3_4_PICTURE:
 278                     p_sys->i_aspect = VOUT_ASPECT_FACTOR * 4 / 3;
 279                     break;
 280                 case AR_16_9_PICTURE:
 281                     p_sys->i_aspect = VOUT_ASPECT_FACTOR * 16 / 9;
 282                     break;
 283                 case AR_221_1_PICTURE:
 284                     p_sys->i_aspect = VOUT_ASPECT_FACTOR * 221 / 100;
 285                     break;
 286                 case AR_SQUARE_PICTURE:
 287                     p_sys->i_aspect = VOUT_ASPECT_FACTOR *
 288                                    p_sys->p_info->sequence->width /
 289                                    p_sys->p_info->sequence->height;
 290                     break;
 291                 }
 292             }
 293             else
 294             {
 295                 /* Use the value provided in the MPEG sequence header */
 296                 if( p_sys->p_info->sequence->pixel_height > 0 )
 297                 {
 298                     p_sys->i_aspect =
 299                         ((uint64_t)p_sys->p_info->sequence->display_width) *
 300                         p_sys->p_info->sequence->pixel_width *
 301                         VOUT_ASPECT_FACTOR /
 302                         p_sys->p_info->sequence->display_height /
 303                         p_sys->p_info->sequence->pixel_height;
 304                 }
 305                 else
 306                 {
 307                     /* Invalid aspect, assume 4:3.
 308                      * This shouldn't happen and if it does it is a bug
 309                      * in libmpeg2 (likely triggered by an invalid stream) */
 310                     p_sys->i_aspect = VOUT_ASPECT_FACTOR * 4 / 3;
 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             /* For still frames */
 484             if( state == STATE_END && p_pic ) p_pic->b_force = VLC_TRUE;
 485
 486             if( p_pic )
 487             {
 488                 /* Avoid frames with identical timestamps.
 489                  * Especially needed for still frames in DVD menus. */
 490                 if( p_sys->i_last_frame_pts == p_pic->date ) p_pic->date++;
 491                 p_sys->i_last_frame_pts = p_pic->date;
 492
 493                 return p_pic;
 494             }
 495
 496             break;
 497
 498         case STATE_INVALID:
 499         {
 500             uint8_t *buf[3];
 501             buf[0] = buf[1] = buf[2] = NULL;
 502
 503             msg_Warn( p_dec, "invalid picture encountered" );
 504             if ( ( p_sys->p_info->current_picture == NULL ) ||
 505                ( ( p_sys->p_info->current_picture->flags &
 506                    PIC_MASK_CODING_TYPE) != B_CODING_TYPE ) )
 507             {
 508                 if( p_sys->p_synchro ) vout_SynchroReset( p_sys->p_synchro );
 509             }
 510             mpeg2_skip( p_sys->p_mpeg2dec, 1 );
 511             p_sys->b_skip = 1;
 512
 513             if( p_sys->p_info->current_fbuf &&
 514                 p_sys->p_info->current_fbuf->id )
 515             {
 516                 p_sys->b_garbage_pic = 1;
 517                 p_pic = p_sys->p_info->current_fbuf->id;
 518             }
 519             else if( !p_sys->p_info->sequence )
 520             {
 521                 break;
 522             }
 523             else
 524             {
 525                 if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 526                     break;
 527                 mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 528             }
 529             p_sys->p_picture_to_destroy = p_pic;
 530
 531             memset( p_pic->p[0].p_pixels, 0,
 532                     p_sys->p_info->sequence->width
 533                      * p_sys->p_info->sequence->height );
 534             memset( p_pic->p[1].p_pixels, 0x80,
 535                     p_sys->p_info->sequence->width
 536                      * p_sys->p_info->sequence->height / 4 );
 537             memset( p_pic->p[2].p_pixels, 0x80,
 538                     p_sys->p_info->sequence->width
 539                      * p_sys->p_info->sequence->height / 4 );
 540
 541             if( p_sys->b_slice_i )
 542             {
 543                 vout_SynchroNewPicture( p_sys->p_synchro,
 544                             I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate );
 545                 vout_SynchroDecode( p_sys->p_synchro );
 546                 vout_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 547             }
 548             break;
 549         }
 550
 551         default:
 552             break;
 553         }
 554     }
 555
 556     /* Never reached */
 557     return NULL;
 558 }
 559
 560 /*****************************************************************************
 561  * CloseDecoder: libmpeg2 decoder destruction
 562  *****************************************************************************/
 563 static void CloseDecoder( vlc_object_t *p_this )
 564 {
 565     decoder_t *p_dec = (decoder_t *)p_this;
 566     decoder_sys_t *p_sys = p_dec->p_sys;
 567
 568     if( p_sys->p_synchro ) vout_SynchroRelease( p_sys->p_synchro );
 569
 570     if( p_sys->p_mpeg2dec ) mpeg2_close( p_sys->p_mpeg2dec );
 571
 572     free( p_sys );
 573 }
 574
 575 /*****************************************************************************
 576  * GetNewPicture: Get a new picture from the vout and set the buf struct
 577  *****************************************************************************/
 578 static picture_t *GetNewPicture( decoder_t *p_dec, uint8_t **pp_buf )
 579 {
 580     decoder_sys_t *p_sys = p_dec->p_sys;
 581     picture_t *p_pic;
 582
 583     p_dec->fmt_out.video.i_width = p_sys->p_info->sequence->width;
 584     p_dec->fmt_out.video.i_height = p_sys->p_info->sequence->height;
 585     p_dec->fmt_out.video.i_aspect = p_sys->i_aspect;
 586
 587     p_dec->fmt_out.i_codec =
 588         ( p_sys->p_info->sequence->chroma_height <
 589           p_sys->p_info->sequence->height ) ?
 590         VLC_FOURCC('I','4','2','0') : VLC_FOURCC('I','4','2','2');
 591
 592     /* Get a new picture */
 593     p_pic = p_dec->pf_vout_buffer_new( p_dec );
 594
 595     if( p_pic == NULL ) return NULL;
 596
 597     p_pic->b_progressive = p_sys->p_info->current_picture != NULL ?
 598         p_sys->p_info->current_picture->flags & PIC_FLAG_PROGRESSIVE_FRAME : 1;
 599     p_pic->b_top_field_first = p_sys->p_info->current_picture != NULL ?
 600         p_sys->p_info->current_picture->flags & PIC_FLAG_TOP_FIELD_FIRST : 1;
 601     p_pic->i_nb_fields = p_sys->p_info->current_picture != NULL ?
 602         p_sys->p_info->current_picture->nb_fields : 2;
 603
 604     p_dec->pf_picture_link( p_dec, p_pic );
 605
 606     pp_buf[0] = p_pic->p[0].p_pixels;
 607     pp_buf[1] = p_pic->p[1].p_pixels;
 608     pp_buf[2] = p_pic->p[2].p_pixels;
 609
 610     return p_pic;
 611 }