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@videolan.org>
   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_previous_pts;
  58     mtime_t          i_current_pts;
  59     mtime_t          i_previous_dts;
  60     mtime_t          i_current_dts;
  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     mtime_t        i_last_frame_pts;
  74
  75 };
  76
  77 /*****************************************************************************
  78  * Local prototypes
  79  *****************************************************************************/
  80 static int  OpenDecoder( vlc_object_t * );
  81 static void CloseDecoder( vlc_object_t * );
  82
  83 static picture_t *DecodeBlock( decoder_t *, block_t ** );
  84
  85 static picture_t *GetNewPicture( decoder_t *, uint8_t ** );
  86
  87 /*****************************************************************************
  88  * Module descriptor
  89  *****************************************************************************/
  90 vlc_module_begin();
  91     set_description( _("MPEG I/II video decoder (using libmpeg2)") );
  92     set_capability( "decoder", 150 );
  93     set_category( CAT_INPUT );
  94     set_subcategory( SUBCAT_INPUT_VCODEC );
  95     set_callbacks( OpenDecoder, CloseDecoder );
  96     add_shortcut( "libmpeg2" );
  97 vlc_module_end();
  98
  99 /*****************************************************************************
 100  * OpenDecoder: probe the decoder and return score
 101  *****************************************************************************/
 102 static int OpenDecoder( vlc_object_t *p_this )
 103 {
 104     decoder_t *p_dec = (decoder_t*)p_this;
 105     decoder_sys_t *p_sys;
 106     uint32_t i_accel = 0;
 107
 108     if( p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','g','v') &&
 109         p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','g','1') &&
 110         /* Pinnacle hardware-mpeg1 */
 111         p_dec->fmt_in.i_codec != VLC_FOURCC('P','I','M','1') &&
 112         /* ATI Video */
 113         p_dec->fmt_in.i_codec != VLC_FOURCC('V','C','R','2') &&
 114         p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','g','2') )
 115     {
 116         return VLC_EGENERIC;
 117     }
 118
 119     /* Allocate the memory needed to store the decoder's structure */
 120     if( ( p_dec->p_sys = p_sys =
 121           (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
 122     {
 123         msg_Err( p_dec, "out of memory" );
 124         return VLC_EGENERIC;
 125     }
 126
 127     /* Initialize the thread properties */
 128     memset( p_sys, 0, sizeof(decoder_sys_t) );
 129     p_sys->p_mpeg2dec = NULL;
 130     p_sys->p_synchro  = NULL;
 131     p_sys->p_info     = NULL;
 132     p_sys->i_current_pts  = 0;
 133     p_sys->i_previous_pts = 0;
 134     p_sys->i_current_dts  = 0;
 135     p_sys->i_previous_dts = 0;
 136     p_sys->p_picture_to_destroy = NULL;
 137     p_sys->b_garbage_pic = 0;
 138     p_sys->b_slice_i  = 0;
 139     p_sys->b_skip     = 0;
 140
 141 #if defined( __i386__ )
 142     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_MMX )
 143     {
 144         i_accel |= MPEG2_ACCEL_X86_MMX;
 145     }
 146
 147     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_3DNOW )
 148     {
 149         i_accel |= MPEG2_ACCEL_X86_3DNOW;
 150     }
 151
 152     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_MMXEXT )
 153     {
 154         i_accel |= MPEG2_ACCEL_X86_MMXEXT;
 155     }
 156
 157 #elif defined( __powerpc__ ) || defined( SYS_DARWIN )
 158     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_ALTIVEC )
 159     {
 160         i_accel |= MPEG2_ACCEL_PPC_ALTIVEC;
 161     }
 162
 163 #else
 164     /* If we do not know this CPU, trust libmpeg2's feature detection */
 165     i_accel = MPEG2_ACCEL_DETECT;
 166
 167 #endif
 168
 169     /* Set CPU acceleration features */
 170     mpeg2_accel( i_accel );
 171
 172     /* Initialize decoder */
 173     p_sys->p_mpeg2dec = mpeg2_init();
 174     if( p_sys->p_mpeg2dec == NULL)
 175     {
 176         msg_Err( p_dec, "mpeg2_init() failed" );
 177         free( p_sys );
 178         return VLC_EGENERIC;
 179     }
 180
 181     p_sys->p_info = mpeg2_info( p_sys->p_mpeg2dec );
 182
 183     p_dec->pf_decode_video = DecodeBlock;
 184
 185     return VLC_SUCCESS;
 186 }
 187
 188 /*****************************************************************************
 189  * RunDecoder: the libmpeg2 decoder
 190  *****************************************************************************/
 191 static picture_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
 192 {
 193     decoder_sys_t   *p_sys = p_dec->p_sys;
 194     mpeg2_state_t   state;
 195     picture_t       *p_pic;
 196
 197     block_t *p_block;
 198
 199     if( !pp_block || !*pp_block ) return NULL;
 200
 201     p_block = *pp_block;
 202
 203     while( 1 )
 204     {
 205         state = mpeg2_parse( p_sys->p_mpeg2dec );
 206
 207         switch( state )
 208         {
 209         case STATE_BUFFER:
 210             if( !p_block->i_buffer )
 211             {
 212                 block_Release( p_block );
 213                 return NULL;
 214             }
 215
 216             if( (p_block->i_flags&BLOCK_FLAG_DISCONTINUITY) &&
 217                 p_sys->p_synchro &&
 218                 p_sys->p_info->sequence &&
 219                 p_sys->p_info->sequence->width != (unsigned)-1 )
 220             {
 221                 vout_SynchroReset( p_sys->p_synchro );
 222                 if( p_sys->p_info->current_fbuf != NULL
 223                     && p_sys->p_info->current_fbuf->id != NULL )
 224                 {
 225                     p_sys->b_garbage_pic = 1;
 226                     p_pic = p_sys->p_info->current_fbuf->id;
 227                 }
 228                 else
 229                 {
 230                     uint8_t *buf[3];
 231                     buf[0] = buf[1] = buf[2] = NULL;
 232                     if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 233                         break;
 234                     mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 235                 }
 236                 p_sys->p_picture_to_destroy = p_pic;
 237
 238                 if ( p_sys->b_slice_i )
 239                 {
 240                     vout_SynchroNewPicture( p_sys->p_synchro,
 241                         I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate );
 242                     vout_SynchroDecode( p_sys->p_synchro );
 243                     vout_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 244                 }
 245             }
 246
 247 #ifdef PIC_FLAG_PTS
 248             if( p_block->i_pts )
 249             {
 250                 mpeg2_pts( p_sys->p_mpeg2dec, (uint32_t)p_block->i_pts );
 251
 252 #else /* New interface */
 253             if( p_block->i_pts || p_block->i_dts )
 254             {
 255                 mpeg2_tag_picture( p_sys->p_mpeg2dec,
 256                                    (uint32_t)p_block->i_pts,
 257                                    (uint32_t)p_block->i_dts );
 258 #endif
 259                 p_sys->i_previous_pts = p_sys->i_current_pts;
 260                 p_sys->i_current_pts = p_block->i_pts;
 261                 p_sys->i_previous_dts = p_sys->i_current_dts;
 262                 p_sys->i_current_dts = p_block->i_dts;
 263             }
 264
 265             p_sys->i_current_rate = p_block->i_rate;
 266
 267             mpeg2_buffer( p_sys->p_mpeg2dec, p_block->p_buffer,
 268                           p_block->p_buffer + p_block->i_buffer );
 269
 270             p_block->i_buffer = 0;
 271             break;
 272
 273         case STATE_SEQUENCE:
 274         {
 275             /* Initialize video output */
 276             uint8_t *buf[3];
 277             buf[0] = buf[1] = buf[2] = NULL;
 278
 279             /* Check whether the input gave a particular aspect ratio */
 280             if( p_dec->fmt_in.video.i_aspect )
 281             {
 282                 p_sys->i_aspect = p_dec->fmt_in.video.i_aspect;
 283                 if( p_sys->i_aspect <= AR_221_1_PICTURE )
 284                 switch( p_sys->i_aspect )
 285                 {
 286                 case AR_3_4_PICTURE:
 287                     p_sys->i_aspect = VOUT_ASPECT_FACTOR * 4 / 3;
 288                     break;
 289                 case AR_16_9_PICTURE:
 290                     p_sys->i_aspect = VOUT_ASPECT_FACTOR * 16 / 9;
 291                     break;
 292                 case AR_221_1_PICTURE:
 293                     p_sys->i_aspect = VOUT_ASPECT_FACTOR * 221 / 100;
 294                     break;
 295                 case AR_SQUARE_PICTURE:
 296                     p_sys->i_aspect = VOUT_ASPECT_FACTOR *
 297                                    p_sys->p_info->sequence->width /
 298                                    p_sys->p_info->sequence->height;
 299                     break;
 300                 }
 301             }
 302             else
 303             {
 304                 /* Use the value provided in the MPEG sequence header */
 305                 if( p_sys->p_info->sequence->pixel_height > 0 )
 306                 {
 307                     p_sys->i_aspect =
 308                         ((uint64_t)p_sys->p_info->sequence->display_width) *
 309                         p_sys->p_info->sequence->pixel_width *
 310                         VOUT_ASPECT_FACTOR /
 311                         p_sys->p_info->sequence->display_height /
 312                         p_sys->p_info->sequence->pixel_height;
 313                 }
 314                 else
 315                 {
 316                     /* Invalid aspect, assume 4:3.
 317                      * This shouldn't happen and if it does it is a bug
 318                      * in libmpeg2 (likely triggered by an invalid stream) */
 319                     p_sys->i_aspect = VOUT_ASPECT_FACTOR * 4 / 3;
 320                 }
 321             }
 322
 323             msg_Dbg( p_dec, "%dx%d, aspect %d, %u.%03u fps",
 324                      p_sys->p_info->sequence->width,
 325                      p_sys->p_info->sequence->height, p_sys->i_aspect,
 326                      (uint32_t)((uint64_t)1001000000 * 27 /
 327                          p_sys->p_info->sequence->frame_period / 1001),
 328                      (uint32_t)((uint64_t)1001000000 * 27 /
 329                          p_sys->p_info->sequence->frame_period % 1001) );
 330
 331             mpeg2_custom_fbuf( p_sys->p_mpeg2dec, 1 );
 332
 333             /* Set the first 2 reference frames */
 334             mpeg2_set_buf( p_sys->p_mpeg2dec, buf, NULL );
 335
 336             if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 337             {
 338                 block_Release( p_block );
 339                 return NULL;
 340             }
 341
 342             mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 343
 344             /* This picture will never go through display_picture. */
 345             p_pic->date = 0;
 346
 347             /* For some reason, libmpeg2 will put this pic twice in
 348              * discard_picture. This can be considered a bug in libmpeg2. */
 349             p_dec->pf_picture_link( p_dec, p_pic );
 350
 351             if( p_sys->p_synchro )
 352             {
 353                 vout_SynchroRelease( p_sys->p_synchro );
 354             }
 355             p_sys->p_synchro = vout_SynchroInit( p_dec,
 356                 (uint32_t)((uint64_t)1001000000 * 27 /
 357                 p_sys->p_info->sequence->frame_period) );
 358             p_sys->b_after_sequence_header = 1;
 359         }
 360         break;
 361
 362         case STATE_PICTURE_2ND:
 363             vout_SynchroNewPicture( p_sys->p_synchro,
 364                 p_sys->p_info->current_picture->flags & PIC_MASK_CODING_TYPE,
 365                 p_sys->p_info->current_picture->nb_fields,
 366                 0, 0, p_sys->i_current_rate );
 367
 368             if( p_sys->b_skip )
 369             {
 370                 vout_SynchroTrash( p_sys->p_synchro );
 371             }
 372             else
 373             {
 374                 vout_SynchroDecode( p_sys->p_synchro );
 375             }
 376             break;
 377
 378         case STATE_PICTURE:
 379         {
 380             uint8_t *buf[3];
 381             mtime_t i_pts, i_dts;
 382             buf[0] = buf[1] = buf[2] = NULL;
 383
 384             if ( p_sys->b_after_sequence_header &&
 385                  ((p_sys->p_info->current_picture->flags &
 386                        PIC_MASK_CODING_TYPE) == PIC_FLAG_CODING_TYPE_P) )
 387             {
 388                 /* Intra-slice refresh. Simulate a blank I picture. */
 389                 msg_Dbg( p_dec, "intra-slice refresh stream" );
 390                 vout_SynchroNewPicture( p_sys->p_synchro,
 391                     I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate );
 392                 vout_SynchroDecode( p_sys->p_synchro );
 393                 vout_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 394                 p_sys->b_slice_i = 1;
 395             }
 396             p_sys->b_after_sequence_header = 0;
 397
 398 #ifdef PIC_FLAG_PTS
 399             i_pts = p_sys->p_info->current_picture->flags & PIC_FLAG_PTS ?
 400                 ( ( p_sys->p_info->current_picture->pts ==
 401                     (uint32_t)p_sys->i_current_pts ) ?
 402                   p_sys->i_current_pts : p_sys->i_previous_pts ) : 0;
 403             i_dts = 0;
 404
 405             /* Hack to handle demuxers which only have DTS timestamps */
 406             if( !i_pts && !p_block->i_pts && p_block->i_dts > 0 )
 407             {
 408                 if( p_sys->p_info->sequence->flags & SEQ_FLAG_LOW_DELAY ||
 409                     (p_sys->p_info->current_picture->flags &
 410                       PIC_MASK_CODING_TYPE) == PIC_FLAG_CODING_TYPE_B )
 411                 {
 412                     i_pts = p_block->i_dts;
 413                 }
 414             }
 415             p_block->i_pts = p_block->i_dts = 0;
 416             /* End hack */
 417
 418 #else /* New interface */
 419
 420             i_pts = p_sys->p_info->current_picture->flags & PIC_FLAG_TAGS ?
 421                 ( ( p_sys->p_info->current_picture->tag ==
 422                     (uint32_t)p_sys->i_current_pts ) ?
 423                   p_sys->i_current_pts : p_sys->i_previous_pts ) : 0;
 424             i_dts = p_sys->p_info->current_picture->flags & PIC_FLAG_TAGS ?
 425                 ( ( p_sys->p_info->current_picture->tag2 ==
 426                     (uint32_t)p_sys->i_current_dts ) ?
 427                   p_sys->i_current_dts : p_sys->i_previous_dts ) : 0;
 428 #endif
 429
 430             vout_SynchroNewPicture( p_sys->p_synchro,
 431                 p_sys->p_info->current_picture->flags & PIC_MASK_CODING_TYPE,
 432                 p_sys->p_info->current_picture->nb_fields, i_pts, i_dts,
 433                 p_sys->i_current_rate );
 434
 435             if( !p_dec->b_pace_control &&
 436                 !(p_sys->b_slice_i
 437                    && ((p_sys->p_info->current_picture->flags
 438                          & PIC_MASK_CODING_TYPE) == P_CODING_TYPE))
 439                    && !vout_SynchroChoose( p_sys->p_synchro,
 440                               p_sys->p_info->current_picture->flags
 441                                 & PIC_MASK_CODING_TYPE,
 442                               /*p_sys->p_vout->render_time*/ 0 /*FIXME*/ ) )
 443             {
 444                 mpeg2_skip( p_sys->p_mpeg2dec, 1 );
 445                 p_sys->b_skip = 1;
 446                 vout_SynchroTrash( p_sys->p_synchro );
 447                 mpeg2_set_buf( p_sys->p_mpeg2dec, buf, NULL );
 448             }
 449             else
 450             {
 451                 mpeg2_skip( p_sys->p_mpeg2dec, 0 );
 452                 p_sys->b_skip = 0;
 453                 vout_SynchroDecode( p_sys->p_synchro );
 454
 455                 if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 456                 {
 457                     block_Release( p_block );
 458                     return NULL;
 459                 }
 460
 461                 mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 462             }
 463         }
 464         break;
 465
 466         case STATE_END:
 467         case STATE_SLICE:
 468             p_pic = NULL;
 469             if( p_sys->p_info->display_fbuf
 470                 && p_sys->p_info->display_fbuf->id )
 471             {
 472                 p_pic = (picture_t *)p_sys->p_info->display_fbuf->id;
 473
 474                 vout_SynchroEnd( p_sys->p_synchro,
 475                             p_sys->p_info->display_picture->flags
 476                              & PIC_MASK_CODING_TYPE,
 477                             p_sys->b_garbage_pic );
 478                 p_sys->b_garbage_pic = 0;
 479
 480                 if ( p_sys->p_picture_to_destroy != p_pic )
 481                 {
 482                     p_pic->date = vout_SynchroDate( p_sys->p_synchro );
 483                 }
 484                 else
 485                 {
 486                     p_sys->p_picture_to_destroy = NULL;
 487                     p_pic->date = 0;
 488                 }
 489             }
 490
 491             if( p_sys->p_info->discard_fbuf &&
 492                 p_sys->p_info->discard_fbuf->id )
 493             {
 494                 p_dec->pf_picture_unlink( p_dec,
 495                                           p_sys->p_info->discard_fbuf->id );
 496             }
 497
 498             /* For still frames */
 499             if( state == STATE_END && p_pic ) p_pic->b_force = VLC_TRUE;
 500
 501             if( p_pic )
 502             {
 503                 /* Avoid frames with identical timestamps.
 504                  * Especially needed for still frames in DVD menus. */
 505                 if( p_sys->i_last_frame_pts == p_pic->date ) p_pic->date++;
 506                 p_sys->i_last_frame_pts = p_pic->date;
 507
 508                 return p_pic;
 509             }
 510
 511             break;
 512
 513         case STATE_INVALID:
 514         {
 515             uint8_t *buf[3];
 516             buf[0] = buf[1] = buf[2] = NULL;
 517
 518             msg_Warn( p_dec, "invalid picture encountered" );
 519             if ( ( p_sys->p_info->current_picture == NULL ) ||
 520                ( ( p_sys->p_info->current_picture->flags &
 521                    PIC_MASK_CODING_TYPE) != B_CODING_TYPE ) )
 522             {
 523                 if( p_sys->p_synchro ) vout_SynchroReset( p_sys->p_synchro );
 524             }
 525             mpeg2_skip( p_sys->p_mpeg2dec, 1 );
 526             p_sys->b_skip = 1;
 527
 528             if( p_sys->p_info->current_fbuf &&
 529                 p_sys->p_info->current_fbuf->id )
 530             {
 531                 p_sys->b_garbage_pic = 1;
 532                 p_pic = p_sys->p_info->current_fbuf->id;
 533             }
 534             else if( !p_sys->p_info->sequence )
 535             {
 536                 break;
 537             }
 538             else
 539             {
 540                 if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 541                     break;
 542                 mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 543             }
 544             p_sys->p_picture_to_destroy = p_pic;
 545
 546             memset( p_pic->p[0].p_pixels, 0,
 547                     p_sys->p_info->sequence->width
 548                      * p_sys->p_info->sequence->height );
 549             memset( p_pic->p[1].p_pixels, 0x80,
 550                     p_sys->p_info->sequence->width
 551                      * p_sys->p_info->sequence->height / 4 );
 552             memset( p_pic->p[2].p_pixels, 0x80,
 553                     p_sys->p_info->sequence->width
 554                      * p_sys->p_info->sequence->height / 4 );
 555
 556             if( p_sys->b_slice_i )
 557             {
 558                 vout_SynchroNewPicture( p_sys->p_synchro,
 559                             I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate );
 560                 vout_SynchroDecode( p_sys->p_synchro );
 561                 vout_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 562             }
 563             break;
 564         }
 565
 566         default:
 567             break;
 568         }
 569     }
 570
 571     /* Never reached */
 572     return NULL;
 573 }
 574
 575 /*****************************************************************************
 576  * CloseDecoder: libmpeg2 decoder destruction
 577  *****************************************************************************/
 578 static void CloseDecoder( vlc_object_t *p_this )
 579 {
 580     decoder_t *p_dec = (decoder_t *)p_this;
 581     decoder_sys_t *p_sys = p_dec->p_sys;
 582
 583     if( p_sys->p_synchro ) vout_SynchroRelease( p_sys->p_synchro );
 584
 585     if( p_sys->p_mpeg2dec ) mpeg2_close( p_sys->p_mpeg2dec );
 586
 587     free( p_sys );
 588 }
 589
 590 /*****************************************************************************
 591  * GetNewPicture: Get a new picture from the vout and set the buf struct
 592  *****************************************************************************/
 593 static picture_t *GetNewPicture( decoder_t *p_dec, uint8_t **pp_buf )
 594 {
 595     decoder_sys_t *p_sys = p_dec->p_sys;
 596     picture_t *p_pic;
 597
 598     p_dec->fmt_out.video.i_width = p_sys->p_info->sequence->width;
 599     p_dec->fmt_out.video.i_visible_width =
 600         p_sys->p_info->sequence->picture_width;
 601     p_dec->fmt_out.video.i_height = p_sys->p_info->sequence->height;
 602     p_dec->fmt_out.video.i_visible_height =
 603         p_sys->p_info->sequence->picture_height;
 604     p_dec->fmt_out.video.i_aspect = p_sys->i_aspect;
 605
 606     if( p_sys->p_info->sequence->frame_period > 0 )
 607     {
 608         p_dec->fmt_out.video.i_frame_rate =
 609             (uint32_t)( (uint64_t)1001000000 * 27 /
 610                         p_sys->p_info->sequence->frame_period );
 611         p_dec->fmt_out.video.i_frame_rate_base = 1001;
 612     }
 613
 614     p_dec->fmt_out.i_codec =
 615         ( p_sys->p_info->sequence->chroma_height <
 616           p_sys->p_info->sequence->height ) ?
 617         VLC_FOURCC('I','4','2','0') : VLC_FOURCC('I','4','2','2');
 618
 619     /* Get a new picture */
 620     p_pic = p_dec->pf_vout_buffer_new( p_dec );
 621
 622     if( p_pic == NULL ) return NULL;
 623
 624     p_pic->b_progressive = p_sys->p_info->current_picture != NULL ?
 625         p_sys->p_info->current_picture->flags & PIC_FLAG_PROGRESSIVE_FRAME : 1;
 626     p_pic->b_top_field_first = p_sys->p_info->current_picture != NULL ?
 627         p_sys->p_info->current_picture->flags & PIC_FLAG_TOP_FIELD_FIRST : 1;
 628     p_pic->i_nb_fields = p_sys->p_info->current_picture != NULL ?
 629         p_sys->p_info->current_picture->nb_fields : 2;
 630
 631     p_dec->pf_picture_link( p_dec, p_pic );
 632
 633     pp_buf[0] = p_pic->p[0].p_pixels;
 634     pp_buf[1] = p_pic->p[1].p_pixels;
 635     pp_buf[2] = p_pic->p[2].p_pixels;
 636
 637     return p_pic;
 638 }