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 the VideoLAN team
   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     vlc_bool_t      b_preroll;
  69
  70     /*
  71      * Output properties
  72      */
  73     vout_synchro_t *p_synchro;
  74     int            i_aspect;
  75     mtime_t        i_last_frame_pts;
  76
  77 };
  78
  79 /*****************************************************************************
  80  * Local prototypes
  81  *****************************************************************************/
  82 static int  OpenDecoder( vlc_object_t * );
  83 static void CloseDecoder( vlc_object_t * );
  84
  85 static picture_t *DecodeBlock( decoder_t *, block_t ** );
  86
  87 static picture_t *GetNewPicture( decoder_t *, uint8_t ** );
  88 static void GetAR( decoder_t *p_dec );
  89
  90 /*****************************************************************************
  91  * Module descriptor
  92  *****************************************************************************/
  93 vlc_module_begin();
  94     set_description( _("MPEG I/II video decoder (using libmpeg2)") );
  95     set_capability( "decoder", 150 );
  96     set_category( CAT_INPUT );
  97     set_subcategory( SUBCAT_INPUT_VCODEC );
  98     set_callbacks( OpenDecoder, CloseDecoder );
  99     add_shortcut( "libmpeg2" );
 100 vlc_module_end();
 101
 102 /*****************************************************************************
 103  * OpenDecoder: probe the decoder and return score
 104  *****************************************************************************/
 105 static int OpenDecoder( vlc_object_t *p_this )
 106 {
 107     decoder_t *p_dec = (decoder_t*)p_this;
 108     decoder_sys_t *p_sys;
 109     uint32_t i_accel = 0;
 110
 111     if( p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','g','v') &&
 112         p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','g','1') &&
 113         /* Pinnacle hardware-mpeg1 */
 114         p_dec->fmt_in.i_codec != VLC_FOURCC('P','I','M','1') &&
 115         /* ATI Video */
 116         p_dec->fmt_in.i_codec != VLC_FOURCC('V','C','R','2') &&
 117         p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','g','2') )
 118     {
 119         return VLC_EGENERIC;
 120     }
 121
 122     /* Allocate the memory needed to store the decoder's structure */
 123     if( ( p_dec->p_sys = p_sys =
 124           (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
 125     {
 126         msg_Err( p_dec, "out of memory" );
 127         return VLC_EGENERIC;
 128     }
 129
 130     /* Initialize the thread properties */
 131     memset( p_sys, 0, sizeof(decoder_sys_t) );
 132     p_sys->p_mpeg2dec = NULL;
 133     p_sys->p_synchro  = NULL;
 134     p_sys->p_info     = NULL;
 135     p_sys->i_current_pts  = 0;
 136     p_sys->i_previous_pts = 0;
 137     p_sys->i_current_dts  = 0;
 138     p_sys->i_previous_dts = 0;
 139     p_sys->p_picture_to_destroy = NULL;
 140     p_sys->b_garbage_pic = 0;
 141     p_sys->b_slice_i  = 0;
 142     p_sys->b_skip     = 0;
 143     p_sys->b_preroll = VLC_FALSE;
 144
 145 #if defined( __i386__ ) || defined( __x86_64__ )
 146     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_MMX )
 147     {
 148         i_accel |= MPEG2_ACCEL_X86_MMX;
 149     }
 150
 151     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_3DNOW )
 152     {
 153         i_accel |= MPEG2_ACCEL_X86_3DNOW;
 154     }
 155
 156     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_MMXEXT )
 157     {
 158         i_accel |= MPEG2_ACCEL_X86_MMXEXT;
 159     }
 160
 161 #elif defined( __powerpc__ ) || defined( SYS_DARWIN )
 162     if( p_dec->p_libvlc->i_cpu & CPU_CAPABILITY_ALTIVEC )
 163     {
 164         i_accel |= MPEG2_ACCEL_PPC_ALTIVEC;
 165     }
 166
 167 #else
 168     /* If we do not know this CPU, trust libmpeg2's feature detection */
 169     i_accel = MPEG2_ACCEL_DETECT;
 170
 171 #endif
 172
 173     /* Set CPU acceleration features */
 174     mpeg2_accel( i_accel );
 175
 176     /* Initialize decoder */
 177     p_sys->p_mpeg2dec = mpeg2_init();
 178     if( p_sys->p_mpeg2dec == NULL)
 179     {
 180         msg_Err( p_dec, "mpeg2_init() failed" );
 181         free( p_sys );
 182         return VLC_EGENERIC;
 183     }
 184
 185     p_sys->p_info = mpeg2_info( p_sys->p_mpeg2dec );
 186
 187     p_dec->pf_decode_video = DecodeBlock;
 188
 189     return VLC_SUCCESS;
 190 }
 191
 192 /*****************************************************************************
 193  * RunDecoder: the libmpeg2 decoder
 194  *****************************************************************************/
 195 static picture_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
 196 {
 197     decoder_sys_t   *p_sys = p_dec->p_sys;
 198     mpeg2_state_t   state;
 199     picture_t       *p_pic;
 200
 201     block_t *p_block;
 202
 203     if( !pp_block || !*pp_block ) return NULL;
 204
 205     p_block = *pp_block;
 206
 207     while( 1 )
 208     {
 209         state = mpeg2_parse( p_sys->p_mpeg2dec );
 210
 211         switch( state )
 212         {
 213         case STATE_BUFFER:
 214             if( !p_block->i_buffer )
 215             {
 216                 block_Release( p_block );
 217                 return NULL;
 218             }
 219
 220             if( (p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY
 221                                       | BLOCK_FLAG_CORRUPTED)) &&
 222                 p_sys->p_synchro &&
 223                 p_sys->p_info->sequence &&
 224                 p_sys->p_info->sequence->width != (unsigned)-1 )
 225             {
 226                 vout_SynchroReset( p_sys->p_synchro );
 227                 if( p_sys->p_info->current_fbuf != NULL
 228                     && p_sys->p_info->current_fbuf->id != NULL )
 229                 {
 230                     p_sys->b_garbage_pic = 1;
 231                     p_pic = p_sys->p_info->current_fbuf->id;
 232                 }
 233                 else
 234                 {
 235                     uint8_t *buf[3];
 236                     buf[0] = buf[1] = buf[2] = NULL;
 237                     if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 238                         break;
 239                     mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 240                 }
 241                 p_sys->p_picture_to_destroy = p_pic;
 242
 243                 if ( p_sys->b_slice_i )
 244                 {
 245                     vout_SynchroNewPicture( p_sys->p_synchro,
 246                         I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate,
 247                         p_sys->p_info->sequence->flags & SEQ_FLAG_LOW_DELAY );
 248                     vout_SynchroDecode( p_sys->p_synchro );
 249                     vout_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 250                 }
 251             }
 252
 253             if( p_block->i_flags & BLOCK_FLAG_PREROLL )
 254             {
 255                 p_sys->b_preroll = VLC_TRUE;
 256             }
 257             else if( p_sys->b_preroll )
 258             {
 259                 p_sys->b_preroll = VLC_FALSE;
 260                 /* Reset synchro */
 261                 vout_SynchroReset( p_sys->p_synchro );
 262             }
 263
 264 #ifdef PIC_FLAG_PTS
 265             if( p_block->i_pts )
 266             {
 267                 mpeg2_pts( p_sys->p_mpeg2dec, (uint32_t)p_block->i_pts );
 268
 269 #else /* New interface */
 270             if( p_block->i_pts || p_block->i_dts )
 271             {
 272                 mpeg2_tag_picture( p_sys->p_mpeg2dec,
 273                                    (uint32_t)p_block->i_pts,
 274                                    (uint32_t)p_block->i_dts );
 275 #endif
 276                 p_sys->i_previous_pts = p_sys->i_current_pts;
 277                 p_sys->i_current_pts = p_block->i_pts;
 278                 p_sys->i_previous_dts = p_sys->i_current_dts;
 279                 p_sys->i_current_dts = p_block->i_dts;
 280             }
 281
 282             p_sys->i_current_rate = p_block->i_rate;
 283
 284             mpeg2_buffer( p_sys->p_mpeg2dec, p_block->p_buffer,
 285                           p_block->p_buffer + p_block->i_buffer );
 286
 287             p_block->i_buffer = 0;
 288             break;
 289
 290 #ifdef STATE_SEQUENCE_MODIFIED
 291         case STATE_SEQUENCE_MODIFIED:
 292             GetAR( p_dec );
 293             break;
 294 #endif
 295
 296         case STATE_SEQUENCE:
 297         {
 298             /* Initialize video output */
 299             uint8_t *buf[3];
 300             buf[0] = buf[1] = buf[2] = NULL;
 301
 302             GetAR( p_dec );
 303
 304             mpeg2_custom_fbuf( p_sys->p_mpeg2dec, 1 );
 305
 306             /* Set the first 2 reference frames */
 307             mpeg2_set_buf( p_sys->p_mpeg2dec, buf, NULL );
 308
 309             if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 310             {
 311                 block_Release( p_block );
 312                 return NULL;
 313             }
 314
 315             mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 316
 317             /* This picture will never go through display_picture. */
 318             p_pic->date = 0;
 319
 320             /* For some reason, libmpeg2 will put this pic twice in
 321              * discard_picture. This can be considered a bug in libmpeg2. */
 322             p_dec->pf_picture_link( p_dec, p_pic );
 323
 324             if( p_sys->p_synchro )
 325             {
 326                 vout_SynchroRelease( p_sys->p_synchro );
 327             }
 328             p_sys->p_synchro = vout_SynchroInit( p_dec,
 329                 (uint32_t)((uint64_t)1001000000 * 27 /
 330                 p_sys->p_info->sequence->frame_period) );
 331             p_sys->b_after_sequence_header = 1;
 332         }
 333         break;
 334
 335         case STATE_PICTURE_2ND:
 336             vout_SynchroNewPicture( p_sys->p_synchro,
 337                 p_sys->p_info->current_picture->flags & PIC_MASK_CODING_TYPE,
 338                 p_sys->p_info->current_picture->nb_fields,
 339                 0, 0, p_sys->i_current_rate,
 340                 p_sys->p_info->sequence->flags & SEQ_FLAG_LOW_DELAY );
 341
 342             if( p_sys->b_skip )
 343             {
 344                 vout_SynchroTrash( p_sys->p_synchro );
 345             }
 346             else
 347             {
 348                 vout_SynchroDecode( p_sys->p_synchro );
 349             }
 350             break;
 351
 352         case STATE_PICTURE:
 353         {
 354             uint8_t *buf[3];
 355             mtime_t i_pts, i_dts;
 356             buf[0] = buf[1] = buf[2] = NULL;
 357
 358             if ( p_sys->b_after_sequence_header &&
 359                  ((p_sys->p_info->current_picture->flags &
 360                        PIC_MASK_CODING_TYPE) == PIC_FLAG_CODING_TYPE_P) )
 361             {
 362                 /* Intra-slice refresh. Simulate a blank I picture. */
 363                 msg_Dbg( p_dec, "intra-slice refresh stream" );
 364                 vout_SynchroNewPicture( p_sys->p_synchro,
 365                     I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate,
 366                     p_sys->p_info->sequence->flags & SEQ_FLAG_LOW_DELAY );
 367                 vout_SynchroDecode( p_sys->p_synchro );
 368                 vout_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 369                 p_sys->b_slice_i = 1;
 370             }
 371             p_sys->b_after_sequence_header = 0;
 372
 373 #ifdef PIC_FLAG_PTS
 374             i_pts = p_sys->p_info->current_picture->flags & PIC_FLAG_PTS ?
 375                 ( ( p_sys->p_info->current_picture->pts ==
 376                     (uint32_t)p_sys->i_current_pts ) ?
 377                   p_sys->i_current_pts : p_sys->i_previous_pts ) : 0;
 378             i_dts = 0;
 379
 380             /* Hack to handle demuxers which only have DTS timestamps */
 381             if( !i_pts && !p_block->i_pts && p_block->i_dts > 0 )
 382             {
 383                 if( p_sys->p_info->sequence->flags & SEQ_FLAG_LOW_DELAY ||
 384                     (p_sys->p_info->current_picture->flags &
 385                       PIC_MASK_CODING_TYPE) == PIC_FLAG_CODING_TYPE_B )
 386                 {
 387                     i_pts = p_block->i_dts;
 388                 }
 389             }
 390             p_block->i_pts = p_block->i_dts = 0;
 391             /* End hack */
 392
 393 #else /* New interface */
 394
 395             i_pts = p_sys->p_info->current_picture->flags & PIC_FLAG_TAGS ?
 396                 ( ( p_sys->p_info->current_picture->tag ==
 397                     (uint32_t)p_sys->i_current_pts ) ?
 398                   p_sys->i_current_pts : p_sys->i_previous_pts ) : 0;
 399             i_dts = p_sys->p_info->current_picture->flags & PIC_FLAG_TAGS ?
 400                 ( ( p_sys->p_info->current_picture->tag2 ==
 401                     (uint32_t)p_sys->i_current_dts ) ?
 402                   p_sys->i_current_dts : p_sys->i_previous_dts ) : 0;
 403 #endif
 404
 405             vout_SynchroNewPicture( p_sys->p_synchro,
 406                 p_sys->p_info->current_picture->flags & PIC_MASK_CODING_TYPE,
 407                 p_sys->p_info->current_picture->nb_fields, i_pts, i_dts,
 408                 p_sys->i_current_rate,
 409                 p_sys->p_info->sequence->flags & SEQ_FLAG_LOW_DELAY );
 410
 411             if( !p_dec->b_pace_control && !p_sys->b_preroll &&
 412                 !(p_sys->b_slice_i
 413                    && ((p_sys->p_info->current_picture->flags
 414                          & PIC_MASK_CODING_TYPE) == P_CODING_TYPE))
 415                    && !vout_SynchroChoose( p_sys->p_synchro,
 416                               p_sys->p_info->current_picture->flags
 417                                 & PIC_MASK_CODING_TYPE,
 418                               /*p_sys->p_vout->render_time*/ 0 /*FIXME*/,
 419                               p_sys->p_info->sequence->flags & SEQ_FLAG_LOW_DELAY ) )
 420             {
 421                 mpeg2_skip( p_sys->p_mpeg2dec, 1 );
 422                 p_sys->b_skip = 1;
 423                 vout_SynchroTrash( p_sys->p_synchro );
 424                 mpeg2_set_buf( p_sys->p_mpeg2dec, buf, NULL );
 425             }
 426             else
 427             {
 428                 mpeg2_skip( p_sys->p_mpeg2dec, 0 );
 429                 p_sys->b_skip = 0;
 430                 vout_SynchroDecode( p_sys->p_synchro );
 431
 432                 if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 433                 {
 434                     block_Release( p_block );
 435                     return NULL;
 436                 }
 437
 438                 mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 439             }
 440         }
 441         break;
 442
 443         case STATE_END:
 444         case STATE_SLICE:
 445             p_pic = NULL;
 446             if( p_sys->p_info->display_fbuf
 447                 && p_sys->p_info->display_fbuf->id )
 448             {
 449                 p_pic = (picture_t *)p_sys->p_info->display_fbuf->id;
 450
 451                 vout_SynchroEnd( p_sys->p_synchro,
 452                             p_sys->p_info->display_picture->flags
 453                              & PIC_MASK_CODING_TYPE,
 454                             p_sys->b_garbage_pic );
 455                 p_sys->b_garbage_pic = 0;
 456
 457                 if ( p_sys->p_picture_to_destroy != p_pic )
 458                 {
 459                     p_pic->date = vout_SynchroDate( p_sys->p_synchro );
 460                 }
 461                 else
 462                 {
 463                     p_sys->p_picture_to_destroy = NULL;
 464                     p_pic->date = 0;
 465                 }
 466             }
 467
 468             if( p_sys->p_info->discard_fbuf &&
 469                 p_sys->p_info->discard_fbuf->id )
 470             {
 471                 p_dec->pf_picture_unlink( p_dec,
 472                                           p_sys->p_info->discard_fbuf->id );
 473             }
 474
 475             /* For still frames */
 476             if( state == STATE_END && p_pic ) p_pic->b_force = VLC_TRUE;
 477
 478             if( p_pic )
 479             {
 480                 /* Avoid frames with identical timestamps.
 481                  * Especially needed for still frames in DVD menus. */
 482                 if( p_sys->i_last_frame_pts == p_pic->date ) p_pic->date++;
 483                 p_sys->i_last_frame_pts = p_pic->date;
 484
 485                 return p_pic;
 486             }
 487
 488             break;
 489
 490         case STATE_INVALID:
 491         {
 492             uint8_t *buf[3];
 493             buf[0] = buf[1] = buf[2] = NULL;
 494
 495             msg_Warn( p_dec, "invalid picture encountered" );
 496             if ( ( p_sys->p_info->current_picture == NULL ) ||
 497                ( ( p_sys->p_info->current_picture->flags &
 498                    PIC_MASK_CODING_TYPE) != B_CODING_TYPE ) )
 499             {
 500                 if( p_sys->p_synchro ) vout_SynchroReset( p_sys->p_synchro );
 501             }
 502             mpeg2_skip( p_sys->p_mpeg2dec, 1 );
 503             p_sys->b_skip = 1;
 504
 505             if( p_sys->p_info->current_fbuf &&
 506                 p_sys->p_info->current_fbuf->id )
 507             {
 508                 p_sys->b_garbage_pic = 1;
 509                 p_pic = p_sys->p_info->current_fbuf->id;
 510             }
 511             else if( !p_sys->p_info->sequence )
 512             {
 513                 break;
 514             }
 515             else
 516             {
 517                 if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 518                     break;
 519                 mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 520             }
 521             p_sys->p_picture_to_destroy = p_pic;
 522
 523             memset( p_pic->p[0].p_pixels, 0,
 524                     p_sys->p_info->sequence->width
 525                      * p_sys->p_info->sequence->height );
 526             memset( p_pic->p[1].p_pixels, 0x80,
 527                     p_sys->p_info->sequence->width
 528                      * p_sys->p_info->sequence->height / 4 );
 529             memset( p_pic->p[2].p_pixels, 0x80,
 530                     p_sys->p_info->sequence->width
 531                      * p_sys->p_info->sequence->height / 4 );
 532
 533             if( p_sys->b_slice_i )
 534             {
 535                 vout_SynchroNewPicture( p_sys->p_synchro,
 536                         I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate,
 537                         p_sys->p_info->sequence->flags & SEQ_FLAG_LOW_DELAY );
 538                 vout_SynchroDecode( p_sys->p_synchro );
 539                 vout_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 540             }
 541             break;
 542         }
 543
 544         default:
 545             break;
 546         }
 547     }
 548
 549     /* Never reached */
 550     return NULL;
 551 }
 552
 553 /*****************************************************************************
 554  * CloseDecoder: libmpeg2 decoder destruction
 555  *****************************************************************************/
 556 static void CloseDecoder( vlc_object_t *p_this )
 557 {
 558     decoder_t *p_dec = (decoder_t *)p_this;
 559     decoder_sys_t *p_sys = p_dec->p_sys;
 560
 561     if( p_sys->p_synchro ) vout_SynchroRelease( p_sys->p_synchro );
 562
 563     if( p_sys->p_mpeg2dec ) mpeg2_close( p_sys->p_mpeg2dec );
 564
 565     free( p_sys );
 566 }
 567
 568 /*****************************************************************************
 569  * GetNewPicture: Get a new picture from the vout and set the buf struct
 570  *****************************************************************************/
 571 static picture_t *GetNewPicture( decoder_t *p_dec, uint8_t **pp_buf )
 572 {
 573     decoder_sys_t *p_sys = p_dec->p_sys;
 574     picture_t *p_pic;
 575
 576     p_dec->fmt_out.video.i_width = p_sys->p_info->sequence->width;
 577     p_dec->fmt_out.video.i_visible_width =
 578         p_sys->p_info->sequence->picture_width;
 579     p_dec->fmt_out.video.i_height = p_sys->p_info->sequence->height;
 580     p_dec->fmt_out.video.i_visible_height =
 581         p_sys->p_info->sequence->picture_height;
 582     p_dec->fmt_out.video.i_aspect = p_sys->i_aspect;
 583
 584     if( p_sys->p_info->sequence->frame_period > 0 )
 585     {
 586         p_dec->fmt_out.video.i_frame_rate =
 587             (uint32_t)( (uint64_t)1001000000 * 27 /
 588                         p_sys->p_info->sequence->frame_period );
 589         p_dec->fmt_out.video.i_frame_rate_base = 1001;
 590     }
 591
 592     p_dec->fmt_out.i_codec =
 593         ( p_sys->p_info->sequence->chroma_height <
 594           p_sys->p_info->sequence->height ) ?
 595         VLC_FOURCC('I','4','2','0') : VLC_FOURCC('I','4','2','2');
 596
 597     /* Get a new picture */
 598     p_pic = p_dec->pf_vout_buffer_new( p_dec );
 599
 600     if( p_pic == NULL ) return NULL;
 601
 602     p_pic->b_progressive = p_sys->p_info->current_picture != NULL ?
 603         p_sys->p_info->current_picture->flags & PIC_FLAG_PROGRESSIVE_FRAME : 1;
 604     p_pic->b_top_field_first = p_sys->p_info->current_picture != NULL ?
 605         p_sys->p_info->current_picture->flags & PIC_FLAG_TOP_FIELD_FIRST : 1;
 606     p_pic->i_nb_fields = p_sys->p_info->current_picture != NULL ?
 607         p_sys->p_info->current_picture->nb_fields : 2;
 608
 609     p_dec->pf_picture_link( p_dec, p_pic );
 610
 611     pp_buf[0] = p_pic->p[0].p_pixels;
 612     pp_buf[1] = p_pic->p[1].p_pixels;
 613     pp_buf[2] = p_pic->p[2].p_pixels;
 614
 615     return p_pic;
 616 }
 617
 618 /*****************************************************************************
 619  * GetAR: Get aspect ratio
 620  *****************************************************************************/
 621 static void GetAR( decoder_t *p_dec )
 622 {
 623     decoder_sys_t   *p_sys = p_dec->p_sys;
 624
 625     /* Check whether the input gave a particular aspect ratio */
 626     if( p_dec->fmt_in.video.i_aspect )
 627     {
 628         p_sys->i_aspect = p_dec->fmt_in.video.i_aspect;
 629         if( p_sys->i_aspect <= AR_221_1_PICTURE )
 630         switch( p_sys->i_aspect )
 631         {
 632         case AR_3_4_PICTURE:
 633             p_sys->i_aspect = VOUT_ASPECT_FACTOR * 4 / 3;
 634             break;
 635         case AR_16_9_PICTURE:
 636             p_sys->i_aspect = VOUT_ASPECT_FACTOR * 16 / 9;
 637             break;
 638         case AR_221_1_PICTURE:
 639             p_sys->i_aspect = VOUT_ASPECT_FACTOR * 221 / 100;
 640             break;
 641         case AR_SQUARE_PICTURE:
 642             p_sys->i_aspect = VOUT_ASPECT_FACTOR *
 643                            p_sys->p_info->sequence->width /
 644                            p_sys->p_info->sequence->height;
 645             break;
 646         }
 647     }
 648     else
 649     {
 650         /* Use the value provided in the MPEG sequence header */
 651         if( p_sys->p_info->sequence->pixel_height > 0 )
 652         {
 653             p_sys->i_aspect =
 654                 ((uint64_t)p_sys->p_info->sequence->display_width) *
 655                 p_sys->p_info->sequence->pixel_width *
 656                 VOUT_ASPECT_FACTOR /
 657                 p_sys->p_info->sequence->display_height /
 658                 p_sys->p_info->sequence->pixel_height;
 659         }
 660         else
 661         {
 662             /* Invalid aspect, assume 4:3.
 663              * This shouldn't happen and if it does it is a bug
 664              * in libmpeg2 (likely triggered by an invalid stream) */
 665             p_sys->i_aspect = VOUT_ASPECT_FACTOR * 4 / 3;
 666         }
 667     }
 668
 669     msg_Dbg( p_dec, "%dx%d, aspect %d, %u.%03u fps",
 670              p_sys->p_info->sequence->width,
 671              p_sys->p_info->sequence->height, p_sys->i_aspect,
 672              (uint32_t)((uint64_t)1001000000 * 27 /
 673                  p_sys->p_info->sequence->frame_period / 1001),
 674              (uint32_t)((uint64_t)1001000000 * 27 /
 675                  p_sys->p_info->sequence->frame_period % 1001) );
 676 }
 677