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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 /*****************************************************************************
  26  * Preamble
  27  *****************************************************************************/
  28 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #include <vlc_common.h>
  33 #include <vlc_plugin.h>
  34 #include <vlc_vout.h>
  35 #include <vlc_codec.h>
  36
  37 #include <mpeg2.h>
  38
  39 #include <vlc_codec_synchro.h>
  40
  41 /*****************************************************************************
  42  * decoder_sys_t : libmpeg2 decoder descriptor
  43  *****************************************************************************/
  44 struct decoder_sys_t
  45 {
  46     /*
  47      * libmpeg2 properties
  48      */
  49     mpeg2dec_t          *p_mpeg2dec;
  50     const mpeg2_info_t  *p_info;
  51     bool                b_skip;
  52
  53     /*
  54      * Input properties
  55      */
  56     mtime_t          i_previous_pts;
  57     mtime_t          i_current_pts;
  58     mtime_t          i_previous_dts;
  59     mtime_t          i_current_dts;
  60     int              i_current_rate;
  61     picture_t *      p_picture_to_destroy;
  62     bool             b_garbage_pic;
  63     bool             b_after_sequence_header; /* is it the next frame after
  64                                                * the sequence header ?    */
  65     bool             b_slice_i;             /* intra-slice refresh stream */
  66     bool             b_second_field;
  67
  68     bool             b_preroll;
  69
  70     /*
  71      * Output properties
  72      */
  73     decoder_synchro_t *p_synchro;
  74     int            i_aspect;
  75     int            i_sar_num;
  76     int            i_sar_den;
  77     mtime_t        i_last_frame_pts;
  78
  79 };
  80
  81 /*****************************************************************************
  82  * Local prototypes
  83  *****************************************************************************/
  84 static int  OpenDecoder( vlc_object_t * );
  85 static void CloseDecoder( vlc_object_t * );
  86
  87 static picture_t *DecodeBlock( decoder_t *, block_t ** );
  88
  89 static picture_t *GetNewPicture( decoder_t *, uint8_t ** );
  90 static void GetAR( decoder_t *p_dec );
  91
  92 /*****************************************************************************
  93  * Module descriptor
  94  *****************************************************************************/
  95 vlc_module_begin();
  96     set_description( N_("MPEG I/II video decoder (using libmpeg2)") );
  97     set_capability( "decoder", 150 );
  98     set_category( CAT_INPUT );
  99     set_subcategory( SUBCAT_INPUT_VCODEC );
 100     set_callbacks( OpenDecoder, CloseDecoder );
 101     add_shortcut( "libmpeg2" );
 102 vlc_module_end();
 103
 104 /*****************************************************************************
 105  * OpenDecoder: probe the decoder and return score
 106  *****************************************************************************/
 107 static int OpenDecoder( vlc_object_t *p_this )
 108 {
 109     decoder_t *p_dec = (decoder_t*)p_this;
 110     decoder_sys_t *p_sys;
 111     uint32_t i_accel = 0;
 112
 113     if( p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','g','v') &&
 114         p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','g','1') &&
 115         /* Pinnacle hardware-mpeg1 */
 116         p_dec->fmt_in.i_codec != VLC_FOURCC('P','I','M','1') &&
 117         p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','2','v') &&
 118         p_dec->fmt_in.i_codec != VLC_FOURCC('m','p','g','2') &&
 119         p_dec->fmt_in.i_codec != VLC_FOURCC('h','d','v','2') )
 120     {
 121         return VLC_EGENERIC;
 122     }
 123
 124     /* Allocate the memory needed to store the decoder's structure */
 125     if( ( p_dec->p_sys = p_sys =
 126           (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
 127         return VLC_ENOMEM;
 128
 129     /* Initialize the thread properties */
 130     memset( p_sys, 0, sizeof(decoder_sys_t) );
 131     p_sys->p_mpeg2dec = NULL;
 132     p_sys->p_synchro  = NULL;
 133     p_sys->p_info     = NULL;
 134     p_sys->i_current_pts  = 0;
 135     p_sys->i_previous_pts = 0;
 136     p_sys->i_current_dts  = 0;
 137     p_sys->i_previous_dts = 0;
 138     p_sys->p_picture_to_destroy = NULL;
 139     p_sys->b_garbage_pic = 0;
 140     p_sys->b_slice_i  = 0;
 141     p_sys->b_second_field = 0;
 142     p_sys->b_skip     = 0;
 143     p_sys->b_preroll = false;
 144
 145 #if defined( __i386__ ) || defined( __x86_64__ )
 146     if( vlc_CPU() & CPU_CAPABILITY_MMX )
 147     {
 148         i_accel |= MPEG2_ACCEL_X86_MMX;
 149     }
 150
 151     if( vlc_CPU() & CPU_CAPABILITY_3DNOW )
 152     {
 153         i_accel |= MPEG2_ACCEL_X86_3DNOW;
 154     }
 155
 156     if( vlc_CPU() & CPU_CAPABILITY_MMXEXT )
 157     {
 158         i_accel |= MPEG2_ACCEL_X86_MMXEXT;
 159     }
 160
 161 #elif defined( __powerpc__ ) || defined( __ppc__ ) || defined( __ppc64__ )
 162     if( vlc_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                 decoder_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                     {
 239                         p_block->i_buffer = 0;
 240                         break;
 241                     }
 242                     mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 243                     mpeg2_stride( p_sys->p_mpeg2dec, p_pic->p[Y_PLANE].i_pitch );
 244                 }
 245                 p_sys->p_picture_to_destroy = p_pic;
 246
 247                 if ( p_sys->b_slice_i )
 248                 {
 249                     decoder_SynchroNewPicture( p_sys->p_synchro,
 250                         I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate,
 251                         p_sys->p_info->sequence->flags & SEQ_FLAG_LOW_DELAY );
 252                     decoder_SynchroDecode( p_sys->p_synchro );
 253                     decoder_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 254                 }
 255             }
 256
 257             if( p_block->i_flags & BLOCK_FLAG_PREROLL )
 258             {
 259                 p_sys->b_preroll = true;
 260             }
 261             else if( p_sys->b_preroll )
 262             {
 263                 p_sys->b_preroll = false;
 264                 /* Reset synchro */
 265                 decoder_SynchroReset( p_sys->p_synchro );
 266             }
 267
 268 #ifdef PIC_FLAG_PTS
 269             if( p_block->i_pts )
 270             {
 271                 mpeg2_pts( p_sys->p_mpeg2dec, (uint32_t)p_block->i_pts );
 272
 273 #else /* New interface */
 274             if( p_block->i_pts || p_block->i_dts )
 275             {
 276                 mpeg2_tag_picture( p_sys->p_mpeg2dec,
 277                                    (uint32_t)p_block->i_pts,
 278                                    (uint32_t)p_block->i_dts );
 279 #endif
 280                 p_sys->i_previous_pts = p_sys->i_current_pts;
 281                 p_sys->i_current_pts = p_block->i_pts;
 282                 p_sys->i_previous_dts = p_sys->i_current_dts;
 283                 p_sys->i_current_dts = p_block->i_dts;
 284             }
 285
 286             p_sys->i_current_rate = p_block->i_rate;
 287
 288             mpeg2_buffer( p_sys->p_mpeg2dec, p_block->p_buffer,
 289                           p_block->p_buffer + p_block->i_buffer );
 290
 291             p_block->i_buffer = 0;
 292             break;
 293
 294 #if MPEG2_RELEASE >= MPEG2_VERSION (0, 5, 0)
 295
 296         case STATE_SEQUENCE_MODIFIED:
 297             GetAR( p_dec );
 298             break;
 299 #endif
 300
 301         case STATE_SEQUENCE:
 302         {
 303             /* Initialize video output */
 304             uint8_t *buf[3];
 305             buf[0] = buf[1] = buf[2] = NULL;
 306
 307             GetAR( p_dec );
 308
 309             mpeg2_custom_fbuf( p_sys->p_mpeg2dec, 1 );
 310
 311             /* Set the first 2 reference frames */
 312             mpeg2_set_buf( p_sys->p_mpeg2dec, buf, NULL );
 313
 314             if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 315             {
 316                 block_Release( p_block );
 317                 return NULL;
 318             }
 319
 320             mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 321             mpeg2_stride( p_sys->p_mpeg2dec, p_pic->p[Y_PLANE].i_pitch );
 322
 323             /* This picture will never go through display_picture. */
 324             p_pic->date = 0;
 325
 326             /* For some reason, libmpeg2 will put this pic twice in
 327              * discard_picture. This can be considered a bug in libmpeg2. */
 328             p_dec->pf_picture_link( p_dec, p_pic );
 329
 330             if( p_sys->p_synchro )
 331             {
 332                 decoder_SynchroRelease( p_sys->p_synchro );
 333             }
 334             p_sys->p_synchro = decoder_SynchroInit( p_dec,
 335                 (uint32_t)((uint64_t)1001000000 * 27 /
 336                 p_sys->p_info->sequence->frame_period) );
 337             p_sys->b_after_sequence_header = 1;
 338         }
 339         break;
 340
 341         case STATE_PICTURE_2ND:
 342             p_sys->b_second_field = 1;
 343             break;
 344
 345         case STATE_PICTURE:
 346         {
 347             uint8_t *buf[3];
 348             mtime_t i_pts, i_dts;
 349             buf[0] = buf[1] = buf[2] = NULL;
 350
 351             if ( p_sys->b_after_sequence_header &&
 352                  ((p_sys->p_info->current_picture->flags &
 353                        PIC_MASK_CODING_TYPE) == PIC_FLAG_CODING_TYPE_P) )
 354             {
 355                 /* Intra-slice refresh. Simulate a blank I picture. */
 356                 msg_Dbg( p_dec, "intra-slice refresh stream" );
 357                 decoder_SynchroNewPicture( p_sys->p_synchro,
 358                     I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate,
 359                     p_sys->p_info->sequence->flags & SEQ_FLAG_LOW_DELAY );
 360                 decoder_SynchroDecode( p_sys->p_synchro );
 361                 decoder_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 362                 p_sys->b_slice_i = 1;
 363             }
 364             p_sys->b_after_sequence_header = 0;
 365
 366 #ifdef PIC_FLAG_PTS
 367             i_pts = p_sys->p_info->current_picture->flags & PIC_FLAG_PTS ?
 368                 ( ( p_sys->p_info->current_picture->pts ==
 369                     (uint32_t)p_sys->i_current_pts ) ?
 370                   p_sys->i_current_pts : p_sys->i_previous_pts ) : 0;
 371             i_dts = 0;
 372
 373             /* Hack to handle demuxers which only have DTS timestamps */
 374             if( !i_pts && !p_block->i_pts && p_block->i_dts > 0 )
 375             {
 376                 if( p_sys->p_info->sequence->flags & SEQ_FLAG_LOW_DELAY ||
 377                     (p_sys->p_info->current_picture->flags &
 378                       PIC_MASK_CODING_TYPE) == PIC_FLAG_CODING_TYPE_B )
 379                 {
 380                     i_pts = p_block->i_dts;
 381                 }
 382             }
 383             p_block->i_pts = p_block->i_dts = 0;
 384             /* End hack */
 385
 386 #else /* New interface */
 387
 388             i_pts = p_sys->p_info->current_picture->flags & PIC_FLAG_TAGS ?
 389                 ( ( p_sys->p_info->current_picture->tag ==
 390                     (uint32_t)p_sys->i_current_pts ) ?
 391                   p_sys->i_current_pts : p_sys->i_previous_pts ) : 0;
 392             i_dts = p_sys->p_info->current_picture->flags & PIC_FLAG_TAGS ?
 393                 ( ( p_sys->p_info->current_picture->tag2 ==
 394                     (uint32_t)p_sys->i_current_dts ) ?
 395                   p_sys->i_current_dts : p_sys->i_previous_dts ) : 0;
 396 #endif
 397
 398             /* If nb_fields == 1, it is a field picture, and it will be
 399              * followed by another field picture for which we won't call
 400              * decoder_SynchroNewPicture() because this would have other
 401              * problems, so we take it into account here.
 402              * This kind of sucks, but I didn't think better. --Meuuh
 403              */
 404             decoder_SynchroNewPicture( p_sys->p_synchro,
 405                 p_sys->p_info->current_picture->flags & PIC_MASK_CODING_TYPE,
 406                 p_sys->p_info->current_picture->nb_fields == 1 ? 2 :
 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                    && !decoder_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                 decoder_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                 decoder_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         mpeg2_stride( p_sys->p_mpeg2dec, p_pic->p[Y_PLANE].i_pitch );
 440             }
 441         }
 442         break;
 443
 444         case STATE_END:
 445         case STATE_SLICE:
 446             p_pic = NULL;
 447             if( p_sys->p_info->display_fbuf
 448                 && p_sys->p_info->display_fbuf->id )
 449             {
 450                 p_pic = (picture_t *)p_sys->p_info->display_fbuf->id;
 451
 452                 decoder_SynchroEnd( p_sys->p_synchro,
 453                             p_sys->p_info->display_picture->flags
 454                              & PIC_MASK_CODING_TYPE,
 455                             p_sys->b_garbage_pic );
 456                 p_sys->b_garbage_pic = 0;
 457
 458                 if ( p_sys->p_picture_to_destroy != p_pic )
 459                 {
 460                     p_pic->date = decoder_SynchroDate( p_sys->p_synchro );
 461                 }
 462                 else
 463                 {
 464                     p_sys->p_picture_to_destroy = NULL;
 465                     p_pic->date = 0;
 466                 }
 467             }
 468
 469             if( p_sys->p_info->discard_fbuf &&
 470                 p_sys->p_info->discard_fbuf->id )
 471             {
 472                 p_dec->pf_picture_unlink( p_dec,
 473                                           p_sys->p_info->discard_fbuf->id );
 474             }
 475
 476             /* For still frames */
 477             if( state == STATE_END && p_pic ) p_pic->b_force = true;
 478
 479             if( p_pic )
 480             {
 481                 /* Avoid frames with identical timestamps.
 482                  * Especially needed for still frames in DVD menus. */
 483                 if( p_sys->i_last_frame_pts == p_pic->date ) p_pic->date++;
 484                 p_sys->i_last_frame_pts = p_pic->date;
 485
 486                 return p_pic;
 487             }
 488
 489             break;
 490
 491         case STATE_INVALID:
 492         {
 493             uint8_t *buf[3];
 494             buf[0] = buf[1] = buf[2] = NULL;
 495
 496             msg_Warn( p_dec, "invalid picture encountered" );
 497             if ( ( p_sys->p_info->current_picture == NULL ) ||
 498                ( ( p_sys->p_info->current_picture->flags &
 499                    PIC_MASK_CODING_TYPE) != B_CODING_TYPE ) )
 500             {
 501                 if( p_sys->p_synchro ) decoder_SynchroReset( p_sys->p_synchro );
 502             }
 503             mpeg2_skip( p_sys->p_mpeg2dec, 1 );
 504             p_sys->b_skip = 1;
 505
 506             if( p_sys->p_info->current_fbuf &&
 507                 p_sys->p_info->current_fbuf->id )
 508             {
 509                 p_sys->b_garbage_pic = 1;
 510                 p_pic = p_sys->p_info->current_fbuf->id;
 511             }
 512             else if( !p_sys->p_info->sequence )
 513             {
 514                 break;
 515             }
 516             else
 517             {
 518                 if( (p_pic = GetNewPicture( p_dec, buf )) == NULL )
 519                     break;
 520                 mpeg2_set_buf( p_sys->p_mpeg2dec, buf, p_pic );
 521                 mpeg2_stride( p_sys->p_mpeg2dec, p_pic->p[Y_PLANE].i_pitch );
 522             }
 523             p_sys->p_picture_to_destroy = p_pic;
 524
 525             memset( p_pic->p[0].p_pixels, 0,
 526                     p_sys->p_info->sequence->width
 527                      * p_sys->p_info->sequence->height );
 528             memset( p_pic->p[1].p_pixels, 0x80,
 529                     p_sys->p_info->sequence->width
 530                      * p_sys->p_info->sequence->height / 4 );
 531             memset( p_pic->p[2].p_pixels, 0x80,
 532                     p_sys->p_info->sequence->width
 533                      * p_sys->p_info->sequence->height / 4 );
 534
 535             if( p_sys->b_slice_i )
 536             {
 537                 decoder_SynchroNewPicture( p_sys->p_synchro,
 538                         I_CODING_TYPE, 2, 0, 0, p_sys->i_current_rate,
 539                         p_sys->p_info->sequence->flags & SEQ_FLAG_LOW_DELAY );
 540                 decoder_SynchroDecode( p_sys->p_synchro );
 541                 decoder_SynchroEnd( p_sys->p_synchro, I_CODING_TYPE, 0 );
 542             }
 543             break;
 544         }
 545
 546         default:
 547             break;
 548         }
 549     }
 550
 551     /* Never reached */
 552     return NULL;
 553 }
 554
 555 /*****************************************************************************
 556  * CloseDecoder: libmpeg2 decoder destruction
 557  *****************************************************************************/
 558 static void CloseDecoder( vlc_object_t *p_this )
 559 {
 560     decoder_t *p_dec = (decoder_t *)p_this;
 561     decoder_sys_t *p_sys = p_dec->p_sys;
 562
 563     if( p_sys->p_synchro ) decoder_SynchroRelease( p_sys->p_synchro );
 564
 565     if( p_sys->p_mpeg2dec ) mpeg2_close( p_sys->p_mpeg2dec );
 566
 567     free( p_sys );
 568 }
 569
 570 /*****************************************************************************
 571  * GetNewPicture: Get a new picture from the vout and set the buf struct
 572  *****************************************************************************/
 573 static picture_t *GetNewPicture( decoder_t *p_dec, uint8_t **pp_buf )
 574 {
 575     decoder_sys_t *p_sys = p_dec->p_sys;
 576     picture_t *p_pic;
 577
 578     p_dec->fmt_out.video.i_width = p_sys->p_info->sequence->width;
 579     p_dec->fmt_out.video.i_visible_width =
 580         p_sys->p_info->sequence->picture_width;
 581     p_dec->fmt_out.video.i_height = p_sys->p_info->sequence->height;
 582     p_dec->fmt_out.video.i_visible_height =
 583         p_sys->p_info->sequence->picture_height;
 584     p_dec->fmt_out.video.i_aspect = p_sys->i_aspect;
 585     p_dec->fmt_out.video.i_sar_num = p_sys->i_sar_num;
 586     p_dec->fmt_out.video.i_sar_den = p_sys->i_sar_den;
 587
 588     if( p_sys->p_info->sequence->frame_period > 0 )
 589     {
 590         p_dec->fmt_out.video.i_frame_rate =
 591             (uint32_t)( (uint64_t)1001000000 * 27 /
 592                         p_sys->p_info->sequence->frame_period );
 593         p_dec->fmt_out.video.i_frame_rate_base = 1001;
 594     }
 595
 596     p_dec->fmt_out.i_codec =
 597         ( p_sys->p_info->sequence->chroma_height <
 598           p_sys->p_info->sequence->height ) ?
 599         VLC_FOURCC('I','4','2','0') : VLC_FOURCC('I','4','2','2');
 600
 601     /* Get a new picture */
 602     p_pic = p_dec->pf_vout_buffer_new( p_dec );
 603
 604     if( p_pic == NULL ) return NULL;
 605
 606     p_pic->b_progressive = p_sys->p_info->current_picture != NULL ?
 607         p_sys->p_info->current_picture->flags & PIC_FLAG_PROGRESSIVE_FRAME : 1;
 608     p_pic->b_top_field_first = p_sys->p_info->current_picture != NULL ?
 609         p_sys->p_info->current_picture->flags & PIC_FLAG_TOP_FIELD_FIRST : 1;
 610     p_pic->i_nb_fields = p_sys->p_info->current_picture != NULL ?
 611         p_sys->p_info->current_picture->nb_fields : 2;
 612
 613     p_dec->pf_picture_link( p_dec, p_pic );
 614
 615     pp_buf[0] = p_pic->p[0].p_pixels;
 616     pp_buf[1] = p_pic->p[1].p_pixels;
 617     pp_buf[2] = p_pic->p[2].p_pixels;
 618
 619     return p_pic;
 620 }
 621
 622 /*****************************************************************************
 623  * GetAR: Get aspect ratio
 624  *****************************************************************************/
 625 static void GetAR( decoder_t *p_dec )
 626 {
 627     decoder_sys_t *p_sys = p_dec->p_sys;
 628
 629     /* Check whether the input gave a particular aspect ratio */
 630     if( p_dec->fmt_in.video.i_aspect )
 631     {
 632         p_sys->i_aspect = p_dec->fmt_in.video.i_aspect;
 633     }
 634     else
 635     {
 636         /* Use the value provided in the MPEG sequence header */
 637         if( p_sys->p_info->sequence->pixel_height > 0 )
 638         {
 639             p_sys->i_aspect =
 640                 ((uint64_t)p_sys->p_info->sequence->picture_width) *
 641                 p_sys->p_info->sequence->pixel_width *
 642                 VOUT_ASPECT_FACTOR /
 643                 p_sys->p_info->sequence->picture_height /
 644                 p_sys->p_info->sequence->pixel_height;
 645             p_sys->i_sar_num = p_sys->p_info->sequence->pixel_width;
 646             p_sys->i_sar_den = p_sys->p_info->sequence->pixel_height;
 647         }
 648         else
 649         {
 650             /* Invalid aspect, assume 4:3.
 651              * This shouldn't happen and if it does it is a bug
 652              * in libmpeg2 (likely triggered by an invalid stream) */
 653             p_sys->i_aspect = VOUT_ASPECT_FACTOR * 4 / 3;
 654             p_sys->i_sar_num = p_sys->p_info->sequence->picture_height * 4;
 655             p_sys->i_sar_den = p_sys->p_info->sequence->picture_width * 3;
 656         }
 657     }
 658
 659     msg_Dbg( p_dec, "%dx%d (display %d,%d), aspect %d, sar %i:%i, %u.%03u fps",
 660              p_sys->p_info->sequence->picture_width,
 661              p_sys->p_info->sequence->picture_height,
 662              p_sys->p_info->sequence->display_width,
 663              p_sys->p_info->sequence->display_height,
 664              p_sys->i_aspect, p_sys->i_sar_num, p_sys->i_sar_den,
 665              (uint32_t)((uint64_t)1001000000 * 27 /
 666                  p_sys->p_info->sequence->frame_period / 1001),
 667              (uint32_t)((uint64_t)1001000000 * 27 /
 668                  p_sys->p_info->sequence->frame_period % 1001) );
 669 }