git.sesse.net Git - vlc/blob - modules/packetizer/mpeg4video.c

   1 /*****************************************************************************
   2  * mpeg4video.c: mpeg 4 video packetizer
   3  *****************************************************************************
   4  * Copyright (C) 2001-2006 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Gildas Bazin <gbazin@videolan.org>
   8  *          Laurent Aimar <fenrir@via.ecp.fr>
   9  *          Eric Petit <titer@videolan.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  24  *****************************************************************************/
  25
  26 /*****************************************************************************
  27  * Preamble
  28  *****************************************************************************/
  29
  30 #ifdef HAVE_CONFIG_H
  31 # include "config.h"
  32 #endif
  33
  34 #include <vlc_common.h>
  35 #include <vlc_plugin.h>
  36 #include <vlc_sout.h>
  37 #include <vlc_codec.h>
  38 #include <vlc_block.h>
  39
  40 #include "vlc_bits.h"
  41 #include "vlc_block_helper.h"
  42
  43 /*****************************************************************************
  44  * Module descriptor
  45  *****************************************************************************/
  46 static int  Open ( vlc_object_t * );
  47 static void Close( vlc_object_t * );
  48
  49 vlc_module_begin ()
  50     set_category( CAT_SOUT )
  51     set_subcategory( SUBCAT_SOUT_PACKETIZER )
  52     set_description( N_("MPEG4 video packetizer") )
  53     set_capability( "packetizer", 50 )
  54     set_callbacks( Open, Close )
  55 vlc_module_end ()
  56
  57 /****************************************************************************
  58  * Local prototypes
  59  ****************************************************************************/
  60 static block_t *Packetize( decoder_t *, block_t ** );
  61
  62 struct decoder_sys_t
  63 {
  64     /*
  65      * Input properties
  66      */
  67     block_bytestream_t bytestream;
  68     int i_state;
  69     size_t i_offset;
  70     uint8_t p_startcode[3];
  71
  72     /*
  73      * Common properties
  74      */
  75     mtime_t i_interpolated_pts;
  76     mtime_t i_interpolated_dts;
  77     mtime_t i_last_ref_pts;
  78     mtime_t i_last_time_ref;
  79     mtime_t i_time_ref;
  80     mtime_t i_last_time;
  81     mtime_t i_last_timeincr;
  82
  83     unsigned int i_flags;
  84
  85     int         i_fps_num;
  86     int         i_fps_den;
  87     int         i_last_incr;
  88     int         i_last_incr_diff;
  89
  90     bool  b_frame;
  91
  92     /* Current frame being built */
  93     block_t    *p_frame;
  94     block_t    **pp_last;
  95 };
  96
  97 enum {
  98     STATE_NOSYNC,
  99     STATE_NEXT_SYNC
 100 };
 101
 102 static block_t *ParseMPEGBlock( decoder_t *, block_t * );
 103 static int ParseVOL( decoder_t *, es_format_t *, uint8_t *, int );
 104 static int ParseVOP( decoder_t *, block_t * );
 105 static int vlc_log2( unsigned int );
 106
 107 #define VIDEO_OBJECT_MASK                       0x01f
 108 #define VIDEO_OBJECT_LAYER_MASK                 0x00f
 109
 110 #define VIDEO_OBJECT_START_CODE                 0x100
 111 #define VIDEO_OBJECT_LAYER_START_CODE           0x120
 112 #define VISUAL_OBJECT_SEQUENCE_START_CODE       0x1b0
 113 #define VISUAL_OBJECT_SEQUENCE_END_CODE         0x1b1
 114 #define USER_DATA_START_CODE                    0x1b2
 115 #define GROUP_OF_VOP_START_CODE                 0x1b3
 116 #define VIDEO_SESSION_ERROR_CODE                0x1b4
 117 #define VISUAL_OBJECT_START_CODE                0x1b5
 118 #define VOP_START_CODE                          0x1b6
 119 #define FACE_OBJECT_START_CODE                  0x1ba
 120 #define FACE_OBJECT_PLANE_START_CODE            0x1bb
 121 #define MESH_OBJECT_START_CODE                  0x1bc
 122 #define MESH_OBJECT_PLANE_START_CODE            0x1bd
 123 #define STILL_TEXTURE_OBJECT_START_CODE         0x1be
 124 #define TEXTURE_SPATIAL_LAYER_START_CODE        0x1bf
 125 #define TEXTURE_SNR_LAYER_START_CODE            0x1c0
 126
 127 /*****************************************************************************
 128  * Open: probe the packetizer and return score
 129  *****************************************************************************/
 130 static int Open( vlc_object_t *p_this )
 131 {
 132     decoder_t     *p_dec = (decoder_t*)p_this;
 133     decoder_sys_t *p_sys;
 134
 135     switch( p_dec->fmt_in.i_codec )
 136     {
 137         case VLC_FOURCC( 'm', '4', 's', '2'):
 138         case VLC_FOURCC( 'M', '4', 'S', '2'):
 139         case VLC_FOURCC( 'm', 'p', '4', 's'):
 140         case VLC_FOURCC( 'M', 'P', '4', 'S'):
 141         case VLC_FOURCC( 'm', 'p', '4', 'v'):
 142         case VLC_FOURCC( 'M', 'P', '4', 'V'):
 143         case VLC_FOURCC( 'D', 'I', 'V', 'X'):
 144         case VLC_FOURCC( 'd', 'i', 'v', 'x'):
 145         case VLC_FOURCC( 'X', 'V', 'I', 'D'):
 146         case VLC_FOURCC( 'X', 'v', 'i', 'D'):
 147         case VLC_FOURCC( 'x', 'v', 'i', 'd'):
 148         case VLC_FOURCC( 'D', 'X', '5', '0'):
 149         case VLC_FOURCC( 'd', 'x', '5', '0'):
 150         case VLC_FOURCC( 0x04, 0,   0,   0):
 151         case VLC_FOURCC( '3', 'I', 'V', '2'):
 152         case VLC_FOURCC( 'm', '4', 'c', 'c'):
 153         case VLC_FOURCC( 'M', '4', 'C', 'C'):
 154             break;
 155
 156         default:
 157             return VLC_EGENERIC;
 158     }
 159
 160     /* Allocate the memory needed to store the decoder's structure */
 161     if( ( p_dec->p_sys = p_sys = malloc( sizeof(decoder_sys_t) ) ) == NULL )
 162         return VLC_ENOMEM;
 163     memset( p_sys, 0, sizeof(decoder_sys_t) );
 164
 165     /* Misc init */
 166     p_sys->i_state = STATE_NOSYNC;
 167     p_sys->bytestream = block_BytestreamInit();
 168     p_sys->p_startcode[0] = 0;
 169     p_sys->p_startcode[1] = 0;
 170     p_sys->p_startcode[2] = 1;
 171     p_sys->i_offset = 0;
 172     p_sys->p_frame = NULL;
 173     p_sys->pp_last = &p_sys->p_frame;
 174
 175     /* Setup properties */
 176     es_format_Copy( &p_dec->fmt_out, &p_dec->fmt_in );
 177     p_dec->fmt_out.i_codec = VLC_FOURCC( 'm', 'p', '4', 'v' );
 178
 179     if( p_dec->fmt_in.i_extra )
 180     {
 181         /* We have a vol */
 182         p_dec->fmt_out.i_extra = p_dec->fmt_in.i_extra;
 183         p_dec->fmt_out.p_extra = malloc( p_dec->fmt_in.i_extra );
 184         memcpy( p_dec->fmt_out.p_extra, p_dec->fmt_in.p_extra,
 185                 p_dec->fmt_in.i_extra );
 186
 187         msg_Dbg( p_dec, "opening with vol size: %d", p_dec->fmt_in.i_extra );
 188         ParseVOL( p_dec, &p_dec->fmt_out,
 189                   p_dec->fmt_out.p_extra, p_dec->fmt_out.i_extra );
 190     }
 191     else
 192     {
 193         /* No vol, we'll have to look for one later on */
 194         p_dec->fmt_out.i_extra = 0;
 195         p_dec->fmt_out.p_extra = 0;
 196     }
 197
 198     /* Set callback */
 199     p_dec->pf_packetize = Packetize;
 200
 201     return VLC_SUCCESS;
 202 }
 203
 204 /*****************************************************************************
 205  * Close: clean up the packetizer
 206  *****************************************************************************/
 207 static void Close( vlc_object_t *p_this )
 208 {
 209     decoder_t *p_dec = (decoder_t*)p_this;
 210
 211     block_BytestreamRelease( &p_dec->p_sys->bytestream );
 212     if( p_dec->p_sys->p_frame ) block_ChainRelease( p_dec->p_sys->p_frame );
 213     free( p_dec->p_sys );
 214 }
 215
 216 /****************************************************************************
 217  * Packetize: the whole thing
 218  ****************************************************************************/
 219 static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
 220 {
 221     decoder_sys_t *p_sys = p_dec->p_sys;
 222     block_t       *p_pic;
 223     mtime_t       i_pts, i_dts;
 224
 225     if( pp_block == NULL || *pp_block == NULL ) return NULL;
 226
 227     if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
 228     {
 229         if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
 230         {
 231             p_sys->i_state = STATE_NOSYNC;
 232             block_BytestreamFlush( &p_sys->bytestream );
 233
 234             if( p_sys->p_frame )
 235                 block_ChainRelease( p_sys->p_frame );
 236             p_sys->p_frame = NULL;
 237             p_sys->pp_last = &p_sys->p_frame;
 238         }
 239 //        p_sys->i_interpolated_pts =
 240 //        p_sys->i_interpolated_dts =
 241 //        p_sys->i_last_ref_pts =
 242 //        p_sys->i_last_time_ref =
 243 //        p_sys->i_time_ref =
 244 //        p_sys->i_last_time =
 245 //        p_sys->i_last_timeincr = 0;
 246
 247         block_Release( *pp_block );
 248         return NULL;
 249     }
 250
 251     block_BytestreamPush( &p_sys->bytestream, *pp_block );
 252
 253     while( 1 )
 254     {
 255         switch( p_sys->i_state )
 256         {
 257
 258         case STATE_NOSYNC:
 259             if( block_FindStartcodeFromOffset( &p_sys->bytestream,
 260                     &p_sys->i_offset, p_sys->p_startcode, 3 ) == VLC_SUCCESS )
 261             {
 262                 p_sys->i_state = STATE_NEXT_SYNC;
 263             }
 264
 265             if( p_sys->i_offset )
 266             {
 267                 block_SkipBytes( &p_sys->bytestream, p_sys->i_offset );
 268                 p_sys->i_offset = 0;
 269                 block_BytestreamFlush( &p_sys->bytestream );
 270             }
 271
 272             if( p_sys->i_state != STATE_NEXT_SYNC )
 273             {
 274                 /* Need more data */
 275                 return NULL;
 276             }
 277
 278             p_sys->i_offset = 1; /* To find next startcode */
 279
 280         case STATE_NEXT_SYNC:
 281             /* TODO: If p_block == NULL, flush the buffer without checking the
 282              * next sync word */
 283
 284             /* Find the next startcode */
 285             if( block_FindStartcodeFromOffset( &p_sys->bytestream,
 286                     &p_sys->i_offset, p_sys->p_startcode, 3 ) != VLC_SUCCESS )
 287             {
 288                 /* Need more data */
 289                 return NULL;
 290             }
 291
 292             /* Get the new fragment and set the pts/dts */
 293             p_pic = block_New( p_dec, p_sys->i_offset );
 294             block_BytestreamFlush( &p_sys->bytestream );
 295             p_pic->i_pts = i_pts = p_sys->bytestream.p_block->i_pts;
 296             p_pic->i_dts = i_dts = p_sys->bytestream.p_block->i_dts;
 297
 298             block_GetBytes( &p_sys->bytestream, p_pic->p_buffer,
 299                             p_pic->i_buffer );
 300
 301             p_sys->i_offset = 0;
 302
 303             /* Get picture if any */
 304             if( !( p_pic = ParseMPEGBlock( p_dec, p_pic ) ) )
 305             {
 306                 p_sys->i_state = STATE_NOSYNC;
 307                 break;
 308             }
 309
 310             /* don't reuse the same timestamps several times */
 311             if( i_pts == p_sys->bytestream.p_block->i_pts &&
 312                 i_dts == p_sys->bytestream.p_block->i_dts )
 313             {
 314                 p_sys->bytestream.p_block->i_pts = 0;
 315                 p_sys->bytestream.p_block->i_dts = 0;
 316             }
 317
 318             /* We've just started the stream, wait for the first PTS.
 319              * We discard here so we can still get the sequence header. */
 320             if( p_sys->i_interpolated_pts <= 0 &&
 321                 p_sys->i_interpolated_dts <= 0 )
 322             {
 323                 msg_Dbg( p_dec, "need a starting pts/dts" );
 324                 p_sys->i_state = STATE_NOSYNC;
 325                 block_Release( p_pic );
 326                 break;
 327             }
 328
 329             /* When starting the stream we can have the first frame with
 330              * a null DTS (i_interpolated_pts is initialized to 0) */
 331             if( !p_pic->i_dts ) p_pic->i_dts = p_pic->i_pts;
 332
 333             /* So p_block doesn't get re-added several times */
 334             *pp_block = block_BytestreamPop( &p_sys->bytestream );
 335
 336             p_sys->i_state = STATE_NOSYNC;
 337
 338             return p_pic;
 339         }
 340     }
 341 }
 342
 343 /*****************************************************************************
 344  * ParseMPEGBlock: Re-assemble fragments into a block containing a picture
 345  *****************************************************************************/
 346 static block_t *ParseMPEGBlock( decoder_t *p_dec, block_t *p_frag )
 347 {
 348     decoder_sys_t *p_sys = p_dec->p_sys;
 349     block_t *p_pic = NULL;
 350
 351     if( p_frag->p_buffer[3] == 0xB0 || p_frag->p_buffer[3] == 0xB1 || p_frag->p_buffer[3] == 0xB2 )
 352     {   /* VOS and USERDATA */
 353 #if 0
 354         /* Remove VOS start/end code from the original stream */
 355         block_Release( p_frag );
 356 #else
 357         /* Append the block for now since ts/ps muxers rely on VOL
 358          * being present in the stream */
 359         block_ChainLastAppend( &p_sys->pp_last, p_frag );
 360 #endif
 361         return NULL;
 362     }
 363     if( p_frag->p_buffer[3] >= 0x20 && p_frag->p_buffer[3] <= 0x2f )
 364     {
 365         /* Copy the complete VOL */
 366         if( (size_t)p_dec->fmt_out.i_extra != p_frag->i_buffer )
 367         {
 368             p_dec->fmt_out.p_extra =
 369                 realloc( p_dec->fmt_out.p_extra, p_frag->i_buffer );
 370             p_dec->fmt_out.i_extra = p_frag->i_buffer;
 371         }
 372         memcpy( p_dec->fmt_out.p_extra, p_frag->p_buffer, p_frag->i_buffer );
 373         ParseVOL( p_dec, &p_dec->fmt_out,
 374                   p_dec->fmt_out.p_extra, p_dec->fmt_out.i_extra );
 375
 376 #if 0
 377         /* Remove from the original stream */
 378         block_Release( p_frag );
 379 #else
 380         /* Append the block for now since ts/ps muxers rely on VOL
 381          * being present in the stream */
 382         block_ChainLastAppend( &p_sys->pp_last, p_frag );
 383 #endif
 384         return NULL;
 385     }
 386     else
 387     {
 388         if( !p_dec->fmt_out.i_extra )
 389         {
 390             msg_Warn( p_dec, "waiting for VOL" );
 391             block_Release( p_frag );
 392             return NULL;
 393         }
 394
 395         /* Append the block */
 396         block_ChainLastAppend( &p_sys->pp_last, p_frag );
 397     }
 398
 399     if( p_frag->p_buffer[3] == 0xb6 &&
 400         ParseVOP( p_dec, p_frag ) == VLC_SUCCESS )
 401     {
 402         /* We are dealing with a VOP */
 403         p_pic = block_ChainGather( p_sys->p_frame );
 404         p_pic->i_flags = p_sys->i_flags;
 405         p_pic->i_pts = p_sys->i_interpolated_pts;
 406         p_pic->i_dts = p_sys->i_interpolated_dts;
 407
 408         /* Reset context */
 409         p_sys->p_frame = NULL;
 410         p_sys->pp_last = &p_sys->p_frame;
 411     }
 412
 413     return p_pic;
 414 }
 415
 416 /* ParseVOL:
 417  *  TODO:
 418  *      - support aspect ratio
 419  */
 420 static int ParseVOL( decoder_t *p_dec, es_format_t *fmt,
 421                      uint8_t *p_vol, int i_vol )
 422 {
 423     decoder_sys_t *p_sys = p_dec->p_sys;
 424     int i_vo_type, i_vo_ver_id, i_ar, i_shape;
 425     bs_t s;
 426
 427     for( ;; )
 428     {
 429         if( p_vol[0] == 0x00 && p_vol[1] == 0x00 && p_vol[2] == 0x01 &&
 430             p_vol[3] >= 0x20 && p_vol[3] <= 0x2f ) break;
 431
 432         p_vol++; i_vol--;
 433         if( i_vol <= 4 ) return VLC_EGENERIC;
 434     }
 435
 436     bs_init( &s, &p_vol[4], i_vol - 4 );
 437
 438     bs_skip( &s, 1 );   /* random access */
 439     i_vo_type = bs_read( &s, 8 );
 440     if( bs_read1( &s ) )
 441     {
 442         i_vo_ver_id = bs_read( &s, 4 );
 443         bs_skip( &s, 3 );
 444     }
 445     else
 446     {
 447         i_vo_ver_id = 1;
 448     }
 449     i_ar = bs_read( &s, 4 );
 450     if( i_ar == 0xf )
 451     {
 452         int i_ar_width, i_ar_height;
 453
 454         i_ar_width = bs_read( &s, 8 );
 455         i_ar_height= bs_read( &s, 8 );
 456     }
 457     if( bs_read1( &s ) )
 458     {
 459         int i_chroma_format;
 460         int i_low_delay;
 461
 462         /* vol control parameter */
 463         i_chroma_format = bs_read( &s, 2 );
 464         i_low_delay = bs_read1( &s );
 465
 466         if( bs_read1( &s ) )
 467         {
 468             bs_skip( &s, 16 );
 469             bs_skip( &s, 16 );
 470             bs_skip( &s, 16 );
 471             bs_skip( &s, 3 );
 472             bs_skip( &s, 11 );
 473             bs_skip( &s, 1 );
 474             bs_skip( &s, 16 );
 475         }
 476     }
 477     /* shape 0->RECT, 1->BIN, 2->BIN_ONLY, 3->GRAY */
 478     i_shape = bs_read( &s, 2 );
 479     if( i_shape == 3 && i_vo_ver_id != 1 )
 480     {
 481         bs_skip( &s, 4 );
 482     }
 483
 484     if( !bs_read1( &s ) ) return VLC_EGENERIC; /* Marker */
 485
 486     p_sys->i_fps_num = bs_read( &s, 16 ); /* Time increment resolution*/
 487     if( !p_sys->i_fps_num ) p_sys->i_fps_num = 1;
 488
 489     if( !bs_read1( &s ) ) return VLC_EGENERIC; /* Marker */
 490
 491     if( bs_read1( &s ) )
 492     {
 493         int i_time_increment_bits = vlc_log2( p_sys->i_fps_num - 1 ) + 1;
 494
 495         if( i_time_increment_bits < 1 ) i_time_increment_bits = 1;
 496
 497         p_sys->i_fps_den = bs_read( &s, i_time_increment_bits );
 498     }
 499     if( i_shape == 0 )
 500     {
 501         bs_skip( &s, 1 );
 502         fmt->video.i_width = bs_read( &s, 13 );
 503         bs_skip( &s, 1 );
 504         fmt->video.i_height= bs_read( &s, 13 );
 505         bs_skip( &s, 1 );
 506     }
 507
 508     return VLC_SUCCESS;
 509 }
 510
 511 static int ParseVOP( decoder_t *p_dec, block_t *p_vop )
 512 {
 513     decoder_sys_t *p_sys = p_dec->p_sys;
 514     int64_t i_time_increment, i_time_ref;
 515     int i_modulo_time_base = 0, i_time_increment_bits;
 516     bs_t s;
 517
 518     bs_init( &s, &p_vop->p_buffer[4], p_vop->i_buffer - 4 );
 519
 520     switch( bs_read( &s, 2 ) )
 521     {
 522     case 0:
 523         p_sys->i_flags = BLOCK_FLAG_TYPE_I;
 524         break;
 525     case 1:
 526         p_sys->i_flags = BLOCK_FLAG_TYPE_P;
 527         break;
 528     case 2:
 529         p_sys->i_flags = BLOCK_FLAG_TYPE_B;
 530         p_sys->b_frame = true;
 531         break;
 532     case 3: /* gni ? */
 533         p_sys->i_flags = BLOCK_FLAG_TYPE_PB;
 534         break;
 535     }
 536
 537     while( bs_read( &s, 1 ) ) i_modulo_time_base++;
 538     if( !bs_read1( &s ) ) return VLC_EGENERIC; /* Marker */
 539
 540     /* VOP time increment */
 541     i_time_increment_bits = vlc_log2(p_dec->p_sys->i_fps_num - 1) + 1;
 542     if( i_time_increment_bits < 1 ) i_time_increment_bits = 1;
 543     i_time_increment = bs_read( &s, i_time_increment_bits );
 544
 545     /* Interpolate PTS/DTS */
 546     if( !(p_sys->i_flags & BLOCK_FLAG_TYPE_B) )
 547     {
 548         p_sys->i_last_time_ref = p_sys->i_time_ref;
 549         p_sys->i_time_ref +=
 550             (i_modulo_time_base * p_dec->p_sys->i_fps_num);
 551         i_time_ref = p_sys->i_time_ref;
 552     }
 553     else
 554     {
 555         i_time_ref = p_sys->i_last_time_ref +
 556             (i_modulo_time_base * p_dec->p_sys->i_fps_num);
 557     }
 558
 559 #if 0
 560     msg_Err( p_dec, "interp pts/dts (%lli,%lli), pts/dts (%lli,%lli)",
 561              p_sys->i_interpolated_pts, p_sys->i_interpolated_dts,
 562              p_vop->i_pts, p_vop->i_dts );
 563 #endif
 564
 565     if( p_dec->p_sys->i_fps_num < 5 && /* Work-around buggy streams */
 566         p_dec->fmt_in.video.i_frame_rate > 0 &&
 567         p_dec->fmt_in.video.i_frame_rate_base > 0 )
 568     {
 569         p_sys->i_interpolated_pts += INT64_C(1000000) *
 570         p_dec->fmt_in.video.i_frame_rate_base /
 571         p_dec->fmt_in.video.i_frame_rate;
 572     }
 573     else if( p_dec->p_sys->i_fps_num )
 574         p_sys->i_interpolated_pts +=
 575             ( INT64_C(1000000) * (i_time_ref + i_time_increment -
 576               p_sys->i_last_time - p_sys->i_last_timeincr) /
 577               p_dec->p_sys->i_fps_num );
 578
 579     p_sys->i_last_time = i_time_ref;
 580     p_sys->i_last_timeincr = i_time_increment;
 581
 582     /* Correct interpolated dts when we receive a new pts/dts */
 583     if( p_vop->i_pts > 0 )
 584         p_sys->i_interpolated_pts = p_vop->i_pts;
 585     if( p_vop->i_dts > 0 )
 586         p_sys->i_interpolated_dts = p_vop->i_dts;
 587
 588     if( (p_sys->i_flags & BLOCK_FLAG_TYPE_B) || !p_sys->b_frame )
 589     {
 590         /* Trivial case (DTS == PTS) */
 591
 592         p_sys->i_interpolated_dts = p_sys->i_interpolated_pts;
 593
 594         if( p_vop->i_pts > 0 )
 595             p_sys->i_interpolated_dts = p_vop->i_pts;
 596         if( p_vop->i_dts > 0 )
 597             p_sys->i_interpolated_dts = p_vop->i_dts;
 598
 599         p_sys->i_interpolated_pts = p_sys->i_interpolated_dts;
 600     }
 601     else
 602     {
 603         if( p_sys->i_last_ref_pts > 0 )
 604             p_sys->i_interpolated_dts = p_sys->i_last_ref_pts;
 605
 606         p_sys->i_last_ref_pts = p_sys->i_interpolated_pts;
 607     }
 608
 609     return VLC_SUCCESS;
 610 }
 611
 612 /* look at ffmpeg av_log2 ;) */
 613 static int vlc_log2( unsigned int v )
 614 {
 615     int n = 0;
 616     static const int vlc_log2_table[16] =
 617     {
 618         0,0,1,1,2,2,2,2, 3,3,3,3,3,3,3,3
 619     };
 620
 621     if( v&0xffff0000 )
 622     {
 623         v >>= 16;
 624         n += 16;
 625     }
 626     if( v&0xff00 )
 627     {
 628         v >>= 8;
 629         n += 8;
 630     }
 631     if( v&0xf0 )
 632     {
 633         v >>= 4;
 634         n += 4;
 635     }
 636     n += vlc_log2_table[v];
 637
 638     return n;
 639 }