git.sesse.net Git - vlc/blob - src/video_parser/vpar_synchro.c

   1 /*****************************************************************************
   2  * vpar_synchro.c : frame dropping routines
   3  *****************************************************************************
   4  * Copyright (C) 1999, 2000 VideoLAN
   5  * $Id: vpar_synchro.c,v 1.76 2001/01/16 17:59:23 massiot Exp $
   6  *
   7  * Authors: Christophe Massiot <massiot@via.ecp.fr>
   8  *          Samuel Hocevar <sam@via.ecp.fr>
   9  *          Jean-Marc Dressler <polux@via.ecp.fr>
  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., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  24  *****************************************************************************/
  25
  26 /*
  27  * DISCUSSION : How to Write an efficient Frame-Dropping Algorithm
  28  * ==========
  29  *
  30  * This implementation is based on mathematical and statistical
  31  * developments. Older implementations used an enslavement, considering
  32  * that if we're late when reading an I picture, we will decode one frame
  33  * less. It had a tendancy to derive, and wasn't responsive enough, which
  34  * would have caused trouble with the stream control stuff.
  35  *
  36  * 1. Structure of a picture stream
  37  *    =============================
  38  * Between 2 I's, we have for instance :
  39  *    I   B   P   B   P   B   P   B   P   B   P   B   I
  40  *    t0  t1  t2  t3  t4  t5  t6  t7  t8  t9  t10 t11 t12
  41  * Please bear in mind that B's and IP's will be inverted when displaying
  42  * (decoding order != presentation order). Thus, t1 < t0.
  43  *
  44  * FIXME: write a few words about stream structure changes.
  45  *
  46  * 2. Definitions
  47  *    ===========
  48  * t[0..12]     : Presentation timestamps of pictures 0..12.
  49  * t            : Current timestamp, at the moment of the decoding.
  50  * T            : Picture period, T = 1/frame_rate.
  51  * tau[I,P,B]   : Mean time to decode an [I,P,B] picture.
  52  * tauYUV       : Mean time to render a picture (given by the video_output).
  53  * tau´[I,P,B] = 2 * tau[I,P,B] + tauYUV
  54  *              : Mean time + typical difference (estimated to tau/2, that
  55  *                needs to be confirmed) + render time.
  56  * DELTA        : A given error margin.
  57  *
  58  * 3. General considerations
  59  *    ======================
  60  * We define three types of machines :
  61  *      14T > tauI : machines capable of decoding all I pictures
  62  *      2T > tauP  : machines capable of decoding all P pictures
  63  *      T > tauB   : machines capable of decoding all B pictures
  64  *
  65  * 4. Decoding of an I picture
  66  *    ========================
  67  * On fast machines, we decode all I's.
  68  * Otherwise :
  69  * We can decode an I picture if we simply have enough time to decode it
  70  * before displaying :
  71  *      t0 - t > tau´I + DELTA
  72  *
  73  * 5. Decoding of a P picture
  74  *    =======================
  75  * On fast machines, we decode all P's.
  76  * Otherwise :
  77  * First criterion : have time to decode it.
  78  *      t2 - t > tau´P + DELTA
  79  *
  80  * Second criterion : it shouldn't prevent us from displaying the forthcoming
  81  * I picture, which is more important.
  82  *      t12 - t > tau´P + tau´I + DELTA
  83  *
  84  * 6. Decoding of a B picture
  85  *    =======================
  86  * On fast machines, we decode all B's. Otherwise :
  87  *      t1 - t > tau´B + DELTA
  88  * Since the next displayed I or P is already decoded, we don't have to
  89  * worry about it.
  90  *
  91  * I hope you will have a pleasant flight and do not forget your life
  92  * jacket.
  93  *                                                  --Meuuh (2000-12-29)
  94  */
  95
  96 /*****************************************************************************
  97  * Preamble
  98  *****************************************************************************/
  99 #include "defs.h"
 100
 101 #include "config.h"
 102 #include "common.h"
 103 #include "threads.h"
 104 #include "mtime.h"
 105 #include "plugins.h"
 106
 107 #include "intf_msg.h"
 108
 109 #include "stream_control.h"
 110 #include "input_ext-dec.h"
 111
 112 #include "video.h"
 113 #include "video_output.h"
 114
 115 #include "video_decoder.h"
 116 #include "../video_decoder/vdec_idct.h"
 117 #include "../video_decoder/vdec_motion.h"
 118
 119 #include "../video_decoder/vpar_blocks.h"
 120 #include "../video_decoder/vpar_headers.h"
 121 #include "../video_decoder/vpar_synchro.h"
 122 #include "../video_decoder/video_parser.h"
 123
 124 #include "main.h"
 125
 126 /*
 127  * Local prototypes
 128  */
 129 static int  SynchroType( void );
 130
 131 /* Error margins */
 132 #define DELTA                   (int)(0.040*CLOCK_FREQ)
 133
 134 #define DEFAULT_NB_P            5
 135 #define DEFAULT_NB_B            1
 136
 137 /*****************************************************************************
 138  * vpar_SynchroInit : You know what ?
 139  *****************************************************************************/
 140 void vpar_SynchroInit( vpar_thread_t * p_vpar )
 141 {
 142     p_vpar->synchro.i_type = SynchroType();
 143     p_vpar->synchro.i_start = p_vpar->synchro.i_end = 0;
 144     vlc_mutex_init( &p_vpar->synchro.fifo_lock );
 145
 146     /* We use a fake stream pattern, which is often right. */
 147     p_vpar->synchro.i_n_p = p_vpar->synchro.i_eta_p = DEFAULT_NB_P;
 148     p_vpar->synchro.i_n_b = p_vpar->synchro.i_eta_b = DEFAULT_NB_B;
 149     memset( p_vpar->synchro.p_tau, 0, 4 * sizeof(mtime_t) );
 150     memset( p_vpar->synchro.pi_meaningful, 0, 4 * sizeof(unsigned int) );
 151     p_vpar->synchro.b_dropped_last = 0;
 152     p_vpar->synchro.current_pts = mdate() + DEFAULT_PTS_DELAY;
 153     p_vpar->synchro.backward_pts = 0;
 154     p_vpar->synchro.i_current_period = p_vpar->synchro.i_backward_period = 0;
 155 #ifdef STATS
 156     p_vpar->synchro.i_trashed_pic = p_vpar->synchro.i_not_chosen_pic =
 157         p_vpar->synchro.i_pic = 0;
 158 #endif
 159 }
 160
 161 /*****************************************************************************
 162  * vpar_SynchroChoose : Decide whether we will decode a picture or not
 163  *****************************************************************************/
 164 boolean_t vpar_SynchroChoose( vpar_thread_t * p_vpar, int i_coding_type,
 165                               int i_structure )
 166 {
 167     /* For clarity reasons, we separated the special synchros code from the
 168      * mathematical synchro */
 169
 170     if( p_vpar->synchro.i_type != VPAR_SYNCHRO_DEFAULT )
 171     {
 172         switch( i_coding_type )
 173         {
 174         case I_CODING_TYPE:
 175             /* I, IP, IP+, IPB */
 176             if( p_vpar->synchro.i_type == VPAR_SYNCHRO_Iplus )
 177             {
 178                 p_vpar->synchro.b_dropped_last = 1;
 179             }
 180             return( 1 );
 181
 182         case P_CODING_TYPE:
 183             if( p_vpar->synchro.i_type == VPAR_SYNCHRO_I ) /* I */
 184             {
 185                 return( 0 );
 186             }
 187
 188             if( p_vpar->synchro.i_type == VPAR_SYNCHRO_Iplus ) /* I+ */
 189             {
 190                 if( p_vpar->synchro.b_dropped_last )
 191                 {
 192                     p_vpar->synchro.b_dropped_last = 0;
 193                     return( 1 );
 194                 }
 195                 else
 196                 {
 197                     return( 0 );
 198                 }
 199             }
 200
 201             return( 1 ); /* IP, IP+, IPB */
 202
 203         case B_CODING_TYPE:
 204             if( p_vpar->synchro.i_type <= VPAR_SYNCHRO_IP ) /* I, IP */
 205             {
 206                 return( 0 );
 207             }
 208             else if( p_vpar->synchro.i_type == VPAR_SYNCHRO_IPB ) /* IPB */
 209             {
 210                 return( 1 );
 211             }
 212
 213             p_vpar->synchro.b_dropped_last ^= 1; /* IP+ */
 214             return( !p_vpar->synchro.b_dropped_last );
 215         }
 216         return( 0 ); /* never reached but gcc yells at me */
 217     }
 218     else
 219     {
 220 #define TAU_PRIME( coding_type )    (p_vpar->synchro.p_tau[(coding_type)] \
 221                                  + (p_vpar->synchro.p_tau[(coding_type)] >> 1) \
 222                                             + tau_yuv)
 223 #define S                           p_vpar->synchro
 224         /* VPAR_SYNCHRO_DEFAULT */
 225         mtime_t         now, pts, period, tau_yuv;
 226         boolean_t       b_decode = 0;
 227 #ifdef DEBUG_VPAR
 228         char            p_date[MSTRTIME_MAX_SIZE];
 229 #endif
 230
 231         now = mdate();
 232         period = 1000000 * 1001 / p_vpar->sequence.i_frame_rate;
 233
 234         tau_yuv = p_vpar->p_vout->render_time;
 235
 236         vlc_mutex_lock( &p_vpar->synchro.fifo_lock );
 237
 238         switch( i_coding_type )
 239         {
 240         case I_CODING_TYPE:
 241             if( S.backward_pts )
 242             {
 243                 pts = S.backward_pts;
 244             }
 245             else
 246             {
 247                 /* displaying order : B B P B B I
 248                  *                      ^       ^
 249                  *                      |       +- current picture
 250                  *                      +- current PTS
 251                  */
 252                 pts = S.current_pts + period * (S.i_n_b + 2);
 253             }
 254
 255             if( (1 + S.i_n_p * (S.i_n_b + 1)) * period >
 256                     S.p_tau[I_CODING_TYPE] )
 257             {
 258                 b_decode = 1;
 259             }
 260             else
 261             {
 262                 b_decode = (pts - now) > (TAU_PRIME(I_CODING_TYPE) + DELTA);
 263             }
 264             if( !b_decode )
 265                 intf_WarnMsg( 3, "vpar synchro warning: trashing I" );
 266             break;
 267
 268         case P_CODING_TYPE:
 269             if( S.backward_pts )
 270             {
 271                 pts = S.backward_pts;
 272             }
 273             else
 274             {
 275                 pts = S.current_pts + period * (S.i_n_b + 1);
 276             }
 277
 278             if( (1 + S.i_n_p * (S.i_n_b + 1)) * period >
 279                     S.p_tau[I_CODING_TYPE] )
 280             {
 281                 if( (S.i_n_b + 1) * period > S.p_tau[P_CODING_TYPE] )
 282                 {
 283                     /* Security in case we're _really_ late */
 284                     b_decode = (pts - now > 0);
 285                 }
 286                 else
 287                 {
 288                     b_decode = (pts - now) > (TAU_PRIME(P_CODING_TYPE) + DELTA);
 289                     /* next I */
 290                     b_decode &= (pts - now
 291                                   + period
 292                               * ( (S.i_n_p - S.i_eta_p) * (1 + S.i_n_b) - 1 ))
 293                                 > (TAU_PRIME(P_CODING_TYPE)
 294                                     + TAU_PRIME(I_CODING_TYPE) + DELTA);
 295                 }
 296             }
 297             else
 298             {
 299                 b_decode = 0;
 300             }
 301             break;
 302
 303         case B_CODING_TYPE:
 304             pts = S.current_pts;
 305
 306             if( (S.i_n_b + 1) * period > S.p_tau[P_CODING_TYPE] )
 307             {
 308                 b_decode = (pts - now) > (TAU_PRIME(B_CODING_TYPE) + DELTA);
 309             }
 310             else
 311             {
 312                 b_decode = 0;
 313             }
 314         }
 315
 316         vlc_mutex_unlock( &p_vpar->synchro.fifo_lock );
 317 #ifdef DEBUG_VPAR
 318         intf_DbgMsg("vpar synchro debug: %s picture scheduled for %s, %s (%lld)",
 319                     i_coding_type == B_CODING_TYPE ? "B" :
 320                     (i_coding_type == P_CODING_TYPE ? "P" : "I"),
 321                     mstrtime(p_date, pts), b_decode ? "decoding" : "trashed",
 322                     S.p_tau[i_coding_type]);
 323 #endif
 324 #ifdef STATS
 325         if( !b_decode )
 326         {
 327             S.i_not_chosen_pic++;
 328         }
 329 #endif
 330         return( b_decode );
 331 #undef S
 332 #undef TAU_PRIME
 333     }
 334 }
 335
 336 /*****************************************************************************
 337  * vpar_SynchroTrash : Update counters when we trash a picture
 338  *****************************************************************************/
 339 void vpar_SynchroTrash( vpar_thread_t * p_vpar, int i_coding_type,
 340                         int i_structure )
 341 {
 342 #ifdef STATS
 343     p_vpar->synchro.i_trashed_pic++;
 344 #endif
 345 }
 346
 347 /*****************************************************************************
 348  * vpar_SynchroDecode : Update timers when we decide to decode a picture
 349  *****************************************************************************/
 350 void vpar_SynchroDecode( vpar_thread_t * p_vpar, int i_coding_type,
 351                          int i_structure )
 352 {
 353     vlc_mutex_lock( &p_vpar->synchro.fifo_lock );
 354
 355     if( ((p_vpar->synchro.i_end + 1 - p_vpar->synchro.i_start)
 356             % MAX_DECODING_PIC) )
 357     {
 358         p_vpar->synchro.p_date_fifo[p_vpar->synchro.i_end] = mdate();
 359         p_vpar->synchro.pi_coding_types[p_vpar->synchro.i_end] = i_coding_type;
 360
 361         FIFO_INCREMENT( i_end );
 362     }
 363     else
 364     {
 365         /* FIFO full, panic() */
 366         intf_ErrMsg("vpar error: synchro fifo full, estimations will be biased");
 367     }
 368     vlc_mutex_unlock( &p_vpar->synchro.fifo_lock );
 369 }
 370
 371 /*****************************************************************************
 372  * vpar_SynchroEnd : Called when the image is totally decoded
 373  *****************************************************************************/
 374 void vpar_SynchroEnd( vpar_thread_t * p_vpar, int i_garbage )
 375 {
 376     mtime_t     tau;
 377     int         i_coding_type;
 378
 379     vlc_mutex_lock( &p_vpar->synchro.fifo_lock );
 380
 381     if (!i_garbage)
 382     {
 383         tau = mdate() - p_vpar->synchro.p_date_fifo[p_vpar->synchro.i_start];
 384         i_coding_type = p_vpar->synchro.pi_coding_types[p_vpar->synchro.i_start];
 385
 386         /* Mean with average tau, to ensure stability. */
 387         p_vpar->synchro.p_tau[i_coding_type] =
 388             (p_vpar->synchro.pi_meaningful[i_coding_type]
 389              * p_vpar->synchro.p_tau[i_coding_type] + tau)
 390             / (p_vpar->synchro.pi_meaningful[i_coding_type] + 1);
 391         if( p_vpar->synchro.pi_meaningful[i_coding_type] < MAX_PIC_AVERAGE )
 392         {
 393             p_vpar->synchro.pi_meaningful[i_coding_type]++;
 394         }
 395 #ifdef DEBUG_VPAR
 396         intf_DbgMsg("vpar synchro debug: finished decoding %s (%lld)",
 397                     i_coding_type == B_CODING_TYPE ? "B" :
 398                     (i_coding_type == P_CODING_TYPE ? "P" : "I"), tau);
 399 #endif
 400     }
 401
 402     FIFO_INCREMENT( i_start );
 403
 404     vlc_mutex_unlock( &p_vpar->synchro.fifo_lock );
 405 }
 406
 407 /*****************************************************************************
 408  * vpar_SynchroDate : When an image has been decoded, ask for its date
 409  *****************************************************************************/
 410 mtime_t vpar_SynchroDate( vpar_thread_t * p_vpar )
 411 {
 412     /* No need to lock, since PTS are only used by the video parser. */
 413     return( p_vpar->synchro.current_pts );
 414 }
 415
 416 /*****************************************************************************
 417  * vpar_SynchroNewPicture: Update stream structure and PTS
 418  *****************************************************************************/
 419 void vpar_SynchroNewPicture( vpar_thread_t * p_vpar, int i_coding_type,
 420                              int i_repeat_field )
 421 {
 422     mtime_t         period = 1000000 * 1001 / p_vpar->sequence.i_frame_rate;
 423
 424     switch( i_coding_type )
 425     {
 426     case I_CODING_TYPE:
 427         if( p_vpar->synchro.i_eta_p
 428                 && p_vpar->synchro.i_eta_p != p_vpar->synchro.i_n_p )
 429         {
 430             intf_WarnMsg( 1, "Stream periodicity changed from P[%d] to P[%d]",
 431                           p_vpar->synchro.i_n_p, p_vpar->synchro.i_eta_p );
 432             p_vpar->synchro.i_n_p = p_vpar->synchro.i_eta_p;
 433         }
 434         p_vpar->synchro.i_eta_p = p_vpar->synchro.i_eta_b = 0;
 435 #ifdef STATS
 436         if( p_vpar->synchro.i_type == VPAR_SYNCHRO_DEFAULT )
 437         {
 438             intf_Msg( "vpar synchro stats: I(%lld) P(%lld)[%d] B(%lld)[%d] YUV(%lld) : trashed %d:%d/%d",
 439                   p_vpar->synchro.p_tau[I_CODING_TYPE],
 440                   p_vpar->synchro.p_tau[P_CODING_TYPE],
 441                   p_vpar->synchro.i_n_p,
 442                   p_vpar->synchro.p_tau[B_CODING_TYPE],
 443                   p_vpar->synchro.i_n_b,
 444                   p_vpar->p_vout->render_time,
 445                   p_vpar->synchro.i_not_chosen_pic,
 446                   p_vpar->synchro.i_trashed_pic -
 447                   p_vpar->synchro.i_not_chosen_pic,
 448                   p_vpar->synchro.i_pic );
 449             p_vpar->synchro.i_trashed_pic = p_vpar->synchro.i_not_chosen_pic
 450                 = p_vpar->synchro.i_pic = 0;
 451         }
 452 #endif
 453         break;
 454     case P_CODING_TYPE:
 455         p_vpar->synchro.i_eta_p++;
 456         if( p_vpar->synchro.i_eta_b
 457                 && p_vpar->synchro.i_eta_b != p_vpar->synchro.i_n_b )
 458         {
 459             intf_WarnMsg( 1, "Stream periodicity changed from B[%d] to B[%d]",
 460                           p_vpar->synchro.i_n_b, p_vpar->synchro.i_eta_b );
 461             p_vpar->synchro.i_n_b = p_vpar->synchro.i_eta_b;
 462         }
 463         p_vpar->synchro.i_eta_b = 0;
 464         break;
 465     case B_CODING_TYPE:
 466         p_vpar->synchro.i_eta_b++;
 467         break;
 468     }
 469
 470     p_vpar->synchro.current_pts += p_vpar->synchro.i_current_period
 471                                         * (period >> 1);
 472
 473 #define PTS_THRESHOLD   (period >> 2)
 474     if( i_coding_type == B_CODING_TYPE )
 475     {
 476         /* A video frame can be displayed 1, 2 or 3 times, according to
 477          * repeat_first_field, top_field_first, progressive_sequence and
 478          * progressive_frame. */
 479         p_vpar->synchro.i_current_period = i_repeat_field;
 480
 481         if( p_vpar->sequence.next_pts )
 482         {
 483             if( p_vpar->sequence.next_pts - p_vpar->synchro.current_pts
 484                     > PTS_THRESHOLD
 485                  || p_vpar->synchro.current_pts - p_vpar->sequence.next_pts
 486                     > PTS_THRESHOLD )
 487             {
 488                 intf_WarnMsg( 2,
 489                         "vpar synchro warning: pts != current_date (%lld)",
 490                         p_vpar->synchro.current_pts
 491                             - p_vpar->sequence.next_pts );
 492             }
 493             p_vpar->synchro.current_pts = p_vpar->sequence.next_pts;
 494             p_vpar->sequence.next_pts = 0;
 495         }
 496     }
 497     else
 498     {
 499         p_vpar->synchro.i_current_period = p_vpar->synchro.i_backward_period;
 500         p_vpar->synchro.i_backward_period = i_repeat_field;
 501
 502         if( p_vpar->synchro.backward_pts )
 503         {
 504             if( p_vpar->sequence.next_dts &&
 505                 (p_vpar->sequence.next_dts - p_vpar->synchro.backward_pts
 506                     > PTS_THRESHOLD
 507               || p_vpar->synchro.backward_pts - p_vpar->sequence.next_dts
 508                     > PTS_THRESHOLD) )
 509             {
 510                 intf_WarnMsg( 2,
 511                         "vpar synchro warning: backward_pts != dts (%lld)",
 512                         p_vpar->sequence.next_dts
 513                             - p_vpar->synchro.backward_pts );
 514             }
 515             if( p_vpar->synchro.backward_pts - p_vpar->synchro.current_pts
 516                     > PTS_THRESHOLD
 517                  || p_vpar->synchro.current_pts - p_vpar->synchro.backward_pts
 518                     > PTS_THRESHOLD )
 519             {
 520                 intf_WarnMsg( 2,
 521                    "vpar synchro warning: backward_pts != current_pts (%lld)",
 522                    p_vpar->synchro.current_pts - p_vpar->synchro.backward_pts );
 523             }
 524             p_vpar->synchro.current_pts = p_vpar->synchro.backward_pts;
 525             p_vpar->synchro.backward_pts = 0;
 526         }
 527         else if( p_vpar->sequence.next_dts )
 528         {
 529             if( p_vpar->sequence.next_dts - p_vpar->synchro.current_pts
 530                     > PTS_THRESHOLD
 531                  || p_vpar->synchro.current_pts - p_vpar->sequence.next_dts
 532                     > PTS_THRESHOLD )
 533             {
 534                 intf_WarnMsg( 2,
 535                         "vpar synchro warning: dts != current_pts (%lld)",
 536                         p_vpar->synchro.current_pts
 537                             - p_vpar->sequence.next_dts );
 538             }
 539             /* By definition of a DTS. */
 540             p_vpar->synchro.current_pts = p_vpar->sequence.next_dts;
 541             p_vpar->sequence.next_dts = 0;
 542         }
 543
 544         if( p_vpar->sequence.next_pts )
 545         {
 546             /* Store the PTS for the next time we have to date an I picture. */
 547             p_vpar->synchro.backward_pts = p_vpar->sequence.next_pts;
 548             p_vpar->sequence.next_pts = 0;
 549         }
 550     }
 551 #undef PTS_THRESHOLD
 552
 553 #ifdef STATS
 554     p_vpar->synchro.i_pic++;
 555 #endif
 556 }
 557
 558 /*****************************************************************************
 559  * SynchroType: Get the user's synchro type
 560  *****************************************************************************
 561  * This function is called at initialization.
 562  *****************************************************************************/
 563 static int SynchroType( void )
 564 {
 565     char * psz_synchro = main_GetPszVariable( VPAR_SYNCHRO_VAR, NULL );
 566
 567     if( psz_synchro == NULL )
 568     {
 569         return VPAR_SYNCHRO_DEFAULT;
 570     }
 571
 572     switch( *psz_synchro++ )
 573     {
 574       case 'i':
 575       case 'I':
 576         switch( *psz_synchro++ )
 577         {
 578           case '\0':
 579             return VPAR_SYNCHRO_I;
 580
 581           case '+':
 582             if( *psz_synchro ) return 0;
 583             return VPAR_SYNCHRO_Iplus;
 584
 585           case 'p':
 586           case 'P':
 587             switch( *psz_synchro++ )
 588             {
 589               case '\0':
 590                 return VPAR_SYNCHRO_IP;
 591
 592               case '+':
 593                 if( *psz_synchro ) return 0;
 594                 return VPAR_SYNCHRO_IPplus;
 595
 596               case 'b':
 597               case 'B':
 598                 if( *psz_synchro ) return 0;
 599                 return VPAR_SYNCHRO_IPB;
 600
 601               default:
 602                 return VPAR_SYNCHRO_DEFAULT;
 603
 604             }
 605
 606           default:
 607             return VPAR_SYNCHRO_DEFAULT;
 608         }
 609     }
 610
 611     return VPAR_SYNCHRO_DEFAULT;
 612 }
 613