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 1.89 2001/05/06 04:32:03 sam 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  * 2. Definitions
  45  *    ===========
  46  * t[0..12]     : Presentation timestamps of pictures 0..12.
  47  * t            : Current timestamp, at the moment of the decoding.
  48  * T            : Picture period, T = 1/frame_rate.
  49  * tau[I,P,B]   : Mean time to decode an [I,P,B] picture.
  50  * tauYUV       : Mean time to render a picture (given by the video_output).
  51  * tau´[I,P,B] = 2 * tau[I,P,B] + tauYUV
  52  *              : Mean time + typical difference (estimated to tau/2, that
  53  *                needs to be confirmed) + render time.
  54  * DELTA        : A given error margin.
  55  *
  56  * 3. General considerations
  57  *    ======================
  58  * We define three types of machines :
  59  *      14T > tauI : machines capable of decoding all I pictures
  60  *      2T > tauP  : machines capable of decoding all P pictures
  61  *      T > tauB   : machines capable of decoding all B pictures
  62  *
  63  * 4. Decoding of an I picture
  64  *    ========================
  65  * On fast machines, we decode all I's.
  66  * Otherwise :
  67  * We can decode an I picture if we simply have enough time to decode it
  68  * before displaying :
  69  *      t0 - t > tau´I + DELTA
  70  *
  71  * 5. Decoding of a P picture
  72  *    =======================
  73  * On fast machines, we decode all P's.
  74  * Otherwise :
  75  * First criterion : have time to decode it.
  76  *      t2 - t > tau´P + DELTA
  77  *
  78  * Second criterion : it shouldn't prevent us from displaying the forthcoming
  79  * I picture, which is more important.
  80  *      t12 - t > tau´P + tau´I + DELTA
  81  *
  82  * 6. Decoding of a B picture
  83  *    =======================
  84  * On fast machines, we decode all B's. Otherwise :
  85  *      t1 - t > tau´B + DELTA
  86  * Since the next displayed I or P is already decoded, we don't have to
  87  * worry about it.
  88  *
  89  * I hope you will have a pleasant flight and do not forget your life
  90  * jacket.
  91  *                                                  --Meuuh (2000-12-29)
  92  */
  93
  94 /*****************************************************************************
  95  * Preamble
  96  *****************************************************************************/
  97 #include "defs.h"
  98
  99 #include <string.h>                                    /* memcpy(), memset() */
 100
 101 #include "config.h"
 102 #include "common.h"
 103 #include "threads.h"
 104 #include "mtime.h"
 105
 106 #include "intf_msg.h"
 107
 108 #include "stream_control.h"
 109 #include "input_ext-dec.h"
 110
 111 #include "video.h"
 112 #include "video_output.h"
 113
 114 #include "video_decoder.h"
 115 #include "vdec_motion.h"
 116
 117 #include "vpar_blocks.h"
 118 #include "vpar_headers.h"
 119 #include "vpar_synchro.h"
 120 #include "video_parser.h"
 121
 122 #include "main.h"
 123
 124 /*
 125  * Local prototypes
 126  */
 127 static int  SynchroType( void );
 128
 129 /* Error margins */
 130 #define DELTA                   (int)(0.040*CLOCK_FREQ)
 131
 132 #define DEFAULT_NB_P            5
 133 #define DEFAULT_NB_B            1
 134
 135 /*****************************************************************************
 136  * vpar_SynchroInit : You know what ?
 137  *****************************************************************************/
 138 void vpar_SynchroInit( vpar_thread_t * p_vpar )
 139 {
 140     p_vpar->synchro.i_type = SynchroType();
 141     p_vpar->synchro.i_start = p_vpar->synchro.i_end = 0;
 142     vlc_mutex_init( &p_vpar->synchro.fifo_lock );
 143
 144     /* We use a fake stream pattern, which is often right. */
 145     p_vpar->synchro.i_n_p = p_vpar->synchro.i_eta_p = DEFAULT_NB_P;
 146     p_vpar->synchro.i_n_b = p_vpar->synchro.i_eta_b = DEFAULT_NB_B;
 147     memset( p_vpar->synchro.p_tau, 0, 4 * sizeof(mtime_t) );
 148     memset( p_vpar->synchro.pi_meaningful, 0, 4 * sizeof(unsigned int) );
 149     p_vpar->synchro.b_dropped_last = 0;
 150     p_vpar->synchro.current_pts = mdate() + DEFAULT_PTS_DELAY;
 151     p_vpar->synchro.backward_pts = 0;
 152     p_vpar->synchro.i_current_period = p_vpar->synchro.i_backward_period = 0;
 153 #ifdef STATS
 154     p_vpar->synchro.i_trashed_pic = p_vpar->synchro.i_not_chosen_pic =
 155         p_vpar->synchro.i_pic = 0;
 156 #endif
 157 }
 158
 159 /*****************************************************************************
 160  * vpar_SynchroChoose : Decide whether we will decode a picture or not
 161  *****************************************************************************/
 162 boolean_t vpar_SynchroChoose( vpar_thread_t * p_vpar, int i_coding_type,
 163                               int i_structure )
 164 {
 165     /* For clarity reasons, we separated the special synchros code from the
 166      * mathematical synchro */
 167
 168     if( p_vpar->synchro.i_type != VPAR_SYNCHRO_DEFAULT )
 169     {
 170         switch( i_coding_type )
 171         {
 172         case I_CODING_TYPE:
 173             /* I, IP, IP+, IPB */
 174             if( p_vpar->synchro.i_type == VPAR_SYNCHRO_Iplus )
 175             {
 176                 p_vpar->synchro.b_dropped_last = 1;
 177             }
 178             return( 1 );
 179
 180         case P_CODING_TYPE:
 181             if( p_vpar->synchro.i_type == VPAR_SYNCHRO_I ) /* I */
 182             {
 183                 return( 0 );
 184             }
 185
 186             if( p_vpar->synchro.i_type == VPAR_SYNCHRO_Iplus ) /* I+ */
 187             {
 188                 if( p_vpar->synchro.b_dropped_last )
 189                 {
 190                     p_vpar->synchro.b_dropped_last = 0;
 191                     return( 1 );
 192                 }
 193                 else
 194                 {
 195                     return( 0 );
 196                 }
 197             }
 198
 199             return( 1 ); /* IP, IP+, IPB */
 200
 201         case B_CODING_TYPE:
 202             if( p_vpar->synchro.i_type <= VPAR_SYNCHRO_IP ) /* I, IP */
 203             {
 204                 return( 0 );
 205             }
 206             else if( p_vpar->synchro.i_type == VPAR_SYNCHRO_IPB ) /* IPB */
 207             {
 208                 return( 1 );
 209             }
 210
 211             p_vpar->synchro.b_dropped_last ^= 1; /* IP+ */
 212             return( !p_vpar->synchro.b_dropped_last );
 213         }
 214         return( 0 ); /* never reached but gcc yells at me */
 215     }
 216     else
 217     {
 218 #define TAU_PRIME( coding_type )    (p_vpar->synchro.p_tau[(coding_type)] \
 219                                  + (p_vpar->synchro.p_tau[(coding_type)] >> 1) \
 220                                             + tau_yuv)
 221 #define S                           p_vpar->synchro
 222         /* VPAR_SYNCHRO_DEFAULT */
 223         mtime_t         now, period, tau_yuv;
 224         mtime_t         pts = 0;
 225         boolean_t       b_decode = 0;
 226 #ifdef TRACE_VPAR
 227         char            p_date[MSTRTIME_MAX_SIZE];
 228 #endif
 229
 230         now = mdate();
 231         period = 1000000 * 1001 / p_vpar->sequence.i_frame_rate
 232                     * p_vpar->sequence.i_current_rate / DEFAULT_RATE;
 233
 234         vlc_mutex_lock( &p_vpar->p_vout->change_lock );
 235         tau_yuv = p_vpar->p_vout->render_time;
 236         vlc_mutex_unlock( &p_vpar->p_vout->change_lock );
 237 #ifdef VDEC_SMP
 238         vlc_mutex_lock( &p_vpar->synchro.fifo_lock );
 239 #endif
 240
 241         switch( i_coding_type )
 242         {
 243         case I_CODING_TYPE:
 244             if( S.backward_pts )
 245             {
 246                 pts = S.backward_pts;
 247             }
 248             else
 249             {
 250                 /* displaying order : B B P B B I
 251                  *                      ^       ^
 252                  *                      |       +- current picture
 253                  *                      +- current PTS
 254                  */
 255                 pts = S.current_pts + period * (S.i_n_b + 2);
 256             }
 257
 258             if( (1 + S.i_n_p * (S.i_n_b + 1)) * period >
 259                     S.p_tau[I_CODING_TYPE] )
 260             {
 261                 b_decode = 1;
 262             }
 263             else
 264             {
 265                 b_decode = (pts - now) > (TAU_PRIME(I_CODING_TYPE) + DELTA);
 266             }
 267             if( !b_decode )
 268                 intf_WarnMsg( 3, "vpar synchro warning: trashing I (%lld)",
 269                              pts - now);
 270             break;
 271
 272         case P_CODING_TYPE:
 273             if( S.backward_pts )
 274             {
 275                 pts = S.backward_pts;
 276             }
 277             else
 278             {
 279                 pts = S.current_pts + period * (S.i_n_b + 1);
 280             }
 281
 282             if( (1 + S.i_n_p * (S.i_n_b + 1)) * period >
 283                     S.p_tau[I_CODING_TYPE] )
 284             {
 285                 if( (S.i_n_b + 1) * period > S.p_tau[P_CODING_TYPE] )
 286                 {
 287                     /* Security in case we're _really_ late */
 288                     b_decode = (pts - now > 0);
 289                 }
 290                 else
 291                 {
 292                     b_decode = (pts - now) > (TAU_PRIME(P_CODING_TYPE) + DELTA);
 293                     /* next I */
 294                     b_decode &= (pts - now
 295                                   + period
 296                               * ( (S.i_n_p - S.i_eta_p) * (1 + S.i_n_b) - 1 ))
 297                                 > (TAU_PRIME(P_CODING_TYPE)
 298                                     + TAU_PRIME(I_CODING_TYPE) + DELTA);
 299                 }
 300             }
 301             else
 302             {
 303                 b_decode = 0;
 304             }
 305             break;
 306
 307         case B_CODING_TYPE:
 308             pts = S.current_pts;
 309
 310             if( (S.i_n_b + 1) * period > S.p_tau[P_CODING_TYPE] )
 311             {
 312                 b_decode = (pts - now) > (TAU_PRIME(B_CODING_TYPE) + DELTA);
 313             }
 314             else
 315             {
 316                 b_decode = 0;
 317             }
 318         }
 319
 320 #ifdef VDEC_SMP
 321         vlc_mutex_unlock( &p_vpar->synchro.fifo_lock );
 322 #endif
 323 #ifdef TRACE_VPAR
 324         intf_DbgMsg("vpar synchro debug: %s picture scheduled for %s, %s (%lld)",
 325                     i_coding_type == B_CODING_TYPE ? "B" :
 326                     (i_coding_type == P_CODING_TYPE ? "P" : "I"),
 327                     mstrtime(p_date, pts), b_decode ? "decoding" : "trashed",
 328                     S.p_tau[i_coding_type]);
 329 #endif
 330 #ifdef STATS
 331         if( !b_decode )
 332         {
 333             S.i_not_chosen_pic++;
 334         }
 335 #endif
 336         return( b_decode );
 337 #undef S
 338 #undef TAU_PRIME
 339     }
 340 }
 341
 342 /*****************************************************************************
 343  * vpar_SynchroTrash : Update counters when we trash a picture
 344  *****************************************************************************/
 345 void vpar_SynchroTrash( vpar_thread_t * p_vpar, int i_coding_type,
 346                         int i_structure )
 347 {
 348 #ifdef STATS
 349     p_vpar->synchro.i_trashed_pic++;
 350 #endif
 351 }
 352
 353 /*****************************************************************************
 354  * vpar_SynchroDecode : Update timers when we decide to decode a picture
 355  *****************************************************************************/
 356 void vpar_SynchroDecode( vpar_thread_t * p_vpar, int i_coding_type,
 357                          int i_structure )
 358 {
 359 #ifdef VDEC_SMP
 360     vlc_mutex_lock( &p_vpar->synchro.fifo_lock );
 361 #endif
 362
 363     if( ((p_vpar->synchro.i_end + 1 - p_vpar->synchro.i_start)
 364             % MAX_DECODING_PIC) )
 365     {
 366         p_vpar->synchro.p_date_fifo[p_vpar->synchro.i_end] = mdate();
 367         p_vpar->synchro.pi_coding_types[p_vpar->synchro.i_end] = i_coding_type;
 368
 369         FIFO_INCREMENT( i_end );
 370     }
 371     else
 372     {
 373         /* FIFO full, panic() */
 374         intf_ErrMsg("vpar error: synchro fifo full, estimations will be biased (%d:%d)",
 375                     p_vpar->synchro.i_start, p_vpar->synchro.i_end);
 376     }
 377 #ifdef VDEC_SMP
 378     vlc_mutex_unlock( &p_vpar->synchro.fifo_lock );
 379 #endif
 380 }
 381
 382 /*****************************************************************************
 383  * vpar_SynchroEnd : Called when the image is totally decoded
 384  *****************************************************************************/
 385 void vpar_SynchroEnd( vpar_thread_t * p_vpar, int i_garbage )
 386 {
 387     mtime_t     tau;
 388     int         i_coding_type;
 389
 390 #ifdef VDEC_SMP
 391     vlc_mutex_lock( &p_vpar->synchro.fifo_lock );
 392 #endif
 393
 394     i_coding_type = p_vpar->synchro.pi_coding_types[p_vpar->synchro.i_start];
 395
 396     if( !i_garbage )
 397     {
 398         tau = mdate() - p_vpar->synchro.p_date_fifo[p_vpar->synchro.i_start];
 399
 400         /* If duration too high, something happened (pause ?), so don't
 401          * take it into account. */
 402         if( tau < 3 * p_vpar->synchro.p_tau[i_coding_type]
 403              || !p_vpar->synchro.pi_meaningful[i_coding_type] )
 404         {
 405             /* Mean with average tau, to ensure stability. */
 406             p_vpar->synchro.p_tau[i_coding_type] =
 407                 (p_vpar->synchro.pi_meaningful[i_coding_type]
 408                  * p_vpar->synchro.p_tau[i_coding_type] + tau)
 409                 / (p_vpar->synchro.pi_meaningful[i_coding_type] + 1);
 410             if( p_vpar->synchro.pi_meaningful[i_coding_type] < MAX_PIC_AVERAGE )
 411             {
 412                 p_vpar->synchro.pi_meaningful[i_coding_type]++;
 413             }
 414         }
 415
 416 #ifdef TRACE_VPAR
 417         intf_DbgMsg("vpar synchro debug: finished decoding %s (%lld)",
 418                     i_coding_type == B_CODING_TYPE ? "B" :
 419                     (i_coding_type == P_CODING_TYPE ? "P" : "I"), tau);
 420 #endif
 421     }
 422     else
 423     {
 424         intf_DbgMsg("vpar synchro debug: aborting %s",
 425                     i_coding_type == B_CODING_TYPE ? "B" :
 426                     (i_coding_type == P_CODING_TYPE ? "P" : "I"));
 427     }
 428
 429     FIFO_INCREMENT( i_start );
 430
 431 #ifdef VDEC_SMP
 432     vlc_mutex_unlock( &p_vpar->synchro.fifo_lock );
 433 #endif
 434 }
 435
 436 /*****************************************************************************
 437  * vpar_SynchroDate : When an image has been decoded, ask for its date
 438  *****************************************************************************/
 439 mtime_t vpar_SynchroDate( vpar_thread_t * p_vpar )
 440 {
 441     /* No need to lock, since PTS are only used by the video parser. */
 442     return( p_vpar->synchro.current_pts );
 443 }
 444
 445 /*****************************************************************************
 446  * vpar_SynchroNewPicture: Update stream structure and PTS
 447  *****************************************************************************/
 448 void vpar_SynchroNewPicture( vpar_thread_t * p_vpar, int i_coding_type,
 449                              int i_repeat_field )
 450 {
 451     mtime_t         period = 1000000 * 1001 / p_vpar->sequence.i_frame_rate
 452                               * p_vpar->sequence.i_current_rate / DEFAULT_RATE;
 453 #if 0
 454     mtime_t         now = mdate();
 455 #endif
 456
 457     switch( i_coding_type )
 458     {
 459     case I_CODING_TYPE:
 460         if( p_vpar->synchro.i_eta_p
 461                 && p_vpar->synchro.i_eta_p != p_vpar->synchro.i_n_p )
 462         {
 463             intf_WarnMsg( 1, "Stream periodicity changed from P[%d] to P[%d]",
 464                           p_vpar->synchro.i_n_p, p_vpar->synchro.i_eta_p );
 465             p_vpar->synchro.i_n_p = p_vpar->synchro.i_eta_p;
 466         }
 467         p_vpar->synchro.i_eta_p = p_vpar->synchro.i_eta_b = 0;
 468 #ifdef STATS
 469         if( p_vpar->synchro.i_type == VPAR_SYNCHRO_DEFAULT )
 470         {
 471             intf_Msg( "vpar synchro stats: I(%lld) P(%lld)[%d] B(%lld)[%d] YUV(%lld) : trashed %d:%d/%d",
 472                   p_vpar->synchro.p_tau[I_CODING_TYPE],
 473                   p_vpar->synchro.p_tau[P_CODING_TYPE],
 474                   p_vpar->synchro.i_n_p,
 475                   p_vpar->synchro.p_tau[B_CODING_TYPE],
 476                   p_vpar->synchro.i_n_b,
 477                   p_vpar->p_vout->render_time,
 478                   p_vpar->synchro.i_not_chosen_pic,
 479                   p_vpar->synchro.i_trashed_pic -
 480                   p_vpar->synchro.i_not_chosen_pic,
 481                   p_vpar->synchro.i_pic );
 482             p_vpar->synchro.i_trashed_pic = p_vpar->synchro.i_not_chosen_pic
 483                 = p_vpar->synchro.i_pic = 0;
 484         }
 485 #endif
 486         break;
 487     case P_CODING_TYPE:
 488         p_vpar->synchro.i_eta_p++;
 489         if( p_vpar->synchro.i_eta_b
 490                 && p_vpar->synchro.i_eta_b != p_vpar->synchro.i_n_b )
 491         {
 492             intf_WarnMsg( 1, "Stream periodicity changed from B[%d] to B[%d]",
 493                           p_vpar->synchro.i_n_b, p_vpar->synchro.i_eta_b );
 494             p_vpar->synchro.i_n_b = p_vpar->synchro.i_eta_b;
 495         }
 496         p_vpar->synchro.i_eta_b = 0;
 497         break;
 498     case B_CODING_TYPE:
 499         p_vpar->synchro.i_eta_b++;
 500         break;
 501     }
 502
 503     p_vpar->synchro.current_pts += p_vpar->synchro.i_current_period
 504                                         * (period >> 1);
 505
 506 #define PTS_THRESHOLD   (period >> 2)
 507     if( i_coding_type == B_CODING_TYPE )
 508     {
 509         /* A video frame can be displayed 1, 2 or 3 times, according to
 510          * repeat_first_field, top_field_first, progressive_sequence and
 511          * progressive_frame. */
 512         p_vpar->synchro.i_current_period = i_repeat_field;
 513
 514         if( p_vpar->sequence.next_pts )
 515         {
 516             if( p_vpar->sequence.next_pts - p_vpar->synchro.current_pts
 517                     > PTS_THRESHOLD
 518                  || p_vpar->synchro.current_pts - p_vpar->sequence.next_pts
 519                     > PTS_THRESHOLD )
 520             {
 521                 intf_WarnMsg( 2,
 522                         "vpar synchro warning: pts != current_date (%lld)",
 523                         p_vpar->synchro.current_pts
 524                             - p_vpar->sequence.next_pts );
 525             }
 526             p_vpar->synchro.current_pts = p_vpar->sequence.next_pts;
 527             p_vpar->sequence.next_pts = 0;
 528         }
 529     }
 530     else
 531     {
 532         p_vpar->synchro.i_current_period = p_vpar->synchro.i_backward_period;
 533         p_vpar->synchro.i_backward_period = i_repeat_field;
 534
 535         if( p_vpar->synchro.backward_pts )
 536         {
 537             if( p_vpar->sequence.next_dts &&
 538                 (p_vpar->sequence.next_dts - p_vpar->synchro.backward_pts
 539                     > PTS_THRESHOLD
 540               || p_vpar->synchro.backward_pts - p_vpar->sequence.next_dts
 541                     > PTS_THRESHOLD) )
 542             {
 543                 intf_WarnMsg( 2,
 544                         "vpar synchro warning: backward_pts != dts (%lld)",
 545                         p_vpar->sequence.next_dts
 546                             - p_vpar->synchro.backward_pts );
 547             }
 548             if( p_vpar->synchro.backward_pts - p_vpar->synchro.current_pts
 549                     > PTS_THRESHOLD
 550                  || p_vpar->synchro.current_pts - p_vpar->synchro.backward_pts
 551                     > PTS_THRESHOLD )
 552             {
 553                 intf_WarnMsg( 2,
 554                    "vpar synchro warning: backward_pts != current_pts (%lld)",
 555                    p_vpar->synchro.current_pts - p_vpar->synchro.backward_pts );
 556             }
 557             p_vpar->synchro.current_pts = p_vpar->synchro.backward_pts;
 558             p_vpar->synchro.backward_pts = 0;
 559         }
 560         else if( p_vpar->sequence.next_dts )
 561         {
 562             if( p_vpar->sequence.next_dts - p_vpar->synchro.current_pts
 563                     > PTS_THRESHOLD
 564                  || p_vpar->synchro.current_pts - p_vpar->sequence.next_dts
 565                     > PTS_THRESHOLD )
 566             {
 567                 intf_WarnMsg( 2,
 568                         "vpar synchro warning: dts != current_pts (%lld)",
 569                         p_vpar->synchro.current_pts
 570                             - p_vpar->sequence.next_dts );
 571             }
 572             /* By definition of a DTS. */
 573             p_vpar->synchro.current_pts = p_vpar->sequence.next_dts;
 574             p_vpar->sequence.next_dts = 0;
 575         }
 576
 577         if( p_vpar->sequence.next_pts )
 578         {
 579             /* Store the PTS for the next time we have to date an I picture. */
 580             p_vpar->synchro.backward_pts = p_vpar->sequence.next_pts;
 581             p_vpar->sequence.next_pts = 0;
 582         }
 583     }
 584 #undef PTS_THRESHOLD
 585
 586 #if 0
 587     /* Removed for incompatibility with slow motion */
 588     if( p_vpar->synchro.current_pts + DEFAULT_PTS_DELAY < now )
 589     {
 590         /* We cannot be _that_ late, something must have happened, reinit
 591          * the dates. */
 592         intf_WarnMsg( 2, "PTS << now (%lld), resetting",
 593                       now - p_vpar->synchro.current_pts - DEFAULT_PTS_DELAY );
 594         p_vpar->synchro.current_pts = now + DEFAULT_PTS_DELAY;
 595     }
 596     if( p_vpar->synchro.backward_pts
 597          && p_vpar->synchro.backward_pts + DEFAULT_PTS_DELAY < now )
 598     {
 599         /* The same. */
 600         p_vpar->synchro.backward_pts = 0;
 601     }
 602 #endif
 603
 604 #ifdef STATS
 605     p_vpar->synchro.i_pic++;
 606 #endif
 607 }
 608
 609 /*****************************************************************************
 610  * SynchroType: Get the user's synchro type
 611  *****************************************************************************
 612  * This function is called at initialization.
 613  *****************************************************************************/
 614 static int SynchroType( void )
 615 {
 616     char * psz_synchro = main_GetPszVariable( VPAR_SYNCHRO_VAR, NULL );
 617
 618     if( psz_synchro == NULL )
 619     {
 620         return VPAR_SYNCHRO_DEFAULT;
 621     }
 622
 623     switch( *psz_synchro++ )
 624     {
 625       case 'i':
 626       case 'I':
 627         switch( *psz_synchro++ )
 628         {
 629           case '\0':
 630             return VPAR_SYNCHRO_I;
 631
 632           case '+':
 633             if( *psz_synchro ) return 0;
 634             return VPAR_SYNCHRO_Iplus;
 635
 636           case 'p':
 637           case 'P':
 638             switch( *psz_synchro++ )
 639             {
 640               case '\0':
 641                 return VPAR_SYNCHRO_IP;
 642
 643               case '+':
 644                 if( *psz_synchro ) return 0;
 645                 return VPAR_SYNCHRO_IPplus;
 646
 647               case 'b':
 648               case 'B':
 649                 if( *psz_synchro ) return 0;
 650                 return VPAR_SYNCHRO_IPB;
 651
 652               default:
 653                 return VPAR_SYNCHRO_DEFAULT;
 654
 655             }
 656
 657           default:
 658             return VPAR_SYNCHRO_DEFAULT;
 659         }
 660     }
 661
 662     return VPAR_SYNCHRO_DEFAULT;
 663 }
 664