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 1.88 2001/04/27 19:29:11 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  * 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 #include "../video_decoder/vdec_idct.h"
 117
 118 #include "vpar_blocks.h"
 119 #include "../video_decoder/vpar_headers.h"
 120 #include "../video_decoder/vpar_synchro.h"
 121 #include "../video_decoder/video_parser.h"
 122
 123 #include "main.h"
 124
 125 /*
 126  * Local prototypes
 127  */
 128 static int  SynchroType( void );
 129
 130 /* Error margins */
 131 #define DELTA                   (int)(0.040*CLOCK_FREQ)
 132
 133 #define DEFAULT_NB_P            5
 134 #define DEFAULT_NB_B            1
 135
 136 /*****************************************************************************
 137  * vpar_SynchroInit : You know what ?
 138  *****************************************************************************/
 139 void vpar_SynchroInit( vpar_thread_t * p_vpar )
 140 {
 141     p_vpar->synchro.i_type = SynchroType();
 142     p_vpar->synchro.i_start = p_vpar->synchro.i_end = 0;
 143     vlc_mutex_init( &p_vpar->synchro.fifo_lock );
 144
 145     /* We use a fake stream pattern, which is often right. */
 146     p_vpar->synchro.i_n_p = p_vpar->synchro.i_eta_p = DEFAULT_NB_P;
 147     p_vpar->synchro.i_n_b = p_vpar->synchro.i_eta_b = DEFAULT_NB_B;
 148     memset( p_vpar->synchro.p_tau, 0, 4 * sizeof(mtime_t) );
 149     memset( p_vpar->synchro.pi_meaningful, 0, 4 * sizeof(unsigned int) );
 150     p_vpar->synchro.b_dropped_last = 0;
 151     p_vpar->synchro.current_pts = mdate() + DEFAULT_PTS_DELAY;
 152     p_vpar->synchro.backward_pts = 0;
 153     p_vpar->synchro.i_current_period = p_vpar->synchro.i_backward_period = 0;
 154 #ifdef STATS
 155     p_vpar->synchro.i_trashed_pic = p_vpar->synchro.i_not_chosen_pic =
 156         p_vpar->synchro.i_pic = 0;
 157 #endif
 158 }
 159
 160 /*****************************************************************************
 161  * vpar_SynchroChoose : Decide whether we will decode a picture or not
 162  *****************************************************************************/
 163 boolean_t vpar_SynchroChoose( vpar_thread_t * p_vpar, int i_coding_type,
 164                               int i_structure )
 165 {
 166     /* For clarity reasons, we separated the special synchros code from the
 167      * mathematical synchro */
 168
 169     if( p_vpar->synchro.i_type != VPAR_SYNCHRO_DEFAULT )
 170     {
 171         switch( i_coding_type )
 172         {
 173         case I_CODING_TYPE:
 174             /* I, IP, IP+, IPB */
 175             if( p_vpar->synchro.i_type == VPAR_SYNCHRO_Iplus )
 176             {
 177                 p_vpar->synchro.b_dropped_last = 1;
 178             }
 179             return( 1 );
 180
 181         case P_CODING_TYPE:
 182             if( p_vpar->synchro.i_type == VPAR_SYNCHRO_I ) /* I */
 183             {
 184                 return( 0 );
 185             }
 186
 187             if( p_vpar->synchro.i_type == VPAR_SYNCHRO_Iplus ) /* I+ */
 188             {
 189                 if( p_vpar->synchro.b_dropped_last )
 190                 {
 191                     p_vpar->synchro.b_dropped_last = 0;
 192                     return( 1 );
 193                 }
 194                 else
 195                 {
 196                     return( 0 );
 197                 }
 198             }
 199
 200             return( 1 ); /* IP, IP+, IPB */
 201
 202         case B_CODING_TYPE:
 203             if( p_vpar->synchro.i_type <= VPAR_SYNCHRO_IP ) /* I, IP */
 204             {
 205                 return( 0 );
 206             }
 207             else if( p_vpar->synchro.i_type == VPAR_SYNCHRO_IPB ) /* IPB */
 208             {
 209                 return( 1 );
 210             }
 211
 212             p_vpar->synchro.b_dropped_last ^= 1; /* IP+ */
 213             return( !p_vpar->synchro.b_dropped_last );
 214         }
 215         return( 0 ); /* never reached but gcc yells at me */
 216     }
 217     else
 218     {
 219 #define TAU_PRIME( coding_type )    (p_vpar->synchro.p_tau[(coding_type)] \
 220                                  + (p_vpar->synchro.p_tau[(coding_type)] >> 1) \
 221                                             + tau_yuv)
 222 #define S                           p_vpar->synchro
 223         /* VPAR_SYNCHRO_DEFAULT */
 224         mtime_t         now, period, tau_yuv;
 225         mtime_t         pts = 0;
 226         boolean_t       b_decode = 0;
 227 #ifdef TRACE_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                     * p_vpar->sequence.i_current_rate / DEFAULT_RATE;
 234
 235         vlc_mutex_lock( &p_vpar->p_vout->change_lock );
 236         tau_yuv = p_vpar->p_vout->render_time;
 237         vlc_mutex_unlock( &p_vpar->p_vout->change_lock );
 238 #ifdef VDEC_SMP
 239         vlc_mutex_lock( &p_vpar->synchro.fifo_lock );
 240 #endif
 241
 242         switch( i_coding_type )
 243         {
 244         case I_CODING_TYPE:
 245             if( S.backward_pts )
 246             {
 247                 pts = S.backward_pts;
 248             }
 249             else
 250             {
 251                 /* displaying order : B B P B B I
 252                  *                      ^       ^
 253                  *                      |       +- current picture
 254                  *                      +- current PTS
 255                  */
 256                 pts = S.current_pts + period * (S.i_n_b + 2);
 257             }
 258
 259             if( (1 + S.i_n_p * (S.i_n_b + 1)) * period >
 260                     S.p_tau[I_CODING_TYPE] )
 261             {
 262                 b_decode = 1;
 263             }
 264             else
 265             {
 266                 b_decode = (pts - now) > (TAU_PRIME(I_CODING_TYPE) + DELTA);
 267             }
 268             if( !b_decode )
 269                 intf_WarnMsg( 3, "vpar synchro warning: trashing I (%lld)",
 270                              pts - now);
 271             break;
 272
 273         case P_CODING_TYPE:
 274             if( S.backward_pts )
 275             {
 276                 pts = S.backward_pts;
 277             }
 278             else
 279             {
 280                 pts = S.current_pts + period * (S.i_n_b + 1);
 281             }
 282
 283             if( (1 + S.i_n_p * (S.i_n_b + 1)) * period >
 284                     S.p_tau[I_CODING_TYPE] )
 285             {
 286                 if( (S.i_n_b + 1) * period > S.p_tau[P_CODING_TYPE] )
 287                 {
 288                     /* Security in case we're _really_ late */
 289                     b_decode = (pts - now > 0);
 290                 }
 291                 else
 292                 {
 293                     b_decode = (pts - now) > (TAU_PRIME(P_CODING_TYPE) + DELTA);
 294                     /* next I */
 295                     b_decode &= (pts - now
 296                                   + period
 297                               * ( (S.i_n_p - S.i_eta_p) * (1 + S.i_n_b) - 1 ))
 298                                 > (TAU_PRIME(P_CODING_TYPE)
 299                                     + TAU_PRIME(I_CODING_TYPE) + DELTA);
 300                 }
 301             }
 302             else
 303             {
 304                 b_decode = 0;
 305             }
 306             break;
 307
 308         case B_CODING_TYPE:
 309             pts = S.current_pts;
 310
 311             if( (S.i_n_b + 1) * period > S.p_tau[P_CODING_TYPE] )
 312             {
 313                 b_decode = (pts - now) > (TAU_PRIME(B_CODING_TYPE) + DELTA);
 314             }
 315             else
 316             {
 317                 b_decode = 0;
 318             }
 319         }
 320
 321 #ifdef VDEC_SMP
 322         vlc_mutex_unlock( &p_vpar->synchro.fifo_lock );
 323 #endif
 324 #ifdef TRACE_VPAR
 325         intf_DbgMsg("vpar synchro debug: %s picture scheduled for %s, %s (%lld)",
 326                     i_coding_type == B_CODING_TYPE ? "B" :
 327                     (i_coding_type == P_CODING_TYPE ? "P" : "I"),
 328                     mstrtime(p_date, pts), b_decode ? "decoding" : "trashed",
 329                     S.p_tau[i_coding_type]);
 330 #endif
 331 #ifdef STATS
 332         if( !b_decode )
 333         {
 334             S.i_not_chosen_pic++;
 335         }
 336 #endif
 337         return( b_decode );
 338 #undef S
 339 #undef TAU_PRIME
 340     }
 341 }
 342
 343 /*****************************************************************************
 344  * vpar_SynchroTrash : Update counters when we trash a picture
 345  *****************************************************************************/
 346 void vpar_SynchroTrash( vpar_thread_t * p_vpar, int i_coding_type,
 347                         int i_structure )
 348 {
 349 #ifdef STATS
 350     p_vpar->synchro.i_trashed_pic++;
 351 #endif
 352 }
 353
 354 /*****************************************************************************
 355  * vpar_SynchroDecode : Update timers when we decide to decode a picture
 356  *****************************************************************************/
 357 void vpar_SynchroDecode( vpar_thread_t * p_vpar, int i_coding_type,
 358                          int i_structure )
 359 {
 360 #ifdef VDEC_SMP
 361     vlc_mutex_lock( &p_vpar->synchro.fifo_lock );
 362 #endif
 363
 364     if( ((p_vpar->synchro.i_end + 1 - p_vpar->synchro.i_start)
 365             % MAX_DECODING_PIC) )
 366     {
 367         p_vpar->synchro.p_date_fifo[p_vpar->synchro.i_end] = mdate();
 368         p_vpar->synchro.pi_coding_types[p_vpar->synchro.i_end] = i_coding_type;
 369
 370         FIFO_INCREMENT( i_end );
 371     }
 372     else
 373     {
 374         /* FIFO full, panic() */
 375         intf_ErrMsg("vpar error: synchro fifo full, estimations will be biased (%d:%d)",
 376                     p_vpar->synchro.i_start, p_vpar->synchro.i_end);
 377     }
 378 #ifdef VDEC_SMP
 379     vlc_mutex_unlock( &p_vpar->synchro.fifo_lock );
 380 #endif
 381 }
 382
 383 /*****************************************************************************
 384  * vpar_SynchroEnd : Called when the image is totally decoded
 385  *****************************************************************************/
 386 void vpar_SynchroEnd( vpar_thread_t * p_vpar, int i_garbage )
 387 {
 388     mtime_t     tau;
 389     int         i_coding_type;
 390
 391 #ifdef VDEC_SMP
 392     vlc_mutex_lock( &p_vpar->synchro.fifo_lock );
 393 #endif
 394
 395     i_coding_type = p_vpar->synchro.pi_coding_types[p_vpar->synchro.i_start];
 396
 397     if( !i_garbage )
 398     {
 399         tau = mdate() - p_vpar->synchro.p_date_fifo[p_vpar->synchro.i_start];
 400
 401         /* If duration too high, something happened (pause ?), so don't
 402          * take it into account. */
 403         if( tau < 3 * p_vpar->synchro.p_tau[i_coding_type]
 404              || !p_vpar->synchro.pi_meaningful[i_coding_type] )
 405         {
 406             /* Mean with average tau, to ensure stability. */
 407             p_vpar->synchro.p_tau[i_coding_type] =
 408                 (p_vpar->synchro.pi_meaningful[i_coding_type]
 409                  * p_vpar->synchro.p_tau[i_coding_type] + tau)
 410                 / (p_vpar->synchro.pi_meaningful[i_coding_type] + 1);
 411             if( p_vpar->synchro.pi_meaningful[i_coding_type] < MAX_PIC_AVERAGE )
 412             {
 413                 p_vpar->synchro.pi_meaningful[i_coding_type]++;
 414             }
 415         }
 416
 417 #ifdef TRACE_VPAR
 418         intf_DbgMsg("vpar synchro debug: finished decoding %s (%lld)",
 419                     i_coding_type == B_CODING_TYPE ? "B" :
 420                     (i_coding_type == P_CODING_TYPE ? "P" : "I"), tau);
 421 #endif
 422     }
 423     else
 424     {
 425         intf_DbgMsg("vpar synchro debug: aborting %s",
 426                     i_coding_type == B_CODING_TYPE ? "B" :
 427                     (i_coding_type == P_CODING_TYPE ? "P" : "I"));
 428     }
 429
 430     FIFO_INCREMENT( i_start );
 431
 432 #ifdef VDEC_SMP
 433     vlc_mutex_unlock( &p_vpar->synchro.fifo_lock );
 434 #endif
 435 }
 436
 437 /*****************************************************************************
 438  * vpar_SynchroDate : When an image has been decoded, ask for its date
 439  *****************************************************************************/
 440 mtime_t vpar_SynchroDate( vpar_thread_t * p_vpar )
 441 {
 442     /* No need to lock, since PTS are only used by the video parser. */
 443     return( p_vpar->synchro.current_pts );
 444 }
 445
 446 /*****************************************************************************
 447  * vpar_SynchroNewPicture: Update stream structure and PTS
 448  *****************************************************************************/
 449 void vpar_SynchroNewPicture( vpar_thread_t * p_vpar, int i_coding_type,
 450                              int i_repeat_field )
 451 {
 452     mtime_t         period = 1000000 * 1001 / p_vpar->sequence.i_frame_rate
 453                               * p_vpar->sequence.i_current_rate / DEFAULT_RATE;
 454 #if 0
 455     mtime_t         now = mdate();
 456 #endif
 457
 458     switch( i_coding_type )
 459     {
 460     case I_CODING_TYPE:
 461         if( p_vpar->synchro.i_eta_p
 462                 && p_vpar->synchro.i_eta_p != p_vpar->synchro.i_n_p )
 463         {
 464             intf_WarnMsg( 1, "Stream periodicity changed from P[%d] to P[%d]",
 465                           p_vpar->synchro.i_n_p, p_vpar->synchro.i_eta_p );
 466             p_vpar->synchro.i_n_p = p_vpar->synchro.i_eta_p;
 467         }
 468         p_vpar->synchro.i_eta_p = p_vpar->synchro.i_eta_b = 0;
 469 #ifdef STATS
 470         if( p_vpar->synchro.i_type == VPAR_SYNCHRO_DEFAULT )
 471         {
 472             intf_Msg( "vpar synchro stats: I(%lld) P(%lld)[%d] B(%lld)[%d] YUV(%lld) : trashed %d:%d/%d",
 473                   p_vpar->synchro.p_tau[I_CODING_TYPE],
 474                   p_vpar->synchro.p_tau[P_CODING_TYPE],
 475                   p_vpar->synchro.i_n_p,
 476                   p_vpar->synchro.p_tau[B_CODING_TYPE],
 477                   p_vpar->synchro.i_n_b,
 478                   p_vpar->p_vout->render_time,
 479                   p_vpar->synchro.i_not_chosen_pic,
 480                   p_vpar->synchro.i_trashed_pic -
 481                   p_vpar->synchro.i_not_chosen_pic,
 482                   p_vpar->synchro.i_pic );
 483             p_vpar->synchro.i_trashed_pic = p_vpar->synchro.i_not_chosen_pic
 484                 = p_vpar->synchro.i_pic = 0;
 485         }
 486 #endif
 487         break;
 488     case P_CODING_TYPE:
 489         p_vpar->synchro.i_eta_p++;
 490         if( p_vpar->synchro.i_eta_b
 491                 && p_vpar->synchro.i_eta_b != p_vpar->synchro.i_n_b )
 492         {
 493             intf_WarnMsg( 1, "Stream periodicity changed from B[%d] to B[%d]",
 494                           p_vpar->synchro.i_n_b, p_vpar->synchro.i_eta_b );
 495             p_vpar->synchro.i_n_b = p_vpar->synchro.i_eta_b;
 496         }
 497         p_vpar->synchro.i_eta_b = 0;
 498         break;
 499     case B_CODING_TYPE:
 500         p_vpar->synchro.i_eta_b++;
 501         break;
 502     }
 503
 504     p_vpar->synchro.current_pts += p_vpar->synchro.i_current_period
 505                                         * (period >> 1);
 506
 507 #define PTS_THRESHOLD   (period >> 2)
 508     if( i_coding_type == B_CODING_TYPE )
 509     {
 510         /* A video frame can be displayed 1, 2 or 3 times, according to
 511          * repeat_first_field, top_field_first, progressive_sequence and
 512          * progressive_frame. */
 513         p_vpar->synchro.i_current_period = i_repeat_field;
 514
 515         if( p_vpar->sequence.next_pts )
 516         {
 517             if( p_vpar->sequence.next_pts - p_vpar->synchro.current_pts
 518                     > PTS_THRESHOLD
 519                  || p_vpar->synchro.current_pts - p_vpar->sequence.next_pts
 520                     > PTS_THRESHOLD )
 521             {
 522                 intf_WarnMsg( 2,
 523                         "vpar synchro warning: pts != current_date (%lld)",
 524                         p_vpar->synchro.current_pts
 525                             - p_vpar->sequence.next_pts );
 526             }
 527             p_vpar->synchro.current_pts = p_vpar->sequence.next_pts;
 528             p_vpar->sequence.next_pts = 0;
 529         }
 530     }
 531     else
 532     {
 533         p_vpar->synchro.i_current_period = p_vpar->synchro.i_backward_period;
 534         p_vpar->synchro.i_backward_period = i_repeat_field;
 535
 536         if( p_vpar->synchro.backward_pts )
 537         {
 538             if( p_vpar->sequence.next_dts &&
 539                 (p_vpar->sequence.next_dts - p_vpar->synchro.backward_pts
 540                     > PTS_THRESHOLD
 541               || p_vpar->synchro.backward_pts - p_vpar->sequence.next_dts
 542                     > PTS_THRESHOLD) )
 543             {
 544                 intf_WarnMsg( 2,
 545                         "vpar synchro warning: backward_pts != dts (%lld)",
 546                         p_vpar->sequence.next_dts
 547                             - p_vpar->synchro.backward_pts );
 548             }
 549             if( p_vpar->synchro.backward_pts - p_vpar->synchro.current_pts
 550                     > PTS_THRESHOLD
 551                  || p_vpar->synchro.current_pts - p_vpar->synchro.backward_pts
 552                     > PTS_THRESHOLD )
 553             {
 554                 intf_WarnMsg( 2,
 555                    "vpar synchro warning: backward_pts != current_pts (%lld)",
 556                    p_vpar->synchro.current_pts - p_vpar->synchro.backward_pts );
 557             }
 558             p_vpar->synchro.current_pts = p_vpar->synchro.backward_pts;
 559             p_vpar->synchro.backward_pts = 0;
 560         }
 561         else if( p_vpar->sequence.next_dts )
 562         {
 563             if( p_vpar->sequence.next_dts - p_vpar->synchro.current_pts
 564                     > PTS_THRESHOLD
 565                  || p_vpar->synchro.current_pts - p_vpar->sequence.next_dts
 566                     > PTS_THRESHOLD )
 567             {
 568                 intf_WarnMsg( 2,
 569                         "vpar synchro warning: dts != current_pts (%lld)",
 570                         p_vpar->synchro.current_pts
 571                             - p_vpar->sequence.next_dts );
 572             }
 573             /* By definition of a DTS. */
 574             p_vpar->synchro.current_pts = p_vpar->sequence.next_dts;
 575             p_vpar->sequence.next_dts = 0;
 576         }
 577
 578         if( p_vpar->sequence.next_pts )
 579         {
 580             /* Store the PTS for the next time we have to date an I picture. */
 581             p_vpar->synchro.backward_pts = p_vpar->sequence.next_pts;
 582             p_vpar->sequence.next_pts = 0;
 583         }
 584     }
 585 #undef PTS_THRESHOLD
 586
 587 #if 0
 588     /* Removed for incompatibility with slow motion */
 589     if( p_vpar->synchro.current_pts + DEFAULT_PTS_DELAY < now )
 590     {
 591         /* We cannot be _that_ late, something must have happened, reinit
 592          * the dates. */
 593         intf_WarnMsg( 2, "PTS << now (%lld), resetting",
 594                       now - p_vpar->synchro.current_pts - DEFAULT_PTS_DELAY );
 595         p_vpar->synchro.current_pts = now + DEFAULT_PTS_DELAY;
 596     }
 597     if( p_vpar->synchro.backward_pts
 598          && p_vpar->synchro.backward_pts + DEFAULT_PTS_DELAY < now )
 599     {
 600         /* The same. */
 601         p_vpar->synchro.backward_pts = 0;
 602     }
 603 #endif
 604
 605 #ifdef STATS
 606     p_vpar->synchro.i_pic++;
 607 #endif
 608 }
 609
 610 /*****************************************************************************
 611  * SynchroType: Get the user's synchro type
 612  *****************************************************************************
 613  * This function is called at initialization.
 614  *****************************************************************************/
 615 static int SynchroType( void )
 616 {
 617     char * psz_synchro = main_GetPszVariable( VPAR_SYNCHRO_VAR, NULL );
 618
 619     if( psz_synchro == NULL )
 620     {
 621         return VPAR_SYNCHRO_DEFAULT;
 622     }
 623
 624     switch( *psz_synchro++ )
 625     {
 626       case 'i':
 627       case 'I':
 628         switch( *psz_synchro++ )
 629         {
 630           case '\0':
 631             return VPAR_SYNCHRO_I;
 632
 633           case '+':
 634             if( *psz_synchro ) return 0;
 635             return VPAR_SYNCHRO_Iplus;
 636
 637           case 'p':
 638           case 'P':
 639             switch( *psz_synchro++ )
 640             {
 641               case '\0':
 642                 return VPAR_SYNCHRO_IP;
 643
 644               case '+':
 645                 if( *psz_synchro ) return 0;
 646                 return VPAR_SYNCHRO_IPplus;
 647
 648               case 'b':
 649               case 'B':
 650                 if( *psz_synchro ) return 0;
 651                 return VPAR_SYNCHRO_IPB;
 652
 653               default:
 654                 return VPAR_SYNCHRO_DEFAULT;
 655
 656             }
 657
 658           default:
 659             return VPAR_SYNCHRO_DEFAULT;
 660         }
 661     }
 662
 663     return VPAR_SYNCHRO_DEFAULT;
 664 }
 665