src/input/clock.h

   1 /*****************************************************************************
   2  * clock.h: clocks synchronisation
   3  *****************************************************************************
   4  * Copyright (C) 2008 the VideoLAN team
   5  * Copyright (C) 2008 Laurent Aimar
   6  * $Id$
   7  *
   8  * Authors: Laurent Aimar < fenrir _AT_ videolan _DOT_ org >
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 #if defined(__PLUGIN__) || defined(__BUILTIN__) || !defined(__LIBVLC__)
  26 # error This header file can only be included from LibVLC.
  27 #endif
  28
  29 #ifndef _INPUT_CLOCK_H
  30 #define _INPUT_CLOCK_H 1
  31
  32 #include <vlc_common.h>
  33 #include <vlc_input.h> /* FIXME Needed for input_clock_t */
  34
  35 /** @struct input_clock_t
  36  * This structure is used to manage clock drift and reception jitters
  37  *
  38  * XXX input_clock_GetTS can be called from any threads. All others functions
  39  * MUST be called from one and only one thread.
  40  */
  41
  42 /**
  43  * This function creates a new input_clock_t.
  44  * You must use input_clock_Delete to delete it once unused.
  45  */
  46 input_clock_t *input_clock_New( int i_rate );
  47
  48 /**
  49  * This function destroys a input_clock_t created by input_clock_New.
  50  */
  51 void           input_clock_Delete( input_clock_t * );
  52
  53 /**
  54  * This function will update a input_clock_t with a new clock reference point.
  55  * It will also tell if the clock point is late regarding our buffering.
  56  *
  57  * \param b_buffering_allowed tells if we are allowed to bufferize more data in
  58  * advanced (if possible).
  59  */
  60 void    input_clock_Update( input_clock_t *, vlc_object_t *p_log,
  61                             bool *pb_late,
  62                             bool b_can_pace_control, bool b_buffering_allowed,
  63                             mtime_t i_clock, mtime_t i_system );
  64 /**
  65  * This function will reset the drift of a input_clock_t.
  66  *
  67  * The actual jitter estimation will not be reseted by it.
  68  */
  69 void    input_clock_Reset( input_clock_t * );
  70
  71 /**
  72  * This functions will return a deadline used to control the reading speed.
  73  */
  74 mtime_t input_clock_GetWakeup( input_clock_t * );
  75
  76 /**
  77  * This functions allows to change the actual reading speed.
  78  */
  79 void    input_clock_ChangeRate( input_clock_t *, int i_rate );
  80
  81 /**
  82  * This function allows to change the pause status.
  83  */
  84 void    input_clock_ChangePause( input_clock_t *, bool b_paused, mtime_t i_date );
  85
  86 /**
  87  * This function returns the original system value date and the delay for the current
  88  * reference point (a valid reference point must have been set).
  89  */
  90 void    input_clock_GetSystemOrigin( input_clock_t *, mtime_t *pi_system, mtime_t *pi_delay );
  91
  92 /**
  93  * This function allows to rebase the original system value date (a valid
  94  * reference point must have been set).
  95  * When using the absolute mode, it will create a discontinuity unless
  96  * called imediatly after a input_clock_Update.
  97  */
  98 void    input_clock_ChangeSystemOrigin( input_clock_t *, bool b_absolute, mtime_t i_system );
  99
 100 /**
 101  * This function converts a pair of timestamp from stream clock to system clock.
 102  *
 103  * If pi_rate is provided it will be filled with the rate value used for
 104  * the conversion.
 105  * p_ts0 is a pointer to a timestamp to be converted (in place) and must be non NULL.
 106  * p_ts1 is a pointer to a timestamp to be converted (in place) and can be NULL.
 107  *
 108  * It will return VLC_EGENERIC if i_ts_bound is not INT64_MAX and if the value *p_ts0
 109  * after conversion is not before the deadline mdate() + i_pts_delay + i_ts_bound.
 110  * It will also return VLC_EGENERIC if the conversion cannot be done successfully. In
 111  * this case, *p_ts0 and *p_ts1 will hold an invalid timestamp.
 112  * Otherwise it will return VLC_SUCCESS.
 113  */
 114 int input_clock_ConvertTS( input_clock_t *, int *pi_rate, mtime_t *pi_ts0, mtime_t *pi_ts1, mtime_t i_ts_bound );
 115
 116 /**
 117  * This function returns the current rate.
 118  */
 119 int input_clock_GetRate( input_clock_t * );
 120
 121 /**
 122  * This function returns current clock state or VLC_EGENERIC if there is not a
 123  * reference point.
 124  */
 125 int input_clock_GetState( input_clock_t *,
 126                           mtime_t *pi_stream_start, mtime_t *pi_system_start,
 127                           mtime_t *pi_stream_duration, mtime_t *pi_system_duration );
 128
 129 /**
 130  * This function allows the set the minimal configuration for the jitter estimation algo.
 131  */
 132 void input_clock_SetJitter( input_clock_t *,
 133                             mtime_t i_pts_delay, int i_cr_average );
 134
 135 /**
 136  * This function returns an estimation of the pts_delay needed to avoid rebufferization.
 137  * XXX in the current implementation, the pts_delay will never be decreased.
 138  */
 139 mtime_t input_clock_GetJitter( input_clock_t * );
 140
 141 #endif
 142