src/clock/input_clock.h

   1 /*****************************************************************************
   2  * input_clock.h: Input clocks synchronisation
   3  *****************************************************************************
   4  * Copyright (C) 2008-2018 VLC authors and VideoLAN
   5  * Copyright (C) 2008 Laurent Aimar
   6  *
   7  * Authors: Laurent Aimar < fenrir _AT_ videolan _DOT_ org >
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software Foundation,
  21  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 #ifndef LIBVLC_INPUT_CLOCK_H
  25 #define LIBVLC_INPUT_CLOCK_H 1
  26
  27 #include <vlc_common.h>
  28 #include <vlc_input.h> /* FIXME Needed for input_clock_t */
  29
  30 /** @struct input_clock_t
  31  * This structure is used to manage clock drift and reception jitters
  32  *
  33  * This API is reentrant but not thread-safe.
  34  */
  35 typedef struct input_clock_t input_clock_t;
  36
  37 /**
  38  * This function creates a new input_clock_t.
  39  * You must use input_clock_Delete to delete it once unused.
  40  */
  41 input_clock_t *input_clock_New( float rate );
  42
  43 /**
  44  * This function destroys a input_clock_t created by input_clock_New.
  45  */
  46 void           input_clock_Delete( input_clock_t * );
  47
  48 /**
  49  * This function will update a input_clock_t with a new clock reference point.
  50  * It will also tell if the clock point is late regarding our buffering.
  51  *
  52  * \param b_buffering_allowed tells if we are allowed to bufferize more data in
  53  * advanced (if possible).
  54  * \return clock update delay
  55  */
  56 vlc_tick_t input_clock_Update( input_clock_t *, vlc_object_t *p_log,
  57                             bool b_can_pace_control, bool b_buffering_allowed,
  58                             vlc_tick_t i_clock, vlc_tick_t i_system );
  59 /**
  60  * This function will reset the drift of a input_clock_t.
  61  *
  62  * The actual jitter estimation will not be reseted by it.
  63  */
  64 void    input_clock_Reset( input_clock_t * );
  65
  66 /**
  67  * This functions will return a deadline used to control the reading speed.
  68  */
  69 vlc_tick_t input_clock_GetWakeup( input_clock_t * );
  70
  71 /**
  72  * This functions allows changing the actual reading speed.
  73  */
  74 void    input_clock_ChangeRate( input_clock_t *, float rate );
  75
  76 /**
  77  * This function allows changing the pause status.
  78  */
  79 void    input_clock_ChangePause( input_clock_t *, bool b_paused, vlc_tick_t i_date );
  80
  81 /**
  82  * This function returns the original system value date and the delay for the current
  83  * reference point (a valid reference point must have been set).
  84  */
  85 void    input_clock_GetSystemOrigin( input_clock_t *, vlc_tick_t *pi_system, vlc_tick_t *pi_delay );
  86
  87 /**
  88  * This function allows rebasing the original system value date (a valid
  89  * reference point must have been set).
  90  * When using the absolute mode, it will create a discontinuity unless
  91  * called imediatly after a input_clock_Update.
  92  */
  93 void    input_clock_ChangeSystemOrigin( input_clock_t *, bool b_absolute, vlc_tick_t i_system );
  94
  95 /**
  96  * This function returns the current rate.
  97  */
  98 float input_clock_GetRate( input_clock_t * );
  99
 100 /**
 101  * This function returns current clock state or VLC_EGENERIC if there is not a
 102  * reference point.
 103  */
 104 int input_clock_GetState( input_clock_t *,
 105                           vlc_tick_t *pi_stream_start, vlc_tick_t *pi_system_start,
 106                           vlc_tick_t *pi_stream_duration, vlc_tick_t *pi_system_duration );
 107
 108 /**
 109  * This function allows the set the minimal configuration for the jitter estimation algo.
 110  */
 111 void input_clock_SetJitter( input_clock_t *,
 112                             vlc_tick_t i_pts_delay, int i_cr_average );
 113
 114 /**
 115  * This function returns an estimation of the pts_delay needed to avoid rebufferization.
 116  * XXX in the current implementation, the pts_delay will never be decreased.
 117  */
 118 vlc_tick_t input_clock_GetJitter( input_clock_t * );
 119
 120 #endif