src/input/clock.h

   1 /*****************************************************************************
   2  * clock.h: clocks synchronisation
   3  *****************************************************************************
   4  * Copyright (C) 2008 VLC authors and VideoLAN
   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 it
  11  * under the terms of the GNU Lesser General Public License as published by
  12  * the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with this program; if not, write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 #ifndef LIBVLC_INPUT_CLOCK_H
  26 #define LIBVLC_INPUT_CLOCK_H 1
  27
  28 #include <vlc_common.h>
  29 #include <vlc_input.h> /* FIXME Needed for input_clock_t */
  30
  31 /** @struct input_clock_t
  32  * This structure is used to manage clock drift and reception jitters
  33  *
  34  * XXX input_clock_GetTS can be called from any threads. All others functions
  35  * MUST be called from one and only one thread.
  36  */
  37 typedef struct input_clock_t input_clock_t;
  38
  39 /**
  40  * This function creates a new input_clock_t.
  41  * You must use input_clock_Delete to delete it once unused.
  42  */
  43 input_clock_t *input_clock_New( int i_rate );
  44
  45 /**
  46  * This function destroys a input_clock_t created by input_clock_New.
  47  */
  48 void           input_clock_Delete( input_clock_t * );
  49
  50 /**
  51  * This function will update a input_clock_t with a new clock reference point.
  52  * It will also tell if the clock point is late regarding our buffering.
  53  *
  54  * \param b_buffering_allowed tells if we are allowed to bufferize more data in
  55  * advanced (if possible).
  56  */
  57 void    input_clock_Update( input_clock_t *, vlc_object_t *p_log,
  58                             bool *pb_late,
  59                             bool b_can_pace_control, bool b_buffering_allowed,
  60                             mtime_t i_clock, mtime_t i_system );
  61 /**
  62  * This function will reset the drift of a input_clock_t.
  63  *
  64  * The actual jitter estimation will not be reseted by it.
  65  */
  66 void    input_clock_Reset( input_clock_t * );
  67
  68 /**
  69  * This functions will return a deadline used to control the reading speed.
  70  */
  71 mtime_t input_clock_GetWakeup( input_clock_t * );
  72
  73 /**
  74  * This functions allows changing the actual reading speed.
  75  */
  76 void    input_clock_ChangeRate( input_clock_t *, int i_rate );
  77
  78 /**
  79  * This function allows changing the pause status.
  80  */
  81 void    input_clock_ChangePause( input_clock_t *, bool b_paused, mtime_t i_date );
  82
  83 /**
  84  * This function returns the original system value date and the delay for the current
  85  * reference point (a valid reference point must have been set).
  86  */
  87 void    input_clock_GetSystemOrigin( input_clock_t *, mtime_t *pi_system, mtime_t *pi_delay );
  88
  89 /**
  90  * This function allows rebasing the original system value date (a valid
  91  * reference point must have been set).
  92  * When using the absolute mode, it will create a discontinuity unless
  93  * called imediatly after a input_clock_Update.
  94  */
  95 void    input_clock_ChangeSystemOrigin( input_clock_t *, bool b_absolute, mtime_t i_system );
  96
  97 /**
  98  * This function converts a pair of timestamp from stream clock to system clock.
  99  *
 100  * If pi_rate is provided it will be filled with the rate value used for
 101  * the conversion.
 102  * p_ts0 is a pointer to a timestamp to be converted (in place) and must be non NULL.
 103  * p_ts1 is a pointer to a timestamp to be converted (in place) and can be NULL.
 104  *
 105  * It will return VLC_EGENERIC if i_ts_bound is not INT64_MAX and if the value *p_ts0
 106  * after conversion is not before the deadline mdate() + i_pts_delay + i_ts_bound.
 107  * It will also return VLC_EGENERIC if the conversion cannot be done successfully. In
 108  * this case, *p_ts0 and *p_ts1 will hold an invalid timestamp.
 109  * Otherwise it will return VLC_SUCCESS.
 110  */
 111 int input_clock_ConvertTS( vlc_object_t *, input_clock_t *, int *pi_rate,
 112                            mtime_t *pi_ts0, mtime_t *pi_ts1, mtime_t i_ts_bound );
 113
 114 /**
 115  * This function returns the current rate.
 116  */
 117 int input_clock_GetRate( input_clock_t * );
 118
 119 /**
 120  * This function returns current clock state or VLC_EGENERIC if there is not a
 121  * reference point.
 122  */
 123 int input_clock_GetState( input_clock_t *,
 124                           mtime_t *pi_stream_start, mtime_t *pi_system_start,
 125                           mtime_t *pi_stream_duration, mtime_t *pi_system_duration );
 126
 127 /**
 128  * This function allows the set the minimal configuration for the jitter estimation algo.
 129  */
 130 void input_clock_SetJitter( input_clock_t *,
 131                             mtime_t i_pts_delay, int i_cr_average );
 132
 133 /**
 134  * This function returns an estimation of the pts_delay needed to avoid rebufferization.
 135  * XXX in the current implementation, the pts_delay will never be decreased.
 136  */
 137 mtime_t input_clock_GetJitter( input_clock_t * );
 138
 139 #endif