1 /* GStreamer

     2  * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>

     3  *                    2000 Wim Taymans <wtay@chello.be>

     4  *

     5  * audioclock.c: Clock for use by audio plugins

     6  *

     7  * This library is free software; you can redistribute it and/or

     8  * modify it under the terms of the GNU Library General Public

     9  * License as published by the Free Software Foundation; either

    10  * version 2 of the License, or (at your option) any later version.

    11  *

    12  * This library is distributed in the hope that it will be useful,

    13  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    15  * Library General Public License for more details.

    16  *

    17  * You should have received a copy of the GNU Library General Public

    18  * License along with this library; if not, write to the

    19  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

    20  * Boston, MA 02111-1307, USA.

    21  */

    22 

    23 /**

    24  * SECTION:gstaudioclock

    25  * @short_description: Helper object for implementing audio clocks

    26  * @see_also: #GstBaseAudioSink, #GstSystemClock

    27  *

    28  * #GstAudioClock makes it easy for elements to implement a #GstClock, they

    29  * simply need to provide a function that returns the current clock time.

    30  *

    31  * This object is internally used to implement the clock in #GstBaseAudioSink.

    32  *

    33  * Last reviewed on 2006-09-27 (0.10.12)

    34  */

    35 

    36 #ifdef HAVE_CONFIG_H

    37 #include "config.h"

    38 #endif

    39 

    40 #include "gstaudioclock.h"

    41 

    42 static void gst_audio_clock_class_init (GstAudioClockClass * klass);

    43 static void gst_audio_clock_init (GstAudioClock * clock);

    44 

    45 static GstClockTime gst_audio_clock_get_internal_time (GstClock * clock);

    46 

    47 static GstSystemClockClass *parent_class = NULL;

    48 

    49 /* static guint gst_audio_clock_signals[LAST_SIGNAL] = { 0 }; */

    50 #ifdef __SYMBIAN32__

    51 EXPORT_C

    52 #endif

    53 

    54 

    55 GType

    56 gst_audio_clock_get_type (void)

    57 {

    58   static GType clock_type = 0;

    59 

    60   if (!clock_type) {

    61     static const GTypeInfo clock_info = {

    62       sizeof (GstAudioClockClass),

    63       NULL,

    64       NULL,

    65       (GClassInitFunc) gst_audio_clock_class_init,

    66       NULL,

    67       NULL,

    68       sizeof (GstAudioClock),

    69       4,

    70       (GInstanceInitFunc) gst_audio_clock_init,

    71       NULL

    72     };

    73 

    74     clock_type = g_type_register_static (GST_TYPE_SYSTEM_CLOCK, "GstAudioClock",

    75         &clock_info, 0);

    76   }

    77   return clock_type;

    78 }

    79 

    80 

    81 static void

    82 gst_audio_clock_class_init (GstAudioClockClass * klass)

    83 {

    84   GObjectClass *gobject_class;

    85   GstObjectClass *gstobject_class;

    86   GstClockClass *gstclock_class;

    87 

    88   gobject_class = (GObjectClass *) klass;

    89   gstobject_class = (GstObjectClass *) klass;

    90   gstclock_class = (GstClockClass *) klass;

    91 

    92   parent_class = g_type_class_peek_parent (klass);

    93 

    94   gstclock_class->get_internal_time = gst_audio_clock_get_internal_time;

    95 }

    96 

    97 static void

    98 gst_audio_clock_init (GstAudioClock * clock)

    99 {

   100   clock->last_time = 0;

   101   GST_OBJECT_FLAG_SET (clock, GST_CLOCK_FLAG_CAN_SET_MASTER);

   102 }

   103 

   104 /**

   105  * gst_audio_clock_new:

   106  * @name: the name of the clock

   107  * @func: a function

   108  * @user_data: user data

   109  *

   110  * Create a new #GstAudioClock instance. Whenever the clock time should be

   111  * calculated it will call @func with @user_data. When @func returns

   112  * #GST_CLOCK_TIME_NONE, the clock will return the last reported time.

   113  *

   114  * Returns: a new #GstAudioClock casted to a #GstClock.

   115  */

   116 #ifdef __SYMBIAN32__

   117 EXPORT_C

   118 #endif

   119 

   120 GstClock *

   121 gst_audio_clock_new (gchar * name, GstAudioClockGetTimeFunc func,

   122     gpointer user_data)

   123 {

   124   GstAudioClock *aclock =

   125       GST_AUDIO_CLOCK (g_object_new (GST_TYPE_AUDIO_CLOCK, "name", name, NULL));

   126 

   127   aclock->func = func;

   128   aclock->user_data = user_data;

   129 

   130   return (GstClock *) aclock;

   131 }

   132 

   133 static GstClockTime

   134 gst_audio_clock_get_internal_time (GstClock * clock)

   135 {

   136   GstAudioClock *aclock = GST_AUDIO_CLOCK (clock);

   137   GstClockTime result;

   138 

   139   result = aclock->func (clock, aclock->user_data);

   140   if (result == GST_CLOCK_TIME_NONE)

   141     result = aclock->last_time;

   142   else

   143     aclock->last_time = result;

   144 

   145   return result;

   146 }