gstreamer/gst-libs/gst/audio/gstaudioclock.c
Wim Taymans 4231d54823 audioclock: add methods for the internal offset
Add two methods for getting the unadjusted time of the clock and one for
adjusting an internal time. We will need these methods for correctly handling
the time after a gst_audio_clock_reset().

Add a debug category and some debug lines to the audio clock.

API: gst_audio_clock_get_time()
API: gst_audio_clock_adjust()
API: GST_AUDIO_CLOCK_CAST()
2009-04-14 13:08:52 +02:00

223 lines
5.8 KiB
C

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* audioclock.c: Clock for use by audio plugins
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:gstaudioclock
* @short_description: Helper object for implementing audio clocks
* @see_also: #GstBaseAudioSink, #GstSystemClock
*
* #GstAudioClock makes it easy for elements to implement a #GstClock, they
* simply need to provide a function that returns the current clock time.
*
* This object is internally used to implement the clock in #GstBaseAudioSink.
*
* Last reviewed on 2006-09-27 (0.10.12)
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "gstaudioclock.h"
GST_DEBUG_CATEGORY_STATIC (gst_audio_clock_debug);
#define GST_CAT_DEFAULT gst_audio_clock_debug
static void gst_audio_clock_class_init (GstAudioClockClass * klass);
static void gst_audio_clock_init (GstAudioClock * clock);
static GstClockTime gst_audio_clock_get_internal_time (GstClock * clock);
static GstSystemClockClass *parent_class = NULL;
/* static guint gst_audio_clock_signals[LAST_SIGNAL] = { 0 }; */
GType
gst_audio_clock_get_type (void)
{
static GType clock_type = 0;
if (!clock_type) {
static const GTypeInfo clock_info = {
sizeof (GstAudioClockClass),
NULL,
NULL,
(GClassInitFunc) gst_audio_clock_class_init,
NULL,
NULL,
sizeof (GstAudioClock),
4,
(GInstanceInitFunc) gst_audio_clock_init,
NULL
};
clock_type = g_type_register_static (GST_TYPE_SYSTEM_CLOCK, "GstAudioClock",
&clock_info, 0);
}
return clock_type;
}
static void
gst_audio_clock_class_init (GstAudioClockClass * klass)
{
GObjectClass *gobject_class;
GstObjectClass *gstobject_class;
GstClockClass *gstclock_class;
gobject_class = (GObjectClass *) klass;
gstobject_class = (GstObjectClass *) klass;
gstclock_class = (GstClockClass *) klass;
parent_class = g_type_class_peek_parent (klass);
gstclock_class->get_internal_time = gst_audio_clock_get_internal_time;
GST_DEBUG_CATEGORY_INIT (gst_audio_clock_debug, "audioclock", 0,
"audioclock");
}
static void
gst_audio_clock_init (GstAudioClock * clock)
{
clock->last_time = 0;
clock->abidata.ABI.time_offset = 0;
GST_OBJECT_FLAG_SET (clock, GST_CLOCK_FLAG_CAN_SET_MASTER);
}
/**
* gst_audio_clock_new:
* @name: the name of the clock
* @func: a function
* @user_data: user data
*
* Create a new #GstAudioClock instance. Whenever the clock time should be
* calculated it will call @func with @user_data. When @func returns
* #GST_CLOCK_TIME_NONE, the clock will return the last reported time.
*
* Returns: a new #GstAudioClock casted to a #GstClock.
*/
GstClock *
gst_audio_clock_new (const gchar * name, GstAudioClockGetTimeFunc func,
gpointer user_data)
{
GstAudioClock *aclock =
GST_AUDIO_CLOCK (g_object_new (GST_TYPE_AUDIO_CLOCK, "name", name, NULL));
aclock->func = func;
aclock->user_data = user_data;
return (GstClock *) aclock;
}
/**
* gst_audio_clock_reset:
* @clock: a #GstAudioClock
* @time: a #GstClockTime
*
* Inform @clock that future calls to #GstAudioClockGetTimeFunc will return values
* starting from @time. The clock will update an internal offset to make sure that
* future calls to internal_time will return an increasing result as required by
* the #GstClock object.
*/
void
gst_audio_clock_reset (GstAudioClock * clock, GstClockTime time)
{
GstClockTimeDiff time_offset;
if (clock->last_time >= time)
time_offset = clock->last_time - time;
else
time_offset = -(time - clock->last_time);
clock->abidata.ABI.time_offset = time_offset;
GST_DEBUG_OBJECT (clock,
"reset clock to %" GST_TIME_FORMAT ", offset %" GST_TIME_FORMAT,
GST_TIME_ARGS (time), GST_TIME_ARGS (time_offset));
}
static GstClockTime
gst_audio_clock_get_internal_time (GstClock * clock)
{
GstAudioClock *aclock;
GstClockTime result;
aclock = GST_AUDIO_CLOCK_CAST (clock);
result = aclock->func (clock, aclock->user_data);
if (result == GST_CLOCK_TIME_NONE)
result = aclock->last_time;
else {
result += aclock->abidata.ABI.time_offset;
aclock->last_time = result;
}
return result;
}
/**
* gst_audio_clock_get_time:
* @clock: a #GstAudioClock
*
* Report the time as returned by the #GstAudioClockGetTimeFunc without applying
* any offsets.
*
* Returns: the time as reported by the time function of the audio clock
*
* Since: 0.10.23
*/
GstClockTime
gst_audio_clock_get_time (GstClock * clock)
{
GstAudioClock *aclock;
GstClockTime result;
aclock = GST_AUDIO_CLOCK_CAST (clock);
result = aclock->func (clock, aclock->user_data);
return result;
}
/**
* gst_audio_clock_adjust:
* @clock: a #GstAudioClock
* @time: a #GstClockTime
*
* Adjust @time with the internal offset of the audio clock.
*
* Returns: @time adjusted with the internal offset.
*
* Since: 0.10.23
*/
GstClockTime
gst_audio_clock_adjust (GstClock * clock, GstClockTime time)
{
GstAudioClock *aclock;
GstClockTime result;
aclock = GST_AUDIO_CLOCK_CAST (clock);
result = time + aclock->abidata.ABI.time_offset;
return result;
}