diff -r 9b2c3c7a1a9c -r 567bb019e3e3 gst_plugins_base/gst-libs/gst/audio/gstaudioclock.c
--- a/gst_plugins_base/gst-libs/gst/audio/gstaudioclock.c	Wed Mar 31 22:03:18 2010 +0300
+++ b/gst_plugins_base/gst-libs/gst/audio/gstaudioclock.c	Tue Aug 31 15:30:33 2010 +0300
@@ -39,6 +39,9 @@
 
 #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);
 
@@ -92,12 +95,16 @@
   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);
 }
 
@@ -118,7 +125,7 @@
 #endif
 
 GstClock *
-gst_audio_clock_new (gchar * name, GstAudioClockGetTimeFunc func,
+gst_audio_clock_new (const gchar * name, GstAudioClockGetTimeFunc func,
     gpointer user_data)
 {
   GstAudioClock *aclock =
@@ -130,17 +137,119 @@
   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.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+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 = GST_AUDIO_CLOCK (clock);
+  GstAudioClock *aclock;
   GstClockTime result;
 
+  aclock = GST_AUDIO_CLOCK_CAST (clock);
+
   result = aclock->func (clock, aclock->user_data);
-  if (result == GST_CLOCK_TIME_NONE)
+  if (result == GST_CLOCK_TIME_NONE) {
     result = aclock->last_time;
-  else
-    aclock->last_time = result;
+  } else {
+    result += aclock->abidata.ABI.time_offset;
+    /* clock must be increasing */
+    if (aclock->last_time < result)
+      aclock->last_time = result;
+    else
+      result = aclock->last_time;
+  }
+
+  GST_DEBUG_OBJECT (clock,
+      "result %" GST_TIME_FORMAT ", last_time %" GST_TIME_FORMAT,
+      GST_TIME_ARGS (result), GST_TIME_ARGS (aclock->last_time));
 
   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
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+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);
+  if (result == GST_CLOCK_TIME_NONE) {
+    result = aclock->last_time - aclock->abidata.ABI.time_offset;
+  }
+
+  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
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+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;
+}