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diff --git a/gst-libs/gst/audio/gstbaseaudiosink.h b/gst-libs/gst/audio/gstbaseaudiosink.h
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+/* GStreamer
+ * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
+ *                    2005 Wim Taymans <wim@fluendo.com>
+ *
+ * gstbaseaudosink.h: 
+ *
+ * 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.
+ */
+
+/* a base class for audio sinks.
+ *
+ * It uses a ringbuffer to schedule playback of samples. This makes
+ * it very easy to drop or insert samples to align incomming 
+ * buffers to the exact playback timestamp.
+ *
+ * Subclasses must provide a ringbuffer pointing to either DMA
+ * memory or regular memory. A subclass should also call a callback
+ * function when it has processed N samples in the buffer. The subclass
+ * is free to use a thread to signal this callback, use EIO or any
+ * other mechanism.
+ *
+ * The base class is able to operate in push or pull mode. The chain
+ * mode will queue the samples in the ringbuffer as much as possible.
+ * The available space is calculated in the callback function.
+ *
+ * The pull mode will pull_range() a new buffer of N samples with a
+ * configurable latency. This allows for high-end real time 
+ * audio processing pipelines driven by the audiosink. The callback
+ * function will be used to perform a pull_range() on the sinkpad.
+ * The thread scheduling the callback can be a real-time thread.
+ */
+
+#ifndef __GST_BASEAUDIOSINK_H__
+#define __GST_BASEAUDIOSINK_H__
+
+#include <gst/gst.h>
+#include <gst/base/gstbasesink.h>
+#include "gstringbuffer.h"
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_BASEAUDIOSINK  	 (gst_baseaudiosink_get_type())
+#define GST_BASEAUDIOSINK(obj) 		 (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_BASEAUDIOSINK,GstBaseAudioSink))
+#define GST_BASEAUDIOSINK_CLASS(klass) 	 (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_BASEAUDIOSINK,GstBaseAudioSinkClass))
+#define GST_BASEAUDIOSINK_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_BASEAUDIOSINK, GstBaseAudioSinkClass))
+#define GST_IS_BASEAUDIOSINK(obj)  	 (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_BASEAUDIOSINK))
+#define GST_IS_BASEAUDIOSINK_CLASS(obj)  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_BASEAUDIOSINK))
+
+#define GST_BASEAUDIOSINK_CLOCK(obj)	 (GST_BASEAUDIOSINK (obj)->clock)
+#define GST_BASEAUDIOSINK_PAD(obj)	 (GST_BASEAUDIOSINK (obj)->sinkpad)
+
+typedef struct _GstBaseAudioSink GstBaseAudioSink;
+typedef struct _GstBaseAudioSinkClass GstBaseAudioSinkClass;
+
+struct _GstBaseAudioSink {
+  GstBaseSink 	 element;
+
+  GstRingBuffer *ringbuffer;
+};
+
+struct _GstBaseAudioSinkClass {
+  GstBaseSinkClass parent_class;
+
+  /* subclass ringbuffer allocation */
+  GstRingBuffer* (*create_ringbuffer)  (GstBaseAudioSink *sink);
+};
+
+GType gst_baseaudiosink_get_type(void);
+
+GstRingBuffer *gst_baseaudiosink_create_ringbuffer (GstBaseAudioSink *sink);
+
+G_END_DECLS
+
+#endif /* __GST_BASEAUDIOSINK_H__ */