Ticket #879:

 - Added pjmedia synchronizer port.
 - Updated affected components, i.e: sound port, AEC, conference bridge.




git-svn-id: http://svn.pjsip.org/repos/pjproject/trunk@2747 74dad513-b988-da41-8d7b-12977e46ad98

1 files changed, 104 insertions, 0 deletions

diff --git a/pjmedia/include/pjmedia/sync_port.h b/pjmedia/include/pjmedia/sync_port.h
new file mode 100644
index 00000000..128833c4
--- /dev/null
+++ b/pjmedia/include/pjmedia/sync_port.h
@@ -0,0 +1,104 @@
+/* $Id$ */
+/* 
+ * Copyright (C) 2009 Teluu Inc. (http://www.teluu.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
+ */
+#ifndef __PJMEDIA_SYNC_PORT_H__
+#define __PJMEDIA_SYNC_PORT_H__
+
+/**
+ * @file sync_port.h
+ * @brief Media clock synchronization port.
+ */
+#include <pjmedia/port.h>
+
+/**
+ * @defgroup PJMEDIA_SYNC_PORT Clock Synchronization Port
+ * @ingroup PJMEDIA_PORT_CLOCK
+ * @brief Media clock synchronizer
+ * @{
+ *
+ * It is a common problem that audio device does not always provide a smooth
+ * clock for application, therefore the application may suffer from jitter, 
+ * burst, or even clock skew/drift. Processing audio frames in such 'messy'
+ * clock will just increase the complexity. So, before delivering the stream
+ * to other components, it could be very helpful to tidy up the clock first.
+ *
+ * This clock synchronizer port provides solutions in encountering burst and 
+ * clock skew, by simply inserting it between the port with 'unhealty' clock
+ * (upstream port) and the port requiring 'healthy' clock (downstream port) 
+ * using pjmedia port framework. Moreover, it also has an optional feature 
+ * to remove jitter by employing an external clock (@ref PJMEDIA_CLOCK),
+ * this feature will be enabled when PJMEDIA_SYNC_USE_EXT_CLOCK is specified
+ * in @pjmedia_sync_option upon its creation.
+ *
+ * A synchronizer port internally has instance(s) of @ref PJMED_DELAYBUF, 
+ * which provides buffering and wave-form manipulation (shrink/expand) to 
+ * handle burst and clock skew/drift, and may also have instance of @ref 
+ * PJMEDIA_CLOCK, which provides the external clock timer.
+ */
+
+PJ_BEGIN_DECL
+
+/**
+ * Synchronization port option.
+ */
+typedef enum pjmedia_sync_option
+{
+    /** 
+     * When this flag is specified, synchronizer will provide external clock,
+     * instead of using original parent clock.
+     */
+    PJMEDIA_SYNC_USE_EXT_CLOCK = 1,
+
+    /** 
+     * When this flag is specified, synchronizer will not destroy downstream
+     * port when synchronizer port is destroyed.
+     */
+    PJMEDIA_SYNC_DONT_DESTROY_DN = 128,
+
+} pjmedia_sync_option;
+
+typedef struct pjmedia_sync_param
+{
+    pjmedia_sync_option	    options;
+
+} pjmedia_sync_param;
+
+/**
+ * Create synchronizer port. 
+ *
+ * @param pool		Pool to allocate memory.
+ * @param dn_port	Downstream port.
+ * @param param		Synchronizer param, see @pjmedia_sync_param.
+ * @param p_port	Pointer to receive the port instance.
+ *
+ * @return		PJ_SUCCESS on success.
+ */
+PJ_DECL(pj_status_t) pjmedia_sync_port_create(pj_pool_t *pool,
+					      pjmedia_port *dn_port,
+					      const pjmedia_sync_param *param,
+					      pjmedia_port **p_port );
+
+
+PJ_END_DECL
+
+/**
+ * @}
+ */
+
+
+#endif	/* __PJMEDIA_SYNC_PORT_H__ */