Index: pjproject/trunk/build.symbian/pjmedia_audiodev.mmp
===================================================================
--- pjproject/trunk/build.symbian/pjmedia_audiodev.mmp	(revision 3101)
+++ pjproject/trunk/build.symbian/pjmedia_audiodev.mmp	(revision 3102)
@@ -18,4 +18,5 @@
 SOURCE		symb_mda_dev.cpp
 SOURCE		symb_vas_dev.cpp
+SOURCE		null_dev.c
 
 SYSTEMINCLUDE	..\pjmedia\include
Index: pjproject/trunk/pjmedia/build/Makefile
===================================================================
--- pjproject/trunk/pjmedia/build/Makefile	(revision 3101)
+++ pjproject/trunk/pjmedia/build/Makefile	(revision 3102)
@@ -72,6 +72,6 @@
 #
 export PJMEDIA_AUDIODEV_SRCDIR = ../src/pjmedia-audiodev
-export PJMEDIA_AUDIODEV_OBJS +=  audiodev.o audiotest.o errno.o legacy_dev.o pa_dev.o \
-				 wmme_dev.o alsa_dev.o
+export PJMEDIA_AUDIODEV_OBJS +=  audiodev.o audiotest.o errno.o \
+				 legacy_dev.o null_dev.o pa_dev.o wmme_dev.o alsa_dev.o
 export PJMEDIA_AUDIODEV_CFLAGS += $(_CFLAGS)
 
Index: pjproject/trunk/pjmedia/include/pjmedia-audiodev/config.h
===================================================================
--- pjproject/trunk/pjmedia/include/pjmedia-audiodev/config.h	(revision 3101)
+++ pjproject/trunk/pjmedia/include/pjmedia-audiodev/config.h	(revision 3102)
@@ -64,4 +64,12 @@
 #ifndef PJMEDIA_AUDIO_DEV_HAS_ALSA
 #   define PJMEDIA_AUDIO_DEV_HAS_ALSA		0
+#endif
+
+
+/**
+ * This setting controls whether null audio support should be included.
+ */
+#ifndef PJMEDIA_AUDIO_DEV_HAS_NULL_AUDIO
+#   define PJMEDIA_AUDIO_DEV_HAS_NULL_AUDIO	0
 #endif
 
Index: pjproject/trunk/pjmedia/src/pjmedia-audiodev/audiodev.c
===================================================================
--- pjproject/trunk/pjmedia/src/pjmedia-audiodev/audiodev.c	(revision 3101)
+++ pjproject/trunk/pjmedia/src/pjmedia-audiodev/audiodev.c	(revision 3102)
@@ -91,4 +91,8 @@
 #endif
 
+#if PJMEDIA_AUDIO_DEV_HAS_NULL_AUDIO
+pjmedia_aud_dev_factory* pjmedia_null_audio_factory(pj_pool_factory *pf);
+#endif
+
 #define MAX_DRIVERS	16
 #define MAX_DEVS	64
@@ -390,4 +394,7 @@
 #if PJMEDIA_AUDIO_DEV_HAS_SYMB_MDA
     aud_subsys.drv[aud_subsys.drv_cnt++].create = &pjmedia_symb_mda_factory;
+#endif
+#if PJMEDIA_AUDIO_DEV_HAS_NULL_AUDIO
+    aud_subsys.drv[aud_subsys.drv_cnt++].create = &pjmedia_null_audio_factory;
 #endif
 
Index: pjproject/trunk/pjmedia/src/pjmedia-audiodev/null_dev.c
===================================================================
--- pjproject/trunk/pjmedia/src/pjmedia-audiodev/null_dev.c	(revision 3102)
+++ pjproject/trunk/pjmedia/src/pjmedia-audiodev/null_dev.c	(revision 3102)
@@ -0,0 +1,379 @@
+/* $Id$ */
+/*
+ * Copyright (C) 2008-2010 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
+ */
+#include <pjmedia-audiodev/audiodev_imp.h>
+#include <pj/assert.h>
+#include <pj/log.h>
+#include <pj/os.h>
+
+#if PJMEDIA_AUDIO_DEV_HAS_NULL_AUDIO
+
+#define THIS_FILE		"null_dev.c"
+
+/* null_audio device info */
+struct null_audio_dev_info
+{
+    pjmedia_aud_dev_info	 info;
+    unsigned			 dev_id;
+};
+
+/* null_audio factory */
+struct null_audio_factory
+{
+    pjmedia_aud_dev_factory	 base;
+    pj_pool_t			*pool;
+    pj_pool_factory		*pf;
+
+    unsigned			 dev_count;
+    struct null_audio_dev_info	*dev_info;
+};
+
+/* Sound stream. */
+struct null_audio_stream
+{
+    pjmedia_aud_stream	 base;		    /**< Base stream	       */
+    pjmedia_aud_param	 param;		    /**< Settings	       */
+    pj_pool_t           *pool;              /**< Memory pool.          */
+
+    pjmedia_aud_rec_cb   rec_cb;            /**< Capture callback.     */
+    pjmedia_aud_play_cb  play_cb;           /**< Playback callback.    */
+    void                *user_data;         /**< Application data.     */
+};
+
+
+/* Prototypes */
+static pj_status_t null_factory_init(pjmedia_aud_dev_factory *f);
+static pj_status_t null_factory_destroy(pjmedia_aud_dev_factory *f);
+static unsigned    null_factory_get_dev_count(pjmedia_aud_dev_factory *f);
+static pj_status_t null_factory_get_dev_info(pjmedia_aud_dev_factory *f,
+					     unsigned index,
+					     pjmedia_aud_dev_info *info);
+static pj_status_t null_factory_default_param(pjmedia_aud_dev_factory *f,
+					      unsigned index,
+					      pjmedia_aud_param *param);
+static pj_status_t null_factory_create_stream(pjmedia_aud_dev_factory *f,
+					      const pjmedia_aud_param *param,
+					      pjmedia_aud_rec_cb rec_cb,
+					      pjmedia_aud_play_cb play_cb,
+					      void *user_data,
+					      pjmedia_aud_stream **p_aud_strm);
+
+static pj_status_t null_stream_get_param(pjmedia_aud_stream *strm,
+					 pjmedia_aud_param *param);
+static pj_status_t null_stream_get_cap(pjmedia_aud_stream *strm,
+				       pjmedia_aud_dev_cap cap,
+				       void *value);
+static pj_status_t null_stream_set_cap(pjmedia_aud_stream *strm,
+				       pjmedia_aud_dev_cap cap,
+				       const void *value);
+static pj_status_t null_stream_start(pjmedia_aud_stream *strm);
+static pj_status_t null_stream_stop(pjmedia_aud_stream *strm);
+static pj_status_t null_stream_destroy(pjmedia_aud_stream *strm);
+
+/* Operations */
+static pjmedia_aud_dev_factory_op factory_op =
+{
+    &null_factory_init,
+    &null_factory_destroy,
+    &null_factory_get_dev_count,
+    &null_factory_get_dev_info,
+    &null_factory_default_param,
+    &null_factory_create_stream
+};
+
+static pjmedia_aud_stream_op stream_op =
+{
+    &null_stream_get_param,
+    &null_stream_get_cap,
+    &null_stream_set_cap,
+    &null_stream_start,
+    &null_stream_stop,
+    &null_stream_destroy
+};
+
+
+/****************************************************************************
+ * Factory operations
+ */
+/*
+ * Init null_audio audio driver.
+ */
+pjmedia_aud_dev_factory* pjmedia_null_audio_factory(pj_pool_factory *pf)
+{
+    struct null_audio_factory *f;
+    pj_pool_t *pool;
+
+    pool = pj_pool_create(pf, "null audio", 1000, 1000, NULL);
+    f = PJ_POOL_ZALLOC_T(pool, struct null_audio_factory);
+    f->pf = pf;
+    f->pool = pool;
+    f->base.op = &factory_op;
+
+    return &f->base;
+}
+
+
+/* API: init factory */
+static pj_status_t null_factory_init(pjmedia_aud_dev_factory *f)
+{
+    struct null_audio_factory *nf = (struct null_audio_factory*)f;
+    struct null_audio_dev_info *ndi;
+
+    /* Initialize input and output devices here */
+    nf->dev_count = 1;
+    nf->dev_info = (struct null_audio_dev_info*)
+ 		   pj_pool_calloc(nf->pool, nf->dev_count,
+ 				  sizeof(struct null_audio_dev_info));
+    ndi = &nf->dev_info[0];
+    pj_bzero(ndi, sizeof(*ndi));
+    strcpy(ndi->info.name, "null device");
+    strcpy(ndi->info.driver, "null");
+    ndi->info.input_count = 1;
+    ndi->info.output_count = 1;
+    ndi->info.default_samples_per_sec = 16000;
+    /* Set the device capabilities here */
+    ndi->info.caps = 0;
+
+    PJ_LOG(4, (THIS_FILE, "null audio initialized"));
+
+    return PJ_SUCCESS;
+}
+
+/* API: destroy factory */
+static pj_status_t null_factory_destroy(pjmedia_aud_dev_factory *f)
+{
+    struct null_audio_factory *nf = (struct null_audio_factory*)f;
+    pj_pool_t *pool = nf->pool;
+
+    nf->pool = NULL;
+    pj_pool_release(pool);
+
+    return PJ_SUCCESS;
+}
+
+/* API: get number of devices */
+static unsigned null_factory_get_dev_count(pjmedia_aud_dev_factory *f)
+{
+    struct null_audio_factory *nf = (struct null_audio_factory*)f;
+    return nf->dev_count;
+}
+
+/* API: get device info */
+static pj_status_t null_factory_get_dev_info(pjmedia_aud_dev_factory *f,
+					     unsigned index,
+					     pjmedia_aud_dev_info *info)
+{
+    struct null_audio_factory *nf = (struct null_audio_factory*)f;
+
+    PJ_ASSERT_RETURN(index < nf->dev_count, PJMEDIA_EAUD_INVDEV);
+
+    pj_memcpy(info, &nf->dev_info[index].info, sizeof(*info));
+
+    return PJ_SUCCESS;
+}
+
+/* API: create default device parameter */
+static pj_status_t null_factory_default_param(pjmedia_aud_dev_factory *f,
+					      unsigned index,
+					      pjmedia_aud_param *param)
+{
+    struct null_audio_factory *nf = (struct null_audio_factory*)f;
+    struct null_audio_dev_info *di = &nf->dev_info[index];
+
+    PJ_ASSERT_RETURN(index < nf->dev_count, PJMEDIA_EAUD_INVDEV);
+
+    pj_bzero(param, sizeof(*param));
+    if (di->info.input_count && di->info.output_count) {
+	param->dir = PJMEDIA_DIR_CAPTURE_PLAYBACK;
+	param->rec_id = index;
+	param->play_id = index;
+    } else if (di->info.input_count) {
+	param->dir = PJMEDIA_DIR_CAPTURE;
+	param->rec_id = index;
+	param->play_id = PJMEDIA_AUD_INVALID_DEV;
+    } else if (di->info.output_count) {
+	param->dir = PJMEDIA_DIR_PLAYBACK;
+	param->play_id = index;
+	param->rec_id = PJMEDIA_AUD_INVALID_DEV;
+    } else {
+	return PJMEDIA_EAUD_INVDEV;
+    }
+
+    /* Set the mandatory settings here */
+    /* The values here are just some examples */
+    param->clock_rate = di->info.default_samples_per_sec;
+    param->channel_count = 1;
+    param->samples_per_frame = di->info.default_samples_per_sec * 20 / 1000;
+    param->bits_per_sample = 16;
+
+    /* Set the device capabilities here */
+    param->flags = 0;
+
+    return PJ_SUCCESS;
+}
+
+/* API: create stream */
+static pj_status_t null_factory_create_stream(pjmedia_aud_dev_factory *f,
+					      const pjmedia_aud_param *param,
+					      pjmedia_aud_rec_cb rec_cb,
+					      pjmedia_aud_play_cb play_cb,
+					      void *user_data,
+					      pjmedia_aud_stream **p_aud_strm)
+{
+    struct null_audio_factory *nf = (struct null_audio_factory*)f;
+    pj_pool_t *pool;
+    struct null_audio_stream *strm;
+
+    /* Create and Initialize stream descriptor */
+    pool = pj_pool_create(nf->pf, "null_audio-dev", 1000, 1000, NULL);
+    PJ_ASSERT_RETURN(pool != NULL, PJ_ENOMEM);
+
+    strm = PJ_POOL_ZALLOC_T(pool, struct null_audio_stream);
+    pj_memcpy(&strm->param, param, sizeof(*param));
+    strm->pool = pool;
+    strm->rec_cb = rec_cb;
+    strm->play_cb = play_cb;
+    strm->user_data = user_data;
+
+    /* Create player stream here */
+    if (param->dir & PJMEDIA_DIR_PLAYBACK) {
+    }
+
+    /* Create capture stream here */
+    if (param->dir & PJMEDIA_DIR_CAPTURE) {
+    }
+
+    /* Apply the remaining settings */
+    /* Below is an example if you want to set the output volume */
+    if (param->flags & PJMEDIA_AUD_DEV_CAP_OUTPUT_VOLUME_SETTING) {
+	null_stream_set_cap(&strm->base,
+		            PJMEDIA_AUD_DEV_CAP_OUTPUT_VOLUME_SETTING,
+		            &param->output_vol);
+    }
+
+    /* Done */
+    strm->base.op = &stream_op;
+    *p_aud_strm = &strm->base;
+
+    return PJ_SUCCESS;
+}
+
+/* API: Get stream info. */
+static pj_status_t null_stream_get_param(pjmedia_aud_stream *s,
+					 pjmedia_aud_param *pi)
+{
+    struct null_audio_stream *strm = (struct null_audio_stream*)s;
+
+    PJ_ASSERT_RETURN(strm && pi, PJ_EINVAL);
+
+    pj_memcpy(pi, &strm->param, sizeof(*pi));
+
+    /* Example: Update the volume setting */
+    if (null_stream_get_cap(s, PJMEDIA_AUD_DEV_CAP_OUTPUT_VOLUME_SETTING,
+			    &pi->output_vol) == PJ_SUCCESS)
+    {
+        pi->flags |= PJMEDIA_AUD_DEV_CAP_OUTPUT_VOLUME_SETTING;
+    }
+
+    return PJ_SUCCESS;
+}
+
+/* API: get capability */
+static pj_status_t null_stream_get_cap(pjmedia_aud_stream *s,
+				       pjmedia_aud_dev_cap cap,
+				       void *pval)
+{
+    struct null_audio_stream *strm = (struct null_audio_stream*)s;
+
+    PJ_UNUSED_ARG(strm);
+
+    PJ_ASSERT_RETURN(s && pval, PJ_EINVAL);
+
+    /* Example: Get the output's volume setting */
+    if (cap==PJMEDIA_AUD_DEV_CAP_OUTPUT_VOLUME_SETTING)
+    {
+	/* Output volume setting */
+	*(unsigned*)pval = 0; // retrieve output device's volume here
+	return PJ_SUCCESS;
+    } else {
+	return PJMEDIA_EAUD_INVCAP;
+    }
+}
+
+/* API: set capability */
+static pj_status_t null_stream_set_cap(pjmedia_aud_stream *s,
+				       pjmedia_aud_dev_cap cap,
+				       const void *pval)
+{
+    struct null_audio_stream *strm = (struct null_audio_stream*)s;
+
+    PJ_UNUSED_ARG(strm);
+
+    PJ_ASSERT_RETURN(s && pval, PJ_EINVAL);
+
+    /* Example */
+    if (cap==PJMEDIA_AUD_DEV_CAP_OUTPUT_VOLUME_SETTING)
+    {
+	/* Output volume setting */
+	// set output's volume level here
+	return PJ_SUCCESS;
+    }
+
+    return PJMEDIA_EAUD_INVCAP;
+}
+
+/* API: Start stream. */
+static pj_status_t null_stream_start(pjmedia_aud_stream *strm)
+{
+    struct null_audio_stream *stream = (struct null_audio_stream*)strm;
+
+    PJ_UNUSED_ARG(stream);
+
+    PJ_LOG(4, (THIS_FILE, "Starting null audio stream"));
+
+    return PJ_SUCCESS;
+}
+
+/* API: Stop stream. */
+static pj_status_t null_stream_stop(pjmedia_aud_stream *strm)
+{
+    struct null_audio_stream *stream = (struct null_audio_stream*)strm;
+
+    PJ_UNUSED_ARG(stream);
+
+    PJ_LOG(4, (THIS_FILE, "Stopping null audio stream"));
+
+    return PJ_SUCCESS;
+}
+
+
+/* API: Destroy stream. */
+static pj_status_t null_stream_destroy(pjmedia_aud_stream *strm)
+{
+    struct null_audio_stream *stream = (struct null_audio_stream*)strm;
+
+    PJ_ASSERT_RETURN(stream != NULL, PJ_EINVAL);
+
+    null_stream_stop(strm);
+
+    pj_pool_release(stream->pool);
+
+    return PJ_SUCCESS;
+}
+
+#endif	/* PJMEDIA_AUDIO_DEV_HAS_NULL_AUDIO */
