diff --git a/src/include/private/switch_core_pvt.h b/src/include/private/switch_core_pvt.h
index c55ff05951..d623ac0cfa 100644
--- a/src/include/private/switch_core_pvt.h
+++ b/src/include/private/switch_core_pvt.h
@@ -105,7 +105,9 @@ struct switch_core_session {
 
 	switch_io_event_hooks_t event_hooks;
 	switch_codec_t *read_codec;
+	switch_codec_t *real_read_codec;
 	switch_codec_t *write_codec;
+	switch_codec_t *real_write_codec;
 	switch_codec_t *video_read_codec;
 	switch_codec_t *video_write_codec;
 
diff --git a/src/include/switch_core.h b/src/include/switch_core.h
index 53040be6f6..79346bdc14 100644
--- a/src/include/switch_core.h
+++ b/src/include/switch_core.h
@@ -1129,6 +1129,13 @@ SWITCH_DECLARE(switch_status_t) switch_core_session_set_read_codec(_In_ switch_c
 */
 SWITCH_DECLARE(switch_codec_t *) switch_core_session_get_read_codec(_In_ switch_core_session_t *session);
 
+/*! 
+  \brief Retrieve the effevtive read codec from a given session
+  \param session session to retrieve from
+  \return a pointer to the codec
+*/
+SWITCH_DECLARE(switch_codec_t *) switch_core_session_get_effective_read_codec(_In_ switch_core_session_t *session);
+
 /*! 
   \brief Assign the write codec to a given session
   \param session session to add the codec to
@@ -1144,6 +1151,13 @@ SWITCH_DECLARE(switch_status_t) switch_core_session_set_write_codec(_In_ switch_
 */
 SWITCH_DECLARE(switch_codec_t *) switch_core_session_get_write_codec(_In_ switch_core_session_t *session);
 
+/*! 
+  \brief Retrieve the effevtive write codec from a given session
+  \param session session to retrieve from
+  \return a pointer to the codec
+*/
+SWITCH_DECLARE(switch_codec_t *) switch_core_session_get_effective_write_codec(_In_ switch_core_session_t *session);
+
 /*! 
   \brief Assign the video_read codec to a given session
   \param session session to add the codec to
diff --git a/src/switch_core_codec.c b/src/switch_core_codec.c
index 7b7ae4b994..44d62596c7 100644
--- a/src/switch_core_codec.c
+++ b/src/switch_core_codec.c
@@ -49,7 +49,30 @@ SWITCH_DECLARE(switch_status_t) switch_core_session_set_read_codec(switch_core_s
 	switch_channel_t *channel = switch_core_session_get_channel(session);
 	char tmp[30];
 
-	switch_assert(codec->implementation);
+	if (!codec || !codec->implementation) {
+		if (session->real_read_codec) {
+			session->read_codec = session->real_read_codec;
+			session->real_read_codec = NULL;
+		} else {
+			switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Cannot set NULL codec!\n");
+			return SWITCH_STATUS_FALSE;
+		}
+	} else if (session->read_codec) {
+		if (session->real_read_codec) {
+			if (codec == session->real_read_codec) {
+				session->read_codec = codec;
+				session->real_read_codec = NULL;
+			} else {
+				switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Cannot double-set codec!\n");
+				return SWITCH_STATUS_FALSE;
+			}
+		} else {
+			session->real_read_codec = session->read_codec;
+			session->read_codec = codec;
+		}
+	} else {
+		session->read_codec = codec;
+	}
 
 	if (switch_event_create(&event, SWITCH_EVENT_CODEC) == SWITCH_STATUS_SUCCESS) {
 		switch_channel_event_set_data(session->channel, event);
@@ -65,7 +88,7 @@ SWITCH_DECLARE(switch_status_t) switch_core_session_set_read_codec(switch_core_s
 	switch_snprintf(tmp, sizeof(tmp), "%d", codec->implementation->actual_samples_per_second);
 	switch_channel_set_variable(channel, "read_rate", tmp);
 
-	session->read_codec = codec;
+
 	session->raw_read_frame.codec = session->read_codec;
 	session->raw_write_frame.codec = session->read_codec;
 	session->enc_read_frame.codec = session->read_codec;
@@ -74,18 +97,46 @@ SWITCH_DECLARE(switch_status_t) switch_core_session_set_read_codec(switch_core_s
 	return SWITCH_STATUS_SUCCESS;
 }
 
-SWITCH_DECLARE(switch_codec_t *) switch_core_session_get_read_codec(switch_core_session_t *session)
+SWITCH_DECLARE(switch_codec_t *) switch_core_session_get_effective_read_codec(switch_core_session_t *session)
 {
 	return session->read_codec;
 }
 
+SWITCH_DECLARE(switch_codec_t *) switch_core_session_get_read_codec(switch_core_session_t *session)
+{
+	return session->real_read_codec ? session->real_read_codec : session->read_codec;
+}
+
 SWITCH_DECLARE(switch_status_t) switch_core_session_set_write_codec(switch_core_session_t *session, switch_codec_t *codec)
 {
 	switch_event_t *event;
 	switch_channel_t *channel = switch_core_session_get_channel(session);
 	char tmp[30];
 
-	switch_assert(codec->implementation);
+	if (!codec || !codec->implementation) {
+		if (session->real_write_codec) {
+			session->write_codec = session->real_write_codec;
+			session->real_write_codec = NULL;
+		} else {
+			switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Cannot set NULL codec!\n");
+			return SWITCH_STATUS_FALSE;
+		}
+	} else if (session->write_codec) {
+		if (session->real_write_codec) {
+			if (codec == session->real_write_codec) {
+				session->write_codec = codec;
+				session->real_write_codec = NULL;
+			} else {
+				switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Cannot double-set codec!\n");
+				return SWITCH_STATUS_FALSE;
+			}
+		} else {
+			session->real_write_codec = session->write_codec;
+			session->write_codec = codec;
+		}
+	} else {
+		session->write_codec = codec;
+	}
 
 	if (switch_event_create(&event, SWITCH_EVENT_CODEC) == SWITCH_STATUS_SUCCESS) {
 		switch_channel_event_set_data(session->channel, event);
@@ -102,13 +153,18 @@ SWITCH_DECLARE(switch_status_t) switch_core_session_set_write_codec(switch_core_
 	switch_snprintf(tmp, sizeof(tmp), "%d", codec->implementation->actual_samples_per_second);
 	switch_channel_set_variable(channel, "write_rate", tmp);
 
-	session->write_codec = codec;
 	return SWITCH_STATUS_SUCCESS;
 }
 
+
+SWITCH_DECLARE(switch_codec_t *) switch_core_session_get_effective_write_codec(switch_core_session_t *session)
+{
+	return session->write_codec;
+}
+
 SWITCH_DECLARE(switch_codec_t *) switch_core_session_get_write_codec(switch_core_session_t *session)
 {
-	return session->write_codec;
+	return session->real_write_codec ? session->real_write_codec : session->write_codec;
 }