add loopback_initial_codec variable to specifiy the codec of a one legeded loopback channel

src/include/switch_loadable_module.h

@@ -115,6 +115,8 @@ SWITCH_DECLARE(switch_endpoint_interface_t *) switch_loadable_module_get_endpoin
  */
 SWITCH_DECLARE(switch_codec_interface_t *) switch_loadable_module_get_codec_interface(const char *name);
 
+SWITCH_DECLARE(char *) switch_parse_codec_buf(char *buf, uint32_t *interval, uint32_t *rate, uint32_t *bit);
+
 /*!
   \brief Retrieve the dialplan interface by it's registered name
   \param name the name of the dialplan

src/mod/endpoints/mod_loopback/mod_loopback.c

@@ -122,8 +122,8 @@ static void clear_queue(private_t *tech_pvt)
 static switch_status_t tech_init(private_t *tech_pvt, switch_core_session_t *session, switch_codec_t *codec)
 {
 	const char *iananame = "L16";
-	int rate = 8000;
-	int interval = 20;
+	uint32_t rate = 8000;
+	uint32_t interval = 20;
 	switch_status_t status = SWITCH_STATUS_SUCCESS;
 	switch_channel_t *channel = switch_core_session_get_channel(session);
 	const switch_codec_implementation_t *read_impl;
@@ -132,6 +132,15 @@ static switch_status_t tech_init(private_t *tech_pvt, switch_core_session_t *ses
 		iananame = codec->implementation->iananame;
 		rate = codec->implementation->samples_per_second;
 		interval = codec->implementation->microseconds_per_packet / 1000;
+	} else {
+		const char *var;
+
+		if ((var = switch_channel_get_variable(channel, "loopback_initial_codec"))) {
+			char *dup = switch_core_session_strdup(session, var);
+			uint32_t bit;
+			iananame = switch_parse_codec_buf(dup, &interval, &rate, &bit);
+		}
+		
 	}
 
 	if (switch_core_codec_ready(&tech_pvt->read_codec)) {

src/switch_loadable_module.c

@@ -2075,7 +2075,7 @@ SWITCH_DECLARE(int) switch_loadable_module_get_codecs(const switch_codec_impleme
 
 }
 
-char *parse_codec_buf(char *buf, uint32_t *interval, uint32_t *rate, uint32_t *bit)
+SWITCH_DECLARE(char *) switch_parse_codec_buf(char *buf, uint32_t *interval, uint32_t *rate, uint32_t *bit)
 {
 	char *cur, *next = NULL, *name, *p;
 
@@ -2119,7 +2119,7 @@ SWITCH_DECLARE(int) switch_loadable_module_get_codecs_sorted(const switch_codec_
 		uint32_t interval = 0, rate = 0, bit = 0;
 
 		switch_copy_string(buf, prefs[x], sizeof(buf));
-		name = parse_codec_buf(buf, &interval, &rate, &bit);
+		name = switch_parse_codec_buf(buf, &interval, &rate, &bit);
 
 		for(j = 0; j < x; j++) {
 			char *jname;
@@ -2135,7 +2135,7 @@ SWITCH_DECLARE(int) switch_loadable_module_get_codecs_sorted(const switch_codec_
 			}
 
 			switch_copy_string(jbuf, prefs[j], sizeof(jbuf));
-			jname = parse_codec_buf(jbuf, &jinterval, &jrate, &jbit);
+			jname = switch_parse_codec_buf(jbuf, &jinterval, &jrate, &jbit);
 
 			if (jinterval == 0) {
 				jinterval = switch_default_ptime(jname, 0);