This change adds a SIP peer configuration feature to allow the peer's

configured codecs to take precedence on an outgoing call.

This change introduces a new peer configuration property named
'ignore_requested_pref' that causes the requested codec to be ignored when
determining the preferred codec for an outgoing call leg. The consequence is
that Asterisk's usual efforts to prefer avoiding transcoding can be overridden
on a peer-by-peer basis where appropriate. 


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@377971 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -13167,10 +13167,11 @@ static enum sip_result add_sdp(struct sip_request *resp, struct sip_pvt *p, int
 		   - Then other codecs in capabilities, including video
 		*/
 
-		/* Prefer the audio codec we were requested to use, first, no matter what
-		   Note that p->prefcodec can include video codecs, so mask them out
-		*/
-		if (ast_format_cap_has_joint(tmpcap, p->prefcaps)) {
+
+		/* Unless otherwise configured, the prefcaps is added before the peer's
+		 * configured codecs.
+		 */
+		if (!ast_test_flag(&p->flags[2], SIP_PAGE3_IGNORE_PREFCAPS) && ast_format_cap_has_joint(tmpcap, p->prefcaps)) {
 			ast_format_cap_iter_start(p->prefcaps);
 			while (!(ast_format_cap_iter_next(p->prefcaps, &tmp_fmt))) {
 				if (AST_FORMAT_GET_TYPE(tmp_fmt.id) != AST_FORMAT_TYPE_AUDIO) {
@@ -30766,6 +30767,8 @@ static struct sip_peer *build_peer(const char *name, struct ast_variable *v, str
 				ast_set2_flag(&peer->flags[2], ast_true(v->value), SIP_PAGE3_USE_AVPF);
 			} else if (!strcasecmp(v->name, "icesupport")) {
 				ast_set2_flag(&peer->flags[2], ast_true(v->value), SIP_PAGE3_ICE_SUPPORT);
+			} else if (!strcasecmp(v->name, "ignore_requested_pref")) {
+				ast_set2_flag(&peer->flags[2], ast_true(v->value), SIP_PAGE3_IGNORE_PREFCAPS);
 			} else {
 				ast_rtp_dtls_cfg_parse(&peer->dtls_cfg, v->name, v->value);
 			}

channels/sip/include/sip.h

@@ -373,10 +373,11 @@
 #define SIP_PAGE3_DIRECT_MEDIA_OUTGOING  (1 << 4)  /*!< DP: Only send direct media reinvites on outgoing calls */
 #define SIP_PAGE3_USE_AVPF               (1 << 5)  /*!< DGP: Support a minimal AVPF-compatible profile */
 #define SIP_PAGE3_ICE_SUPPORT            (1 << 6)  /*!< DGP: Enable ICE support */
+#define SIP_PAGE3_IGNORE_PREFCAPS        (1 << 7)  /*!< DP: Ignore prefcaps when setting up an outgoing call leg */
 
 #define SIP_PAGE3_FLAGS_TO_COPY \
 	(SIP_PAGE3_SNOM_AOC | SIP_PAGE3_SRTP_TAG_32 | SIP_PAGE3_NAT_AUTO_RPORT | SIP_PAGE3_NAT_AUTO_COMEDIA | \
-	 SIP_PAGE3_DIRECT_MEDIA_OUTGOING | SIP_PAGE3_USE_AVPF | SIP_PAGE3_ICE_SUPPORT)
+	 SIP_PAGE3_DIRECT_MEDIA_OUTGOING | SIP_PAGE3_USE_AVPF | SIP_PAGE3_ICE_SUPPORT | SIP_PAGE3_IGNORE_PREFCAPS )
 
 #define CHECK_AUTH_BUF_INITLEN   256
 

configs/sip.conf.sample

@@ -1259,6 +1259,8 @@ srvlookup=yes                   ; Enable DNS SRV lookups on outbound calls
 ; dtlscafile
 ; dtlscapath
 ; dtlssetup
+; ignore_requested_pref ; Ignore the requested codec and determine the preferred codec
+;						; from the peer's configuration.
 ;
 
 ;------------------------------------------------------------------------------