Add support for parsing SDP attributes, generating SDP attributes, and passing it through.

This support includes codecs such as H.263, H.264, SILK, and CELT. You are able to set up a call and have attribute information pass. This should help considerably with video calls.

Review: https://reviewboard.asterisk.org/r/2005/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@370055 65c4cc65-6c06-0410-ace0-fbb531ad65f3

2 files changed, 57 insertions, 0 deletions

diff --git a/res/res_format_attr_celt.c b/res/res_format_attr_celt.c
index bd38b29e2..aea3eb482 100644
--- a/res/res_format_attr_celt.c
+++ b/res/res_format_attr_celt.c
@@ -45,6 +45,29 @@ struct celt_attr {
 	unsigned int framesize;
 };
 
+static int celt_sdp_parse(struct ast_format_attr *format_attr, const char *attributes)
+{
+	struct celt_attr *attr = (struct celt_attr *) format_attr;
+	unsigned int val;
+
+	if (sscanf(attributes, "framesize=%30u", &val) == 1) {
+		attr->framesize = val;
+	}
+
+	return 0;
+}
+
+static void celt_sdp_generate(const struct ast_format_attr *format_attr, unsigned int payload, struct ast_str **str)
+{
+	struct celt_attr *attr = (struct celt_attr *) format_attr;
+
+	if (!attr->framesize) {
+		return;
+	}
+
+	ast_str_append(str, 0, "a=fmtp:%d framesize=%d\r\n", payload, attr->framesize);
+}
+
 static enum ast_format_cmp_res celt_cmp(const struct ast_format_attr *fattr1, const struct ast_format_attr *fattr2)
 {
 	struct celt_attr *attr1 = (struct celt_attr *) fattr1;
@@ -161,6 +184,8 @@ static struct ast_format_attr_interface celt_interface = {
 	.format_attr_set = celt_set,
 	.format_attr_isset = celt_isset,
 	.format_attr_get_val = celt_get_val,
+	.format_attr_sdp_parse = celt_sdp_parse,
+	.format_attr_sdp_generate = celt_sdp_generate,
 };
 
 static int load_module(void)
diff --git a/res/res_format_attr_silk.c b/res/res_format_attr_silk.c
index 4f9bae739..7d4fa5bf8 100644
--- a/res/res_format_attr_silk.c
+++ b/res/res_format_attr_silk.c
@@ -47,6 +47,36 @@ struct silk_attr {
 	unsigned int packetloss_percentage;
 };
 
+static int silk_sdp_parse(struct ast_format_attr *format_attr, const char *attributes)
+{
+	struct silk_attr *attr = (struct silk_attr *) format_attr;
+	unsigned int val;
+
+	if (sscanf(attributes, "maxaveragebitrate=%30u", &val) == 1) {
+		attr->maxbitrate = val;
+	}
+	if (sscanf(attributes, "usedtx=%30u", &val) == 1) {
+		attr->dtx = val;
+	}
+	if (sscanf(attributes, "useinbandfec=%30u", &val) == 1) {
+		attr->fec = val;
+	}
+
+	return 0;
+}
+
+static void silk_sdp_generate(const struct ast_format_attr *format_attr, unsigned int payload, struct ast_str **str)
+{
+	struct silk_attr *attr = (struct silk_attr *) format_attr;
+
+	if ((attr->maxbitrate > 5000) && (attr->maxbitrate < 40000)) { 
+		ast_str_append(str, 0, "a=fmtp:%d maxaveragebitrate=%d\r\n", payload, attr->maxbitrate);
+	}
+
+	ast_str_append(str, 0, "a=fmtp:%d usedtx=%d\r\n", payload, attr->dtx);
+	ast_str_append(str, 0, "a=fmtp:%d useinbandfec=%d\r\n", payload, attr->fec);
+}
+
 static enum ast_format_cmp_res silk_cmp(const struct ast_format_attr *fattr1, const struct ast_format_attr *fattr2)
 {
 	struct silk_attr *attr1 = (struct silk_attr *) fattr1;
@@ -195,6 +225,8 @@ static struct ast_format_attr_interface silk_interface = {
 	.format_attr_set = silk_set,
 	.format_attr_isset = silk_isset,
 	.format_attr_get_val = silk_get_val,
+	.format_attr_sdp_parse = silk_sdp_parse,
+	.format_attr_sdp_generate = silk_sdp_generate,
 };
 
 static int load_module(void)