use codec derived capabilities

combined.c

@@ -32,9 +32,6 @@ typedef struct {
 #define RTCP_PORT_RECV_SINK 5003
 #define RTCP_PORT_RECV_SRC 5007
 
-// get this from gst-rfc3551.h
-#define CAPS "application/x-rtp,media=(string)audio,clock-rate=(int)8000,encoding-name=(string)G722,payload=(int)9"
-
 /* TODO:
  * watch the gstreamer busses
  * remove previously linked pads (if any) in the "pad-added" handler
@@ -146,6 +143,7 @@ main (int argc,
   GstCodec *codec = NULL;
   GstPad *srcpad, *sinkpad;
   GstCaps *caps;
+  g_autofree gchar *caps_string = NULL;
 
   const gchar *codec_name = g_getenv ("CODEC");
   const gchar *remote = g_getenv ("REMOTE");
@@ -161,7 +159,8 @@ main (int argc,
 
   gst_init (&argc, &argv);
 
-  g_debug ("Capabilities:\n%s", gst_codec_get_gst_capabilities (codec));
+  caps_string = gst_codec_get_gst_capabilities (codec);
+  g_debug ("Capabilities:\n%s", caps_string);
 
   /* could also use autoaudiosink instead of pulsesink */
   data.audiosink = gst_element_factory_make ("pulsesink", "sink");
@@ -212,7 +211,7 @@ main (int argc,
   gst_bin_add (GST_BIN (data.send_pipeline), data.send_rtpbin);
   gst_bin_add (GST_BIN (data.recv_pipeline), data.recv_rtpbin);
 
-  caps = gst_caps_from_string (CAPS);
+  caps = gst_caps_from_string (caps_string);
   /* set udp sinks and sources for RTP and RTCP */
   /* receive/in direction */
   g_object_set (data.rtp_src,