diff -ruN b/gst/fsrtpconference/fs-rtp-codec-negotiation.c a/gst/fsrtpconference/fs-rtp-codec-negotiation.c
--- b/gst/fsrtpconference/fs-rtp-codec-negotiation.c	2010-01-05 02:39:41.000000000 +0500
+++ a/gst/fsrtpconference/fs-rtp-codec-negotiation.c	2010-06-22 12:10:04.512659247 +0500
@@ -617,6 +617,10 @@
           codec->ABI.ABI.ptime = codec_pref->ABI.ABI.ptime;
           ca->codec = codec;
 
+          /* ptime/maxptime in the CA come from the negotiation */
+          ca->ptime = 0;
+          ca->maxptime = 0;
+
           ca->send_profile = dup_param_value (codec_pref, SEND_PROFILE_ARG);
           ca->recv_profile = dup_param_value (codec_pref, RECV_PROFILE_ARG);
 
@@ -1315,16 +1319,19 @@
   while (codec_associations)
   {
     CodecAssociation *tmpca = codec_associations->data;
-    FsCodec *tmpcodec;
 
-    if (!codec_association_is_valid_for_sending (tmpca, FALSE))
-      continue;
+    if (codec_association_is_valid_for_sending (tmpca, FALSE))
+    {
+      FsCodec *tmpcodec = codec_copy_without_config (tmpca->codec);
 
-    tmpcodec = codec_copy_without_config (tmpca->codec);
+      tmpcodec->ABI.ABI.ptime = tmpca->ptime;
+      tmpcodec->ABI.ABI.maxptime = tmpca->maxptime;
+
+      if (fs_codec_are_equal (tmpcodec, lookup_codec))
+        ca = tmpca;
+      fs_codec_destroy (tmpcodec);
+    }
 
-    if (fs_codec_are_equal (tmpcodec, lookup_codec))
-      ca = tmpca;
-    fs_codec_destroy (tmpcodec);
     if (ca)
       break;