Hi,
i have a similar problem using gstreamer to send an rtp stream to wowza.
The player starts playing for 1s then it stops for about 40s then starts playing again.
When i make two sdp files one for audio and one for video i can play them, using the same gstream-cmd and everything is fine. But i would like to be able to use just one flash-player 
It would be nice if we would have an example of an gstreamer-cmd working with wowza, in the forum i only find stuff not working.
gst-cmd:
gst-launch-0.10 -vvv videotestsrc ! capsfilter caps="video/x-raw-yuv, format=(fourcc)I420, width=(int)640, height=(int)480, framerate=(fraction)30/1" ! queue ! x264enc byte-stream=true bitrate=300 ! rtph264pay ! udpsink port=6000 host=127.0.0.1 sync=false audiotestsrc ! "audio/x-raw-int, rate=(int)48000" ! faac ! rtpmp4gpay ! udpsink host=127.0.0.1 port=6002
gst-log:
/GstPipeline:pipeline0/GstRtpH264Pay:rtph264pay0.GstPad:src: caps = application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264, profile-level-id=(string)4d401e, sprop-parameter-sets=(string)Z01AHpJUBQHtgIgAAAMACAAAAwHkeLF1, payload=(int)96, ssrc=(guint)2198359392, clock-base=(guint)614858601, seqnum-base=(guint)21776
/GstPipeline:pipeline0/GstUDPSink:udpsink1.GstPad:sink: caps = application/x-rtp, media=(string)audio, clock-rate=(int)48000, encoding-name=(string)MPEG4-GENERIC, encoding-params=(string)1, streamtype=(string)5, profile-level-id=(string)1, mode=(string)AAC-hbr, config=(string)0988, sizelength=(string)13, indexlength=(string)3, indexdeltalength=(string)3, payload=(int)96, ssrc=(guint)2805765163, clock-base=(guint)4260627807, seqnum-base=(guint)57770
sdp-file:
v=0
o=- 116704633 116704633 IN IP4 127.0.0.1
s=GStreamer
t=0 0
c=IN IP4 127.0.0.1
m=video 6000 RTP/AVP 96
a=rtpmap:96 H264/90000
a=control:trackID=1
m=audio 6002 RTP/AVP 96
a=rtpmap:96 MPEG4-GENERIC/48000/2
a=fmtp:96 media=audio; clock-rate=48000; encoding-name=MPEG4-GENERIC; encoding-params=1; streamtype=5; profile-level-id=1; mode=AAC-hbr; config=0b88; sizeLength=13; indexLength=3; indexDeltaLength=3; payload=96; ssrc=2805765163; clock-base=4260627807; seqnum-base=57770
a=control:trackID=2
other information:
GStreamer Core Library version 0.10.22
Wowza Media Server Pro10 1.7.2 build12107
Played with setting in post
http://community.wowza.com/t/-/57
systemclock
12000
sortPackets
sortBufferSize
any idea?