regarding omx h264 decoder delay in live video stream on omap4(pandaboard)

I am using Pandaboard with Ubuntu 10.10 for developing a videoconferencing system. I read through the "Ducati for Dummies" document and understood the architecture. Also, based on the previous mail, I understood that the code that runs on the Ducati system (Cortex-M3) are available only as binaries and those are integrated into the Ubuntu to be loaded/run on boot on the Cortex-A9. Hope my understandings are correct till this. 

A little background, I have worked with DM368 dvsdk4 to build a videoconferencing system (h264 based). We used gstreamer to do the encode/decode. The decode would usually start after 4 to 5 seconds of starting to receive media data. This was because of the dmaibuffer that was buffering data (as the decoder should be feed with only >= 1 frame worth of data) in gstreamer, after optimizing the buffer size, I was able to get realtime decode. Now with that as background, I now see a similar effect with Pandaboard(Ducati system). So I was wondering if there is a similar buffering, if so is there some way to tune the buffers to reduce the latency or any alternatives? One more test that makes me think of possibility of buffering is that when I send stream @800Kbps the delay to start decode is more (5-7secs) and when I send 2Mbps stream the decode starts in 3-4 secs. 

Also, the "Ducati for Dummies" page reports that codecs are available for various formats H264, H263, etc. but I see that in the Ubuntu 10.10, GStreamer only the h264 decoder is available. Is it that the other codes are NOT available or they are not integrated in Gstreamer?