Streaming h264 not working when we don't know the sink specs

[fgfernandez0321]

I'm trying to get video from source using h264. Just I know that the stream comes via udp nothing more. In this case I received video but the pipeline shows the result after 2 or 3 minutes.

gst-launch-1.0 udpsrc port=xxxxx ! application/x-rtp,encoding-name=H264,payload=96 ! rtph264depay ! h264parse ! avdec_h264 ! autovideosink

How can I inspect the packet that I'm receiving by port via UDP in order to find the specification packets?

Any advice?