UDP vs TCP

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Hi Guys,

I'm trying to live stream a v4l2src over a tethered mobile phone local 
area network between two IP addresses 192.168.43.134 and 192.168.43.247. 
  The video capture card is plugged into 192.168.43.134.

I have live streaming with very little lag initially in TCP, apart from 
network buffering which gets worse by the minute, using these commands:

# TCP host command

gst-launch v4l2src device=/dev/video0 queue-size=1 always-copy=0 ! 
videoscale ! videorate ! ffmpegcolorspace ! videobalance brightness=.3 
contrast=.8 ! gamma gamma = .5 ! tee name=t1 \
t1. ! queue ! xvimagesink sync=false \
t1. ! queue ! videorate ! 
video/x-raw-yuv,format=I420,width=640,height=480,framerate=30000/1001 ! 
theoraenc quality=63 keyframe-force=1 ! oggmux ! filesink 
location=video.ogg \
t1. ! queue ! jpegenc ! tcpserversink port=5000

# TCP client command

gst-launch tcpclientsrc host=192.168.43.134 port=5000 ! jpegdec ! tee 
name=t1  \
t1. ! queue ! xvimagesink sync=false \
t1. ! queue ! videorate ! 
video/x-raw-yuv,width=640,height=480,framerate=30000/1001 ! theoraenc 
quality=63 keyframe-force=1 ! oggmux ! filesink location=video.ogg

So I'm trying to switch to UDP, and I can't get it to work.  Here is 
what I'm using:

# UDP

gst-launch -v v4l2src device=/dev/video0 queue-size=1 always-copy=0 ! 
videoscale ! videorate ! ffmpegcolorspace ! videobalance brightness=.3 
contrast=.8 ! gamma gamma = .5 ! video/x-raw-yuv, framerate=30000/1001, 
width=640, height=480, pixel-aspect-ratio=1/1 ! tee name=t1  \
t1. ! queue ! xvimagesink sync=false \
t1. ! queue ! theoraenc quality=63 keyframe-force=1 ! filesink 
location=video.ogg \
t1. ! queue !  rtpvrawpay ! udpsink host=192.168.43.134 port=5000

gst-launch  udpsrc caps="application/x-rtp, format=I420, 
framerate=30000/1001, width=640, height=480, interlaced=false, 
pixel-aspect-ratio=1/1" port=5000 ! rtpvrawdepay ! xvimagesink

I'd be very grateful for any help.

Regards

Steve.