This application allows the server to adapt the encoding bitrate to the measured sender rate given by the DCCP information. We use the CCID-3 (RFC 4342) that implements a receiver-based congestion control algorithm in which the sender is rate-limited by the receiver. The receiver sends feedback packets to the sender containing RTT, lost event information and other connection statistics that are plugged into the TCP-Friendly Rate Control equation (TFRC) (RFC 3448).
Based on the current server sending rate, we adapt the encoding bitrate to make the transmission more suitable for applications such as media streaming, for which a relatively smooth sending rate is important.
On the other hand, to validate the transmission behavior of our application, we use Iperf to generate enough traffic to saturate the link and make trouble in the transmission.
In the source package, you will find a python script that uses a matplotlib library for plotting dynamically the current transmission rate.
********** How it works: ************
== Compile :
- Run make command to compile sources
== Server side :
- Run ./server -p
== Client side :
- Run ./client -p -i
-
Server :
-p : The port to listen to (default: 4000), -c : The Congestion Control IDentified to be used (default: 3).
-Client :
-p : The port to receive packets from (default: 4000),
-i : The host IP address to receive packets from (default: localhost),
-c : The Congestion Control IDentified to be used (default: 3).
==NOTE : the current version doesn't support CCID 2.
- Run ./plot.py to plot in real time the current sender rate. (make sure that python-matplotlib is installed)
== Generate trafic :
- Use Iperf to generate trafic and trouble the transmission between server and client.
- Server : iperf -s
- client : iperf -c -t 60
- Check the reduction of the transmission rate on the plot.
== Server :
gst-launch v4l2src ! videoscale videorate ! video/x-raw-yuv,width=640, height=480,framerate=25/1 ! x264enc bitrate=5000 tune=zerolatency ! video/x-h264,stream-format=byte-stream ! dccpserversink ccid=3 port=XXX
== Client :
gst-launch dccpclientsrc ccid=3 port=XXX host=YYY ! h264parse ! ffdec_h264 ! ffmpegcolorspace ! ximagesink