WRCT Webstream Service

How to Start on a New Computer

Make sure your computer is connected to both CMU's internet, and the Axia/WRCT infranet (10.216.0.1/24)

sudo apt install git sox ezstream icecast2 libsox-fmt-mp3

clone [this rtptools repo](https://github.com/irtlab/rtptools) and `make install`

git clone https://github.com/wrct883/stream-service.git /home/wrct/stream
cd /home/wrct/stream
mkdir logs

# change all passwords and paths in files

sudo cp ./systemd-services/wrct-icecast.service /etc/systemd/system/
sudo cp ./systemd-services/wrct-stream-ip_route.service /etc/systemd/system/
sudo cp ./systemd-services/wrct-stream.service /etc/systemd/system/

sudo systemctl daemon-reload

sudo systemctl enable --now wrct-icecast.service
sudo systemctl enable --now wrct-stream-ip_route.service
sudo systemctl enable --now wrct-stream.service

Then go on yxorp and modify stream.wrct.org and streamalt.wrct.org to point to the ip addrss of the new machine

backup stream

broadcast what's actually playing on radio using rtl-sdr:

sudo apt install rtl-sdr

sudo cp ./systemd-services/wrct-broadcast.service /etc/systemd/system/

sudo systemctl daemon-reload

sudo systemctl enable --now wrct-broadcast.service

cleanup logs

run the ./clean-logs.sh

Notes

magic numbers

axia

This uses axia's livewire protocol. As of 2025-04-25, our current broadcast channel is 7001. In order to stream 7001 we do a few things:

when this changes put the new ip in the wrct-stream-ip_route.service and the stream.sh

1. Run sudo ip route add 239.192.27.89 dev enx086d41e48818 on host (this is handled by the systemd oneshot service called wrct-stream-ip_route, update the number there)

   • get the ip address (Python) with channel 7001: f"239.192.{7001 // 256}.{7001 % 256}"
   • enx086d41e48 is the interface that's connected on the Axia network (10.216.0.0/24). You can find this using ip a

2. Modify 0xefc01b59 in stream, in the rtpdump -F payload 0xefc01b59/5004 part of the command

   • get the hex code (Python) with channel 7001: hex(239*256**3 + 192*256**2 + 7001)
   • This uses the rtpdump command line utility you installed with the rtptools repo earlier. This listens on rtp to the above ip address, port 5004 (Axia Livewire protocol specification)

sox

rtpdump from the axia network gives us a:

• 2 channel
• 48kHz sample rate (tweaked ffmpeg paramters till something sounded like it was the right speed)
• 24bit big-endian PCM stream (tweaked ffmpeg parameters till i got something that wasnt just noise)

it then spits out a 48kHz 2channel 128kbps mp3 stream on stdout

barix

remember to not use the url since that will use the internet as it will be getting through the reverse proxy. this is slow for the barix near the transmitter. use the local ip address of the machine running icecast since they should be on the same subnet (and port 8000, default icecast port)

TODO

• maybe script everything including the variables and passwords but that seems too tedious for something this simple, that will realistically need to be done maybe every couple of years
• maybe symlink the systemd-services to keep them all maintained, but maybe that wont work cause iirc systemd symlinks those files too
• script getting all the services set up?