media-router

Configurable media router built on NodeJS with Tailwind CSS, modular-dm and modular-ui.

The media-router makes use of the following Linux audio and video processes / applications:

• Pipewire-pulse
• ffmpeg
• srt-tools
• gstreamer
• streamlink

The media-router can be used to build flexible distributed media routing applications like remote audio translation systems, video feeds for broadcast, education, etc.

Processes

The following processes are part of the media-router project

• server/router.js - process running on the client devices, responsible for all media processing. router.js receives its configuration upon connection to manager.js.
• server/manager.js - process responsible for storing and distributing client configurations.

Important: As the media-router makes use of Pipewire-pulse for audio processing, router.js must be run in a user scope (logged in user) and not as a system service.

Compatibility

This project has been tested on:

• Raspberry Pi OS Bullseye (armhf / 32bit)
• Raspberry Pi OS Bookworm (armhf / 64bit)
• Ubuntu Desktop 23.04 LTS (amd64 / 64bit)

Modules

• AudioInput: Capture audio from hardware and output to a PCM stream.
• AudioOutput: Play a PCM audio stream to hardware.
• SrtOpusInput: Receives an SRT Opus encoded audio stream
• SrtOpusOutput: Publishes an audio stream as Opus encoded SRT.
• Spacer: Visual spacer for web control interface.
• SrtVideoPlayer: Video Player for a srt video stream
• SrtVideoEncoder: Video over SRT Encoder
• SrtRelay: Srt Relay
• SoundProcessor: PCM Sound Processor
• SoundDucking: PCM Sound Ducking
• SrtVideoPlayer: Video Player for a srt video stream
• HlsPlayer: Hls Video Player
• WebRTCClient: WebRTC Client WebApp

Planned modules:

• Video encoding & decoding
• SRT video streaming
• Low latency WiFi audio streaming to mobile devices

Centralized management

The media-router is centrally managed and controlled from a manager server. The manager web-interface default address is http://localhost:8080, and listens for router connections on http://localhost:3000.

The media-router process by default points to the locally installed manager but can be pointed to an external manager through the profile manager web-interface on http://localhost:8082

Local operator web interface

A local operator web-interface is available on http://localhost:8081. This interface can be used for local control of volume controls, etc.

Development environment

• Ensure that your user on the development environment has sudo access (some versions of Debian ships without sudo, and you may need to configure it manually).
• Clone the project to your development environment.
• Open /etc/apt/sources.list and uncomment the deb-src line to enable the Debian source repository (needed to build PulseAudio V16).
• Navigate to the media-router directory
• Install dependencies ./install-dependencies.sh
• Run router.js and manager.js from Visual Studio Code's Run and Debug menu.

Building Tailwind CSS

Tailwind CSS is installed in the tailwind directory. Scripts for building tailwind is available from this directory. The output CSS files are placed in the respective project directories.

Performance tuning

Setting the UDP Buffer limit

Linux is by default configured with a quite small max UDP buffer size. This should be increased on systems with many SRT or other UDP based connections.

Change the max UDP buffer size to e.g. 25 megabytes:

sudo sysctl -w net.core.rmem_max=26214400
sudo sysctl -w net.core.wmem_max=26214400

To make the change permanent, add the following lines to /etc/sysctl.conf:

net.core.rmem_max=26214400
net.core.wmem_max=26214400

References: https://access.redhat.com/documentation/en-us/jboss_enterprise_application_platform/5/html/administration_and_configuration_guide/jgroups-perf-udpbuffer https://www.systutorials.com/how-to-enlarge-linux-udp-buffer-size/

Gstreamer c++ library debug

See: gst_modules

Large scale media-router applications

• Important note on large scale media-router applications, you need to increse the default file limit for your pipewire.service and pipewire-pulse.service config files, otherwise you will be limited to 50 pulseaudio loopbacks
• This can be done by adding the following line in your pipewire.service and pipewire-pulse.service files in /usr/lib/sytstemd/user

[Service]
LimitNOFILE=<Your file count>