ScreamWire

A lightweight, low-latency audio sender for PipeWire, compatible with the Scream protocol. Route any application's audio to a virtual output device or capture from an existing sink – it will be streamed over UDP (multicast or unicast) to any Scream receiver.

Features

• Virtual Sink – automatically creates a ScreamWire output device when no explicit sink is given. Just select it in your mixer and audio flows to the network.
• Existing Sink Capture – alternatively, capture the monitor of any already-available output (--sink <name>). Use --list-sinks to see what's available.
• Voice Activity Detection – pauses transmission after a configurable silence period (1 s by default) and resumes instantly when sound returns, saving bandwidth and CPU.
• Flexible Configuration – all parameters can be set via CLI flags or a TOML file. Defaults are sensible.
  • XDG‑aware: ~/.config/screamwire/config.toml is loaded automatically if present.
  • Generate a default config with --generate-config.
• Robust PipeWire Integration – uses core.sync to reliably enumerate sinks, handles both capture and playback streams, and displays a volume indicator in pavucontrol.
• Logging – --verbose enables detailed diagnostics; normal operation is quiet.
• Systemd User Unit – included in contrib/systemd/ for automatic startup with your session.

Quick Start

# Build and install
cargo install --path . --root ~/.cargo

# Run (virtual sink, multicast target 239.255.77.77:4010)
screamwire

# List available sinks and capture from one
screamwire --list-sinks
screamwire --sink alsa_output.pci-0000_00_1f.3.analog-stereo

Configuration

Create ~/.config/screamwire/config.toml (or use --generate-config) and adjust the settings:

target_addr = "239.255.77.77:4010"
sender_bind_addr = "0.0.0.0:0"
rate = 48000
channels = 2
vad_threshold = 1
silence_packets = 167
ring_buffer_packets = 10
active_sleep_ms = 4
idle_sleep_ms = 30

All options can also be given on the command line (run screamwire --help).

Building from Source

git clone https://github.com/avalak/screamwire.git
cd screamwire
cargo build --release

The binary will be in target/release/screamwire.

License

MIT (see LICENSE).

Acknowledgements

• Scream – the original protocol.
• PipeWire – the modern Linux audio stack.
• pipewire-rs – Rust bindings.