rcast

Rcast - Go DLNA MediaRenderer for macOS (IINA)

A lightweight DLNA/UPnP AV MediaRenderer (DMR) written in Go for macOS.
It announces itself on your LAN, accepts external cast/control requests from DLNA control points, and plays media via IINA.
Includes session ownership (single-controller at a time) and optional system volume linkage.

Features

• SSDP discovery as MediaRenderer
• UPnP services
• AVTransport: SetAVTransportURI, Play, Pause, Stop, Seek, and status queries
  • RenderingControl: SetVolume/GetVolume, SetMute/GetMute
• IINA integration
  • Uses iina-cli if available, otherwise starts the IINA app binary
  • Controls playback through mpv JSON IPC
  • Normalizes the eight-step Douyin iOS volume control to IINA's full range
• Session ownership
  • Single active controller per session
  • Configurable preemption policy
• Optional macOS system volume linkage (via AppleScript, darwin only)
• Per-installation UUID persistence for stable, collision-free discovery identity

Usage

# Run with default settings
rcast

# Enable debug logging
rcast --debug

# Open IINA in fullscreen mode
rcast --fullscreen
# or use the short form
rcast --fs

# Show help
rcast --help

Configuration

Environment variables include:

• DMR_HTTP_PORT: HTTP listen port (default 8200)
• DMR_ADVERTISE_IP: IPv4 address to advertise on multi-homed or VPN-connected Macs
• DMR_ALLOW_PREEMPT: allow a new controller to take the active session
• DMR_LINK_SYSTEM_VOLUME: mirror renderer volume to macOS system volume
• DMR_UUID_PATH: persistent device identity path
• DMR_IINA_FULLSCREEN: open IINA fullscreen

Architecture

• internal/config: configuration and env overrides
• internal/netutil: network helpers (IPv4 selection)
• internal/uuid: device UUID persistence
• internal/state: player and session state (thread-safe)
• internal/player: IINA and macOS system volume control
• internal/upnp: SOAP helpers, service descriptions, AVTransport/RenderingControl handlers
• internal/httpserver: HTTP routes and handlers
• internal/ssdp: SSDP announce and M-SEARCH responder

License

MIT