한국어 문서는 README.ko.md를 참고하세요.
A low-latency OMT stream receiver and player for Raspberry Pi, rewritten in Rust for maximum performance.
The original C#/.NET implementation required a 200MB+ .NET runtime and suffered from GC pauses and managed-to-native marshalling overhead. The Rust port eliminates all of that:
| C# (.NET 8 AOT) | Rust | |
|---|---|---|
| Runtime dependency | .NET 8 (~200MB) | None (static binary) |
| Binary size | ~30MB + runtime | ~5MB standalone |
| VMX decode | Managed array + P/Invoke marshal | Zero-copy, pre-allocated buffer |
| Audio path | GC-managed buffers, pool allocation | Direct ALSA FFI, no allocator pressure |
| Frame delivery | Async socket + frame pool + GC | Blocking TCP read, zero-copy parse |
| Memory | ~150MB RSS | ~70MB RSS |
| Video latency | ~20-30ms | ~18-30ms (decode 7-12ms + vsync) |
Player thread: TCP read → audio writei → video channel
Video thread: channel recv → VMX decode → DRM page-flip
Tokio runtime: Web server + mDNS discovery (non-interfering)
- No GC, no runtime — deterministic latency, no pause spikes
- Zero-copy frame parsing —
BytesMutsplits directly from TCP buffer - Pre-allocated decode buffer — VMX decodes into a reused buffer, no per-frame allocation
- Direct ALSA FFI —
snd_pcm_writeicalled from the TCP read thread, matching C#'s P/Invoke path exactly - DRM page-flip — triple-buffered vsync output with dedicated event thread
Built-in web control panel with dark theme (matching omt-encoder style):
- Source selection with mDNS auto-discovery
- Video quality selector (Low / Medium / High) — sends quality hint to encoder, adjustable at runtime
- Audio output device selection
- Volume slider (0-200%)
- Multi-language support (English, Korean, Japanese, Spanish)
- Toast notifications
Audio can be routed to any USB DAC connected to the Raspberry Pi. The web UI lists all available ALSA output devices — simply check the USB DAC and uncheck HDMI outputs. This enables high-quality audio playback through external DACs, headphone amps, or powered speakers with USB input.
The player can request the encoder to adjust video bitrate by sending <OMTSettings Quality="..." />:
| Quality | Estimated Bitrate (1080p30) | Use Case |
|---|---|---|
| Low | ~30-40 Mbps | WiFi, congested networks |
| Medium | ~60-80 Mbps | Default, balanced |
| High | ~100-120 Mbps | Wired LAN, best quality |
Quality can be changed at runtime from the web UI without reconnecting.
omtdecoder outputs directly via DRM — desktop mode must be disabled.
sudo raspi-configChoose 1 System Options -> S5 Boot -> B1 Console Text console.
git clone https://github.com/stephen-kim/omt-decoder.git
cd omt-decoder
chmod +x build_and_install_service.sh
./build_and_install_service.shThe script installs Rust toolchain + dependencies, builds the project, deploys to /opt/omtdecoder, and registers the systemd service.
sudo systemctl status omtdecoderWeb UI: http://<pi-ip>:8080/
MIT License. See LICENSE for details.